Parts & Pieces Matter

June 13, 2013 by Bruce Landsberg

aircraft maintenanceIn about 10 to 15 percent of GA accidents something mechanical broke or failed to work as planned. Usually it’s the engine, sometimes the landing gear (retractable), and very seldom the flight controls. But if ever there were a place for Murphy to cause mischief that might be it.

Here’s why: Flight controls almost always work. The systems are relatively simple, well-designed, and robust. They are checked on every annual (supposedly), and I would guess that 99.999 percent of the time everything is good.

But a recent NASA ASRS report indicates that just when you thought it was OK to ignore that most reliable system…

Weather:  clear, wind 030 at 7 kts. Student was landing on Runway 08. Upon touchdown the airplane veered significantly to the left. Student attempted to straighten the ground roll using rudders. Student then stated she could not move the rudder. Instructor immediately initiated a go around. Once airborne and stable, instructor verified rudder pedal was ‘stuck.’ Upon visual inspection, instructor noticed that the bushing holding the left rear rudder pedal had come loose when the cotter pin had come off and bushing had become lodged into the side wall of the airplane. Instructor managed to reposition the bushing and landed without incident. Mechanic replaced the cotter pin and verified aircraft was airworthy.

Although this flight ended without incident, it could have been catastrophic had either a less-experienced PIC and/or a more aggressive maneuver (spin) been in operation. My suggestion is to “wiggle” the rudder pedals prior to spin entry and landings to ensure the rudder pedals are not stuck. A visual inspection would not hurt either.

We don’t know the general condition of the aircraft, so it’s possible that the cotter pin was just the tip of the proverbial iceberg, but it does serve as a reminder that all those seemingly inconsequential pieces can become critical at exactly the wrong time. Has anyone suffered a similar or worse mishap?

Bruce Landsberg
Senior Safety Advisor, Air Safety Institute

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  • David Jack Kenny

    No engine or flight control failures, but a number of electrical problems — including three alternator failures (solved when I ditched the archaic OEM Chrysler alternator for a PMA aftermarket replacement), one voltage regulator, one gear-extension contactor, and a starter motor with an unreliable Bendix drive. That’s in 11 years of ownership and about 1,500 hours of operation.

    — DJK

  • Bill Duff

    King Air C90A sitting on the ramp in the rain. Take-off and quick climb to 20,000 ft. Upon level-off discover that elevator trim is frozen solid. Careful easy nudges back and forth on trim wheel slowly brings trim back to operation. This has happened to me at least 3 times. Each time mechanics check it out and lubricate saying it works just fine.

  • Bruce Landsberg


    That’s a bit unnerving. Does Beech have anything on it? Have you filed an NASA ASRS report to see if this is more widespread?

    Once is anomaly, twice is a concern and the third time, it’s a fact!

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