Ryanair Assessment Preparation
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RYANAIR INTERVIEW
CONTENTS
1
PHONE CALL .............................................................................................................................................................. 2
2
HUMAN RESOURCE QUESTIONS ............................................................................................................................... 3
Personal questions ........................................................................................................................................................ 3
Question about previous courses ................................................................................................................................. 5
Behavioral and skill-about questions ............................................................................................................................ 6
Questions about Ryanair............................................................................................................................................... 7
3
TECHNICAL KNOWLEDGE QUESTIONS ...................................................................................................................... 9
Principle of flight questions .......................................................................................................................................... 9
Performance questions ............................................................................................................................................... 16
Systems questions....................................................................................................................................................... 25
4
Meteorology questions ........................................................................................................................................... 30
5
Seneca V PA34 questions ........................................................................................................................................ 33
6
Questions about 737NG and 737MAX .................................................................................................................... 35
7
Other questions ...................................................................................................................................................... 38
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1 PHONE CALL
1. Do you have first time passes in ATPL exams and IR/CPL/ME?
GNav 2 times
2. ATPL average
89
3. Have you received your licenses from the authorities?
In the first days of September
4. How many hours PIC/total?
75 / 226
5. Last aircraft flight ME? (must be one hour logged in last 6 months)
PA-34
6. When was your last flight?
14th October
7. When was the last SIM?
26th October
8. Have you completed MCC?
Completed on 27th June 18
9. Base preferences
BGY,MXP, BLG
10. Do you have your license and what is it JAR/EASA?
European Aviation Safety Agency (07/2002)
11. Rating expiry dates?
21st July 2019
12. When does your ME IR expires?
21st July 2019
13. When does you medical class 1expires?
13th September 2019
14. Valid EU passport?
28th August 2028
The interviewer will read an aviation related sentence 2 times and then he would ask you some question about it. for
example:
A.-The sentence had to do with a passenger sick or injured in the cabin and the Captain diverting to an alternate
field. He then asked me what the cabin crew and the captain had to do in this case.
- What should do the cabin crew when he learns that a passenger is ill or injured?
- Who has to be informed? (the captain)
- What must the captain do?
B.-it was about a fire (un-contained) on board an A/C and how deadly the smoke/fumes are. The questions were:
1, was the fire contained or un-contained
2, what is the most dangerous thing about the fire
3, what would cause the most harm to people.
Basically it was a way to see if you can listen and understand English.
- Common reasons to fail the telephone interview are for theory fails or insufficient language skills.
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2 HUMAN RESOURCE QUESTIONS
PERSONAL QUESTIONS
Talk about yourself
Where do you live? Do you like your city?
What are your hobbies?
Why do you want to be a pilot?
How did you get into aviation
What do your parents think about you choosing this line of work?
Who paid your aviation career?
Talk about your current job, why do you like it or why not
Why should we hire you?
Why would you be an asset for Ryanair, what qualities would you bring to Ryanair?
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Tell negative thing of you (Weak sides)
Where do you see yourself in 5 years
Do you have siblings (brother) and what do they do
When can you start?
Which 3 bases would you like in order of preference?
Where do you usually fly from?
Do you have a question for us?
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QUESTION ABOUT PREVIOUS COURSES
why have you chosen your flight school?
Do you think the training at flight school was good
What did you think of the integrated program? What was the quality like?
How did you get on with your instructors?
Did you ever have to request a different instructor due to his lack of teaching skills?
What was the most difficult time during training?
What is important in the MCC course?
What was the most important thing you learned from the MCC?
What was the most important moment of your MCC course?
What about doing MCC one more time?
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BEHAVIORAL AND SKILL-ABOUT QUESTIONS
What are the qualities necessary to be a good RYR pilot?
What do you do if you have a problem with a CPT
How do you deal with a problematic colleague ?
What makes a good captain
How can your academic background help you in the cockpit?
What would you do if you lose your medical?
Are you aware that type rating is going to be very challenging?
What challenges would you face if you took this position?
The hardest decision in your life
Any accidents/incidents/unexpected event during flying ? And what did you learn from it as a result?
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QUESTIONS ABOUT RYANAIR
Why did you choose Ryanair
I’ve read a lot about Ryanair on the web and I also talk with some friend of mine which are working for Ryanair, I’ve
got a good scenario of what working for Ryanair means, the environment is very friendly, rosters are planned in
advance, the training captain are well prepared and sociable, available to answer every kind of question. So in
Ryanair I can work in a friendly environment, getting a good training while making a lot of experience, which from my
point of view are the most important things in this part of my life.
What do you know about Ryanair
I know that Ryanair is the largest European airline by passenger carried, covering more than 37 countries in Europe,
Africa and Middle-East. It has more than 14 500 employees and operates more than 400 737-800, with 80 new 737800 and 135 new 737 MAX8 ordered, taking to Ryanair a fleet of over 500 aircraft by 2024. Nowadays Ryanair carries
more than 110 million passengers per year, growing up every day, aiming to 180 million passengers per year in 2024.
The economic success of Ryanair has been possible thanks to the great management and standardization of the
company, along with the “low fares” philosophy.
How many Ryanair bases?
Ryanair has 86 bases, from which more than 1800 daily flight take-off to more than 220 destination in 33 countries
all over Europe, Africa and middle-east.
How many 737s?
Ryanair is currently operating more than 400 737-800, with 80 new 737-800 and 135 new 737 MAX8 ordered, taking
to Ryanair a fleet of over 500 aircraft by 2024.
How many flights per day?
Nowadays more than 1800 flights take-off every day, carrying more than 300 000 passengers per day to more than
220 destination.
Why Ryanair has a so good economic success?
I think that the economic success of Ryanair is due to the great management of the company that added to the “low
fares” philosophy and the efficient service granted to the passengers, Ryanair with the 90% of punctuality is the best
one in Europe, gives an unbeatable offer to the passengers.
Why did we order the 737 Max
Compared to the competitors the B737 MAX has 8% lower operating cost than the competitors, just the new
winglets design reduces fuel consumption by approximately 2%, giving an overall reduction of 20% fuel consumed
per seat. Furthermore the B737 MAX has better environmental performance, which means less limitation due to
noise abatement and better sustainability for Ryanair. The interior design has been renewed giving a better comfort
to the passengers.
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Why does it have 197 seats and not 200 (Emergency Exits CS 25.803)
Smaller lavatory makes the 200 seats configuration possible, but an additional emergency exit was required in order
to make the evacuation through half of the emergency exit in less than 90 seconds possible, however Ryanair choose
the 197 seat configuration in order to keep a seat pitch of 30’’ instead of reducing it to 29’’ with a 200 seats
configuration, and maintaining the number of required cabin crew at 4 instead of the required 5 for the 200 seats
configuration.
What will be the most challenging aspect if you join Ryanair
I think that the type rating will require all of my skills and capacities, but that will be balanced by my willingness to
learn new think. So it won’t be easy but I will give all of myself to succeed.
Ryanair Management
Mr Michael O’LEARY (Exec)
Michael O’Leary has served as a director of Ryanair since 1988. He was appointed CEO of Ryanair in 1994.
Mr David BONDERMAN (Non Exec Chairman)
David Bonderman has served as a director since August 1996 and has served as the chairman of the Board of
Directors since December 1996. Mr. Bonderman is also an officer, director and shareholder of 1996 Air G.P. Inc.,
which owns shares of Ryanair. He is a U.S. citizen.
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3 TECHNICAL KNOWLEDGE QUESTIONS
PRINCIPLE OF FLIGHT QUESTIONS
Forces acting on an aircraft
The main forces acting on an aircraft are 5: thrust, drag, lift, weight and tail download. When the aircraft is in straight
an level flight, thrust is equal to drag giving a constant speed, lift must be equal to the aircraft weight plus the tail
download giving a constant flight altitude.
→ level attitude
lift and weight are in equilibrium. To climb, lift must exceed the weight
→ steady speed
thrust and drag are in equilibrium. To accelerate, thrust must exceed the value of drag.
→ banked turn
weight is a constant, but vertical component of lift is a fraction. To maintain altitude,
value needs to be restored by increasing speed and/or the angle of attack.
Radius =
1% GS
Bank Angle =
(TAS / 10)*1.5
lift
What causes lift?
Lift is the phenomenon generated by the airfoil shape causing a pressure differences above and below the airfoil.
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How lift is produced, how it can be increased, why high pressure and low pressure over the wing
Lift is produced by a pressure differential acting on the wing surface. The greater the difference in pressure between
the upper and the lower surface of the wing, the greater the lift produced. If we want to increase lift we have to
increase the pressure differential. To do that we can:
✓
✓
✓
increase the angle of attack,
increase speed while maintaining a constant angle of attack,
increasing the camber and/or the surface of the wing by using high lift devices.
High and low pressure on the wing are caused by the relative airflow speeds difference. Higher speed means higher
dynamic pressure, higher dynamic pressure means lower static pressure. In this case we obtain a low pressure
situation, vice-versa we obtain an high pressure situation.
What cause drag?
Drag is a natural consequence of the movement of the aircraft in the air.
What are the different types of drag?
Drag is categorized in two main component:
→ parasite drag which is caused by
- friction drag due to the friction of the air with the skin of the aircraft,
- shape (form) drag due to the pressure differential between the trailing and the leading edge of the wing,
- interference drag due to the interference between airflows caused by the different aircraft components.
→ induced drag caused by wing tip vortices. Wing tip vortices are due to the pressure differential between the
upper and the lower surface of the wing, air will tent to balance this pressure difference, creating a span-wise
flow through the wing tip, creating an air flow at the tip from the lower to the upper surface.
Explain how a glider can stay up in the air, why doesn't it just fall from the sky? Explain wing loading
The gliders wings are designed to have an high lift to drag
ratio, that means that they can run much more distance
horizontally than the altitude they loses. To do that their
wings have an high aspect ratio (= high lift but les top
speed).
