ECOS pilot school-Aircharter
FLIGT PATH CONTROL ( RULES OF THUMB,
FORMULAE, CONVERSION TABLES &
RECOMMENDATIONS
ECOS pilot school-Aircharter
1. INTERNATIONAL STANDARD ATMOSPHERE (ISA)
The International Standard Atmosphere is one in wihch at Mean Sea Level the temperature is +15°C, the pressure is
1013.24hPa, and the realtive density 100% (1225 g/m³). The temperature is assumed to decrease with height at rate
of 1,98°C per 1000 ft (6,5°C and density are also assumed to decrease with height, according to a more complicated
formulea. Decrease in pressure and density is not linear with height.
An extract, giving some values of the ISA, is tabulated below
Height
(ft)
0
5 000
10 000
15 000
20 000
25 000
30 000
35 000
40 000
45 000
Temp. (°C)
+15,0
+5,1
-4,8
-14,7
-24,6
34,5
-44,3
-54,2
-56,5
-56,5
Pressure
(hPa)
1013,25
843,10
696,90
572,00
466,00
376,50
301,50
239,10
188,20
148,20
Speed of Sound
(KT)
661,03
649,59
637,93
626,09
613,95
601,64
589,06
576,20
573,20
148,20
2. PRESSURE
2.1. Units of Measurement Conversion
1 hectopascal (hPa) = 1 Milibar (mbar)
1 (inch Hg) = 33,86 (mbar)
= 33,86 (hPa) = 25,4 (mm Hg)
1 (mm Hg) = 1,33 (mbar)
= 1,33 (hPa) = 0,0394 (mm Hg)
1 (mbar)
= 0,75 (mm Hg) = 1 (hPa)
= 0,0295 (inch Hg)
14,2 (psi) % ~ 1 (atm)
0,073 (atm) ~ 1 (psi)
( for information only)
2.2. Height Difference corresponding to a Pressure Difference of 1 hPa and 1 mmHg (ISA, sea Level)
1 (hPa)
→ 27,29 ft = 8,32 m
1 (mm Ha) → 36,30 ft = 11,07 m
1 (mbar) → 27,29 ft = 8,32 m
2.3. Height Difference corresponding to a Pressure Difference of 1 (hPa) depending on Altitude
Alt. (ft)
h (ft / hPa)
0
27,29
2000
28,94
5000
31,67
10 000
36,94
20 000
51,21
30 000
72,82
ECOS pilot school-Aircharter
2.4. (hpa) to (Inches Hg) conversion
RULE OF THUMB
Remember
-
1016 (hPa) = 30,00 (inch Hg)
1 (hPa) = 0,03 (inch Hg)
The difference in (hPa) from 1016 (hPa) multiply by 3 and add to / subtract from 30,00 (inch Hg)
( in hundredths).
3. TEMPERATURE
0° = 32°F
100° = 212°F
= 273,16°K
= 372,16°K
°C – degrees on Celsius scale
°F – degrees on Fahrenheit scale
°K – degrees on Kelvin scale
3.1 conversion Formulae
9x(°C)
°F =
+ 32
5
5
°C = ─ (°F – 32 )
9
°K = °C + 273
3.2. Fahrenheit Celsius Conversion Table
Celsius
40°
39
38
37
36
35
34
33
32
31
30
29
28
27
26
Fahrenheit
104.0°
102,2
100,4
98,6
96,8
95,0
93,2
91,4
89,6
87,8
86,0
84,2
82,4
80,6
78,8
Celsius
25°
24
23
22
21
20
19
18
17
16
15
14
13
12
11
Fahrenheit
77,0°
75,2
73,4
71,6
69,8
68,0
66,2
64,4
62,6
60,8
59,0
57,2
55,4
53,6
51,8
Celsius
10°
9
8
7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
Fahrenheit
50,0°
48,2
46,4
44,6
42,8
41,0
39,2
37,4
35,6
33,8
32,0
30,2
28,4
26,6
24,8
23,0
ECOS pilot school-Aircharter
3.3. Standard temperature Vertical Gradient
g t = 6,5°C/km
g t = 1,98°C/1000 ft
up to 11 km (36 090ft)
3.4. Static Air temperature (SAT) – Total Air Temperature (TAT) Relation
The temperature difference between SAT and TAT can be calculated by formula
∆t = 0,000137 TAS²
∆t = SAT – TAT (°C)
TAS = True Air Speed (KT)
For example:
∆t
3,1 °C
5,5 °C
8,6 °C
12,3 °C
16,8 °C
21,9 °C
27,7 °C
TAS
150 KT
200 KT
250 KT
300 KT
350 KT
400 KT
450 KT
4. MASS
4.1. Conversion formulae
1 kg
1 lb
= 2,205 lb
= 0,454 kg
RULES OF THUMB
- to convert ”kg” into ”lb” , multiply ”kg” by 2 and add 10%.
