RULES OF THUMB PIH – 5

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1. INTERNATIONAL STANDARD ATMOSPHERE (ISA)

The International Standard Atmosphere is one in which at Mean

Sea Level the temperature is +15° C, the pressure is 1013.24 mb
and the relative density is 100 % (1225 g/m3). The temperature is
assumed to decrease with height at the rate of 1.98° C per 1000
ft (6.5° C per 1000 m) up to 36 090 ft (11 km), remaining constant
at -56.5° C thereafter. Pressure and density are also assumed to
decrease with height, according to a more complicated formula.
Decrease in pressure and density is not linear with height.

An extract, giving some values of the ISA, is tabulated below.

Height Temp. Pressure Speed of Sound

ft °C mb (hPa) KT
0 + 15.0 1013,25 661,03
5 000 + 5,1 843,10 649,59
10 000 - 4,8 696,90 637,93
15 000 - 14,7 572,00 626,09
20 000 - 24,6 466,00 613,95
25 000 - 34,5 376,50 601,64
30 000 - 44,3 301,50 589,06
35 000 - 55,0 239,10 576,20
40 000 - 56,5 188,20 573,20
45 000 - 56,5 148,20 573,20

- For mental calculation up to FL 350:

 FL 
15 +  - x 2  = STD T
 10  FL

N e.g.: FL 350
15 + (-35 x 2) = -70 + 15 = - 55º C

N UPPER WIND CHARTS:

200 mb = 390 FL
250 mb = 340 FL
300 mb = 300 FL
500 mb = 180 FL

ALL Rev.03 20 Jun 00

PIH – 5 RULES OF THUMB
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2. PRESSURE

UNITS OF MEASUREMENT CONVERSION

1 Millibar (mbar) = 1 hectopascal (hPa)

1 (inch Mg) = 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)

- Height difference corresponding to a pressure difference of 1 mbar

and 1 mm Hg (ISA, Sea Level)

1 (mbar) → 27,29 ft = 8,32 m

1 (mmHg) → 36,30 ft = 11,07 m
1 (hPa) → 27,29 ft = 8,32 m
- Height difference corresponding to a pressure difference of 1 mbar
or (1hPa) depending on altitude

Alt. (ft) 0 2 000 5 000 10 000 20 000 30 000

h(ft/mb) 27,29 28,94 31,67 36,94 51,21 72,82

RULE OF THUMB for (mbars) to (inches Hg) conversion

Remember 1016 (mbar) = 30.00 (inch Hg) and

1 (mbar) = 0.03 (inch Hg)

The difference in (mbars) from 1016 (mbars) multiply by 3 and add

to/subtract from 30.00 (inch Hg) (in hundredths).

20 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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3. TEMPERATURE

0° C = 32° F = 273,16 ° K ° C - degrees on Celsius scale

100° C = 212° F = 373,16 ° K ° F - degrees on Fahrenheit scale
° K - degrees on Kelvin scale
CONVERSION FORMULAE

9° C
°F = + 32
5
5
° C = (° F - 32)
9
°K = °C + 273

STANDARD TEMPERATURE VERTICAL GRADIENT

gt = 6,5 ° C/km
gt = 1,98 ° C/1000 ft up to 11 km (36 090 ft)

Fahrenheit ° F Celsius ° C Fahrenheit ° F Celsius ° C

104,0° 40 62,6 17
102,2 39 60,8 16
100,4 38 59,0 15
98,6 37 57,2 14
96,8 36 55,4 13
95,0 35 53,6 12
93,2 34 51,8 11
91,4 33 50,0 10
89,6 32 48,2 9
87,8 31 46,4 8
86,0 30 44,6 7
84,2 29 42,8 6
82,4 28 41,0 5
80,6 27 39,2 4
78,8 26 37,4 3
77,0 25 35,6 2
75,2 24 33,6 1
73,4 23 32,0 0
71,6 22 30,2 -1
69,8 21 28,4 -2
68,0 20 26,6 -3
66,2 19 24,8 -4
64,4 18 23,0 -5

ALL Rev.03 20 Jun 00

PIH – 5 RULES OF THUMB
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3. TEMPERATURE (contd.)

STATIC AIR TEMPERATURE (SAT) - TOTAL RAM AIR

TEMPERATURE (RAT) RELATION

The temperature difference between SAT and RAT can be calculated by

the following formula:

2
∆t = 0,000137 TAS ∆t = SAT - RAT (° C)
TAS = True Air Speed (KT)

TAS ∆t
150 KT 3,1° C
200 KT 5,5° C
250 KT 8,6° C
300 KT 12,3° C
350 KT 16,8° C
400 KT 21,9° C
450 KT 27,7° C

20 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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4. DISTANCE

R 1 NM = 1,8520 km NM - Nautical mile(s)

1 SM = 1,609 km SM - Statute mile(s)

1 NM = 1,15 SM
1 SM = 0,87 NM
1 km = 0,54 NM
1 km = 0,62 SM

RULE 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

Altitude (ft) - Altitude (m) multiply by 3 and add 10 %

Altitude (m) - Altitude (ft) divide by 3 and subtract 10 %

1 yard (yd) = 0,9144 m

1m = 1,0936 yd
1 inch (in) = 0,0254 m = 25,4 mm

ALL Rev.03 20 Jun 00

PIH – 5 RULES OF THUMB
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5. MASS

1 kg = 2,205 lb.
1 lb. = 0,454 kg

RULE OF THUMB

- To convert "kg" into "lb." multiply "kg" by 2 and add 10 %.

- To convert "lb." into "KG", divide "lb." by 2 and subtract 10 %.

6. VOLUME

1 IMP.GALL = 4,546 lit

1 lit = 0,22 IMP.GALL
1 BARREL = 159 lit

1 US.GALL = 3,785 lit

1 lit = 0,26 US.GALL

7. SPEED AND MACH NUMBER

1 KT = 1,852 km/hr KT - knot(s) R

1 mpH = 1,609 km/hr MPH - statute mile(s) per hour
1 KT = 1,15 MPH km/hr - kilometers per hour
1 MPH = 0,87 KT
1 km/hr = 0,54 KT
1 km/hr = 0,62 MPH
1 ft/min = 0,00508 m/sec
1 m/sec = 196,85 ft/min

Approximately for mental calculation

1 m/sec = 200 ft/min

1 KT = 0,514 m/sec
1 m/sec = 1,946 KT

Approximately for mental calculation

1 m/sec = 2 KT

1 km/hr = 0,278 m/sec

1 m/sec = 3,6 km/hr

26 Jun 00 Rev.04 ALL

 RULES OF THUMB PIH – 5
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7. SPEED AND MACH NUMBER (contd.)

TRUE AIR SPEED (TAS) (Approximate formula)

F L x IAS
TAS = IAS +
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)

EG: TAS = 290 + (5 x 31) ≅ 445 IAS = 290

ALT = 31000 ft

SPEED OF SOUND

C = 20,1 T (m/s)
C = 72,36 T (km/h) T = OAT + 273
C = 39 T ( KT) T = Kelvin absolute temperature (° K)
OAT = Outside Air Temperature (° C)

AIRCRAFT MACH NUMBER (Approximately)

TAS
M=
R 39 x OAT + 273

ALL Rev.4 26 Jun 00

PIH – 5 RULES OF THUMB
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SPEED FACTORS

Speed factor is the distance covered in one minute.

TAS (KT) ASF

60 1
120 2
180 3
240 4
300 5
360 6
420 7
480 8

GSF GROUND SPEED FACTOR (TAS corrected for wind component)

FL 150 or above: Use Mach indicator for direct reading of ASF.

Mach 1.0 ASF 10

Mach 0.7 ASF 7

GROUND SPEED GS

GSF x 60 = GS

To minimize the reading error on the DME, take 3 min. timing.

Example: (DME 100 to 80 after 3 min.)

20 x 20 = 400 KT Multiply the difference by 20 = GS

The DME station should be at least as far away as your FL divided by 10.

0 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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8. SLOPE

There are three usual ways of expressing and

calculating the slope GRADIENT (%) - gradient
shown by percent - a slope expressed as
vertical distance H percentage of horizontal
distance. Units of measurement must be the
same for H and D. H
GR AD % = ×100
D
GRADIENT (ft/NM) - gradient shown in feet
per nautical mile - a slope expressed as H(ft)
a ratio of the vertical distance (ft) to
D (NM)
the horizontal distance (NM).
H
GR AD (ft / NM ) =
SLOPE (°) - shown by angle in relation to D
horizontal surface in degrees.

CONVERSION FORMULAE

GRAD (ft/NM) = 60,8 (%)

GR AD (ft / NM )
GRAD (%) = 0,0164 GRAD (ft/NM) =
6080

GRAD (%) = tg α ° 100

GR AD ( ft / NM )
α (°) = arc tg x
100

GRAD (ft/NM) = tg α ° 6080

GR AD (ft / NM )
α (°) = arc tg x
6080
REMEMBER:
3° = 5,2 % = 319 ft/NM

TRY TO REMEMBER
3,5° = 6,1 % = 372 ft/NM
2,5° = 4,4 % = 265 ft/NM

ALL Rev.4 26 Jun 00

PIH – 5 RULES OF THUMB
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8. SLOPE (contd.)

RATE OF DESCENT (ROD) CALCULATION

ROD depends on slope and aircraft's ground speed (GS).

ROD = 101,33 . GS . tg α
GS
ROD = . GRAD (ft/NM)
60
ROD = 1,0133 . GS . GRAD (%)

The rate of climb (ROC) can be calculated in the same manner.

RULES OF THUMB

1. Whenever descent gradient in percent is available (Jeppesen

approach chart - non-precision approach) ROD may be simply
mentally calculated by multiplying the percent value by the ground
speed.

ROD ≅ GRAD (%) GS (KT)

2. The standard rate of descent (ROD) is always known for 3° GP, no

wind conditions and particular type of aircraft and its approach
speed. For each 10 KT head/tail wind component decrease/increase
ROD by 50 FPM.

3. For descent planning purposes, desired altitude (3° GP) in relation to

the distance to the landing runway may be mentally calculated.

AFL = 3 x D AFL - altitude expressed in flight levels

Aft = 300 x D Aft - altitude expressed in feet
D - distance to the landing runway in (NM)

A FL
D = or AFL x 3 = D
3

A ft A ft
D = x 3= D
300 1000

0 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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4. SINK RATE

This rule is valid for 3° glide path only:

GS 320
X 10 Example: GS = 320 x 10 = 1600 (ft / min)
2 2

If the GP is steeper another rule can be applied:

GP° x GSF x 100 = SINK RATE

Example: GP = 4° 4 x 3 x 100 = 1200 (ft/min)

GS = 180

ALL Rev.3 20 Jun 00

PIH – 5 RULES OF THUMB
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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

TDZE 2 (ft) - runways slope
TDZE 1 (ft) - touch-down zone elevation at the beginning of runway
RL (ft) - runway length

For TDZE 2, TDZE 1, RL see Jeppesen RM, Airport plan view, for each
particular airport and runway.

9. TURNS

STANDARD TURN - rate of turn R = 3 (degrees/second)

RADIUS OF STANDARD TURN

r = 19 seconds

TAS ( KT )
r= (NM) R
189,4

for mental calculation in practical use

TAS ( KT )
r= (NM)
200

0 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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9. TURNS (contd.)

BANK ANGLE OF STANDARD TURN (Contd.)

TAS (KT) TAS (KT)

tgα = α = arc tg
343 343

for mental calculation in practical use

TAS (KT)
α= + 7
10

All IFR manoeuvres (holding, race track, procedure turn, base

turn) are calculated with turns at a bank angle of 25° or at a rate
of 3 degrees/second (standard turn), 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.

ALL Rev.3 20 Jun 00

PIH – 5 RULES OF THUMB
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10. CORRECTIONS FOR WIND EFFECT

W - wind vector, i.e. wind speed (KT) and direction

CWC - cross-wind component (KT)
TC - track component (KT)
CA - correction angle ( ° )
α - wind/track angle ( ° )

CORRECTION ANGLE AND GROUND SPEED

(approximate calculation)

1. Wind/track angle (α). Find out by heart wind/track angle from

known track and wind direction. Visualise the situation and
find out if the wind is head-wind or tail-wind, from the right or
from the left. Wind/track angle should be less than 90°.

2. Cross-wind component (CWC). Calculate cross-wind

component.

CWC = W . sin α (KT)

inserting approximate values for sin α (known by heart)

sin 30° = 0,5
sin 45° = 0,7
sin 60° = 0,9
sin 90° = 1,0

3. Track-wind component (TC). Calculate track-wind component

by heart

TC = W . cos. α (KT)

inserting approximate values for cos. α (known by heart)

cos. 30° = 0,9

cos. 45° = 0,7
cos. 60° = 0,5
cos. 90° = 0,0

0 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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4. Correction angle (CA)

60 x CWC CWC - cross-wind component (KT)

CA = (°) TAS - true air speed (KT)
TAS

CW C
= CA
AS F

Example: CWC = 20 KT
TAS = 180 KT 20
≅ 7° CA
ASF = 3 3

This rule is also valid while flying by Mach number:

Example: Mach = 0,8 120

ASF = 8 ≅ 15° CA
8
CWC = 120 KT

5. Ground speed (GS)

GS = TAS ± TC (KT) TAS - true air speed (KT)

TC - track component (KT)

RULES 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.

CA
80 KT 100 KT 120 KT 150 KT
TAS
CACWC ≅ 10KT 1/2 cwc + 2° 1/2 cwc + 1° 1/2 cwc 1/2 cwc - 1°

CACWC ≅ 20 KT 1/2 cwc + 4° 1/2 cwc + 2° 1/2 cwc 1/2 cwc- 2°

CACWC ≅ 30KT 1/2 cwc + 6° 1/2 cwc +3° 1/2 cwc 1/2 cwc - 3°

ALL Rev.3 20 Jun 00

PIH – 5 RULES OF THUMB
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CORRECTIONS FOR WIND EFFECT IN HOLDING

1. CORRECTIONS FOR CROSS-WIND COMPONENT

- Having entered the holding pattern, turn the aircraft to fly an

outbound track which will most approximately position the
aircraft for 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 (3 x 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. They depend on
undershooting or overshooting the inbound track.

2. CORRECTIONS FOR TRACK COMPONENT

- 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 incorrectly
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 the 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.

0 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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10. CORRECTIONS FOR WIND EFFECT (contd.)

2. CORRECTIONS FOR TRACK COMPONENT (contd.)

- Where 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 limiting DME distance has been
attained.

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 (1) correction in the direction of the wind in order to stay
on parallel track.
- Sector 2 (offset entry) - Apply (1) correction for wind effect
- Turn the aircraft onto a heading to make good a track making
an angle of 30 ° from the reciprocal of the inbound track on the
holding side.
- Do not exceed one minute (below 14 000 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 terminates the outbound entry leg.

ALL Rev.3 20 Jun 00

PIH – 5 RULES OF THUMB
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CORRECTIONS FOR WIND EFFECT DURING INITIAL APPROACH

MANOEUVRES (Procedure turns, base turns, racetracks)

PROCEDURE TURN (45° / 180°)

- Apply (1) correction in the distance of the wind when flying 1

minute outbound from the facility or fix - backtrack on
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.

- The 180° turn 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 incorrectly forecasted wind.

- Intercept the inbound track. There is enough time to stabilise

on the inbound track in case of overshoot due to strong
unfavourable cross-wind component.

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 no need to compensate for the effect of wind during

procedure turn (after 80° turn away from the outbound track).

- Intercept the inbound track. There is enough time to stabilise

on the inbound track in case of overshoot due to strong
unfavourable cross-wind component.

BASE TURNS

- Fly specified outboundtrack (RADIAL or QDR) applying (1)

corrections 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
incorrectly forecasted wind.
- Intercept the inbound track.

0 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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RACETRACK PROCEDURE

- Follow the same principles for corrections 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.

11. NON - PRECISION APPROACH

VISUAL DESCENT POINT (VDP) CALCULATION

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 start timing) to VDP
Tl (sec) - time from VDP to landing threshold
T (sec) - total time from FAF (or last fix for start timing) to
landing threshold
Dvdp (NM) - distance from FAF (or last fix for start timing) to
VDP
Dl (NM) - distance from VDP to landing threshold
D (NM) - total distance from FAF (or last fix for start timing)
to landing threshold
R z (sec/100ft) - time for "100 ft" altitude change on 3° glide path in
no wind conditions (z = 8 sec/100 ft at TAS 140 kt)

ALL Rev.3 20 Jun 00

PIH – 5 RULES OF THUMB
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1. NON-PRECISION APPROACH (contd.)

R
TAS (KT) 70 80 90 100 110 120 130 140 150 160

Z sec/100ft 16 14 13 11 10 10 9 8 8 7

t (sec/NM) - time to fly "1 NM" in no wind conditions

TAS (KT) 70 80 90 100 110 120 130 140 150 160 R

T (sec/NM) 51 45 40 36 3 30 28 26 24 22

Note: "z" and "t" values must be known by heart for particular
type of aircraft.

METHOD - 1

This method is universal regardless of actual non-precision

approach glide path and/or of the position of MAPt (and the way
of determining of MAPt).

Tvdp = T - T1 D - see approach chart for particular app

T = D. t t - see table above

MDH MDH - see approach chart for particular app

Tl = x Z
100 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 landing 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 exactly over the
landing threshold, total time "T" must be calculated by the
formula given above.

0 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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METHOD -I (contd.)

Rate of descent (ROD) of non-precision approach generally should be

calculated or checked by the following formula:

(Afix − MDA) x 60
R ROD = (ft/min)
Tvdp (sec)

Afix (ft) - minimum altitude over the FAF or last fix for start
timing (see app. chart for particular approach).
MDA (ft) - minimum descent altitude (see app. chart for the
particular app.
Tvdp (sec) - time from FAF or last fix for start timing calculated
from formula above.

METHOD II

This method is applicable only when actual glide path of non-precision

approach is exactly or very near 3° (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
R Tvdp = x Z (sec)
100

Afix (ft)- minimum altitude over last fix for start timing
- (see app. chart for particular approach).
MDA (ft) - minimum descent altitude (see app. chart for
particular app.)
R Z (sec) - time for 100 ft altitude change on 3 GP (sec/100 ft) in
no wind conditions (z = 8 sec/100 ft at TAS 140 kt)
N Tvdp (sec) - time from FAF or last fix for start timing calculated
from formula above

ALL Rev.3 20 Jun 00

PIH – 5 RULES OF THUMB
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CORRECTIONS FOR WIND EFFECT IN VDP CALCULATIONS

For aircraft with TAS 140 KT RULE OF THUMB for wind R

correction in VDP calculations runs like this

add/subtract 5 seconds for each 10 KT head/tail

wind component, for every minute of Tvdp

Recommendation:
Tvdp for each particular non-precision approach should be
calculated during pre-flight preparation and airport familiarisation
and noted in approach chart. This will shorten inflight approach
briefing, when only corrections for wind remain to be made.

12. THE 1 - IN - 60 RULE

An error of 1° will account for an aircraft being 1 NM off track

after travelling 60 NM.

1 - in - 60 Rule allows a simple memorental calculation of

lateral distance if the angular difference is known.

LD (NM) - lateral distance

α × D α ( ° ) - angular difference
LD =
60 D (NM) - distance to the navigational facility

This rule can be used only for relatively small values of angle (up
to max. 15°) (Exact formula LD = D . tg α )

0 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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1 - IN-60 RULE 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 ROC - Rate of Climb
caused by 1° pitch ROD - Rate of Descent
150 KT 250 FPM
180 KT 300 FPM
240 KT 400 FPM
300 KT 500 FPM

NOTE: This rule of thumb is valid only for relatively small angles of
attack and small changes of pitch.

13. VOR ( NDB ) TIME -DISTANCE CHECK

Recommendation: for practical reasons take α = 10°

Time to station: Distance to station:

t (sec) T (min) × GS (KT)

T (min) = °
D (NM) =
α 60

When you are fairly close to the NAV AID use another rule based
on 45° - 50° triangle:
You are going to pass abeam VOR, when the VOR needle points
to 45° out, start timing. When the needle points to 90° stop the
timing.
Check your GS and multiply your GSF with time to get the
distance flown.
The obtained distance is equal to the distance abeam the VOR.

ALL Rev.3 20 Jun 00

PIH – 5 RULES OF THUMB
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14. FUEL QUANTITY CHECK

Units of measurement conversion

1 lb. = 0,454 kg
1 kg = 2,205 lb.
1 IMP.GALL = 4,546 lit
1 US GALL = 3,785 lit
1 BARREL = 159 lit N

Assumed density of fuel

0,8 kilograms per litre (kg/lit)

1,76 pounds per litre (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

RULE OF THUMB

- to convert "kg" into "lb.", multiply "kg" by 2 and add 10%

- to convert "lb." into "kg", divide "lb." by 2 and subtract 10%

PROCEDURE

- convert the amount of fuel on Fuelling Receipt into units of

measurements used on the gauges of the respective type of
aircraft (assumed density stated above)

- add this converted amount of fuel to FUEL LEFT (see Board

Book, noted fuel quantity in PARKING CHECK) and be sure
that this total amount corresponds to the fuel quantity on the
cockpit fuel gauges and indicated in the flight plan.

0 Jun 00 Rev.03 ALL

 RULES OF THUMB PIH – 5
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15. DME ARC FLYING

DME arc may provide track guidance for all or a portion of an

initial approach. The minimum arc radius is 7 NM. An arc may join
a track at or before intermediate fix. When joining a track at or
before the intermediate fix, the angle of intersection of the arc and
the track does not exceed 120°. When the angle exceeds 70°, a
radial which 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 20° 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.

When intercepting DME arc take a "lead distance".

TAS
L= (NM)
200
(for angle of interception of 90 degrees)

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's attention because of the higher rate of
deviation and correction.

ALL Rev.3 20 Jun 00

PIH – 5 RULES OF THUMB
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15. DME ARC FLYING (contd)

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 a
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 keep
the needle on the appropriate wingtip reference (90° or 270°) if
there is no cross-word.

If the cross-word 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 (100° or 260°). If the drift is
away from the station, turn toward the station and maintain the
bearing pointer ahead of the appropriate wingtip reference (80° or
280°).

0 Jun 00 Rev.03 ALL