Note: Aspect ratio is the ratio of the wing’s span to its
geometric chord
Wing loading is the ratio between aircraft weight and
wing surface, when the load factor is 1 the wing loading
is that one required to keep the aircraft in level flight,
wing loading can increase in a high load factor maneuver.
A too much high wing loading can cause structural
damage to the airframe structure.
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How would you make an aircraft more aerodynamic? Without taking into account the engines
An aerodynamic aircraft is one that has an high lift to drag ratio, thus meaning that for the same amount of lift
produced there will be less drag. To make this possible the wing and fuselage design are fundamental:
✓
✓
✓
✓
fuselage must be designed according to area rule, so boundary layer can remain laminar as long as possible;
wing has to have a great aspect ratio and winglets should be used in order to minimize the induced drag;
airfoil should be kept as thin as possible with the smallest wing surface possible, in order to obtain the lowest
form and skin friction drag achievable;
use of fairings (cowls) between different aircraft parts is essential to reduce interference drag.
Why does the horizontal stabilizer have opposite airfoil design to the wing?
The horizontal stabilizer have an opposite airfoil design because it has to generate a download force, in order to
counteract the pitching down moment caused by the lift. Lift is acting on the center of pressure, located on the wing
aft of the center of gravity.
Why T-Tail
A T-tail configuration let the horizontal stabilizer to be placed further from the center of gravity, which means:
→
→
→
→
→
less download force is required by the tail to balance the pitching down moment
less lift has to be generated
less drag is generated
less thrust is required
lower fuel consumption.
What is a stall? At what AoA do aircraft normally stall?
Stall is a phenomena caused by boundary layer separation from the wing surface, causing a reduction in lift produced
till when is not enough to balance the aircraft weight. Boundary layer separation can occur due to airflow loss of
kinetic energy or by a too great adverse pressure gradient. The boundary layer will start losing kinetic energy as soon
as the angle of attack is increased causing a reduction in lift, till when the critical angle of attack is reached and the
loss of lift will cause a stall. Usually the critical angle of attack is around 16°.
High lift devices
High lift devices are used to change the airfoil characteristics by changing the camber of the airfoil, increasing the
surface of the wing and creating passages (slot) for the air in order to reinforce the boundary layer. This is done in
order to have better lift during take-off and to let the aircraft fly at a lower airspeed during approach and landing.
This allows aircrafts to operate on shorter runway and to improve lifting characteristics of swept wings.
High lift devices can be located on the trailing edge or on the leading edge of the wing, usually both the type are
installed, trailing edge devices are used mainly to increase CL and CD of the wing, while leading edge devices are used
to reinforce the boundary layer in order to increase the stall margin, that’s why leading edge devices are always
extended before the trailing edge devices and retracted after.
There are many types of high lift devices, like:
1.
Trailing edge flaps (Fowler flaps) increase lift at lower angles of deflection.
2.
Leading edge flaps (Krueger flaps) and slats increase lift by creating a longer wing chord line, chamber, and
area.
3.
Slots (boundary layer control) prevent/delay the separation of the airflow boundary layer and therefore
produce an increase in the coefficient of lift maximum.
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Why are there high lift devices on swept wings?
High lift devices are important on every kind of wing, however are much more
essential on a swept wing.
A swept wing decompose the relative wind, this is a good things at high speed
because gives an higher MCRIT but at low speed its require higher speed or a higher
angle of attack in order to produce the same amount of lift. This issue has been
overcome by the usage of high lift devices, increasing the amount of lift produced
at take-off and giving an higher stall margin for landing. Furthermore they help to
counteract the tip stall tendency of the swept wing, because by installing slats on
the external part of the wing we can increase the energy of the boundary layer,
increasing the stall margin at the wing tips.
Explain winglets
Winglets are an effective means of reducing wing tip vortices. They are aerodynamic efficient surfaces located at the
wing tips. They are designed to reduce induced drag. They dispense the spanwise airflow from the upper and lower
surface at different points, thus preventing the intermixing of these airflows that otherwise would create induced
drag vortices. Reduction of wing tip vortices causes a reduction of induced drag and of fuel consumption.
New technologies and new design of wing tip has improved the fuel efficiency of aircraft by approximately 8 to 10
percent. The new 737-MAX8 will have a 1.8% more higher fuel efficiency than the 737-800NG giving an overall
increased efficiency of approximately 10.
Where does a (swept) wing stall first and why? Where the wing stall first on the 737? Why is this bad?
The 737 wing is a swept back wing, so it will stall first at the tip. A swept back wing basically decompose the relative
wind into 2 main components, a wing axis perpendicular component and a wing axis parallel component, the last
one induces a span-wise flow of the boundary layer from the root to the tip which causes the tendency to stall at the
tip first. In a stall situation the tip stall will induce a center of pressure movement towards the root, by moving
towards the root it will also move forward, causing a reduction in the nose down pitching moment, which will make
the aircraft to pitch up (tailplane overbalance the natural wing pitch-down moment), making the stall worse.
This tendency could be reduced by the usage of wing fences or by mounting the engine under the wing, the fences
and/or the pylon of the engine mounting will decreases the span-wise flow, reducing the tip stall tendency.
Furthermore a wing twist could reduce the tip stall tendency, designing a wing with less angle of incidence at the tip
will retard the stall onset at the tip, and a greater chamber at the tip increases airflow speed over the surface, which
delays the stall.
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Swept back wings? Advantage and disadvantage? Compensation?
The main characteristic of the swept back wing is that it decomposes the relative wind into 2 main components: one
perpendicular to the wing axis and the other parallel to the wing axis. The wing is “aerodynamically” influenced only
by the perpendicular component. So the aircraft will have a higher Mcrit because the wing is influenced only by a part
of the aircraft speed, thus letting the aircraft to fly faster because of the retarded shock wave formation,
furthermore the aircraft will be less influenced by gusts, because less excess of lift is gained while under gust.
On the other hand the wing has poor lift quality, because at the same angle of attack a
swept back wing produces less lift and so the wing will be less efficient at low speeds
because of the higher angle of attack required to produce the same amount of lift at the
same speed. This issue is solved by the usage of high lift devices. The poor lift qualities of
the wing will also reduce the aileron effectiveness, the use of outer aileron can partially
solve this problem. The span-wise flow from the root to the tip will cause a tip stall
tendency (see previous question).
Moreover at speed close to Mcrit the center of pressure will move backward causing a phenomenon called “tuck
under” due to the increased pitch-down moment. To avoid “tuck under” a Mach trim is provided on the horizontal
tail surface, which will increase the tail download when speed increases above a certain Mach number.
The combined effect of tip stall and “tuck under” gives to the swept back wing a negative longitudinal speed stability.
On the other side, the swept back wing shape gives a positive directional and lateral stability qualities.
What are some dangers with swept wings?
The main dangers associated with the swept back wing are his tendency to pitch up during low speed flight due to
the tip stall tendency and the pitch down tendency during high speed flight due to the backward movement of the
center of pressure (“tuck under” effect). A further danger associated is the poor lift quality of the wing.
How do we operate in lower speed ranges with swept wings?
The swept back wing design is stall prone at low speed, due to the poor lift quality, requiring an higher speed or
higher angle of attack to produce the same amount of lift. To overcome this issue high lift devices are installed on
the wing, trailing edge flaps are used to increase the amount of lift produced while leading edge slats are used to
retard stall onset, thus reducing the stall speed and increasing the critical angle of attack.
How to recover from a spin?
The first thing to do during a spin is to recover speed in order to reenergize the boundary layer and coming out from
the stall situation, to do that the control wheel must be pushed. To prevent a secondary spin entry the aileron must
be kept neutral, to interrupt rotation the rudder shall be used opposite to the rotation. As soon as the rotation stop
the power must be re-established and the normal flight attitude can be resumed.
What is Mach?
Mach Number express our true air speed in terms of speed of sound percentage, for example flying at Mach .50
means flying at the 50% of the local speed of sound. Mach Number formula is TAS/LSS.
𝑁=
𝑇𝐴𝑆
𝑇𝐴𝑆
=
𝐿𝑆𝑆
38.95 ∗ √°𝐾
Why do we fly at Mach Number
The higher the altitude the lower the local speed of sound, so flying at a constant TAS while climbing we will
approach more and more the local speed of sound, making us more prone to be subject to compressibility effects
(shock wave formation). So above a certain altitude, well known as the cross-over altitude, the reference speed
changes from IAS to MN in order to have a continuous reference about compressibility effects possible onset.
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What is Mcrit, why is it good for it to be high
Mcrit is the flight speed expressed in Mach Number at which somewhere on the airplane, usually on the upper
surface of the wing, a speed of Mach 1, equal to the local speed of sound, is firstly reached. So flying at Mcrit we will
firstly experience compressibility effects, such as a shock wave. So flying above Mcrit is unadvisable, due to the high
structural load and high value of drag caused by the shock wave. Furthermore the center of pressure will move
backward while approaching Mcrit with a swept wing, causing the “tuck under” phenomenon.
Having an higher Mcrit let us to fly faster without suffering from all of the previous effect.
What risk if you overreach Mcrit?
Flying above Mcrit is unadvisable because of shock wave formation. A show wave is essentially a boundary between
supersonic and subsonic speed, in which a great energy loss is experienced. Behind the shock wave the boundary
layer energy is greatly reduced causing him to separate from the wing surface, this means a high lift loss over the
wing, furthermore this separation will induce an increase in vortices behind the wing, causing an extremely high
increase in drag. This 2 factors will impose a great structural load on wings and fuselage components with the
possibility of a structural damage which could result in a catastrophic failure.
What is Mach Tuck
Mach Tuck also known as “tuck under” is a phenomenon that arises during high speed flight due to the backward
movement of the center of pressure that causes an increase in pitching down moment, thus increasing further the
speed which increases the pitching down moment. To avoid this chain of events a Mach trim is provided, which
increases the tail download during high speed flight above a certain Mach number.
What are the characteristics for high altitude and high speed flight?
What is “coffin corner”?