- to convert “lb” into “kg” , divide “kg” by 2 and subtract 10%
5. VOLUME
1 IMP. GALL = 4,546 lit
1 lit
= 0,22 IMP. GALL
1 US.GALL
1 lit
= 3,785 lit
= 0,26 US.GALL
6. FUEL QUANTITY CHECK
6.1. Conversion formulae
1 lb = 0,454 kg
1 kg = 2,205 lb
1 IMP. GALL = 4,546 lit
1 US GALL = 3,785 lit
ECOS pilot school-Aircharter
Assumed fuel density
0,8 kilograms per litre
1,76 pounds per litre
(kg/lit)
(lb/lit)
3,04 kilograms per U.S. GALLON
6,7 pounds per U.S. GALLON
3,65 kilograms per IMP. GALLON
8,05 pounds per IMP. GALLON
RULES OF THUMB
- to convert ”kg” into ”lb” , multiply ”kg” by 2 and add 10%.
- to convert “lb” into “kg” , divide “kg” by 2 and subtract 10%
6.2. Procedure
-
the amount of fuel on Fuel receipt convert into units of measurement used on the gauges of the respective
type of aircraft ( assume density stated above)
add this converted amount of fuel to FUEL LEFT ( remain fuel from the previous flight) and be sure that
this total amount correspond with the total fuel quantity on the cockpit fuel gauges and fuel specified in the
flight plan.
7. DISTANCE
7.1. Conversion Formulae
1 NM = 1,853 km
1 SN = 1,609 km
1 NM
1 SM
= 1,15 SM
= 0,87 NM
1 km
1 km
=
=
NM – Nautical Mile (s)
SM – Statute Mile (s)
0,54 NM
0,52 SN
RULES OF THUMB
- distance (NM) = Distance (km) divide by 2 and add 10%
- distance (km) = Distance (NM) multiply by 2 and subtract 10%
1 ft = 0,3048 m
1m = 3,2808 ft
RULES OF THUMB
- altitude (ft) =
altitude (m) divide by 3 and multiply by 10
- altitude (m) = altitude (ft) multiply by 3 and divide by 10
Or a little bit more accurately
ECOS pilot school-Aircharter
RULES OF THUMB
- altitude (ft) =
altitude (m) multiply by 3 and add 10%
- altitude (m) = altitude (ft) divide by 3 and subtract 10%
1 yard (yd)
1m
1 inch (in)
= 0,9144 m
= 1,0936 yd
= 0,0254 m = 25,4 mm
8. SPEED AND MACH NUMBER
8.1. Conversion formulae
1 KT
1 MPH
= 1,853 km/hr
= 1,609 km/hr
1 KT
1 MPH
= 1,15 MPH
= 0,87 KT
1 km/hr
1 km/hr
= 0,54 KT
= 0,62 MPH
1 ft/min
1 m/sec
= 0,00508 m/sec
= 196,85 ft/min
KT – knot(s)
MPH - statute mile(s) per hour
Km/hr – kilometer (s) per hour
RULES OF THUMB
1 m/sec ≈ 200 ft/min
100 ft/min ≈ 0,5 m/sec
1 m/sec = 1,942 KT
1 KT
= 0,5148 m/sec
RULES OF THUMB
1 m/sec ≈ 200 ft/min
100 ft/min ≈ 0,5 m/sec
1 km/hr = 0,278 m/sec
1 m/sec = 3,6 km/hr
8.2. True Air Speedn (TAS) – indicated Air Speed (IAS) Relation
(Approximate formula)
FL X IAS
TAS = ──────
500
TAS – True Air Speed (KT)
IAS – Indicated Air speed (KT)
FL - Flight level
TAS = IAS + ( 1,75% of IAS per 1000 ft of altitude)
ECOS pilot school-Aircharter
8.3. Speed of Sound in the Air
C = 20,1
√T (m/s)
T = OAT + 273
C = 72,36 √T (km/h)
C = 39
T - Kelvin absolute temperature ( º K )
√T (KT)
OAT = Outside Air Temperature (º C )
Mach number is a number indicating the ratio of the speed of an object to the speed of sound in the medium through
the object is moving.
