Torqued: Pilots and Mechanics Must Communicate after Critical Maintenance

 - June 1, 2015, 4:30 AM

If you missed the NTSB’s safety alerts this past month, three were targeted at general aviation pilots and one at GA mechanics. The three aimed at pilots involve flying in mountainous terrain; transition training when flying different aircraft or aircraft with different flying characteristics or avionics; and the importance of performing detailed preflight checks after maintenance, especially maintenance involving flight control and trim systems. The alert targeted to the GA maintenance community stems from recent accidents involving improperly rigged flight controls and trim system. The alerts targeted to the GA pilots and mechanics involving maintenance raise an issue near and dear to my heart: the importance of communication between maintenance and flight operations. Communications between maintenance and flight ops is critical no matter whether the operation involved is an airline operated under Part 121 or Part 135 or a private operation under Part 91. Of course, in general aviation, the pilot is often the only person in the “flight department” so communication directly between the maintenance provider and the pilot is crucial to ensuring safety after maintenance is performed.

In my experience as a mechanic who worked on both airline and general aviation aircraft and as an NTSB member reviewing accidents, communication between those who maintain aircraft and those who fly aircraft is not as good as it could and should be. In these alerts, the NTSB highlights one particular area where the failure to communicate clearly can have tragic results for the GA pilot. 

The alert to mechanics reminds them to verify correct directional travel of controls and trim. This alert is predicated on four general aviation incidents over the last two years that involved similar problems and caused in-flight emergencies. [Problems with improperly rigged flight controls are not limited to GA mechanics. An Air Midwest Beech 1900 flying as a regional carrier for USAirways crashed on takeoff at Charlotte, N.C., in January 2003 because a mechanic had rigged the elevator control incorrectly. This error, combined with the aircraft being outside its c.g. envelope, prevented the pilots from being able to control the pitch of the aircraft. The resulting stall and crash killed all 19 passengers and two crewmembers.]

Communication Is a Two-way Street

According to the NTSB’s current safety alert to GA mechanics, the common threads in the recent accidents were “maintenance personnel who serviced or checked the systems did not recognize that the control or trim surfaces were moving in the wrong direction” and “pilots who flew the airplanes did not notice the control anomalies during their preflight checks.” The NTSB noted that these errors occurred despite the high experience of the mechanics.

The alerts make specific recommendations for mechanics about preparing to perform maintenance and actually performing it. They include becoming familiar with the systems before disassembly. “It is easier to recognize ‘abnormal’ if you are familiar with what ‘normal looks like’; follow up-to-date procedures from the manufacturer and any airworthiness directives; and remember that human factors such as fatigue and stress can affect the performance of your work. Be alert for these factors and guard against the risk that they pose.”

But I was particularly struck by this recommendation: “Ensure that the aircraft owner or pilot is thoroughly briefed about the work that has been performed. This may prompt them to thoroughly check the system during preflight or help them successfully troubleshoot if an in-flight problem occurs.” Too often maintenance is done and logbooks are handed back to customers without this kind of thorough and detailed debriefing. But just as it’s important for mechanics to communicate directly with customers after maintenance, it’s important for pilots to seek out that information. If mechanics aren’t forthcoming with details of what work was done on their aircraft, owners, especially owner-pilots, should be asking. Communication must always be a two-way street.

In conjunction with the release of the general aviation safety alerts, the NTSB released a video to supplement the flight control and rigging safety alerts, Lessons Learned from a Close Call. If a picture is worth a thousand words, this video is worth a thousand safety alerts. Although the two pilots speak calmly and professionally of a flight-test they were asked to perform after maintenance on an aircraft, which included rigging of the flight controls, it’s obvious that having an unresponsive aircraft made for a harrowing flight. The video includes interviews of the two pilots and the mechanic, with 24 years of experience, who did the work. Kudos to the two pilots for calmly handling a difficult in-flight emergency. And kudos, as well, to the mechanic for coming forward and describing the mistake so that others could learn from it. It takes a lot of guts to admit a mistake publicly.

And while I’m on the subject of general aviation communication with pilots, it’s worth mentioning that one of the other safety alerts issued by the NTSB (titled Mastering Mountain Flying) highlights the importance of communication between FBO personnel and GA pilots. The recommendation says “FBO staff should be alert for customers who appear to be planning flight into mountainous terrain who could benefit from mountain flying instruction.” Of course they need to be alert, but then the FBO needs to communicate with the pilot. The FBO should have procedures in place for staff personnel that set out how to handle these situations where a pilot appears to be unfamiliar with the local airport and the local flying conditions. The alert doesn’t explicitly say what the FBO staff should do; it merely notes that a pilot could “benefit from mountain flying instruction.” Without more explicit guidance, the alert doesn’t help get the pilot the instruction he or she might need.