The loss of a Gulfstream IV several weeks ago with all on board is tragic, and the cause seems obvious and yet a mystery. From what we now know or think we know, it appears that the big jet accelerated down the runway and reached rotation speed when the crew belatedly discovered that the flight controls were locked. There was no escape—no way to fly or to stop. They skidded for over half a mile on the remaining runway, into the overrun, through the localizer antenna, breached the airport fence, and down into a ravine where the G-IV broke up and burned.
The mantra about flight controls being ” Free and correct” MUST be done prior to every takeoff in every aircraft. It’s a killer item. So how could a professional crew with so much experience miss this most basic of before-takeoff checks? A friend brought up a key point point—that most factory checklists are absurdly long and too many pilots ignore them or significant parts of them. They are written to prevent lawsuits, not to help pilots prepare for flight.
With my usual caveat about speculation so early in an investigation, part of the answer may be perfectly obvious—complacency and/or distraction. It is present in almost every accident involving experienced pilots. We become complacent because we’ve seen or done this many times before and it’s always worked. One should never get too comfortable in an aircraft, which is never a totally benign environment.
Distraction means not putting first things first. Humans are no good at multi-tasking—it’s amazing that job-seekers still think this is a good buzzword to put on their resumes. In aviation, as in business, deal with the nearest biggest alligator first. If the first one gets you, everything else is irrelevant! Shorter, more relevant checklists perhaps?
Now to the mystery part. The G-IV designers, anticipating that humans make the most basic of errors, added a thrust lever interlock that would prevent engine thrust from being increased beyond taxi speed if the gust lock was engaged. That should have prevented takeoff power from being applied. Was there a “black swan event” (a one in a gazillion chance) that the interlock failed at the same time the crew failed to check the controls? Or, did the gust lock release mechanism fail to release the controls while releasing the thrust lever interlock?
How would a crew know if the interlock failed in routine operation because they always checked the controls and everything worked normally? Suppose a key human factors device became inoperative? And in the one in a gazillion times that the crew failed to verify flight controls “free and correct,” the safety backup would not be there to save them.
A good way to check flight controls: “Box them.” That means to move the yoke or stick all the way left, then pull it all the way aft, then all the way to the right, then full forward and finally back to neutral. Of course, you could go clockwise instead, if you’re of that political persuasion. Full control movement is needed, and please actually look to see that the controls did as commanded. There have been dyslexic mechanics who reversed rigged the system, and that will really mess your mind on takeoff. Let’s pare checklists down to essential items only and make it easy to check—there’s more to learn after this accident.