8.4. Aircfat Mach Number
Approximate formula:
T = OAT + 273
T - Kelvin absolute temperature ( º K )
OAT = Outside Air Temperature (º C )
TAS
M = ──────────
39 x √ OAT + 273
9. SPEED DISTANCE AND TIME RELATIONS
During a flight the airspeed will vary during different stages of the flight, so the distance covered during a given
time will also vary.
9.1. Speed factor
RULE OF THUMB
To be able to calculate speed-time-distance relations we are introducing with a speed factor (SF)
Speed factor (SF) is the distance covered in one minute, i.e. this is the speed in (KT) divided by 60.
Speed (KT)
Speed
Factor (SF)
(Nm/min)
60
120
180
240
300
360
420
480
540
600
1
2
3
4
5
6
7
8
9
10
Air Speed factor (ASF) is based on True Air Speed (TAS) and give us the distance covered in one
minute through the air.
Ground Speed factor (GSF) is based on Ground Speed (GS) and give us the distance covered in one
minute over ground.
To get the time (ETO) divide a given distance with GSF
9.2. Use of Mach Meter
RULE OF THUMB
Use your mach meter for direct reading of ASF above FL 150.
ECOS pilot school-Aircharter
Explanation: The speed of sound equals 600 KT at -35ºC. that is the temperature in standard atmosphere at FL 250.
Therefore:
Mach 1,0 = TAS 600 KT → ASF = 10 (Nm/min)
or
Mach 0,7 = TAS 420 KT → ASF = 7 (Nm/min)
or
Mach 0,6 = TAS 360 KT → ASF = 6 (Nm/min) etc.
You can use the mach meter (multiplying the indication by 10) for direct reading of ASF. At the temperatures other
than -35º there will be some small errors which can be disregarded compared to the importance of quick
calculations.
9.3. Ground Speed
Ground speed can be found by means of using of the stop watch when established at a certain TAS and tuned in on
a DME station in front or behind.
RULE OF THUMB
Start the stop watch and note how many NM is covered during one minute and this is exactly GSF which multiplied
by 60 gives the Ground speed (GS).
By comparing GS to TAS, the head – or tailwind component can be found.
The reading error on the DME can be minimized by continuing the timing to 3 minutes. The distances covered
multiply by 20 to get the GS.
Another simple rule is:
36 sec equal 1/100 of one hour, so DME distance for 36 sec times 100 equals GS. However it is very difficult to get
an exact DME reading during that short time span.
The DME station should be at least as far away as the FL divided by 10. This is because of slant distance which is
measuring. For example at FL 350 the distance should be minimum 35 Nm.
