Pilot Counsel

VFR fuel requirements

January 1, 2000

In a recent FAA enforcement action, a pilot’s Airline Transport Pilot (ATP) certificate was suspended for 30 days for violating the regulation on the minimum fuel requirements for the flight of an airplane in VFR conditions. It’s a regulation that we don’t have much occasion to look at in detail.

FAR 91.151(a) says: "No person may begin a flight in an airplane under VFR conditions unless [considering wind and forecast weather conditions] there is enough fuel to fly to the first point of intended landing and, assuming normal cruising speed: (1) During the day, to fly after that for at least 30 minutes; or (2) At night, to fly after that for at least 45 minutes." (A helicopter requires a 20-minute reserve, and there are other requirements for flights in IFR conditions.)

How is this regulation interpreted? How does a potential violation come to the attention of the FAA? What does the FAA do about it?

There is not much question of interpretation about how to account for wind and weather in estimating flight time and fuel requirements. Pilots are trained to do it, and they do it all the time in practice. But one term that does raise an interesting question is what is "normal cruising speed" for computing a fuel reserve? We know that there is a whole range of fuel consumption figures for various cruise configurations of an airplane. Would it be legal to select the most fuel-efficient cruise configuration in figuring the required reserve? After all, you could always go to that configuration in flight if fuel becomes a problem.

There is not much legal authority on this point. The most conservative answer is no, unless you are using that same cruise configuration in planning for the flight itself. It is based on a 20-year-old FAA interpretation dealing with a similar airline requirement. The interpretation is not right on point because of the need to standardize the approach for the airline fleet, but it does give us a pretty good insight into FAA thinking. In that interpretation, the FAA told the airline that it should calculate the required fuel reserve using "the cruising power most often used." This interpretation suggests that the FAA would not consider it "normal" to use a different cruising speed for computing the fuel reserve than that used for the flight itself. Stated in another way, the FAA would consider it "normal," and in compliance with the regulation, to use the same cruise speed (and hence the same cruise configuration) for computing the required fuel reserve as you use for the flight itself.

What about landing with less than 30 (or 45) minutes of fuel in your tanks? Is that an automatic violation of the regulation? This question was answered authoritatively in a National Transportation Safety Board case that we reported in this column two years ago ("Pilot Counsel: Fuel Requirements," January 1998 Pilot). The answer is no. For one thing, the regulation, by its terms, imposes its requirement at the beginning of a flight. While landing with a short supply of fuel could be some evidence that you began the flight with insufficient fuel, it is not conclusive. It could be explained by unexpected conditions that extended the time of the flight or the loss of fuel in flight, which are the reasons why you are required to have a reserve. A good example would be unforecasted headwinds. Of course, if you cut it too close, there could be violations of other regulations, but not FAR 91.151(a).

How does a potential violation come to the attention of the FAA? The FAA does not typically ramp check non-air-carrier aircraft after they land. The usual way in which the FAA finds out about a potential violation is that the agency is called to investigate an off-airport landing and discovers empty fuel tanks. Or, as in this recent case, an FAA inspector just happens to notice something unusual.

According to the FAA inspector, he was on an airport investigating an unrelated matter when he happened to notice a Cessna 180 being towed by an automobile from the runway area of the airport to the apron in front of a skydiving operation. He decided to look into this unusual situation. He approached the pilot of the aircraft, who was part-owner of the skydiving operation, and asked her if she had a problem. She said, "Yes," her airplane’s oil pressure light had come on during flight, so she had shut down the engine and landed. The inspector looked the airplane over and questioned whether the problem could have been fuel exhaustion.

After some discussion, the inspector decided to initiate a formal investigation. The result was an FAA order suspending the operator’s ATP certificate for 90 days, charging that she had begun a flight with insufficient fuel in violation of FAR 91.151 (a)(1). The FAA also charged her with operating an unairworthy aircraft in violation of FAR 91.7(a) (in an effort to blunt her defense that she had subsequently discovered a leak caused by a faulty fuel strainer). And, finally, a charge that the FAA always throws in—being "careless or reckless" in violation of FAR 91.13(a). She appealed the suspension to the NTSB.

On appeal to the Board, the pilot offered evidence that she had begun the flights with sufficient fuel and reserve. She testified about the flight times and altitudes of the parachute hops, the fueling of the aircraft, the fuel consumption of the Cessna 180, and her contemporaneous logging of these details. Her partner, who had personally fueled the aircraft and checked the fuel, corroborated her testimony. She offered evidence of the discovery the next day of a leak from a defective fuel strainer plunger, which was then repaired. All to no avail. The Board determined that there had been a violation of FAR 91.151(a). The Board did dismiss the FAR 91.7(a) charge and did reduce the sanction from a 90-day suspension to 30 days.

This recent case reflects the attitude and action of the FAA and NTSB in fuel mismanagement cases.

The 30-day suspension is fairly common in such cases. The suspension could be longer if there are aggravating circumstances or a past violation history.

John S. Yodice