Special Emphasis
Areas - 2
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Index
• Positive Aircraft control.
• Positive exchange of flight controls.
• Collision avoidance.
• Stall & Spin awareness.
• Wake turbulence avoidance.
• LASHO (Land and hold short operations).
• CFIT (Controlled flight into terrain).
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• ADM (Aeronautical decision making).
• CRM vs SRM.
• Checklist usage.
• Icing conditions and other hazards.
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Wake Turbulence
Avoidance
• Every aircraft generates wake turbulence from the
moment the wing produces lift and the aircraft leaves
the ground until it lands.
• This wake is also called wingtip or wake vortices.
• It forms when an aerofoil generates a pressure
difference.
• Especially important on an approach to an airport in
visual conditions where the pilot uses visual
separation.
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• Flow is the 3rd dimension is spanwise.
• Spanwise flow involves vortices.
• As air will always flow from a high pressure area to
an area of lower pressure with the end of equalizing,
thru the straight shortest line, that it’s the lowest
distance between two points.
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Factors Influencing Flow
Direction
• The direction of airflow is influenced by two principal
factors.
• The inertia of the mass through the air flow.
• Pressure differentials.
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The Wing Tip Vortex
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Formation of a Tip Vortex
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Factors Affecting Vortex
Intensity
• The intensity of the tip vortex depends on two
factors:
• The pressure differential between the upper and
lower surfaces – the driving force for the vortex
(Difference in value).
• The amount of time the driving force is given to
operate on the air mass (Time).
• The longer the chord, the greater the driving force for
the vortex (Area).
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Vortex Intensity
• Tip vortex intensity will reduce if:
• Aircraft speed increases.
• Wing aspect ratio increases.
• The amount of lift being produced reduces.
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Other Effects of Tip Trailing Vortices
• Tip trailing vortices produce two other effects:
• Downwash - Each tip vortex rotates sharply
downwards behind the trailing edge. This downwash
imparts a small downward velocity component to the
air leaving the trailing edge.
• Drag - The extra energy provided to the tip trailing
vortices is felt by the airplane as drag.
• The stronger the tip trailing vortex the greater the
amount of drag and downwash.
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Factors Affecting Vortex
Intensity
The longer the chord, the greater the vortex force
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Spanwise Flow
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Trailing Edge Vortices
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Vortices and Downwash
• In 2-dimensional flow there is up-wash ahead of the
aerofoil and downwash behind.
• In 3-dimensional flow the downwash is greater than
the up-wash.
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The Angle of Attack
• In 2-dimensional flow the angle of attack is the angle
between the chord line and the relative air flow.
• In 3-dimensional flow the angle of attack is the angle
between the aircraft’s longitudinal axis and the
relative airflow.
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The Downwash Sheet
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The Effective Airflow
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Lift and Induced Drag
• The aerodynamic force acting at 90° to the flow is
inclined backwards by the induced angle of attack
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Lift and Induced Drag
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The Induced Angle of Attack
• The induced angle of attack is the angle between the
effective and relative air flows. The induced angle of
attack is larger when the aircraft is:
• At lower TAS.
• At higher angles of attack (stronger vortices
producing greater downwash).
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The Effective Angle of
Attack
• The effective angle of attack is the angle between
the effective airflow (EAF) and the section chord line
of the wing:
• Determines the pressure distribution and the
production of aerodynamic force.
• The angle of attack (α) is the sum of the induced
angle of attack and the effective angle of attack:
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The Effective Angle of
Attack
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Change of Effective AoA
with Span
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Change of Effective Angle of Attack with Span
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• Light crosswinds may cause the vortices to drift, and
crosswinds in excess of five knots tend to cause
them to break up behind the aircraft. Atmospheric
turbulence generally causes them to break up more
rapidly. Then a crosswind will decrease the lateral
movement of the counter rotating cylindrical vortices.
• A light crosswind could result in the upwind vortex
remaining in the touchdown zone for a period of time
and hasten the drift of the downwind vortex to
another runway. Similarly, a tailwind condition can
move the vortices of the preceding aircraft forward
into the touchdown zone
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• When the vortices of a larger aircraft sink close to
the ground (within 100 to 200 feet), they tend to
move laterally over the ground at a speed of 2 or 3
knots and results in order to have the same scenario
such as crosswind or tailwind.