Above approximately .40 Mach the CLmax start to decrease, because the high
speed induces boundary layer separation on the upper surface, due to
compressibility effects.
Increasing the angle of attack will increase further the relative airflow speed
on the upper surface, making the boundary layer more prone to separate. So
when speed increases:


the critical angle of attack decrease,
the stall speed to increase.
While climbing at constant IAS →
MN increases
the stall speed will start to increase.
→
While climbing at MMO
→
compressibility effects →
→
density decreases
MMO decreases.
The combined effect of the stall speed increase and MMO decrease
will give a range of operating speed that constantly reduces with
altitude till when the stall speed and the MMO coincide, this altitude is
also known as “coffin corner” or absolute ceiling, ideally flying at this
altitude the aircraft will be able to fly only at one speed, a slightly
lower speed will induce a stall while a slightly higher speed will induce
an high speed buffet. To avoid aircraft to operate too close to this
altitude a 1.3 g margin is imposed, usually from 4000 to 6000 ft below
that altitude, called maneuver ceiling / service ceiling.
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Dihedral/Anhedral?
Talking about dihedral and anhedral configuration we refer to the angle between the
wing surface and the lateral axis of the aircraft. When wings lie above the lateral axis we
have a positive or dihedral angle, otherwise we have a negative or anhedral angle.
Dihedral configuration increases lateral stability. The airflow due to a sideslip causes an
increase in the angle of attack (lift) on the lower (leading) wing and a decrease in angle of
attack on the raised wing because of the dihedral angle. The difference in lift causes a
rolling moment that tends to restore the wing to its laterally level position.
Adverse yaw? Opposite Roll?
Adverse yaw is a secondary effects of roll, caused by increased induced drag on the up-going wing due to the
increased angle of attack. The increased drag on the up-going wing, that is also the wing outside the turn, will create
a yawing moment opposite to the turn. To reduce this effects differential and Frise type aileron are used.
Opposite roll: working on the yaw axis, the advancing wing has a grater airflow speed and so a greater lift.
Critical Engine on MEP and 737
The critical engine is defined as the engine which will cause the higher yawing moment if it fails.
There are many factor that can be taken into consideration while establishing the critical engine of an aircraft:



P-Factor (Asymmetric blade effect), propeller blades produce more thrust
in the downward rotation. In aircraft with both propeller rotating
clockwise the critical engine is the left one and vice versa for anticlockwise
propeller. With contra-rotating propellers this issue is eliminated;
Slipstream effect. If the propellers are rotating in the same direction
(clockwise when viewed from behind and counterclockwise when viewed
from front), then only the number 1 (LH) engine will produce a sideways
slipstream force on the fin. This has the effect of assisting the rudder side
force needed to counteract the yawing moment;
the engine on the side from which wind come from.
Critical engine and yaw control range determine the critical control speed (VMCA).
If both propellers rotate inward, toward the fuselage, then thrust moment arm
will be kept as short as possible and slipstream effects is present for both engine
failures. Consequently, aircraft’s critical speed is reduced.
Note: Talking about jet engine the only factor that can determine the critical
engine is wind direction.
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PERFORMANCE QUESTIONS
Stall speeds
A/C Cat.
A
B
C
D
E
→ VSR (reference stall speed)
→ VSR0 (reference stall speed landing config.)
→ VS1G (stall speed clean config. at 1g)
Which speeds are also calculated from stall speed?
VAT (Kts)
≤ 91
≤ 121
≤ 141
≤ 166
≤ 210
From stall speeds we can calculate:
→ VAT (speed at threshold) that is the higher between:
•
VS0 (stall speed with flap)
* 1.3
• VS1 (stall speed clean config.) * 1.23.
→ VMCA (minimum air control speed) must be
→ V2 (take-off safety speed) must be
→ Vref (landing reference speed) must be
VMCA ≥ 1.13 * VSR
V2min ≥ VMCA 1.1 or
Vref ≥ 1.23 * VSR0
VSR * 1.13 (Class A)
or
VS * 1.2 (Class B)
What is my stall speed if V2 is….(147) /if Vref is…..(143)
V2min ≥ VSR * 1.13 (Class A)
Vref ≥ 1.23 * VSR0
or
V2min ≥ VS * 1.2
→
VSR = 147 / 1.13 = 130 Kts or VS = 147/1.2 = 122 Kts
→
VSR0 = 143/1.23 = 116 kts
Vref
Vref is the speed required at 50 feet crossing the landing runway threshold in landing configuration.
VSR
VSR is the stall reference speed, is defined by the manufacturer and may not be lower than Vs1g
Vmcg
Vmcg is the minimum ground control speed. It’s the minimum speed at which after an engine failure during the takeoff run, directional control can be maintained using only aerodynamic control (rudder) with a maximum force of 150
lbs on the commands and a maximum deviation of 30 ft from the center line. It is established with:




critical engine inoperative and windmilling,
take-off thrust on the live engine,
maximum take-off mass (MTOM) and CG rearward (the most unfavorable position),
airplane trimmed for take-off.
The main factor affecting Vmcg is air density, influencing the yaw control. So we can say that the lower the altitude
and the lower the air temperature the higher the Vmcg.
Vmcl
Vmcl is the approach and landing minimum control speed. It’s the lowest speed at which in case of an engine failure
during the approach or landing phase the aircraft remains directionally controllable, with a bank angle not greater
that 5°, with a maximum effort on the controls of 150 lbs and permitting turn of more than 20° in the direction of the
live engine in less than 5 seconds.
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It is established with:




critical engine inoperative and windmilling,
go-around thrust on the live engine,
maximum landing mass (MLM) and CG rearward (the most unfavorable position),
approach and landing configuration.
Vmca
Vmca is the minimum air control speed. It’s the speed that in case of critical engine failure permit the aircraft to
remain controllable, with a maximum effort on the control of 150 lbs and with a maximum heading deviation of 15°.
It is established with:





critical engine inoperative and windmilling,
take-off thrust on the live engine,
maximum take-off mass (MTOM) and CG rearward (the most unfavorable position),
flap set in the take-off position,
landing gear retracted.
Vmbe
It’s the maximum speed on the ground at which an airplane can safely stop with the brake energy only. If take-off is
aborted above Vmbe and full brake is applied, the brake could stop the aircraft within the runway but suffering
damages or melting.
Vmu
Vmu is the minimum un-stick speed. It’s the lowest speed at which the airplane can safely lift-off. Below this speed,
airplane does not lift-off since it is too close to the stall speed and to the Vmca, making it too hard to be controlled.
Vlof
Vlof is the lift-off speed, is the speed at which (after rotation) the main wheel leave the ground and the aircraft
definitely becomes airborne. Vlof must be at least 1.1 Vmu.
V1
V1 is the take-off decision speed, is the maximum speed at which the pilot can choose to reject take-off in order to
remain within the ASDA and the minimum speed at which, following an engine failure, the pilot is able to continue
take-off remaining within the TODA. V1 must be higher than Vmcg and shall be lower than Vmbe or VR. however due
to field limitation two different V1 extremities could be imposed, known as Vgo and Vstop, Vgo is the first speed at
which the take-off can be completed within the TODA while Vstop is the last speed at which take-off can be safely
aborted within ASDA. Since engine failure is assumed to
happen at V1, a low value of V1 will require less distance to
stop (ASDR) but an higher distance to accelerate to VR and
reach the screen height (TODR), however a high value of V1
will require an higher distance to stop the aircraft due to the
speed gained (ASDR) but a lower distance to accelerate to
VR and climb to screen height (TODR). The ideal value of V1
is when the TODR and the ASDR coincide (balance field
condition), an higher or lower V1 will require an higher field
length.
Note: field length is directly proportional to Vstop. A/C mass is directly proportional to Vgo and inversely to Vstop.
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Note: Vgo limitated by Vmcg
Vstop limitated by Vmbe
V1balancedis when TODR = ASDR > shortest distance required or greater MTOW or less thrust required
Factors affecting V1?
The main factors affecting V1 are: airplane mass, configuration, air density, wind and runway slope
→ Airplane MASS (V1 between Vgo and Vstop):
-
if field length is not a limitation, increase mass = increase Vgo, because higher mass require an higher Vr.
Doing this we can take a later decision (higher V1, nearer to Vstop), giving us more time to reject take-off
in case of an engine failure, since stopping on the ground with an engine failed is safer than getting
airborne.
-
if the field length is a limitation, an higher mass require a V1 nearer to Vgo (lower V1), because an higher
mass means more inertia and so higher stopping distance. In this case we have to take a decision earlier.
→ Airplane CONFIGURATION: the higher the flap setting the lower the Vr, since we have to rotate earlier, an
earlier decision has to be taken, that’s why increasing flap configuration decreases V1 (decrease Vgo).
→ Air DENSITY: an high density value will permit the aircraft to lift-off at a lower speed, thus permit Vr to be
reduced, so as for the configuration effect, an earlier rotation require an earlier decision, so the higher the
density the lower the V1 (decrease Vgo).
→ WIND: on the ground, wind has a considerable effect on the airplane TAS, in a way that headwind increases
TAS and tailwind decreases TAS. Since Vr is an indicated airspeed, the aircraft will rotate at the same speed. In
case of headwind the aircraft will run less distance, leaving more distance for the aircraft to stop in case of a
rejected take-off, thus permit V1 to be increased and vice-versa for tailwind(decrease Vgo, increase Vstop).
-
Runway SLOPE: in case of a upslope the aircraft will take more distance to accelerate to Vr but will need less
distance to stop in case of a rejected take-off, thus let V1 to be increased and vice-versa for downslope
(increase Vstop but T/O run could become limiting).
A/C Mass
Vstop
Decrease 
Vgo
Increase 
Field Length Limiting
A/C Config.
Decrease 
Air Density
Decrease 
Wind
Upslope
Increase 
Increase 
Decrease 
✓
✓
Vr
Vr is the rotation speed, is the speed at which the pilot start to raise the aircraft nose in order to get airborne.