ECOS pilot school-Aircharter
10. GOING EAST
10.1. Conversion Formulae
km
♦ ─── + 10% ≈ Nm
2
m
♦ ─── + 10 ≈ feet
3
♦ (Nm x 2) – 10% ≈ km
or
♦ m/s x 2 ≈ knots
ft x 3
♦ ────
10
≈m
knots
♦ ────
2
≈ m/s
ft /min
♦ ────
200
≈ m/s
♦ m/s x 200 ≈ ft/min
10.2. Conversion tables
The conversion tables (m-ft) should be permanently displayed in both pilots fields of view, clearly legible and well
illuminated at night. The conversion should be cross – checked by both pilots.
10.3. Altimetry
Set both altimeters to QNH or QFE ( according to company procedure) when recleared to an altitude below
transition level. If there is any doubt or disagreement as to the correct setting, or the units, call ATC for
confirmation.
When both altimeters are set to QNH or QFE, cross-check that both altimeters are reading the same. This crosscheck should be a standard call-out.
Use a suitable table to convert altitudes and flight levels to the required units.
11. SLOPE
11.1. The Ways of Expressing the Slope:
There are three usual ways of expressing and calculating the slope:
GRADIENT (%) – gradient shown by percent – a slope expressed as vertical distance (H) in percentage of
horizontal distance (D). Units of measurements must be the same for H and D
ECOS pilot school-Aircharter
GRDIENT (ft/Nm) – gradient shown in feet per nautical mile – a slope expressed as a ratio of the vertical distance
H (ft) to the horizontal distance D (Nm)
SLOPE (*) – shown by angle in relation to horizontal surface in degrees.
11.2. Conversion Formulae:
GRAD (ft/Nm) = 60,8 GRAD (%)
GRAD (%)
= 0,0164 grad (ft/min)
GRAD (ft/Nm)
= ─────────
6080
ECOS pilot school-Aircharter
GRAD (%)
= tgα * x 100
α (º)
=
arc tg
GRAD (ft/Nm)
─────────
100
GRAD (ft/Nm) = tgα * x 6080
α (º)
=
GRAD (ft/Nm)
arc tg ─────────
6080
Remember:
3º
= 5,2% = 319 ft/Nm
Try to remember:
3,5º = 6,1% = 372 ft/Nm
2,5 º = 4,4% = 265 ft/Nm
11.3. Rate of Descent ( ROD) Calculation
ROD depends on slope and aircraft's ground speed (GS).
ROD
= 101,33 x Gs x tgα
ROD
GS
= ───── x GRAD (ft/Nm)
60
ROD
= 1,0133 x GS x GRAD (%)
GS – ground speed (KT)
The rate of climb (ROC) can be calculated in the same manner.
RULE OF THUMB
Whenever a descent gradient in percent is available (Jeppesen approach chart – nonprecision approach), a ROD
may be simply mentally calculated by multiplying the percent value by the ground speed.
~
ROD = GRAD (%) x GS (KT)
ECOS pilot school-Aircharter
RULE OF THUMB
The standard rate of descent (ROD) is always known for a 3º GP, no wind conditions, particular type of aircraft and
its approach speed.
For each 10 KT head / tall wind component decrease / increase ROD by 50 FPM
RULES OF THUMB
For descent planning purposes, desired altitude (on 3°GP) in relation to the distance to the landing runway may be
mentally calculated:
A FL = 3 x D
A FL
A ft = 300 x D
A ft
D
- altitude expressed in Flight Levels (FL)
- altitude expressed in (ft)
- distance to the landing runway in (Nm)
11.4. Runway Slope Calculation
TDZE 1
runway length
TDZE 2
Take - off or
landing direction
TDZE 2 – TDZE 1
RS = ──────────── x 100 (%)
RL
RS (%)
- runway slope
TDZE2 (ft)
- touch down zone elevation at the end of runway
TDZE1 (ft)
- touch down zone elevation at the beginning of runway
RL (ft)
- runway length
For TDZE2, TDZE1, RL see Jeppesen Route Manual, Airport plan view for each particular airport or runway.
