RULE OF THUMB
FLIGH PLANNING
TRUE AIR SPEED
ALTITUDE
TAS = IAS + (2%) IAS X
1000
TIME,DISTANCE,FUEL
• D = GS X T
D
• T=
GS
D
• GS =
T
DISTANCE
EXAMPLE
D=?
GS= 90
T = 30 MINUTE
D= 90 X 30
= 2700/60
= 45 NM
TIME
EXAMPLE
D = 30 NM
GS = 100 KNOTS
T=?
T = 30 / 100
= 0,3 X 60
= 18 MINUTE
DISTANCE
EXAMPLE
D = 50 NM
T = 25 MINUTE
GS = ?
GS = 50 / 25
= 2 X 60
= 120 NM PER HOURS
FUEL
GALLON PER HOUR :
GALLONS PER HOUR = GALLON USED / HOURS
FLOWN
DURATION FLIGHT :2 HOURS
GALLON USED
:18 GALLONS
18 / 2 = 9 GALLON PER HOURS
FUEL CONSUMPTION
HORSEPOWER / 2
EXAMPLE :
160/ 2= 80
= 80/10
= 8 gallon per hours
Aircraft endurance
Endurance = usable fuel / fuel burn
usable fuel : 40
fuel burn : 8 gallon per hours
40 / 8 = 5 hours endurance (no reserve)
Time remaining
Time remaining = fuel remaining / fuel burn
fuel remaining : 24 gallon
fuel burn
: 8 gph
24/8 = 3 hours remaining
FUEL REQUIRED
FUEL REQUIRED = TIME ENROUTE X FUEL BURN
TIME ENROUTE = 2 HOURS
FUEL BURN
= 8 GALLONS PER HOURS
8 X 2 = 16 GALLONS REQUIRED PLUS RESERVES