Pilot Rules Of Thumb


Altimeter correction for non-standard pressure

'From high to low, look below'

1 mb = 30 feet

FL 270 QNH 977

ISA - 36 mb 􀃆 36 x 30 = 1080 feet

Altitude = 25920 feet

 

Altimeter correction for non-standard temperature

'From high to low, look below'

Corr (feet) = 4 x Δ ISA x altitude (feet)

                                              1000

FL 300 ISA - 6°C

Corr = 4 x 6 x 30 = 680 feet

Alt = 29320 feet

 

SAT out of TAT

SAT (°C) = TAT (°C) - 3 x Mach

TAT = -17 °C Mach 0.64

SAT = -17 – 3 x 6 = -17 - 18 = -35 °C

 

SAT out of TAT for higher Mach and lower Temp

SAT (°C) = TAT (°C) - (100 x Mach) - 50

TAT = -31 °C Mach 0.74

You have 24 above M 0.50

SAT = -31 -24 = -55 °C

 

Level Off procedure if R/C ≤ 1000 feet/min (also for descent R/D)

Δ feet = R/C (feet/min)

10

Climbing to FL 210 R/C = 2000 feet/min

Δ feet = 200 feet ô€ƒ† start level off at 20800 feet

 

Level Off procedure if R/C > 1000 feet/min (also for descent R/D)

Δ feet = 2 x R/C (feet/min)

                          10

Climbing to FL 300 R/C = 2500 feet/min

Δ feet = 500 feet ô€ƒ† start level off at 29500 feet

 

Cruise Flight Level computation

CruiseFL= Trip Distance (NM)

EBBR-EBOS = 60 NM

Optimum is FL 60

 

Vertical Speed to rejoin assigned altitude

V/S (feet/min) = 2 x Δ feet

If on 6250 feet instead of 6000 feet, correct with V/S = 500 feet/min

 

To obtain TAS out of Mach-number (high altitudes - cruise)

TAS (kt) = 6 x Mach

M 0.72

TAS = 420 kt

 

To find TAS out of IAS and FL

TAS (kt) = IAS (kt) + FL

                                   2

FL 300 IAS = 240 kt

TAS = 240 + 150 = 390 kt

 

Ground Speed out of Mach

GS (NM/min) = 10 x Mach

M 0.72

GS = 7,2 NM/

 

 

Drift computation in cruise

Drift (°) = X-wind (kt)

                   Mach

M 0.7 X-wind 35 kt

Drift = 35 / 7 = 5°

 

Drift computation out of TAS (not IAS, unless during approach)

Drift (°) = X-wind (kt) .

             speed number

TAS 180 kt X-wind 36 kt

Drift = 36 / 3 = 12°

 

To find Ground Speed with DME station available

GS (kt) = 100 x distance (NM) in 36s

Read distance covered in 36 seconds towards or away from station

 

Off-Track distance

Off-Track Distance = Δ° x distance to station

                                                   60

9° off track 11 NM from station

Off-Track Distance = 9 x 11 / 60 = 99 / 60 = 1.6 NM

16) Slant distance overhead a DME – station

each 6000 feet altitude 􀃆 1 NM DME

Overhead station FL 330

you will read 33000 / 6000 = 5.5 NM on DME

 

 Intercepting outbound leg when close to the VOR-DME station (valid for Mach 0.7)

1 NM for each Δ30°

FL 330 Inbound on R-180 (Hdg N) to track 060 outbound

Start your turn to 060 at 2 NM before (+ slant 5.5NM)

 

Intercept Heading when passing over station before turning to outbound Heading

Attack (°) = 1/3 x ΔTrack (°)

Inbound on 180 (Hdg N) to track 060 outbound

Take Heading 080 overhead Station to intercept Radial

 

Intercept Heading when a little bit off-track

Attack (°) = 3 x Off-Track angle (°)

On R-310 outbound instead of R-315

Take attack 15° to rejoin

 

Top of Descent (Idle thrust - 3° descent path)

TOD (NM) = Δ FL

                       3

FL 280 down to 2000 feet

TOD = 260 / 3 = 87 NM

 

R/D required to be down at certain point

R/D (feet/min) = speed number x altitude (feet)

                                      distance (NM)

Descent 17000 feet in the next 28 NM TAS 240 kt

R/D = 4 x 17000 / 28 = 2400 feet/min

 

Vertical speed by changing Body Attitude (valid for high speeds)

R/D (feet/min) = Mach x ΔBA (°)

Mach 0.74 􀃆 One degree BA results in 740 feet/min

 

Vertical speed by changing Body Attitude (valid for lower speeds)

Use TAS or IAS in approach

R/D (feet/min) = speed number x ΔBA (°)

Speed TAS 420 kt BA 3 degrees down

R/D = 7 x 3 = 2100 feet/min

 

 

Distance required if you want to maintain a certain R/D profile

Distance (NM) = speed number x altitude (feet)

                                                 R/D

Descent 23000 feet at 1000 feet/min TAS 300 kt

Distance = 5 x 23 = 115 NM

 

Wind correction for descent distance

Wind Corr (NM) = 10% for each 40 kt component

Example Thumbrule 20) with 20 kts Tailwind

Add 58 to 87 = 92 NM

 

R/D required to follow a certain glide %

R/D (feet/min) = Ground Speed (kt) x %

TAS 350 kts 20 kts tailwind Glide 3° = 5%

R/D = 370 x 5 = 1850 feet/min

 

Conversion % versus degrees for glide path

% = 10 x degrees

                6

ILS 3° Glide Slope ô€ƒ† 30 / 6 = 5%

 

Start the roll-out from a turn when

ΔHeading (°) to go = Bank (°)

                                       3

Bank 25° Right turn to Hdg 080

Start roll-out 8° in advance, thus on Hdg 072

 

Amount of Bank required for a turn

Bank (°) = Δ Heading (°)

Heading North Right to Heading 007

Take 7° Bank

 

Bank required for a rate one turn

Bank (°) = 15% TAS (kt)

TAS 180 kt Rate one turn

Bank = 18 + 9 = 27°

 

Turn diameter of a rate one turn

Diameter (NM) = TAS (kt)

                               100

TAS 150 kt

Turn Ф = 1,5 NM

 

Outbound timing for a base turn, when not mentioned on the chart

Time (min) = 36 .

                   ΔTrack

ILS Rwy 27 (QFU 270) Teardrop 066 outbound

Time = 36 / (090-066) = 1,5 min

 

R/D to follow the glide slope ILS 3° = 5%

R/D (feet/min) = 5 x Ground Speed (kt)

On Glide Slope TAS 140 kt 10 kt Tailwind

R/D = 750 feet/min

 

Visibility required to see threshold at VDP (Non-Precision Approach)

Vis(m) = 6 x MDA (feet)

MDA 430 feet

Visibility = 6 x 430 feet = 2500 m