✓
✓
✓
Vr must be higher than V1 or 1.05 Vmca,
Vr must be sufficient high that Vlof can be at least 1.1 Vmu (AEO) or 1.05 Vmu (OEI),
aircraft can reach V2 at the screen hight.
Factors affecting Vr are basically the same as for the V1:
-
A/C MASS: as mass increases, higher speed is required to get airborne, so the higher is mass the higher is Vr
-
A/C CONFIGURATION: the higher is the flap setting the lower is the speed required, so the lower is Vr
-
Air DENSITY: the higher is the density, the higher is the lift produced, so the lower is the Vr
Vr
A/C Mass
A/C Config.
Air Density
Increase 
Decrease 
Decrease 
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V2
V2 is the take-off safety speed, is the speed that assure directional control and climb capabilities in case of an engine
failure after take-off, it has to be attained at or before the screen height (35ft over RWY threshold). Flying at V2:
✓
✓
✓
guarantees a margin of 1.1 to Vmca, and
can never be less than 1.13 Vsr (Class A)
guarantees a margin of 1.2 to Vs (Class B)
In case of an engine failure V2 must be kept as long as 400 ft AGL. V2 is also the lowest speed at which the aircraft
climb capabilities can cope the required take-off climb gradient.
V3
V3 is the all engine operative steady initial climb speed attained at the screen height.
V4
V4 is the all engine operative take-off climb speed, from the point where acceleration and flap retraction are made,
(it should be greater than 400 AGL).
V speeds summary
VAT (V at threshold)
= VS0
* 1.3
V2 (V T/O safety)
≥ VMCA 1.1
= VS1 * 1.23
or (Class A)
≥ VSR * 1.13
VMCA (Vmin air control) ≥ VSR * 1.13
or (Class B)
≥ VS * 1.2
or
Vref (V reference landing) ≥ VSR0 * 1.23
Vr (V rotation)
or
> V1
> VMCA * 1.05
and
VLO ≥ VMU* 1.1 (AEO)
or
VLO ≥ VMU* 1.05 (OEI)
Note: VSR are for certification only
What happen if you get an EF before Vmcg
Since Vmcg must be lower than V1, the pilot will reject take-off.
The aircraft can be directionally uncontrollable and deviate more than 30 ft from the centerline. However we have to
recognize that Vmcg is established in the most unfavorable conditions possible (see
Vmcg definition) so in a real
case not all these worsening conditions are met and it is possible than the aircraft remains directionally controllable.
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What happens if you abort after v1? What happens if you continue before v1 after EF?
V1 is selected between Vgo and Vstop, it must be higher than Vmcg and lower than Vmbe or Vr.


Rejecting a take-off after V1 can require an extremely high brake effort and if it was higher than Vmbe the brake
will suffer catastrophic damages or melting. Furthermore if the speed gained before aborting decision was
higher than Vstop the ASDA will not be sufficient for a safely stop.
After EF, decide to take-off before V1 could be very dangerous if below Vgo, because the TODA could not be
sufficient due to the higher time required to accelerate to Vr with only one engine operating, required
separation from obstacle could not be assured once in flight. In the worst case runway length could not be
sufficient to get airborne resulting in a runway overrun. Furthermore if the engine failure happen before
reaching Vmcg and thrust on the live engine is not reduced immediately to idle, the airplane would be
directionally uncontrollable.
Take-off with increased V2?
Increased V2 procedure is used when the take-off mass is limited by the climb performance (we cannot increase the
mass, because in case of an engine failure the climb gradient could not be sufficient high)
According to the actual take-off mass, there will be more runway available than the required for the take-off run, so
we can increase the V2 in order to have better climb performance with both engine operating. Since V2 is
considerably lower than Vx, having an higher V2 will make us closer to Vx, gaining a much better climb
performance. We can do that because we can use more runway to accelerate to a higher Vr letting us to be at
“increase V2” at the screen height.
However in case of engine failure, the initial climb out is performed at “original V2”, otherwise the climb
performance could not be sufficient high to cope with the required climb performance.
What is TORA/TODA/ASDA?
TORA / ASDA / TODA are declared distances, published in the airports charts / AIP.
The Take-Off Run Available is the distance between the two (displaced) threshold of the runway, the entire surface of
the TORA must be capable of bearing the aircraft weight under normal conditions.
The Accelerate Stop Distance Available is the TORA plus the stopway length, is the distance within which an aircraft
must be able to stop in case of a rejected take-off after an engine failure occurring at V1.
The Take-Off Distance Available is equal to the TORA plus the clearway length, is the distance within which the
aircraft is supposed to lift-off and reach the screen height.
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Clearway? Stopway?
A clearway is an obstacle free zone extending beyond the runway end, centrally along the extended centerline. Must
be at least 500 ft wide and no longer than 1/2 of the TORA.
A stopway is an area beyond the runway end, capable of bearing the aircraft weight in case of rejected take- off. It
must be at least wide as the runway.
RWY HDG 300, wind 170/20 how much is the crosswind component?
Since the angle between the runway heading and wind direction is 30°, Angle between wind Crosswind component
the cross-wind component is equal to the wind speed multiplied for the and track (degrees)
(% of wind strength)
sinus of the angle, so 20 * sin30° = 20 * sin ½ = 10 Kts
0
0
The analogy with clock provides an easy way to remember this:
15
25%
15 min =
¼ of an hour
15° off = ¼ of the total wind across
30 min =
½ of an hour
30° off =
½ of the total wind across
30
50%
45 min =
¾ of an hour
45° off =
¾ of the total wind across
45
75%
60 min =
A full hour
60° off =
All of the wind across
60 or more
100%
Runway contamination classification
Dry
if it is free of visible moisture.
Damp if there is a moisture layer that is not shiny.
Wet
if there is enough moisture on the runway surface to cause it to be reflective, but without significant areas of
standing water, OR if it is covered in water (or the equivalent) and no more than 25% of that is no more than
3 mm of water or the equivalent in slush or loose snow.
Contaminated if more than 25% of it is covered more than 3 mm by water or the equivalent in slush, loose snow,
compressed or compacted snow, ice, or wet ice.
Take-off with contaminated runway
Contaminated when more than 25% of the runway is covered with water, slush or loose snow more than 3 mm deep.
This will affect both the TODR and the ASDR since the contaminants on the runway increases the wheel drag, so
more distance is required to accelerate to the Vr, furthermore the contaminants decreases the braking action,
requiring more distance to stop in case of a rejected take-off.
A lower V1 (lower Vstop) is required to cope with decreased braking action, so more distance to stop within the
ASDA. For jet aircraft the screen height is reduced from 35 to 15ft in order to avoid excessive weight penalties.
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Hydroplaning formula, what is it?
Dynamic hydroplaning is due to inertial forces preventing water from escaping from tyres footprint. It occurs when
water deposit is sufficient deep. For rotating tyres is 34*√BAR or 9*√PSI, for non-rotating tyres 7.7 * √PSI.
Viscous hydroplaning, due to the viscous properties of the water acting like a lubricant on the tyre, it occur when
water deposit is very thin.
Reverted rubber hydroplaning, due to a prolonged blocked tyre that increases the temperature of the water deposit,
vaporizing it an lifting the wheel.
Take-off with anti-skid inoperative
An inoperative anti-skid increases considerably the ASDR, since the aircraft is supposed to be stopped within ASDA in
case of an engine failure occurring at V1, V1 is reduced. Reducing V1 will give us more distance to stop in case of an
abandoned take-off, but on the other hand it increases the TODR, reducing the airplane mass to remain within the
TODA.
Take-off with reduced thrust?
When the actual take-off mass is lower than the MTOM, a reduced thrust take-off is possible. Taking off with
reduced thrust improves engine life since the greatest ware of the engine occur when the engine is running at high
RPM with a relatively lower TAS, furthermore the immediate temperature increase in the turbine section increases
turbine blade creep and deformation. Another benefit of reduced thrust take-off is noise reduction.
However this procedure can be applied only when no other dangerous conditions exists, like contaminated runway,
anti-skid inoperative, reverse thrust inoperative etc…
What action do you take when your speed bleeds below Vref at 100 ft? What are the symptoms?
There are two main possibility, a pilot error and wind-shear occurrence. in the case of a pilot error, for example a too
high attitude, we will observe a decreasing speed and decreasing rate of descent, according to the magnitude of the
error a correction can be possible by increasing power and lowering the nose otherwise a go-around is required. If
we are subject to wind-shear we will observe decreasing speed and increasing rate of descent, as soon as these
parameters are observed a go-around must be initiated by pulling up the nose while applying full power. The action
required on the control will be large and since it has happened at a very low height a balked landing could results.
Note: during windshear DO NOT change A/C configuration! Only after, during go-around.
VNE – what is it (how much was it on your last flown aircraft)
VNE is the never exceed speed, is a speed above which structural damage resulting in a catastrophic failure can
occur, so the pilot must never fly above that speed. On the PA34 this speed is 204 Kts.
Va (how much was it on your last flown aircraft)
Va is the manoeuvring speed, is the speed below which the aircraft will stall before reaching the limiting load factor if
an external force (pilot action or vertical gust) sudden increases the angle of attack of the wings. It varies according
to the weight of the aircraft, since the higher the weight the lower the load factor increase with the same increase in
the angle of attack. On PA34 is 113 Kts at 3205 lbs and 135 Kts 4407 lbs
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Pressure altitude calculation
Pressure altitude is an altitude measured using the standard vertical barometric gradient of 27 ft/hPa from the 1013
hPa reference isobar. So when the QNH is higher than 1013 the PA will be lower than the QNH indicated altitude and
vice-versa when the QNH is lower than 1013. For example being on the ground on an airport at 2000 ft from MSL
with a QNH of 1003, with the QNH the altimeter reading will be 2000 ft, setting 1013 the reading will be 2270 ft.
QNHA = PA + (27 or 30) * (QNH - 1013)
or
PA = QNHA - (27 or 30) * (QNH - 1013)
What is the absolute ceiling?
