Definition

This article provides flight crews with general guidance on calculating holding fuel endurance. The limit of that endurance is sometimes called "bingo fuel." That is the fuel level at which an aircraft must depart holding and fly either to the filed destination or to an alternate airport. Nothing herein supersedes Aircraft Flight Manual (AFM) guidance or other official publications for a given operator and/or aircraft.

The description below assumes that the flight crew has a dispatch release with a computer flight plan that includes the expected fuel burn from waypoint to waypoint. Even though some Flight Management Systems (FMS) can calculate holding fuel endurance, it is always a good technique to back up the FMS with manual calculations, in case of data entry error or equipment failure.

The numbers used in the description below are for a generic aircraft. Typical numbers for a specific aircraft on a specific route may be quite different.

Description

To calculate bingo fuel for holding, the pilot must begin by adding four figures:

• Fuel burn from the holding point to the destination
• Fuel to reach the alternate
• Fuel to fly an approach
• Required fuel reserve

(For detailed definitions of alternate fuel and reserve fuel, please see the article Fuel - Flight Planning Definitions.)

Alternate fuel and reserve fuel should be provided by the dispatch release. Fuel to fly the approach should be provided by the dispatch release or published in the AFM or company manuals. To calculate the first item, fuel burn from the holding point to destination, add the expected fuel burn for each waypoint from the holding point to the destination. If the computer flight plan lists the planned fuel on board at each waypoint, take planned fuel at the waypoint where you began holding, and subtract from that figure the planned fuel on board at destination. That will give you the figure for fuel to reach the destination.

If you are holding at a point NOT on your flight plan, you will have to calculate destination fuel by other means. The FMS can normally provide this figure. If not, AFM guidance may include a rough estimate for typical fuel burn. For example, if the AFM says typical burn at a given altitude is 1,000 pounds of fuel for every 100 miles, and the destination is 152 miles away, then fuel to reach the destination is 1520 pounds.

For demonstration purposes, we will use the following example:

• Fuel burn from holding point to destination: 1520 pounds. (Calculated by FMS or crew)
• Alternate fuel: 2200 pounds. (Provided on the release)
• Approach fuel: 400 pounds. (Provided in company publications)
• Required fuel reserve: 2000 pounds (Provided on the release in accordance with regulations)

1520+2200+400+2000=6120 pounds.

When fuel quantity on board reaches 6120 pounds, the aircraft must depart holding and fly either to the destination or to the alternate airport. Air Traffic Control (ATC) will want to know how long the aircraft can hold, and they need this fuel endurance expressed in TIME rather than fuel quantity.

To calculate maximum holding time, check fuel quantity on board and subtract from that figure your number for bingo fuel. For demonstration purposes, we will say the aircraft has 8,342 pounds of fuel on board. 8342-6120=2,222 pounds. Therefore, you can burn 2,222 pounds of fuel before you must leave holding.

To convert this figure to a time, check the aircraft's fuel flow. Make sure to do this after the aircraft is established in the hold at the planned holding speed. For demonstration purposes, we will say this is a two-engine aircraft, and both fuel flow gauges show 1200 pounds per hour. This means both engines taken together are using 2400 pounds per hour. Divide 60 into 2400, and you will see that the aircraft is burning 40 pounds per minute. Divide 2,222 by 40, and you will see that you can hold for 55 minutes.

What If I Don't Have An Alternate?

A flight crew can find itself in holding even when destination weather is good enough not to require an alternate airport. An accident or incident can close a runway at the destination. Unforecasted bad weather may appear, especially in climates where thunderstorms can form quickly during the summer. Any number of problems can create a need for holding.

If you do not have an alternate, you calculate holding endurance in the same way described above, except of course you will not have alternate fuel. You would begin the process by adding the other three figures: fuel to destination, required reserve, and approach fuel.

In this case your time available for holding is likely to be very limited. Be prepared to declare "minimum fuel" as the situation requires.