Fatal accidents involving Hawker 800 and 900XP jets have prompted the National Transportation Safety Board (NTSB) to issue emergency recommendations for post-maintenance stall tests.
According to the 20-page report, the agency found deficiencies in the information provided to aircraft owners, operators, and pilots relating to training and procedures required to safely conduct post-maintenance stall test flights of Hawker aircraft, including the 700, 800, 800XP, 850XP, and 900XP.
“We identified the need for action during our investigations of two fatal accidents (2024 in Utah, and 2025 in Michigan) that occurred during manufacturer-required post-maintenance stall test flights conducted in Hawker 800XP and 900XP airplanes after routine, four-year inspections were performed,” the NTSB report reads, noting that the 2025 accident is still under investigation. “[However,] both accident flights were flown by the respective operator’s flight crews who, although qualified to fly the airplanes, were unprepared to safely address the adverse stall behavior they encountered during the stall test flights.
“We are concerned that, due to deficiencies we identified in the information available to airplane owners, operators, and pilots related to the training and procedures needed to safely perform manufacturer-required post-maintenance stall test flights in certain Hawker airplane models, other flight crews tasked to perform such flights may be similarly unprepared.”
Unacceptable Stall Characteristics
Per the NTSB, unacceptable behavior includes a stall that occurs before stick shaker or stick pusher activation, or an uncommanded roll that exceeds 20 degrees and cannot be limited by a pilot’s aileron control input.
The Hawker Structural Repair Manual (SRM) notes that this applies to the Hawker 750, 800, 800XP, 850XP, and 900XP airplanes and specifies the stall flight test requirements. The range of acceptable tolerances for some wing component installations must be achieved within a few hundredths of an inch to avoid introducing unacceptable stall characteristics and discontinuities or ridges in the sealant between the leading edge and upper wing skin. As the NTSB investigation into the 2024 crash noted, contamination on the skin in the form of ice can also result in unacceptable stall characteristics.
The report includes a page from the Hawker Beechcraft Corp. pilot’s operating manual for the Hawker 900XP, which notes a “frequent reason for unacceptable stall characteristics is a tendency to roll at the stall” and “aileron snatch (when an aileron violently snaps to full deflection, often pulling the control stick or yoke with it, causing significant roll and a loss of control) may occur at or prior to stall and is not acceptable and may be strong enough to affect recovery using aileron input.”
The POM warns that there is no natural stall warning or aerodynamic buffet prior to the stall. Stall warning is provided by a stick shaker, which is set to operate at an indicated airspeed of 7 percent to 9 percent above the stalling speed.
The manual further states that pilots conducting stall checks “should have prior experience in performing stalls in the Hawker and must be prepared for unacceptable stall behavior at any point leading up to and throughout the maneuver.”
In addition to the two fatal accidents, the NTSB notes during the investigation that it was made aware of two other stall test flight events involving uncommanded roll behavior in airplane models that are on the same type certificate as the accident Hawker 800XP and 900XP airplanes.
As part of the accident investigation, the NTSB scrutinized the pilot experience and training in the accident aircraft, noting there was not clear language on the procedures for the post-maintenance stall tests.
Urgent Safety Recommendations
The NTSB has made the following new urgent safety recommendations:
To Textron Aviation:
- Define manufacturer-authorized pilot training and experience qualification criteria for pilots who perform post-maintenance stall test flights in Hawker 700, 800, 800XP, 850XP, and 900XP airplanes to ensure that they are prepared with the competencies needed to safely respond to an encounter with unacceptable stall characteristics.
- Develop a stall test plan that describes unacceptable stall characteristics, recovery procedures, and safety considerations needed to prepare manufacturer-authorized flight crewmembers to safely perform post-maintenance stall test flights in Hawker 750, 800, 800XP, 850XP, and 900XP airplanes.
- Review all other airplane models (besides the Hawker 750, 800, 800XP, 850XP, and 900XP) listed on type certificate A3EU, and, for each model that is subject to post-maintenance stall test flights, define stall test flight pilot training and experience qualification criteria and develop a stall test plan.
- Review the pilot’s operating manual and airplane flight manual for the airplanes on type certificate A3EU and revise them, as necessary, to provide a description of the adverse effects of certain wing surface anomalies, such as visually imperceptible defects or light ice accretion, on the airplane’s stall behavior, including:
— the possibility of stall before stick shaker or stick pusher activation;
— a description of unacceptable stall characteristics; and
— procedures for recovering the airplane from an inadvertent encounter with a stall and adverse stall behavior.
- Inform owners and operators of the airplane models on type certificate A3EU that are subject to post-maintenance stall flight tests of the circumstances of these accidents to increase their awareness of the possibility of unacceptable stall behavior, such as an uncommanded roll through 360 degrees and entry into a spin, and that the flight crew training and experience needed to ensure the safety of these flights exceeds that which is typically provided to operational line pilots.
To the FAA:
- Require Textron Aviation to complete the actions specified in safety recommendations and ensure that the information is accurate and correctly incorporated into the appropriate FAA-approved manual or document for each airplane.
To the National Business Aviation Association:
- Inform your members about the recent accidents that occurred during post-maintenance stall flight tests required for certain Hawker airplanes, including the Hawker 750, 800, 800XP, 850XP, 900XP, and others on type certificate A3EU, to increase owner, operator, and pilot awareness that unacceptable stall behavior may occur and that the flight crew training and experience needed to ensure the safety of these flights exceeds that which is typically provided to operational line pilots.
The complete NTSB report can be found below:
