Pilot Counsel

In-flight mechanical problems

June 1, 2005

John S. Yodice's legal offices are located near the FAA and NTSB offices in Washington, D.C.

As you will see, here is a regulation that could bite you. The first sentence of FAR 91.7(b) states the obvious: "The pilot in command [PIC] of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight." But it then goes on to say: "The pilot in command shall discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur." (The emphasis is mine.) The FAA and the NTSB have been very strict in interpreting this regulation. They say that such a condition requires a pilot to land his aircraft at the first available location consistent with the safe operation of the aircraft.

Here is the most recent case confirming that interpretation. It involves an airline flight, and the case is against the captain of that flight. The ruling applies equally to all of us, whether operating privately or commercially.

The captain was commanding a Midwest Express Douglas DC-9 passenger-carrying flight that departed from Kansas City, Missouri, bound for Boston. After the aircraft had reached its cruising altitude of 33,000 feet, when it was over the Carleton VOR (west of Jamestown, New York), it had control problems. The autopilot aileron trim indicator showed full deflection while the aircraft was in level flight. The captain disengaged the autopilot and the airplane rolled to the left. The copilot then applied pressure to the controls, "popping" them free. The aircraft became controllable, but the crew could still feel some tightness and binding.

The crew contacted company dispatch and maintenance personnel located in Milwaukee to discuss the problem. At that point the flight was flying over Lake Erie, about equidistant between Milwaukee and Boston. The discussion was whether the crew should divert to Milwaukee, where Midwest Express' main maintenance facility was located, or continue on to Boston. A decision was made to divert the flight to Milwaukee. In the process of diverting, the crew performed a couple of shallow 5- to 10-degree heading changes that were uneventful. At Milwaukee, the crew requested and received clearance to use a longer runway than that originally assigned, and performed shallow turns and a long final approach so that they might minimize the need for aileron inputs. The flight landed without further incident.

After the flight, it was determined the problem was water runoff from the landing-gear wheel wells that had frozen on the aileron control cable. This was a condition that was known, and subject to a manufacturer's service bulletin and an FAA airworthiness directive. If the drain valves become clogged, water can accumulate in the wheel well, freeze, and restrict controllability of the aileron cables. The valves are required to be checked for clogs, but this recommended maintenance had not yet been accomplished on this aircraft.

In the investigation of the incident, the FAA became concerned that there did not appear to be any discussion among the crew and the company about other possible landing sites that were closer. For example, Detroit was much closer than Milwaukee, and was on the same heading after the flight had turned to divert to Milwaukee. There were a number of other airports with long runways within a 20-minute radius. Weather was not a problem at any of them. The FAA suspected that diverting to Milwaukee was a financial decision. That is, it would be cheaper to repair the airplane there than elsewhere and easier to rebook the passengers.

As a result, the FAA took enforcement action against the captain, suspending his pilot certificate for 90 days. The FAA charged him with violation of FAR 91.7(b), quoted above, and, for good measure, added the charge of "careless or reckless" operation. Essentially, the FAA charged the captain with failing to discontinue the flight when he became aware of an unairworthy condition. The captain appealed the suspension to the NTSB. After a hearing before an NTSB administrative law judge, and a further appeal to the full board, the board sustained the charges and the suspension.

In his appeal the captain argued that the icing problem was a minor one and that he had adequate control of the aircraft. The board disagreed, saying that in light of the persistent "binding" and "tightness" in the aileron controls, the captain "no longer had adequate control over the aircraft and that the cause of the problem was unknown. The airplane, therefore, was not in condition for safe flight. Accordingly, the aircraft had an unairworthy condition and respondent [the captain] was obliged under section 91.7(b) to land as soon as practically possible (in other words, at the first location consistent with the safe operation of that aircraft)."

So the message of this case to pilots is that if we have a mechanical problem that amounts to an unairworthy condition (a big question in and of itself; see the dissent below), we should land at the first practical airport.

NTSB member Richard F. Healing filed a dissenting statement disagreeing with the board's finding of violation of FAR 91.7(b). He said the captain as PIC "determined after checking for controllability that he could safely fly the plane to either Boston or Milwaukee. Subsequent to this determination, his decision to fly to Milwaukee was made, not on the basis of airworthiness, but on the preference of the mechanical department of the airline to have the plane in Milwaukee. The section respondent is being charged with clearly places the burden on the judgment of the pilot flying the aircraft as to its airworthiness, and much more evidence of erroneous judgment would be required to support a violation of 91.7." Healing makes a good point. Safety requires that a pilot in command be given the discretion to make reasonable judgments about mechanical conditions unexpectedly encountered in flight, and not to have to worry about having his judgment second-guessed afterward.

Another aspect of the case bears mention. The captain had timely filed a NASA report under the Aviation Safety Reporting System. He expected that, in any event, the certificate suspension would be waived because he did so. But the board agreed with the FAA that the captain was not entitled to the benefits of the program because his action in diverting to Milwaukee had been a deliberate, purposeful one, not an inadvertent one. The program applies only if "the violation was inadvertent and not deliberate." (See " Pilot Counsel: The Aviation Safety Reporting Program," May 1999 Pilot.)