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• In order to avoid wake turbulence, we have
different scenarios;
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Heavy
B-757
Large
Small
Small - Heavy
Small - B757
Small - Large
Large - Heavy
Large - B757
Heavy - Heavy
Heavy - B757
More than 255.000 lbs
A category by it self.
41.000 lbs - 255.000 lbs
0 lbs - 41.000 lbs
Departure / Takeoff (1) Departure / Takeoff (2)
3 minutes
2 minutes
3 minutes
2 minutes
3 minutes
2 minutes
3 minutes
2 minutes
3 minutes
2 minutes
3 minutes
2 minutes
3 minutes
2 minutes
Cruise
5NM
5NM
4 NM
5NM
4NM
4NM
4NM
Approach / Landing
6 NM
5 NM
4 NM
5 NM
4 NM
4 NM
4 NM
1.- Departure / takeoff from an intersection (same or opposite
direction), when the preceding aircraft make a low/missed
approach or upon specific pilot request.
2.- Departure / takeoff from same threshold, on a crossing
runway and projected flight path will cross, or from threshold of a
parallel runways separated by less than 2,500 feet.
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• Wing tip modifications reduce the leakage of
airflow around the wing tip and limit the size of the
vortex.
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• Why a large or heavy aircraft, with slow speed in
a clean configuration is producing very strong
wake vortices?
Heavy; The heavier the airplane, the more lift needs to be
generated for the airplane to be airborne.
Slow; If flying slowly, to generate enough lift. AOA needs
to be increased and so induced drag will be increased.
Clean configuration; The entire wing generates equal lift
forces along the wing.
Dirty configuration;
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LAND AND HOLD SHORT
OPERATIONS (LAHSO)
• Term used for operations that involve aircraft landing
and holding short of an intersecting runway, taxiway
or some other designated point on a runway.
• For enhance busy airports.
• System efficiency.
• Pilots may deny a LASHO at discretion.
• The certificated landing distance; From your Aircraft
Flight Manual or Pilot Operating Handbook (AFM /
POH) for the configuration being flown plus an
additional 1,000 feet.
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• The bottom line is that you need to know the LAHSO
available landing distance for your aircraft, and
whether the runway you’re landing on, meets that
distance.
• Rejected landing procedures must be precisely
executed to assure safe separation. Know what you
are supposed to fly and how you are going to fly it
before you do it.
• LAHSO is authorized for dry runways only. "DRY" is
defined as having no visible moisture. In addition,
the runway cannot be contaminated.
• Vertical Guidance: LAHSO requires vertical
guidance to be installed and operational for day or
night operations. A PAPI, VASI or ILS is acceptable.
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• After February 8, 2000, night LAHSO requires either
a VASI or PAPI — ILS will not be acceptable.
• Weather Minimums: Where a PAPI or VASI is
installed and operating, the minimum ceiling is 1,000
feet and the minimum visibility is 3 statute miles.
• If an ILS is the only vertical guidance available, the
minimums are a ceiling of 1,500 feet and visibility of
5 statute miles.
• Lights consists of five, six, or seven pulsing white
lights installed across the runway, in the pavement
at the hold-short point.
• They must be turned on when LAHSO operations
are effective.
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• Be aware that if you decline a LAHSO clearance and
are landing full-length on a runway with operational
lights, the lights will remain on. Also, if you take off
from a runway, the LAHSO lights will be on if LAHSO
is in use.
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Controlled Flight
Into Terrain (CFIT)
• Controlled flight into terrain (CFIT) describes an
accident in which an airworthy aircraft, under pilot
control, is unintentionally flown into the ground, a
mountain, water, or an obstacle. The term was
coined by engineers at Boeing in the late 1970s. The
pilots are generally unaware of the danger until it is
too late.
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Aeronautical Decision
Making (ADM)
• ADM is a systematic approach to the mental process
used by pilots to consistently determine the best
course of action in response to a given set of
circumstances.
• To minimize its errors we can follow some steps:
• Identifying personal attitudes hazardous to safe flight.