12. TURNS
12.1. Standard Turn
Standard turn is a turn with a rate of 3° per second
ECOS pilot school-Aircharter
12.1.1. Radius of Standard Turn:
r = 19 sec.
TAS (KT)
R = ────── (Nm)
188,4
For mental calculation in practical use
RULE OF THUMB
TAS (KT)
R = ────── (Nm)
200
12.1.2. Bank Angle of Standard Turn
TAS (KT)
TAS (KT)
R = ────── → α * = arc tg ──────
343
343
RULE OF THUMB
TAS (KT)
R = ────── + 7
10
All IFR manoeuvres ( holdings, race tracks, procedure turns, base turns ) are calculated with standard turns (3°/sec.)
or with turns at a bank angle of 25°, whichever requires the lesser bank.
~
Up to TAS = 180 KT , standard turns are to be made ( with bank angles up to 25°).
For TAS > 180 KT, bank angle of 25° must be maintained.
ECOS pilot school-Aircharter
13. CORRECTIONS FOR WIND EFFECT
13.1. Definitions
W
CWC
TC
CA
α
- wind vector, i.e. wind speed (KT) and direction (º)
- crosswind component (KT)
- track component (KT)
- correction angle (º)
- wind – to – track angle
13.2. Calculation of Crosswind component ( CWC ) & Correction Angle ( CA )
Procedure:
1. Wind / track Angle (α) – Find out by heart wind / track angle from known track and wind direction. Visualise
the situation and fin out if the wind is headwind or tailwind, from the right or from the left. Wind / track angle
should be less than 90 º
2. Crosswind Component (CWC) – calculate the crosswind component by heart.
CWC = W • sin α (KT)
inserting approximate values for sin α ( known by heart )
Sin 30 º = 0,5
Sin 45 º = 0,7
Sin 60 º = 0,9
Sin 90 º = 1,0
3. Correction Angle (CA)
60x CWC
CA = ────── (°)
TAS
CWC – crosswind component (KT)
TAS - true air speed (KT)
ECOS pilot school-Aircharter
RULE OF THUMB
1. For TAS = 120 KT →
CA = 0,5 CWC
2. For correction angle (CA) calculation during approach apply one of formulae shown in the table below. It's easy
to remember the particular formulae for the particular type of aircraft depending on the approach speed.
CA
TAS
80 KT
100 KT
120 KT
CA cwc ≈ 10 KT
0,5 CWC + 2º
0,5 CWC + 1 º
0,5 CWC
0,5 CWC - 1 º
CA cwc ≈ 20 KT
0,5 CWC + 4 º
0,5 CWC + 2 º
0,5 CWC
0,5 CWC - 2 º
CA cwc ≈ 30 KT
0,5 CWC + 6 º
0,5 CWC + 3 º
0,5 CWC
0,5 CWC - 3 º
13.3. Calculation of Track wind Component (TC) & Ground Speed (GS)
Procedure:
1. Track wind Component (TC) –
Calculate track wind component by heart:
TC = W • cos α (KT)
Insert approximate values for cosines α ( known by heart )
cos 30 º = 0,9
cos 45 º = 0,7
cos 60 º = 0,5
cos 90 º = 0,0
2. Ground Speed ( GS )
GS = TAS ± TC ( KT )
13.4. Corrections for Wind Effect in Holding pattern
TAS – True Air Speed (KT)
TC - Track Component
150 KT
ECOS pilot school-Aircharter
13.4.1. Corrections for Cross wind Component in Holding Pattern
-
Having entered the holding pattern turn the aircraft to fly an outbound track which will most approximately
position the turn onto the inbound track.
Try to asses a drift while flying to join the holding fix and determine or calculate correction angle (CA)
along inbound track.
Apply triple correction angle ( 3x CA ) along outbound leg for 1 minute pattern ( for 1.5 minute pattern
apply 2,5 x CA ).
On the second and subsequent arrivals over the fix make adjustments to the outbound heading, depends on
undershooting or overshooting the inbound track.
