When a Piper PA–46-350P Malibu Mirage veered left after touchdown and ran off a runway in Houston, in December 2014, investigators had a pretty good idea from past experience about where to look for any likely mechanical causes of the accident.
Examination of the airplane turned up a fractured engine mount in the area of the nose landing gear actuator. It was a familiar scenario, for which preventive measures had already been taken.
“As a result of similar accidents, the airplane’s manufacturer had issued (about 12 1/2 years before the accident) a mandatory service bulletin (SB) that included a 100-hour recurring inspection to determine if cracks had developed on the engine mount in the area of the actuator feet. The latest version of the SB was issued about six months before the accident,” said the National Transportation Safety Board’s summary of the mishap.
When an accident fits a familiar profile, notwithstanding measures taken to avoid it, investigators also check to see whether an aircraft’s owner or maintenance team has complied with any recommended or mandatory preventive steps. Those steps could be put forth in a manufacturer’s service bulletin, as was the case with the Malibu Mirage, or in an airworthiness directive (AD) issued by the FAA if the agency determined that an unsafe condition exists. Service bulletins are optional for most Part 91 operations, while ADs are always mandatory.
The AD might mandate a variety of remedies—from recurring inspections to repair or replacement of a part. An AD may also require, in lieu of a physical fix, measures to make the aircraft’s pilot more clearly aware of an operating limitation. For example, after reviewing a history of hard-landing accidents related to icing accumulations in some twin-engine Cessna models, in March 2014 the FAA issued an AD requiring that a maintenance-record supplement be added, or a placard be installed to inform the pilot that “the aircraft is prohibited from flight into known icing conditions.” Another placard was to be installed “that increases published airspeed on approach at least 17 mph (15 knots) when there is an inadvertent encounter with icing.” The AD, which was based on a study of 51 accidents, included a requirement that an entry be added to the aircraft’s records to show compliance.
Given the existence of a service bulletin and an accident fitting the known profile, an examination of the Malibu Mirage’s aircraft’s maintenance history followed.
“A review of the airplane’s maintenance records revealed that maintenance personnel had completed the SB inspection during three previous annual inspections; however, there was no record that the SB inspection was conducted during the last annual inspection, which occurred about six months before the accident. The accident is consistent with an uncommanded left turn during landing as a result of a broken engine mount. Based on the evidence and the events, it’s likely that maintenance personnel did not inspect the engine mount during the most recent annual inspection or that they did inspect the area and missed the cracks that had likely developed on the engine mount.”
The NTSB determined the probable cause of the accident as “the nose landing gear collapse as a result of the fracture of the engine mount at the nose gear actuator attachment point in an area that a service bulletin (SB) recommended for inspection. Contributing to the accident was maintenance personnel’s inadequate compliance with the SB.”
OK, but you say that you rent aircraft to fly, and questions about SBs, ADs, AMOCs (alternate methods of compliance), and required documentation of compliance are not your concern?
Presumably you purged that pitfall of misinformation in your ground study, or when you and your designated examiner reviewed your aircraft’s airworthiness before a checkride.
If not—or if it has been a while—a refresher on the regulation covering civil aircraft airworthiness is in order. In two terse passages, it mandates that “no person may operate a civil aircraft unless it is in an airworthy condition,” and that “the pilot in command of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight. The pilot in command shall discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur.”
Ask your FBO’s aircraft maintenance personnel to show you how an aircraft’s airworthiness is documented in maintenance logs. Perhaps you can witness an AD-related repair. You may also view all ADs that are still in effect on the FAA website (http://rgl.faa.gov/).
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