Fuel Planning
Preflight Fuel Planning
Before departing, it is critical that you ensure the fuel on board is sufficient for your intended flight, including any required reserve or holding fuel. The sections below outline the categories of fuel which may be required. A sample fuel plan is included to highlight the practical use of each fuel category.
Trip Fuel
Trip fuel (also called Flight Fuel) is the amount of fuel you expect to burn to fly your planned route, including an allowance for climb and descent if required. It is generally calculated by dividing your route distance by your expected ground speed (accounting for forecast wind).
Reserve Fuel
Reserve fuel is an allowance which helps cater for anything which may increase the flight fuel (such as unforecast headwinds) and provides a safety margin in case an unexpected event results in a fuel emergency. It is broken up into Final Reserve fuel and Contingency fuel.
In the real world, reserve fuel rules are divided into aircraft category and weight class. The following table simplifies these rules for VATSIM use.
| Aircraft Type | Flight Rules | Final Reserve | Contingency Fuel |
|---|---|---|---|
| Piston engine or small turboprop | Day VFR | 30 min | |
| Piston engine or small turboprop | Night VFR or IFR | 45 min | |
| Jet engine or commuter turboprop | VFR or IFR | 30 min | 5% of flight & alternate fuel |
| Helicopter | VFR | 20 min | |
| Helicopter | IFR | 30 min |
Contingency fuel is designed to be used, to cater for unexpected headwinds, unusual fuel burns, or other small factors which may impact overall fuel usage. Final Reserve fuel is designed as a safety buffer and should not be used. It is a requirement that you land with your Final Reserve fuel intact. See Inflight Fuel Emergencies for what is required when you expect to have to use your Final Reserve fuel.
Taxi Fuel
Taxi fuel is required to cater for the fuel required to taxi to the runway for departure, and to the gate after landing. It may also include a fuel allowance to run the APU. The actual burn rate will depend on the aircraft.
Instrument Approach Fuel
Instrument approaches often involve configuring the aircraft earlier than normal and tracking via points not planned to originally. As such, extra fuel must be carried when an instrument approach is expected.
The exact amount of fuel depends on the aircraft you are flying, but as a general rule of thumb, allowing 10-15 min at the normal burn rate is normally sufficient.
Approach fuel is only required when the weather indicates an instrument approach will be required to land. This is generally indicated by the following meteorological minima:
| Cloud | Visibility |
|---|---|
| Any cloud below LSALT +500ft | Less than 8km |
Weather Holding/Alternate Fuel
Where the weather (or other factors) are expected to be unsuitable, sufficient fuel must be carried to either hold until conditions improve or divert to a suitable alternate aerodrome. See Alternate Requirements for more information.
If the weather is forecast to be below the alternate minima, an alternate must be carried. If the poor weather is associated with an INTER or TEMPO, holding fuel must be carried to wait until conditions improve, in accordance with the table below.
| Term | Description | Holding Fuel Required |
|---|---|---|
| INTER | Intermittent period lasting up to 30 minutes | 30 min |
| TEMPO | Temporary period lasting up to 60 minutes | 60 min |
If a forecast indicates a probability (PROB30 or PROB40) of poor weather below the alternate minima, you must assume that the weather will eventuate, and hold an alternate or carry holding fuel as required.
Example
Alternate minima: cloud base of 1,200ft and visibility of 5km
TAF (snippet): PROB30 INTER 0312/0318 4000 SHOWERS OF MODERATE RAIN BKN010
Fuel Required: 30 min weather holding fuel (if ETA falls between 1130z and 1830z)
Traffic Holding Fuel
Traffic holding fuel is required when operating into certain busy aerodromes. In the real world, traffic levels are consistent and planned, whereas on VATSIM, traffic levels are variable and often unpredictable.
Real world traffic holding requirements are found in an aerodrome's ERSA FAC entry. On VATSIM, it is more important to carry traffic holding fuel during busy events. Regular events, like Milk Run Monday, Panic Stations, and WorldFlight, where high traffic levels are expected, require additional holding fuel to cater for enroute delaying action (such as vectors, holds, and extended periods of time at lower altitudes).
The amount of fuel required is left up to the pilot, but as a general rule, regular events like Milk Run Monday require roughly 20 min of holding fuel, whereas more renowned events like WorldFlight may require up to 90 min. If in doubt, carry a little extra.
Extra Fuel
The pilot in command may dictate any extra fuel they wish to carry and it is their responsibility to ensure that the fuel onboard is sufficient to complete the flight. If you believe that extra fuel is required for any reason, you must carry that fuel.