13.4.2. Corrections for Track wind Component in Holding Pattern
-
After the first arrival over the holding fix, the outbound time should not exceed 1 minute ( or 1,5 minute
above 14000 ft ), in order to stay in basic holding area in case of incorrect forecasted wind.
after the second and subsequent arrivals over the holding fix compensate for track wind component in the
following manner:
- determine the duration of the inbound leg ( timing )
- correct the outbound time so that
Outbound time + inbound time = 2 minutes
Example:
In the first holding inbound time is 40 sec. → Increase outbound time for 10 sec. so that:
- outbound time in second holding
= 1 min. 10 sec.
- inbound time in second holding
=
50 sec.
- outbound time + inbound time
= 2 min.
- The limiting DME distance always terminates the outbound leg.
- When a limiting radial is also published, and this radial is encountered first, this radial shall be followed until a
turn is initiated, at latest when the DME distance is attained.
13.4.3. Corrections for Wind Effect during holding Entry
-
Sector 1 ( Parallel entry ) – Fly parallel to the inbound track, there is no need to backtrack on it. Apply one
correction in the direction of the wind in order to stay on parallel track.
Sector 2 ( Offset entry )- Apply one correction for the wind effect – turn the aircraft onto a heading to make
a good track making an angle of 30° from the reciprocal of the inbound track on the holding side. Do not
exceed 1 minute (below 14000 ft ) flying the outbound entry heading. If the length of the outbound entry is
specified in terms of distance (DME) instead of time, this limiting DME distance always terminale the
outbound entry leg.
13.5. Corrections for Wind Effect during Initial Approach Maneuvers
13.5.1. Procedure Turn ( 45°/180°)
-
Apply one correction in the direction of the wind when flying one minute outbound from the facility or fix –
backtrack on the outbound QDR or RADIAL.
There is no need to compensate for the effect of the wind during procedure turn ( after 45° turn away from
the outbound track). Fly specified headings.
ECOS pilot school-Aircharter
The 180° should be started within the specified time ( 1 minute for Categories A and B, and 1 minute 15
seconds for Categories C, D and E aircraft ) in order to stay within protected area in case of incorrect
forecasted wind.
Intercept the inbound track. There is enough time to stabilize on the inbound track in case of overshoot due
to strong unfavorable cross wind component.
-
-
13.5.2.Procedure Turn (80°/260°)
Apply 1 correction in the direction of the wind when flying 1 minute outbound from the facility or fix –
backtrack on outbound QDR or RADIAL.
There is not need to compensate for the effect of wind during procedure turn ( after 80° turn from the
outbound track).
Intercept the inbound track. There is enough time to stabilize on the inbound track in case of overshoot due
to strong unfavorable cross wind component.
-
13.5.3. Base Turns
-
Fly specified outbound track (RADIAL or QDR) applying 1 correction for wind effect.
The turn onto the inbound track should be started within the specified time in order to stay within protected
area in case of incorrect forecasted wind.
Intercept the inbound track.
-
13.5.4. Racetrack Procedure
-
Follow the same procedures for correction for wind effect as in holding pattern.
Do not extend time on outbound leg and start inbound turn within the specified time in order to stay within
protected area.
14. NON PRECISION APPROACH
14.1. Safety recommendation for non-precision approach :( ICAO & Flight Safety Foundations, CFIT 1997.)
A step- down non-precision approach, with level-off at MDA in the conventional manner, involves flying a nonstabilized profile with power and attitude changes close to the ground. Such techniques are unsuitable for modern
jet aircraft, add to workload and increase the risk of landing accidents.
Non-precision approaches should be performed in accordance with the following recommendations

Briefing for a non-precision approach should include:
- Review of the procedure and technique to be used
- calculation of VDP if check altitude / distances are not published (see 14.2. below)
- Required or rate of descent
- Minimum crossing altitudes and MDA
- allocation of tasks

Indentify the required flight path slope ; this is normally published as an gradient on the approach chart. If
must be such as to clear all minimum crossing altitudes, and preferably be close to 3°.
