40. Aircraft Performance Edit¶
The dialog allows editing of all aircraft performance related parameters on three tabs. The labels for all values required for fuel calculation are highlighted bold.
The dialog is opened when clicking on the edit button in the tab
Fuel Report, when selecting
New Aircraft Performance ... or
Edit Aircraft Performance ... in
the main menu.
40.2. Tab Aircraft¶
Aircraft model: Can be used freely. Determined from aircraft name when Little Navmap collects data for a performance profile.
Aircraft type: The ICAO aircraft type designator. Little Navmap will show a warning in the tab
Fuel Reportif the flown aircraft does not match the type. Detected automatically when collecting performance.
Required runway: Only for information. Shown in the fuel report if bigger than zero.
Required runway type: Only for information. Shown in the fuel report if it differs from default
40.2.1. Aircraft Type¶
Its value can be read with X-Plane Plane Maker program, opening the
related aircraft file
.acf, then main menu ->
ICAO code for ATC. It is stored as e.g.
P acf/_ICAO BE58 in the
126.96.36.199. FSX, FSX-SE and Prepar3D¶
The model can be found with any text editor, opening the related
aircraft.cfg file, key
ATC_model under the section
40.3. Tab Performance¶
All speeds are entered in true airspeed. This makes the values independent of wind influence which would be the case of ground speed. It also makes the values independent of cruise altitude and deviation from ISA atmospheric conditions which would be the case when using the Mach number or indicated airspeed.
Fuel Units: Either
Volume(gallons or liters) or
Weight(lbs or kilograms). The numbers in the dialog will be converted using the weight of the selected
Fuel Typewhen changing the unit. Rounding errors might occur when switching forth and back noticeable a small changes.
Jetfuel. Needed to convert fuel numbers between weight and volume. This is detected automatically when collecting aircraft performance.
See Fuel - Flight Planning Definitions (SKYbrary) for more information on the various fuel types.
40.3.2. Usable Fuel¶
Used to calculate estimated range and to check if block fuel exceeds fuel capacity of aircraft.
Estimated range with reserve shows the maximum distance and
time to fly with reserves.
40.3.3. Reserve Fuel¶
Final reserve fuel is the minimum fuel required to fly for 30 minutes at 1,500 ft above the alternate airport or at the destination airport at holding speed if an alternate is not required. Some authorities require sufficient fuel for 45 minutes holding time.
Alternate fuel is the amount of fuel required to fly the missed approach at the destination airport and to the alternate airport.
Reserve fuel is the sum of alternate fuel and final reserve fuel.
You have to set this value to avoid running out of fuel at the destination when relying on this profile.
40.3.4. Taxi Fuel¶
Taxi fuel is the fuel used prior to takeoff and includes APU
consumption, engine start and taxi fuel.
40.3.5. Extra Fuel¶
Fuel that is added at the discretion of the captain or the dispatcher.
40.3.6. Contingency Fuel¶
Contingency fuel is carried to account for additional en-route fuel consumption caused by wind, routing changes or traffic management restrictions.
The value is given in percent of trip fuel.
ICAO recommends to use 5 percent contingency fuel for all flights.
Values for climb are detected automatically when collecting performance.
Average climb speed: Average true airspeed from takeoff to cruise altitude.
Average vertical climb speed: Vertical speed in climb phase. Either ft per minute (
fpm) or meter per second (
Average fuel flow in climb: Fuel flow in climb phase. Either
Climb speed and vertical climb speed are used to calculate the top of climb which also varies with wind conditions.
Values for the cruise phase are detected automatically when collecting performance.
Cruise speed at typical cruise altitude: True airspeed at cruise.
Fuel flow in cruise: Fuel flow in cruise phase.
Descent values are detected automatically when collecting performance.
Average descent speed: True airspeed in descent phase.
Average vertical descent speed: Average vertical speed.
Average fuel flow for descent: Average fuel flow on descent.
Descent Rule of Thumb shows the calculated rule of thumb for
descent. The default is 3 NM per 1,000 ft.
Descent speed and vertical descent speed are used to calculate the top of descent which also varies with wind conditions.
Average speed for alternate: True airspeed when flying to alternate.
Average fuel flow for alternate: Average fuel flow when flying to alternate.
Little Navmap uses the values from the cruise phase as a default. The flight to the alternate airport usually happens at a lower altitude than cruise altitude and therefore results in a higher fuel flow. Adjust the values accordingly here.