The absolute (max) ceiling is an altitude at which the airplane cannot longer climb, at this altitude the low speed and
high speed stall speeds coincide. This altitude is a theoretical altitude, it could not be really reached.
A margin of 1.3 g is established, this altitude is called service ceiling.
Can we fly at max (absolute) ceiling?
The maximum ceiling of aircraft can be established considering:
→ the aircraft performance is the altitude at which the low speed and high speed stall coincide, so in this case is
not possible to fly at this altitude.
→ the maximum cabin differential pressure can decrease the maximum ceiling (B738 has a maximum ceiling of
41000 ft due to maximum cabin differential pressure).
Cruising altitude along a transatlantic flight
The lower the aircraft weight the higher the service ceiling, so the lower the weight the higher we can fly, flying
higher means less fuel consumption, higher TAS, so a better specific range (NM/Kg). Optimum altitude is the altitude
where we have the best specific range.
During a transatlantic flight the aircraft weight decreases due to fuel consumed, this means that the optimum
altitude constantly increases, to remain as close as possible to the optimum altitude without being on a constant
climb, a step-climb procedure is performed.
Where do jet engines are most efficient? Why?
Engine efficiency (jet) refers to Specific Fuel Consumption (SFC). SFC is the quantity of fuel required to produce a unit
of thrust, the lower the SFC the higher the efficiency. To obtain the lowest possible SFC the jet engine has to be
operated at low temperature and high RPM. Low temperature increases the thermal efficiency of the engine. To
obtain the highest possible RPM an higher TAS must be established, in order to prevent compressor stall. To obtain
these two benefit the best way is to fly at the highest altitude possible. Climbing to a higher altitude reduces the
maximum thrust produced by the engine, but decreases the SFC.
What’s screen height? Where is it located?
Take-off screen height is an imaginary screen placed at the end of the TODR, it marks the end of the take-off and the
beginning of the take-off climb. The screen height is 50 ft above the highest obstacle for propeller driven aircrafts, 35
ft above the highest obstacle for jet aircraft, for jet aircraft can be reduced to 15 ft in case of a wet runway. The
screen height has to be overflown at a speed equal to V2.
Landing screen height marks the beginning of the landing distance required, it is placed at 50 ft above the highest
obstacle and must be overflow at Vref.
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Take off climb segments
First segment: starts at screen height (35 ft jet, 50ft
prop) at V2 with take-off power, landing gear is
selected up and ends when the gear is completely
retracted.
Second segment: starts when the gear is completely
retracted, it is flown at V2 with take-off power, a
climb to 400 ft AGL is established, it ends when 400 ft
AGL are gained.
Third segment: starts at 400 ft AGL, it is flown initially
at V2, then acceleration to Vzf (V zero flap) is made
and flap are retracted, the power is reduced to
maximum continuous and the last part is flown at Vfto
(V final take off= Vx) or Vfs (V final segment = Vx).
Fourth segment: this segment is flown at Vfto till an
altitude of 1500 ft AGL where it ends.
NADP (Noise Abatement Procedures)
ICAO Doc. 6168 sec. 7
0 - 800 ft
NADP 1) town near the aerodrome
keep V2+10/20kts
NADP 2) town far from aerodrome
keep V2+10/20kts
800 - 3000 ft
power reduction
keep V2+10/20kts
power reduction
keep VZF+10/20kts
flaps retraction
> 3000 ft
flaps retraction
Every operator must establish noise abatement procedure > the same for every airport, for each A/C type.
The noise abatement procedures shall:
 not prohibit the use of reverse thrust
 not required a turn coincident to a power reduction
✓ RWY has to be clear and dry
✓ ceiling >= 500ft AGL and VIS >=1 NM
✓ Xwind < 15 kts, tail wind < 5 kts no windshear.
Preferential runway for NADP shall have an ILS or slope guide for VMC approaches.
Why do we take off with mixture full rich?
The full rich settings is not the best power setting, but has 2 main advantages compared to the best power that we
must consider during take-off: the first one is that a leaned mixture increases the risk of fuel blockage to the engine,
furthermore a leaned mixture increases engine heating, since during take-off we set the maximum RPM, a leaned
mixture could cause an engine overheating, especially during the take-off climb, where the engine cooling is less
efficient due to the nose-up attitude and low speed, this could cause the engine to overheat and detonate.
Carb ice and carb heat
In the carburetor there is a temperature drop from 25 to 35 °C, this is due to 2 main factors:


in the carburetor the cross-sectional area decreases, this causes the static temperature to drop,
fuel is vaporized in the carburetor, these causes latent heat to be absorbed, thus decreasing the temperature.
To avoid that, carburetor heat is provided, it consist in heating the external air through an heat exchanger with the
exhaust manifold, this air is then passed through the carburetor, preventing or melting ice.
Note: hot air application decreases the air density in the induction manifold, decreasing the engine efficiency and
causing an RPM drop, generally from 75 to 125 RPM.
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SYSTEMS QUESTIONS
TCAS, really basic operation
The TCAS is the Traffic Collision Avoidance System, is a system based on the radar principle of interrogation and
response and uses the aircrafts transponders. Between two traffics:
-
distance is determined by calculating the time lapse between an interrogation and a response,
bearing of the other traffic is determined by 2 directional antennas.
This system shows on the navigation display the position of the other traffics. According to the other traffic position
and the time between collision, the traffics are shown on the navigation display as:
⚫ TCAS I and II generates a Traffic Advisory (TA) when a potential collision threat exists (one XPDR mode A)
◼ TCAS II generates a Resolution Advisory (RA) when a serious collision threat exists (both XPDR mode C or S)
- Preventative RA advises the pilot to avoid certain deviations from the current vertical rate, but does not
require any change to be made. Preventative RA advises pilot to keep the vertical speed within given limits.
- Corrective RA command the pilot to effectively modified the vertical speed without delay.
A TCAS resolution advisory (RA) voice message “climb-climb now” repeated twice is generated after a “descend” RA
when a reversal in the vertical maneuver sense is required
No threat
white/cyan
empty
Proximate (±1200ft 6NM)
white/cyan
full
Threat (45-35 sec)
yellow/amber
Threat (20-30 sec)
red
Number:
vertical distance in K ft
Arrows:
climb / descent if >= ± 500 vertical speed
IRS/INS?
The INS is the Inertial Navigation System, is a self-contained system since it doesn’t depend on external source.
Basically the INS continuously compute the aircraft position, attitude, heading, track and ground speed. To do that it
uses 2 accelerometer placed on a gyro stabilized platform, which uses 3 gyroscopes. To operate the INS the platform
must be aligned while on the ground with the aircraft fully stopped. During the alignment phase the platform is
firstly levelled parallel to the horizontal plane by sensing the earth gravity and then it is aligned to the true north by
sensing the earth rotation (east-west direction), this alignment situation is kept constant by the gyroscopes. When
the INS is fully aligned the NAV mode can be selected and the accelerometer will now start measuring the
acceleration along the north-south and east-west direction.
By making the first integral of the acceleration in time we obtain the speed along the meridian and parallel, the
vector sum of these speed will give the aircraft ground speed.
The second integral of the acceleration in time will give the distance travelled along the meridian and parallel letting
the INS to calculate the actual latitude and longitude and track followed. By knowing the initial heading and attitude
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it is also capable of calculating the actual heading and aircraft attitude. The INS is influenced by the astronomical and
travel precession, since the platform has to be kept aligned with the north direction the latitude and longitude
information given by the accelerometers are used to calculate the correction to be applied, this information is then
sent to the platform gyroscopes which correct through the torque motor attached to the platform the alignment. By
taking the TAS information from the air data computer the INS is also capable to calculate the actual wind.
The IRS is the Inertial Reference System, the principle of operation of the IRS is basically the same of that of the INS.
The difference is that it uses a strap down system, three accelerometer fixed along the aircraft axis are used to
measure the acceleration along the aircraft axis and 3 laser gyros fixed along the aircraft axis are used to measure
the turn rate around the aircraft axis. This let to align the reference mathematically instead of mechanically, which
means higher accuracy of the system and the removal of moving mechanical parts (gimbals, bearings, torque motor).
GPS
The global positioning system used by aviation is the GNSS NAVSTAR, which is the USA Global Navigation Satellite
System. It comprises three segments:
space segment that comprises a constellation of 24 satellites placed at an altitude of approximately 20200 Km on an
orbital plane inclined by 55° compared to the equatorial plan with a revolution period of 12 hours. 21 of this
satellites are fully operational, the other three are backup satellites. Each satellite broadcast a PRN Pseudo Random
Code Noise on two main frequencies, an L2 carrier wave of 1227 MHz modulated with a P code for military users and
an L1 carrier wave of 1575 MHz modulated with the CA Course Acquisition and NAV data on which information
about satellite position, clock time, clock error and almanac data are broadcasted.
user segment comprises all the receiver using the space segment information to determine the actual position. The
basic functioning consist in receiving the NAV data and updating the receiver clock time, then signals from satellites
are received, each signal contain the time at which the signal was broadcasted from the satellite, the difference in
time between the time of broadcast and time of reception multiplied for light speed will give the distance between
the satellite and the receiver. This distance is used as a radius to create a sphere centered on the satellite position,
having three satellite it is possible to determine a bi-dimensional position, adding a fourth satellite will give us a
three-dimensional position.
control segment, which consist is a master station plus 5 monitoring stations on the earth surface, the duty of these
station is to update each satellite clock time and data and checking the proper functioning of each satellite at least
once every 12 hours.
Let's pretend you're on the ground at Marseille, 40degrees outside, how do we cool the 737-800? How to
heat the cabin during the cruise?
The air conditioning / pressurization system works both for
heating and cooling the cabin. Air is normally spilled from
the low pressure compressor bleed valve (also from HP
compressor on ground and low RPM operation).
Bleed air is used for many services, like engine and wing
anti-icing, as pneumatic energy source for engine starting
and for pressurizing the water tank and the hydraulic
reservoir. The air is then routed through air condition
packs where the air is first passed through the primary
heat exchanger, where air is cooled by exchanging heat
with ram air. Then air passes through a compressor and
then again into a secondary heat exchanger, subsequently
goes through a turbine where it is cooled by expansion and lastly through a water separator which reduces the air
humidity. The air is then convoy to a temperature regulator where the cold air is mixed with hot air to obtain the
required temperature. Exiting the pack the air goes to a mix manifold where air from packs is mixed and routed to
the cabin and cargo compartment.
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The cabin pressure is regulated by controlling the outflow of air through the outflow valves.
AC and DC current
DC current is created by a flow of electron from one poles to
the other while AC current is created by electrons keep
moving towards one pole and then back to the other,
creating a sort of electrons vibration known as frequency.
These characteristics made DC possible to be accumulated
in batteries since the flow of electrons creates a potential
difference between the battery cathode and anode
(impossible for AC). Calculations for circuits are based on
Kirchhoff's laws:
AC permits to have a much higher voltage compared to DC, this means that less current is required to produce the
same amount of power (Electrical Power W = V * I), less current means that cables and all the conductive materials
used could be reduced in dimension (Resistance (Ω) R = (ρ*L)/A where ρ = resistivity, L = conductor length, A = conductor A) letting
the aircraft weight to be reduced substantially. Furthermore AC allows the transformer usage, which means that
current can be transmitted to one point to another at high voltage, letting cable dimension to be reduced, and then
it could be reduced in voltage according to the equipment required voltage.
Talking about current generation, AC compared to DC has no commutation
problem, moreover AC generator has a higher efficiency compared to DC
generator. On the other hand AC generator are harder to be placed in parallel
because they must have the same voltage, frequency and frequency phase. So
in order to obtain the best overall system efficiency, AC current is generated by
alternators coupled to engine by CSD (Constant Speed Drive | AC GEN Freq. = (RPM * Pairs of Poles) / 60) unit and each
alternators supply its own bus bar.
To storage current AC is converted to DC by TRU (Transformer Rectifier Unit), when needed the batteries current could be
used to supply AC equipment through static inverter units.
Generators/alternators difference?
The essential difference between aircraft AC alternators and DC generators (dynamos) is that:
 induced (output) windings of the alternators are fixed
stator is the source of current = magnetic field is rotating
 the dynamos have a fixed inductor (field) coil
rotor is the source of current = magnetic field is static
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What is anti-skid and how is it working?
The anti-skid system is a mechanical or electronic system which prevents wheels blockage or skidding. This is done
by measuring and comparing wheels speeds and releasing brake pressure on the skidding wheel. The most common
used system is the electronic one. It is composed by speed sensors mounted in each wheel axle, an Anti-Skid Unit
(ASU) computer and servo valves to modulate brakes pressure. The electronic system provides three main function:
Touchdown protection will avoid brake being applied before touchdown, only when wheel rotation is detected the
system will allow brakes to be operated.
Antiskid protection consist in measuring each wheel speed, sending this information to the ASU which compares this
signals, detect when a wheel is skidding and send signals to the servo valves to modulate brake pressure on the
skidding wheels.
Locked wheel protection works in the same manner of the antiskid protection, but when a wheel speed fall to zero,
for example due to ice or wet patch on the runway, the ASU will completely release brake pressure on the locked
wheel, until the wheel spins up again and brake pressure is re-applied.
What Fly by wire? Advantages of FBW?
On a fly by wire system the inputs to the control surfaces are electrical instead of mechanical. The pilot operate the
flight deck controls, the mechanical input to the control is then converted to an electrical output which is processed
by a computer and then sent to a servo valve which controls the movement of hydraulic actuator on the control
surfaces. Redundancy is provided electrically rather than mechanically, this means that each control surface is
provided with multiple input line from different computers. The main advantages of a fly by wire system are: weight
savings, lower maintenance costs, greater precision and safety in flying. Replacement of heavy mechanical control
cables reduces weight and maintenance costs since electrical control are less complex and easier to maintain. System
monitors pilot commands providing maximum performance without running the risk of exceeding safety margin.
ELT? Can you turn it on from the cockpit? Does it work in water?
The ELT is the Emergency Locator Transmitter, is a device which start broadcasting emergency signal on the
frequencies 121.5 and 406 MHz as soon as it is activated either manually by the pilot, by an impact or by immersion
in water. The pilot can set the ELT in three position: ON, ARMED and OFF. With the ON mode selected the ELT start
transmitting, in the ARMED mode the ELT will start transmitting as soon as activated. Some ELT are also the ULB
(underwater locator beacon), this provides an ultrasonic emergency signal.
Each ELT has its own battery, making it independent from the aircraft power.
Bypass engines
Jet engine’s thrust is created by accelerating a certain mass of air:
𝑇 = 𝑚(𝑉𝑗 − 𝑉𝑣 ) + 𝐴(𝑃𝑗 − 𝑃0 )
m=
Vj =
Vv =
A=
Pj =
P0 =
mass of the airflow
(kg/s)
speed of the exhaust gasses
(m/s)
speed of the inlet air (TAS)
(m/s)
cross section area of the inlet
(m2)
pressure of the exhaust gasses
(Pa=N/m2)
ambient static pressure
(Pa=N/m2)
In a pure turbo-jet engine a relatively low value of mass is accelerated at a relatively high speeds, this requires a very
high fuel consumption with a relatively low engine propulsive efficiency. The best way to increase the efficiency and
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reducing the fuel consumption is to increase the air mass flow through the engine while reducing the air speed at the
exhaust. This has been done by bypassing the air from the jet engine core, through the by-pass duct.
The by-pass ratio is the ratio of by-pass air mass flow to HP compressor mass flow
The majority of all the airline aircraft operated nowadays uses high-bypass turbofan engines, in which a fan is
attached on the low pressure shaft. For example the B738 engines are the CFM56-7B with a bypass ratio of 5.5.
What is FADEC?
FADEC is the Full Authority Digital Engine Control, is an electronic system which provides engine performance
management and starting and shut sown automatic sequence.
Each engine has his own dual channel FADEC. Each FADEC operates through two EEC (Electronic engine control) unit,
one EEC is sufficient to provide all FADEC duties, the other one will take place in case of main EEC failure.
Main inputs to FADEC are:
→
→
→
→
→
thrust lever angle or FMC target inputs,
air data computer data (altitude, speed, temperature etc…),
N1 and N2 data,
engine air inlet temperature and EGT,
bleed air demands.
Based on this inputs FADEC provides: engine control and over-speed protection, engine stall and surge protection,
automatic engine starting and shut down sequence, auto-thrust and thrust reverser operation. To sum up FADEC
improves engine performance and life, reduces pilot workload, improved safety and engine stall/surge prevention.
Altimeter? Anemometer?
Blockages while climbing and descending?
Without re-adjusting the barometric setting of the altimeter, it will over-read when flying from a high pressure area
into a low pressure area: “High to low, look down below” → Reference isobar descending
Static P blockage climbing
→ anemometer under-read ( accelerate, overspeed!), altimeter under-read ( try to climb faster)
Total P blockage climbing
→ anemometer over-read (decelerate, stall!)
Static P blockage descending → anemometer over-read ((decelerate, stall!), altimeter over-read ( try to descend faster)
Total P blockage descending → anemometer under-read (accelerate, overspeed!)
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4 METEOROLOGY QUESTIONS
METAR coding -What means br mifg dz in a METAR -What is mist and fog in a METAR
A METeorological Air Report (METAR) is a written coded routine aviation weather report for an aerodrome. It is an
observation of the actual weather given by an observer at the aerodrome. METARs are usually issued every 30’/1h.
Note: Cloud base in a METAR (and TAF) is given above ground level (AGL).
Note: Wind direction in a METAR (and TAF) is given True.
Note: A rule of thumb would be “If you read it, it's true. If you hear it, it's magnetic”.
BR =
mist (vis > 1Km)
MI =
shallow (= low)
FG =
fog (vis < 1 Km)
BC =
patches
DZ =
drizzle
DR =
drifting
GR =
hail
BL =
blowing
What is the difference between METAR and TAF?
A Terminal Aerodrome Forecast (TAF) is a written coded routine weather forecast for an aerodrome. It is given by a
qualified meteorological forecaster based at the aerodrome. TAFs are usually issued for a 9-hour period and updated
every 3h. However, they may be issued for up to 24 hours with updates every 6h.
A weather trend is usually attached to an aerodrome weather report like a METAR. Because a trend period is much
shorter than a normal forecast (e.g. TAF) it’s much more accurate.
SHVC what does it mean if you see it in a METAR
It means shower in the vicinity of the airport from 8 to 16 Km from the A/D
What is BR in a METAR?
BR is mist, visibility is reduced below 5000m but more than 1000m by water particles (hydrometeors)
Arrival airport conditions of temperature 2 degrees and dew point 2 degrees. What conditions can we expect?
Since the actual temperature is equal to the dew point temperature, condensation is taking place = visibility reducing
phenomena, in particular fog if the wind is calm.
Different types of fog
Fog is a visibility reducing (< 1000m) phenomena, caused by vapor condensation when temperature ≤ dew point.
There are different kind of fog, categorized according to the cause of the temperature decrease.
Radiation fog is caused by the earth releasing heat and cooling the lower portion of the air, thus creating a
temperature inversion, during clear sky night with high relative humidity and light wind.
Orographic or hill fog is caused by a light wind raising a humid air mass along a slope, thus decreasing the air mass
temperature and causing the water vapor condensation.
Advection fog is caused by a humid air mass moving over a colder surface.
Frontal fog is caused by the precipitation in front of a warm front, increasing the relative humidity of the air,
furthermore the water droplets will evaporate once on the ground, thus decreasing the temperature.
Steam fog is caused by a humid and hotter surface over pass by a colder and slowly moving air mass. (Artic Smoke)
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Tropopause height ? why differences ?
The tropopause height vary with latitude and temperature. The
highest tropopause height will be found above the ITCZ and the
lowest above the poles. In ISA condition, tropopause is placed at a
height of 20 Km with a temperature of approximately -80 °C above
the equator, at 11 Km at 45° N with a temperature of -56.5 °C and
at 8 Km over the poles with a temperature of approximately -30 °C.
Tropopause height decreases when latitude increases, while
tropopause temperature increases when latitude increases.
Is it faster to travel over the Atlantic westbound or
eastbound?
Travelling over the Atlantic we will found two main jetstreams, the subtropical and the polar jetstream, both are
westerly, so travelling eastbound will be faster, since we will have tailwind instead of headwind.
Jetstream? Why westerly? What direction is the jetstream above us? Minimum Speed?
Jetstreams are narrow bands of high-speed upper thermal (their speed is directly proportional to horizontal thermal
gradient) winds at very high altitudes (just below the upper tropopause in the warm air), characterized by strong
vertical and/or lateral windshear (CAT). Note: isotachs are line of equal wind speed
The wind speed must be greater than 60 knots for a wind to be classified as a jetstream.
Pressure gradient force goes from high to low temp./pres., then do to Coriolis effect (turn clockwise in the Northern
Hem., counter-clockwise in the Southern), jetstreams overall direction generally is from west to east (westerly).
Over Ireland (atmosphere high = : Arctic Jetstream, winter: 50°-60°N, summer: /, FL 200-250, about 200 Kts
Polar Jetstream, winter: 40°-45°N, summer: 50°-60°N, FL 300-350, about 220-240 Kts
Clear Air Turbulence
CAT is not associated with cloud formation. Usually CAT occur above FL150 due to the marked wind shear on the
cold air side of a jet stream. The higher the jet stream strength the higher the CAT intensity, furthermore CAT is
usually more severe in the curved part of a jet stream.
What are lenticular clouds? Would you fly into them?
Lenticular (lens-shaped) clouds indicate standing (mountain) wave clear air turbulence (CAT) around them. They are
found at height in rising air above the downwind side of a range of hills, often extending for up to 100 nautical miles
downward of a line of hills and at a height of up to 25,000 ft. Don’t fly close or below lenticular clouds
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You are out for a walk in the mountain
and you are facing the wind, where is the low
pressure?
In the northern hemisphere the low pressure is
to the right, in the southern hemisphere to the
left
..
How are thunderstorms created?
Weather associated with thunderstorms including CB formation?
Thunderstorms are associated with cumulonimbus (CB) clouds.
Four conditions are required for a cumulonimbus cloud to develop:
1.
A high moisture content in the air.
2.
A trigger lifting action (or catalyst) to cause a parcel of air to start rising. The 4 main lifting actions are
a.
Convection
b.
Turbulence
c.
Frontal (cold front over warm air, at least 10 Kts wind)
d.
Orographic
3.
Adiabatic cooling of the rising air.
4.
A highly unstable atmosphere so that once the air starts to rise, it will continue rising. Effectively, the
environmental lapse rate (ELR) must be greater than the saturated adiabatic lapse rate (SALR) for over 10,000
ft.
Within a single CB cloud may be several thunderstorm cells. Life cycle of the cumulonimbus cloud, and its associated
thunderstorm, can be divided into three phases:
1.
Developing stage. During the development of the cumulonimbus cloud, updrafts move air aloft, allowing
condensation to take place throughout the ascent of the convective currents.
2.
Mature stage. During this stage, water drops start to fall through the cloud, drawing air down. Although it is
dependent on the shape of the storm and the prevailing wind gradient, this downdraft is often in the middle of
the storm, surrounded on all sides by strong continuing updrafts, which are providing further fuel for the
storm. Downdrafts can reach 3000 ft/min, and updrafts can reach 5000 to 6000 ft/min. The mature phase is
the most hazardous stage of the thunderstorms and include:
3.
a.
Torrential rain
b.
Hail
c.
Severe turbulence
d
Severe icing
e.
Windshear and microbursts
f.
Lightning
Decaying stage. This is the final stage of the cumulonimbus cloud. It starts with the end of the thunderstorm,
which is marked by the end of continuous rain and the start of sporadic showers, sometimes as virga due to a
temperature inversion beneath the cloud base, which can still cause a marked windshear. At the higher levels
it may take on the familiar anvil shape as upper winds spread out under the tropopause. An anvil can have
marked downward vertical currents beneath it, which cause a strong windshear that also should be avoided.
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5 SENECA V PA34 QUESTIONS
Engine mounted on PA34
PA34 has contra-rotating engine, so the left engine is a TSIO-360RB and the right one is a LTSIO-360RB. TSIO stands
for turbo supercharged Injection Opposite, the L stands for Left rotating (counter-clockwise). The 360 is the
displacement volume in cubic inches, approximately 5900 cubic centimetres. Each engine produces 220 hP giving a
total power of 440 hP.
Piper Seneca De-Icing system
PA34 is equipped with wings and tail de-icing boot, propeller heating, windshield and Pitot heating.
The inflatable boots are installed on the leading edges of the wings and tail surfaces, they are activated by a springloaded button in the cockpit. As long as the pilot keep the button pushed, the boots will take compressed air from
the 2 vacuum pump located on the engine, one for each engine, and inflate at regular intervals of 6 seconds or till
when they reach a pressure of 17 PSI.
Propeller heating take energy from the aircraft electrical system, once activated the system provide current to one
propeller for 90 seconds then to the other one. The electric resistance are placed on the propellers leading edge
roots.
Windshield and Pitot heating are provided with electric resistance, supplied with current from the aircraft electrical
system, activated by two different switches located in the cockpit.
Max x/wind on PA34?
The maximum demonstrated cross-wind component on the PA34 is 17 Kts
Does your MEP has a VMCA/VMCG ?
My MEP was a PA34, a light twin, it has a Vmca of 66 kts, but it doesn’t have a Vmcg since the regulation doesn’t
require Vmcg to be calculated for light twin
OAT Limit of you current a/c?
According to the performance graphs the OAT limits are from -20 to +50 °C
Tell me about the PA34 electrical system?
The electrical system of the PA34 has 3 main components: 2 alternators, one in each engine, supplying 28
VDC 85A when operated at 2500 RPM; a battery supplying 24 VDC 19 A/h and an alternators control unit that
maintain bus voltage at 28 V while maintaining an effective load sharing between the alternators and take an
alternator offline if voltage exceeds 32 V. there is also an external power unit, connected directly to the main bus,
thus require the external power source to be removed before starting an engine.
How many batteries are on PA34 and why?
Only one battery is provided on the PA34 since it is sufficient to supply the artificial horizon and the radio for
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30 minutes if both engine fails.
What is the PA34 maximum ceiling?
PA34 can fly up to 25000 ft if equipped with oxygen, but it cannot climb further since the regulation requires a
demand flow oxygen system to fly above 25000 ft, and the PA34 that I’m used to fly with doesn’t have it.
How is the PA34 feather system? Why is useful?
The PA34 has a manual feathering system, it is activated by pulling the propeller lever to the feather position. The
propeller can be feathered only if it is rotating at more than 800 RPM since an un-feathering pin doesn’t let the
propeller to be feathered under 800 RPM, this avoid the propeller to be feathered when the engines are stopped.
The feathering system is very useful since a feather propeller generate much less drag than a windmilling propeller
when an engine fails.
How is the PA34 landing gear system?
The PA34 has an Hydraulic landing gear system, operated by an electric pump. When extend the landing gear is
locked down by an over-center mechanism, when retracted there is no mechanical up-lock, the landing gear is kept
retracted by a condition of hydraulic lock in the hydraulic system, this means that a leakage in the hydraulic system
will release the landing gear. In case of electric pump failure there is a manual override system, when the knob is
pulled the hydraulic lock condition is bypassed leaving the landing gear free to fall by gravity action. Speed has to be
less than 85 knts.
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6 QUESTIONS ABOUT 737NG AND 737MAX
737 MTOM/MLM
The 737-800 MTOM is 79000 Kg/ the B737-800 MLM is 66350 Kg
Seats on the B737
Ryanair B738 are configured with 189 seats, the ordered 737 MAX will be configured with 197
How many cabin crew?
EASA regulation part-ORO section CC (organization requirements for air operation section cabin crew) requires a
minimum of 1 cabin crew member for every 50, or fraction of 50, passenger seats installed on the same deck of the
aircraft to be operated. So both the 738 and 737MAX requires a minimum of 4 cabin crew.
Engines on the B737
The 737-800 engines are the CFM56-7B (joint venture between GE and the French SNECMA) providing from 24500 to
32900 lbs of thrust, while the new 737 MAX8 will be equipped with the new generation CFM engine LEAP-1B
How many batteries are on 737 and why?
The 737 is equipped with two 24 v battery, a main and an auxiliary battery, the batteries operate in parallel when
powering the standby system providing a source of current to the essential equipment for 60 minutes. During normal
operation the battery are isolated and charged through an automatic charging unit.
737 fuel system
Fuel is stored in three tanks located in the wings and in the central fuselage. Each tank is equipped with two
centrifugal electrical pump which feed the engine with fuel under pressure. In the engine the fuel is firstly heated
through two oil/fuel heat exchanger, then is passed through a fuel filter and then through a second stage high
pressure engine driven fuel pump and lastly through the fuel metering unit where fuel is delivered under pressure to
the fuel injector according to the EEC inputs.
Max Mach number for 737
.82
Hydraulic pressure in 737
The normal hydraulic pressure is 3000 PSI, the minimum value is 2800 and the maximum is 3500 PSI
Max ceiling for 737
The maximum ceiling for the 737 is 41000 ft due to maximum cabin differential pressure that is 9.1 PSI
Max range for 737
4000 NM (737-900ER 3200)
How control surfaces are operated in 737?
Roll control is provided by hydraulically powered aileron and spoiler, inputs to the aileron hydraulic system is
provided by cables attached to the control wheel, the spoiler mixer system is attached to the aileron control system
and operates spoiler according to the aileron deflection. If the hydraulic system fails, manual reversion can provide
both spoiler and aileron operation. Pitch control is provided by two hydraulically operated elevator and an
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electrically operated stabilizer. If the hydraulic system fails, manual reversion for elevator control is possible. Yaw
control is provided by hydraulic operated rudder and digital yaw damper. Full moving stabilizer to reduce drag.
How are the flaps powered on a 737-800. What if this fails?
Leading edge flap system consist in two inboard flap and four outboard slats per wing while trailing edge flap system
consist in a double-slotted flap inboard and outboard of the engine. The main power source for flap and slat
operation is the hydraulic system, in case of an hydraulic system failure, an electric motor can be used to extend the
leading edge flaps and to extend or retract the trailing edge flaps.
Hydraulics PSI and How many on 737
The hydraulic system operate on a normal pressure of 3000 PSI. there are two main system A and B with a STBY
system connected to the system B. a power transfer unit is provided between system A and B to transfer pressure
from one system to the other in case of a system failure.
Max 737-800 ceiling, cruise speed, max speed
737 max ceiling is 41000 due to maximum cabin pressure differential. Cruise speed depends on actual flight
conditions and cost index. The maximum speed is mach .82, the recommended speed for turbulent air penetration
is mach .76
What is the sweep angle of the B737-800 and why this value and not another one?
25°, best compromise for high speed and low speed performance
How many emergency exit are in 737?
There are 8 emergency exit on the 737-800, 2 forward and 2 aft and 2 on each wing while on the 737 MAX
there are 10 emergency exits, 2 forward and 2 aft, 2 on each wing and 2 between the wing and the aft exits.
Where do the swept wings start to stall, and what things are fitted to the wing of the 737 to retard that
(Vortex Generators, Winglets and Slats)
Swept wing stall first at the tip due to the span-wise flow of the boundary layer, to retard low speed stall the
737-800 is equipped with wing fences and engine pylon below the wing which contribute to decrease the span-wise
flow while vortex generator in front of the aileron provide increased roll maneuverability close to the stall, by
reinforcing the boundary layer on the aileron.
737-800 de-ice and anti-ice systems
The 737-800 is provided with thermal and electrical anti-icing systems. Windshield and probe anti-ice
system is electric and uses current from the aircraft electrical system to heat the windshield and the probes. Wing
inboard leading edge slats and engine inlets are heated through thermal exchange with hot air spilled from engine
bleed air system.
How much time does the emergency power supply system feed the 737
Two fully charged battery provides standby power for at least 60 minutes
Difference between 738 and max
The main differences between B738 and MAX are in the MOPSC (maximum operational passenger seating
configuration), in the performance and in the cockpit design. The B737-800 has a MOPSC of 189 while the B737MAX8 200, but Ryanair B737-MAX will be configured with 197 seats. The MAX has a new internal cabin design, with
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new seats type, providing more comfort to the passenger and less turnaround time required for embarking and
disembarking passengers, thanks to the increased aisle space. Regarding the performance, the main factor
contributing to performance improvement are the new engine and winglets design. The B737-800 is equipped with
the CMF56-7B engine providing from 24500 to 32900 lbs of thrust while the B737-MAX8 will be equipped with the
new LEAP-1B engines providing from 23000 to 28000 lbs of thrust, 15% improvement in fuel efficiency, increasing
the range by 620 NM. The engine diameter will be
8 in greater, thus has required the landing gear to be enlarged in order to provide the required ground clearance, but
it will be 500 lbs less heavy than the CFM56-7B. the B737-800 has blended winglets mounted while the new 737
MAX will have the new advanced technology split-tipped straight-edged winglets, designed with the new laminar
natural airflow technology, providing an increased fuel savings by 1.5%. about the new cockpit design, the B737MAX
will be equipped with new LCD screen, providing easier flight management. A fly by wire system will be adopted for
the spoiler system, making the aircraft easier to fly, safer and more comfortable for the passenger while improving
further the aircraft performance.
Explain the A320 and B738 differences
Considering the main factor such us the MOPSC (maximum operational passenger seating configuration), engine
type, winglet type and range, the B737 has a MOPSC of 189 seats, is equipped with CFM56-7B, it has blended type
winglets, the maximum range at MTOM is approximately 4000 NM. The A320 has a MOPSC of
180 seats, is equipped with CFM56-5B (most common used engine), it has wing tip fence or shark-lets
winglets type, the maximum range at MTOM is 3200 NM. The main difference between the two is in the flight
control system, the B737-800 is equipped with conventional control wheel connected to the hydraulic system with
cables while the A320 is equipped with a side-stick connected to the fly by wire computers which give inputs to the
servo valves in the hydraulic system.
B737-800
B737-MAX8
A320
A320neo
MOPSC
189
200 (197 Ryanair)
180
189
MTOM
79000 Kg
82200 Kg
78000 Kg
79000 Kg
Engine
CFM56-7B
LEAP-1B
CFM56-5B
LEAP-1A
split-tipped straightedged winglets
Wing-tip fence or
sharklets
Winglets
blended
Range
3200 NM
3600 NM
3300 NM
3500 NM
Conventional
Conventional with
FBW for spoiler
FBW
FBW
Flight control
system
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7 OTHER QUESTIONS
What are the main differences between flying in a land airplane compared to a seaplane?
Surely taxi, take-off and landing are completely different. while taxiing on a seaplane you can’t stop, so you have to
perform all the checklist and the briefing while the aircraft is moving on the water and keeping attention on the
possible waves and boats that can cross your path. Take-off is completely different because while taking-off on the
water you have to raise the nose of the aircraft, gain speed and then pushing the nose down to start “gliding” on the
water, this maneuver is called the climb on the Redan, that is the little step below the floats. Then during the take-off
roll you have to kept a constant attitude counteracting wave and wind influence and just waiting the aircraft to get
airborne. Landing is very similar to that one performed in land airplane, but the flare is different, because the
touchdown has to be performed with a precise attitude, to high and the aircraft tail could strike the water, too low
and the aircraft can somersault. The right touchdown attitude is lightly higher compared to a landplane. During
cruise the speed is limited due to the high drag created by the floats. However the floats have a stabilizing effect,
making seaplane harder to be maneuvered.
VOR range
The VOR uses VHF radio wave, VHF wave are optical propagation wave, this means that to receive a VOR station, the
station must be “in sight”. Considering the mid radius of the earth and the aircraft and station height in feet, to
obtain a result in nautical miles the range could be calculated with the following formula:
where H1 is the height of the transmitter and H2 is the height of the receiver.
Great circle/rhumb line
A great circle route is an arc identified between two point by a plan intersecting the earth sphere by passing through
the earth center, so on a sphere is the shortest distance between the two point. A rhumb line is a route between two
point intersecting all the meridians at a constant angle, so during the route the true course remain constant.
They would draw a great circle in the northern hemisphere curved towards the Equator. It is wrong and
explain why.
To be a great circle, the route must be an arc identified on the earth surface by a plan cutting the earth and passing
through the center of the earth. So the great circle is always curved towards the nearest pole.
In which direction the fan rotates?
Fan rotates in the same direction since gyroscopic effect are almost negligible on jet aircrafts, thus allow to reduce
maintenance costs since the right and the left engine almost identical. I’m not 100% sure, but as I remember the fan
on the CFM56-7B rotates clockwise.
Fire extinguishers, types (CS 25.851)
The two most common type of fire extinguisher available on board an aircraft are water and halon type. At least one
halon fire extinguisher must be available on the flight deck. The number of fire extinguisher in the cabin depends on
the MOPSC (maximum operational passenger seating configuration) so for example the 737-800 has 189 seats, so
from 61 to 200 seats, at least 3 fire extinguisher are required in the cabin. At least two of these three must be halon
and the other one could be water. Halon fire extinguisher are suitable to be used against class A (ordinary
combustible, wood, paper, plastic..),B (combustible liquids) and C (electrical equipment) fires. Water fire extinguisher
are suitable only for class A fire.
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Which is the difference between DA and MDA?
The DA is the altitude at which a pilot must commence a missed approach procedure if the required visual reference
are not obtained. The MDA is the altitude below which the minimum obstacle clearance requirements are no longer
provided for the procedure. DA already consider pilot reaction time and aircraft loss of altitude during go-around
initiation while MDA doesn’t consider that, that’s why each operator shall determine according to the aircraft type
an appropriate margin of altitude to be added to the published MDA. DA is used for precision approach procedure
while MDA is used for non-precision and circling procedure. Sometimes it is possible to have a DA on non-precision
procedure, that why it is a CDFA approach procedure, where there is no level flight portion provided at the minima.
To avoid confusion sometimes charts designer, like Jeppesen, write DA instead of MDA, but the calculation of that
minima is made according to the MDA requirements, so it is still required to add a margin to that minima.
How many cc per seats in an aircraft
EASA regulation part-ORO section CC (organization requirements for air operation section cabin crew) requires a
minimum of 1 cabin crew member for every 50, or fraction of 50, passenger seats installed on the same deck of the
aircraft to be operated. So both the 738 and 737MAX requires a minimum of 4 cabin crew.
VFR vs VMC?
VFR are the rules according to which a pilot must operate if it is performing a VFR flight. VMC are the meteorological
conditions required in order to operate a flight in VFR. This condition varies according to the class of airspace
interested.
CFIT (controlled flight into terrain) what do you know about it
Controlled flight into terrain occur when an airworthy aircraft under complete control of the pilot is inadvertently
flown into terrain or obstacles. The pilot is generally unaware of the danger until is too late. CFIT occur because of
loss of situational awareness, particularly during the approach phase, often associated with non-precision approach
procedures. Obviously CFIT consequences are catastrophic, resulting in hull loss with multiple injuries and fatalities.
The best way to avoid CFIT is a good situational awareness in relation to terrain, SOP application and the
implementation of terrain avoidance warning system on-board.
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