• Learning behavior modification techniques.
• Learning how to recognize and cope with stress.
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• Developing risk assessment skills.
• Using all resources.
• Evaluating the effectiveness of one’s ADM skills.
Most preventable accidents have one common
factor: human error, rather than a mechanical
malfunction.
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Hazardous Attitudes
Antidote
Antiauthority: Don't tell me.
Follow the rules. They are usually
right.
Impulsivity: Do something quickly.
Not so fast. Think first.
Invulnerability: It won't happen to me.
It could happen to me.
Macho: I can do it.
Taking chances is foolish.
Resignation: What's the use? I'm not helpless.
I can make a difference.
• The Perceive-Process-Perform (3P);
• Perceive the given set of circumstances for a flight.
• Process by evaluating their impact on flight safety.
• Perform by implementing the best course of action.
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• Decide model;
• Detect. The decision maker detects the fact that
change has occurred.
• Estimate. The decision maker estimates the need to
counter or react to the change.
• Choose. The decision maker chooses a desirable
outcome (in terms of success) for the flight.
• Identify. The decision maker identifies actions that
could successfully control the change.
• Do. The decision maker takes the necessary action.
• Evaluate. The decision maker evaluates the effect(s)
of his action countering the change.
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CRM vs SRM
• CRM; Crew Resource Management.
• SRM; Single Resource Management.
• “TRACK” it’s used by the FAA to defined 5 important
steps of Single pilot resource management;
• T = Take command.
• R = Recognize resources.
• A = Avoid work overload.
• C = Communicate effectively.
• K = Know your situation.
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• Five P model:
• Plan – Planning, weather, route, fuel, publications,
ATC reroutes/delays.
• Plane – Mechanical status, database currency,
automation status, backup systems.
• Pilot – Illness, medication, stress, alcohol, fatigue,
eating (IMSAFE).
• Passengers – Pilot or non-pilot, experienced or
inexperienced, nervous or calm, etc.
• Programming – GPS, autopilot, PFD/MFD, possible
reroutes requiring reprogramming.
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Checklist Usage
I
M
S
A
F
E
IMSAFE CHECKLIST
Illnesses.
Medication & Drugs.
Sleep (Last 24 hours).
Alcohol.
Food and water.
Environment & Stress.
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•
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Preflight inspection: Arrive early!! Shift attention to flight.
Before Starting Engines: After door is closed, pax briefed.
Taxi: Out of chocks.
Before Takeoff: Arriving at run-up area, or end of active rwy.
Lineup: Cleared by tower for takeoff (or t/o decision made).
After takeoff/climb: 500 or 1000 ft. above airport.
Cruise: reaching cruise altitude.
Descent: Beginning descent into terminal area.
In-range: 10 miles out - sometimes combined with approach briefing.
Approach: Cleared for IAP or IAF, base leg at latest . . .
Before Landing: FAF inbound (IFR); TPA or 3 miles (VFR).
After landing: Hold when clear of runway.
Shutdown: In chocks again.
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Icing conditions
• Icing conditions / Operational Hazards
• De-icing & Anti-icing system’s.
• The formation of ice in the aircraft has several
effects on the aircraft performance;
• Reduced thrust.
• Increased drag.
• Reduction of lift.
• Increase of weight.
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• This results in a increase of stall speed and in a
reduction on the aircraft performance.
• A pilot can expect icing when flying in visible
precipitation (Humidity) and temperatures between
+2ºC and -10ºC.
• Quantum of ice formation – Trace, light, moderate
and severe.
• Types of ice – Glace ice, intercycle ice, know or
observed or detected ice creation, mixed ice,
residual ice, rime ice and runback ice.
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• Icing conditions – Forecast icing conditions, freezing
drizzle (FZDZ), freezing precipitation, freezing rain
(FZRA), icing in cloud, icing in precipitation, know
icing conditions, potential icing conditions, super
cooled drizzle drops (SCDD), super cooled drops or
droplets, super cooled large drops (SLD).
• There are two types of systems on board, de-icing
systems and anti-icing systems.
• Anti-icing.
• De-icing.
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QUESTIONS?
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