Use the auto flight if available to fly a stabilized profile at the required flight path angle ( preferably close
to 3° ).

ECOS pilot school-Aircharter


Continuously monitor position and track by reference to the basic approach navaid(s). The non-flying pilot
should call check altitude / distances if these are published.
If check altitude / distances are not published the briefing for a non-precision approach should include the
calculation of Visual Descent Point (VDP) according 14.2.
When reaching MDA at the Visual Descent Point ( VDP):
-


if approach lights / runway in sight, and correctly positioned, continue
if not in sight, go around ; do not level off.
At some terrain-critical locations where there are more than one limiting obstacle in the approach path, it
may not be possible to use a unique approach gradient in such a case, the procedure should be designed with
2 segments at constant slope, with a suitable defined transition point.
Where it is not possible, due to obstacle considerations, for the final approach segment to be at an angle
close to 3°. from at least 1000 ft above touchdown, a direct approach should not be attempted visual from
that height.
14.2. Visual Descent Point (VDP) Calculation
14.2.1. Definitions
Visual Descent Point is always calculated as an intersection of 3° glide path and MDA/H surface, regardless of
actual non-precision approach glide path.
TVDP (sec) – time from FAF (or last Fix for Timing) to VDP
T1 (sec) – time from VDP to landing threshold
(sec) – total time from FAF (or Last Fix for Timing) to landing threshold
DVDP (Nm) – distance from FAF (or last Fix for Timing) to VDP
D1 (Nm) – distance from VDP to landing threshold
D (Nm) – total distance from FAF (or Last Fix for Timing) to landing threshold
T
ECOS pilot school-Aircharter
14.2.2. Calculation Precedure:
Note: Pilots should know values “z” and “t” by heart for the approach speed of the particular type of aircraft.
Time needed for 100 ft altitude change on 3º glide path in no wind conditions
z ( sec/100ft)
TAS (KT)
z ( sec/100ft)
70
16
80
14
90
13
100
11
110
10
120
10
130
9
140
8
150
8
160
7
Time needed to fly 1 Nm in no wind condition depending on TAS ≈ IAS
t ( sec/ NM)
TAS (KT)
t ( sec/ Nm)
70
51
80
45
90
40
100
36
110
33
120
30
130
28
140
26
For further calculation use Method 1 or Method 2 depend on circumstances as described below:
Method 1
This method is universal regardless of the actual non-precision approach glide path gradient and/or of the position
of MAPt ( and the way of determining of MAPt ).
TVDP = T – T1
D - see approach chart for particular approach
t - see table above
TVDP = D • T
MDH
T1 = --------------- • Z
100
MDH – see approach chart for particular approach
z - see table above
Note: In some cases, when the missed approach point (MAPt) is defined as a specified distance from the FAF ( and
calculated on time / speed bases ), and position on MAPt is exactly over the lading threshold, total time “T” can be
found in a conversion table at the bottom of the Jeppesen approach chart page.
In all other cases, when MAPt is defined by a navigational facility or a fix, and its position is not be exactly over
the landing threshold, total time “T” must be calculated by formula given above.
Always check rate of descent (ROD) of non-precision approach by formula
(AFIX – MDA) • 60
ROD = -----------------------
TVDP
ECOS pilot school-Aircharter
AFIX (ft)
- minimum altitude over the FAF or last fix start timing (see app. chart for particular approach).
MDA (ft) - minimum descent altitude ( see app. chart for the particular approach ).
TVDP (sec) - time from FAF or last fix for start timing calculated from formula above
Method – 2
This method is applicable only when actual glide path of non-precision approach is exactly or very near 3º (with
negligible differences ). It is consequently, applicable for VDP calculation in most LOC ( GS out ) approaches and
other non- precision approaches with the same profile view as the existing ILS (3° GP) approach for that particular
runway.
AFIX – MDA
TVDP = --------------- • z (sec)
100
AFIX (ft) - minimum altitude over last fix start timing (see app. chart for particular approach).
MDA (ft) - minimum descent altitude ( see app. chart for the particular approach ).
Z ( sec / 100ft ) - time for 100 ft altitude change on 3 º GP in no wind conditions
14.2.3. Corrections for Wind Effect in VDP Calculations
RULE OF THUMB
Rule of thumb for wind correction in VDP calculations runs like this Add / substact 5 seconds for each 10 KT
head / tall wind component, for every minute of Tvdp
Recommendation:
Tvdp for each particular non-precision approach should be calculated during preflight preparation and airport
familiarization and noted in approach chart. This will shorten in flight approach briefing, when only corrections for
wind remain to be made.
15. THE 1 – IN - 60 RULE
15.1. Definition
An error of 1º will account for an aircraft being 1 Nm off track after travelling 60 Nm.
1 – in - 60 Rule allows a simple mental calculation of lateral distance if the angular difference is known.
ECOS pilot school-Aircharter
α•D
LD = -------60
LD (Nm)
α (º)
D (Nm)
- lateral distance
- angular difference
- distance to the navigational aid
This rule can be used only for relatively small values of angle “α” ( up to max. 15º ) ( Exact formula is LD = D tga)
1 - in – 60 Rules for Pitch – ROC / ROD Relation
For each 60 KT of TAS - 1° change in pitch causes 100 FPM change in ROC / ROD
For instance:
TAS
Change in ROC / ROD
Caused by 1 º pitch change
80 KT
130 FPM
120 KT
200 FPM
150 KT
250 FPM
180 KT
300 FPM
240 KT
400 FPM
300 KT
500 FPM
ROC – Rate of Climb
ROD – Rate of Descent
Note: This rule of thumb is valid only for relatively small angles of attack and small changes of pitch.
16. VOR (NDB) TIME – DISTANCE CHECK
Time to station:
T (sec)
TMIN = --------------α°
Recommendation: for practical reason take α = 10°
ECOS pilot school-Aircharter
Distance to station:
TMIN • TAS (KT)
D(Nm) = ---------------------60
17. DME ARC FLYING
DME arc may provide track guidance for all or a portion of an initial approach. This minimum arc radius is 7 Nm.
An arc may join a track at or before intermediate fix. The angle of intersection of the arc and the track does not
exceed 120°. When the angle exceeds 70°, a radial that provides at least 2 Nm of lead is identified to assist in
leading the turn onto the intermediate track. The recommended technique to maintain a DME arc is to fly a series of
straight lines from one radial 20º away rather than a curving course. Under no wind condition, fly a heading 100°
away from the radial just crossed. This method tends to keep you on the “inside” of the arc.
ECOS pilot school-Aircharter
When flying the DME arc it is important to keep a continuous mental picture of position. Since the drift correction
angle is constantly changing, wind orientation is important. In some cases wind can be used to return to desired
track. Large radius arcs are easier to fly because of their “flat” curve. High ground speeds require more pilot
attention because of the higher rate of deviation and correction.
Maintaining the arc is simplified by keeping slightly inside the curve. Thus, the arc is always turning toward the
aircraft and distance corrections may be accomplished by holding a straight course…. Being outside the curve, the
arc is turning away and greater correction is required.
Using a RMI simplifies flying a DME arc. Since the RMI (bearing pointer) points toward the VOR / DME, all you
have to do is to keep the needle on the appropriate wingtip reference (90º or 270º) if there is no crosswind.
If a crosswind exists it is easy to counter. If you are drifting toward the station (distance decreasing) turn into the
wind slightly (away from the station) and maintain the bearing pointer behind the appropriate wingtip reference
(100º or 260º). If the drift is away from the station, turn toward the station and maintain the bearing pointer ahead
of the appropriate wingtip reference (80º or 280º)