There are other situations where you may wish to carry extra fuel, including fuel tankering (carrying enough fuel for the return leg) or when flying to an isolated aerodrome with minimal suitable divert points. It is also worth remembering that you will be sharing the airspace with pilots of all competency levels, which may result in unexpected go arounds or approaches, so extra fuel may be required to compensate.
Example Fuel Plan
Below are several sample fuel plans for various aircraft types. These are provided as an example of how to utilise each category of fuel described above. The burn rates and described fuel figures are examples only and should not be used in an operational sense.
Example
Aircraft: Cessna 172
Flight Rules: VFR
Route: YSBK PRT PENH HSY LRF HBB SYHD JIBN SECF APPN CAMB TWRN YSBK
Route Distance: 102 nm
Estimated Enroute Time: 56 min
Planned Burn Rate: 36 L/hr
Destination Weather: Clear skies, calm winds
Additional Notes: Harbour Scenic One planned, extra fuel carried in case of holding
| Category | Amount |
|---|---|
| Trip Fuel | 34 L |
| Alternate Fuel | |
| Weather Holding | |
| Traffic Holding | |
| Instrument Approach | |
| Final Reserve | 18 L |
| Contingency Fuel | |
| Taxi Fuel | 5 L |
| Extra Fuel | 12 L (20 min holding) |
| Total Fuel Required | 69 L |
Example
Aircraft: SAAB 340
Flight Rules: IFR
Route: YGTH BORLI V300 AKMIR W113 TESAT YSSY
Route Distance: 256 nm
Estimated Enroute Time: 57 min
Planned Burn Rate: 500 kg/hr
Holding Burn Rate: 450 kg/hr
Destination Weather: Consistent weather below the alternate minima, Canberra (YSCB) nominated as destination alternate
Additional Notes: Flight conducted during Milk Run Monday event
| Category | Amount |
|---|---|
| Trip Fuel | 475 kg |
| Alternate Fuel | 257 kg |
| Weather Holding | |
| Traffic Holding | 150 kg (20 min) |
| Instrument Approach | 200 kg (2 approaches) |
| Final Reserve | 225 kg |
| Contingency Fuel | 37 kg |
| Taxi Fuel | 25 kg |
| Extra Fuel | |
| Total Fuel Required | 1,369 kg |
Inflight Diversion
Some situations, such as heavy traffic, thunderstorms, or mechanical failure, may result in extended holding at your destination. In these cases, an inflight fuel plan should be done to determine the minimum amount of fuel required to divert to a suitable alternate (either nominated during preflight planning or determined then and there). Once a suitable alternate has been found, determine the flight fuel required to get there, any weather, traffic, or other holding requirements it may have, whether an approach will be required, and any other fuel you may need.
Add your required reserves to determine your calculated minimum fuel, then apply a conservative buffer. By assessing your current fuel state and actual burn rate, you can determine how much time you have remaining in the hold before you must divert. It is important to keep ATC in the loop when approaching your divert time and ensure you start tracking for your alternate without delay. If your fuel state deteriorates further, you may need to advise ATC as per Inflight Fuel Emergencies below.
Example
Aircraft: SAAB 340
Flight Rules: IFR
Alternate Weather: Good, with an INTER below the alternate minima
| Category | Amount |
|---|---|
| Flight Fuel to Alternate | 219 kg |
| Final Reserve | 225 kg |
| Contingency Fuel | 22 kg |
| Weather Holding | 225 kg (30 min) |
| Traffic Holding | |
| Instrument Approach | |
| Extra Fuel | |
| Total Fuel Required | 691 kg |
| Minimum Fuel with Buffer | 750 kg |
Fuel Onboard: 1,050 kg
Current Fuel Burn: 350 kg/hr
The aircraft can remain in the hold for another 51 minutes before a diversion becomes necessary.
Inflight Fuel Emergencies
As explained in Reserve Fuel, you are required to land with your Final Reserve fuel intact (untouched). During the course of normal operations, this should not be a problem. If, through poor planning or unexpected enroute delays, you are expecting to land with less than your Final Reserve fuel onboard, you must notify ATC, as per below.
See Radio Telephony - Emergency for notes on how to communicate these emergencies over the radio.
Minimum Fuel
You must declare MINIMUM FUEL to ATC when you are informed of a delay which will result in you using all of the holding fuel you have onboard. This means that the current delay will not result in you landing with less than your Final Reserve fuel onboard, but any additional delay will.
In response to a declaration of MINIMUM FUEL, you will not receive any priority from ATC, however you will be informed of any expected additional delay.
Mayday Fuel
You must declare MAYDAY FUEL when you determine that you will be landing with less than your Fixed Reserve onboard. The declaration of MAYDAY FUEL constitutes an emergency and you will receive priority from ATC to enable you to land as soon as possible.