It is a truth universally acknowledged that when an airplane stalls, the pilot must push its nose down. And yet it sometimes happens that even quite experienced pilots do the opposite. That was the case in February 2024, when two airline transport pilots, who had a combined total of more than 23,000 hours in their logbooks, conducted a post-maintenance stall check on a Hawker Beechcraft 900XP.
The stall check is required after the leading edges of the wings have been removed for a routine, every-four-years inspection. The purpose is to confirm that some subtle, perhaps invisible distortion of leading-edge contour or change in the position of a stall strip has not changed the stalling behavior of the airplane.
The maintenance had been performed at Grand Junction, Colorado. After it was completed, the airplane was needed at Gig Harbor, Washington, and the crew decided to perform the stall check during the positioning flight.
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The pilot’s operating handbook (POH) for the Hawker devotes a 16-page section to the stall check procedure. It specifies, among other things, that the test must be conducted at or below FL 180, at least 10,000 feet above the ground or clouds, and with a “good visual horizon.” Importantly, the airplane must be free of ice.
It would have been difficult to comply with those requirements on the day of the flight. There were broken to overcast layers above 8,200 feet msl with tops around 15,000 and a potential for light to moderate icing in the clouds. Possibly feeling that the stall test was a mere formality, the crew took off and climbed to FL 200, where they initiated the stall test. Even though the airplane was 2,000 feet above the mandated maximum altitude, it was not 10,000 feet above the cloud tops, and had been exposed to icing conditions during the climb.
The test consisted, essentially, in slowing the airplane, noting stick shaker and pusher activation speeds, and verifying that there was no abnormal rolling behavior or “aileron snatch,” the latter being uncommanded movement of the ailerons caused by roughness on the wing ahead of them.
The test did not go as expected. At an indicated airspeed of 114 knots, 5 knots below shaker activation, the airplane suddenly rolled to the right. The PIC applied full opposite ailerons and full aft control column. The nose dropped, and the roll continued through inverted. Presumably, the airplane was soon in IMC. It settled into a slow, flat spin, 15 seconds per rotation. The PIC continued to hold full aft stick and full left aileron, although the second pilot repeatedly urged him to get the nose down. The Hawker fell for a little more than a minute before it hit the ground.
The National Transportation Safety Board (NTSB) attributed the accident to two principal causes. One was the crew’s decision to conduct the test in an area of probable icing conditions. (The NTSB demoted the flight crew’s disregard of all altitude and visibility parameters in the POH to the status of a mere “contributing factor.”) The other principal cause was the manufacturer’s failure to establish training and experience requirements for pilots performing the stall tests. The NTSB claimed, somewhat oddly, that this omission led to the pilot’s inappropriate “attempted remedial action,” i.e., applying full up elevator—as if special training and experience were required to know that was the wrong thing to do.
The evidence that the upset was triggered by ice contamination was circumstantial but persuasive. The airplane’s right wing stalled prematurely, just as it would be expected to do if its surface were roughened by rime ice.
A post-maintenance stall check of a business jet is unusual. Only the Hawker series and Learjets, both with type certificates dating back to the 1960s, require it. It is burdensome for owners and operators, and manufacturers probably want to keep the burden as light as possible. Thus, the Hawker test protocol merely requires that the pilot performing it be “familiar with the stall identification system and stall characteristics” and have prior experience stalling the Hawker—whether in a simulator or in real life is not clear. It adds that the pilots, who need not be trained test pilots, “must be prepared for unacceptable stall behavior at any point leading up to and throughout the maneuver.”
The protocol mainly defines “unacceptable behavior” as abnormal roll or aileron feel. But what prepares an ordinary line pilot, who has performed approaches to stalls under controlled conditions in a simulator or well-trimmed airplane, for a roll through inverted and a flat spin? Obviously, unacceptable behavior is thought to be possible, even if unlikely. Otherwise no test would be necessary. The requirement that the test be conducted with 10,000 feet of clear air below and with a good visual horizon hints that authors of the POH contemplated the possibility of an upset.
Often, when an accident is of an unusual type but not a one-off, the NTSB will cite previous occurrences of a similar kind. In this case it cited only one, because both icing and flying above a cloud layer were involved. That incident, in 2006, was not fatal. Upon emerging from clouds, the pilot performed a pullout that overstressed the airplane but saved his life. A stall training accident in 2003 with three fatalities went unmentioned. There was another crash during an attempted stall test in 2025, with three fatalities, which the NTSB may have omitted because its final report on that accident had not yet been completed.
In the accident under discussion here, the crewmembers put themselves in harm’s way by performing the stall test at an altitude and in weather conditions that were outside the factory-specified parameters. They probably felt they were taking minor liberties and failed to consider that what did happen could happen.
They also probably failed to consider—and most pilots fail to consider—the impact of an unexpected stall upon a pilot’s mental state.
In principle, the airplane would have gradually slowed, the stick shaker would have been activated, and a few knots later the stick pusher. The PIC would then have lowered the nose, added power, and gotten on with the flight. The rapid right roll and the disconcerting sensation of the airplane falling out from under him so affected the pilot that he did what no pilot thinks he would ever do: He pulled the control column back and held it back throughout the descent.
We know from multiple examples—the Colgan Air and Air France accidents in 2009 are two famous cases—that an unexpected stall sometimes triggers in pilots an instinctive, startle-driven, back-stick reaction that swamps all knowledge and training. We know this happens to other people, but we cannot imagine it happening to us.
Neither could they.
This column first appeared in the June Ultimate Issue 971 of the FLYING print edition.
