Career Pilot: Control checks

Flight control checks were not on the mind of the crew taxiing a Gulfstream IV to depart the Laurence G. Hanscom Airport in Bedford, Massachussetts, on May 31, 2014. Had control checks been done as prescribed during taxi and lineup checks, they would have realized that the gust lock was still installed. After belatedly aborting the takeoff at a peak groundspeed of 162 knots, the G-IV left the paved overrun at 105 knots. It ran through a ravine where it finally came to rest and became engulfed by fire that killed all seven on board. The investigation turned up a faulty gust lock as well as a pattern of control-check neglect among the pilots.

In April 2017, a Piper PA–12 crashed at the Orlando-Sanford International Airport near Orlando, Florida. The airplane was on its first flight after a two-year restoration project and was piloted by the 25,000-hour airline pilot/owner. Witnesses who watched the takeoff said the airplane became airborne and continued to pitch up until it stalled, rolled off to the right, and crashed nose first into the grass adjacent to the runway.

It didn’t take investigators long to discover the cause. The elevator controls were rigged backwards. Up was down and vice-versa. In other words, a simple preflight check would have saved this pilot and his pristine airplane. The pilot flew an Airbus for an airline and performed control checks before every takeoff at work, per company policy. So why, especially after a major restoration, was no control check conducted prior to takeoff in the Super Cruiser? That answer will never be known, but it can be assumed that after a two-year restoration, the pilot was anxious to finally get the Piper back in the air. Needless to say, after a major renovation is the best time to be most cautious.

Gust lock design can also be a factor. In the case of the G-IV accident, the thrust levers were supposed to be limited to six degrees of lever advancement if the gust lock is engaged. National Transportation Safety Board investigators determined that the accident airplane’s (as well as many others Gulfstreams the NTSB looked at) thrust levers could move as much as four times farther than intended. In the Bedford accident, the crew was able to get significant thrust—yet still short of the thrust required for the specific takeoff. The crew realized what was going on when the pilot flying attempted to rotate the airplane. Had the decision been made to abort the takeoff at that point, the airplane could have stopped on the remaining runway. Aerodynamic forces acting on the elevator at that speed made releasing the gust lock physically impossible. Rejected takeoff efforts didn’t start for another 11 seconds, dooming the G-IV.

Gulfstream has since redesigned the gust lock for all G-IV airplanes, and training providers have stressed the importance of gust lock procedures that were ignored by the crew of the accident airplane. At the lighter end of general aviation, gust locks also have been a factor in several crashes. Besides the obvious lack of a flight control check by the pilot, the gust lock itself sometimes is at fault.

Often, the airplane’s original gust lock is lost or broken and rather than replace it with an expensive new one, the owner (or a mechanic) fabricates his or her own replacement. The designs of these home-brew gust locks may cause their own problems. I’ve seen people who simply stick a bolt in the hole, which invites disaster since there’s no flag or obvious clues that the controls are locked. Sometimes the bolt goes in the underside of the yoke and is impossible to see. Not having a flag alerting a pilot to the locked controls is pretty obvious. But not having a barrier of a component required to start or operate the airplane also is a trap. Omitting these safeguards is an invitation to your own gust-lock disaster.

Perform a flight control check—on every flight. Be sure to move the controls and check that they are moving in the right direction with no binding and no restrictions. If your gust lock is missing a flag, reinstall one now. If your gust lock is broken, buy a quality replacement that has obvious flags and a restrictor. Using these techniques may someday save your life.