History of Flight
On May 24, 2021, at approximately 1417 Pacific daylight time, an experimental Dassault Aviation Mirage F-1 turbo-jet, registration N567EM, was destroyed in an accident near Nellis Air Force Base (LSV), Las Vegas, Nevada. The pilot sustained fatal injuries. The aircraft was operated by Draken International as a public-use aircraft supporting United States Air Force simulated combat training.
The accident aircraft was the lead of a two-ship formation returning from Weapons School support flights in the Nevada Test and Tactics Range. The second aircraft returned to LSV earlier due to fuel status. About 15 minutes later, the lead aircraft returned. En route, the pilot reported the aircraft was “code 1,” indicating no maintenance discrepancies.
Airport surveillance radar and air traffic control communications showed the aircraft entered the traffic pattern and reported initial for runway 3R at 14:16:05. At 14:16:26, it was aligned with the runway at about 2,000 ft above ground level (agl) with an airspeed of about 260 knots. The aircraft executed a right break for the overhead pattern. While on downwind and approaching the final turn, at 14:17:12, the pilot stated he would perform a low approach and then proceed to Flex (LSV 338/04).
As the aircraft began the final turn at about 1,400 ft agl and 170 knots slowing, its descent rate increased from 1,000 ft/min to over 3,000 ft/min. At 14:17:20, airspeed dropped below 160 knots, and the pilot reported a flap issue. The tower asked if he was declaring an emergency, to which he affirmed. The last recorded data point, at 14:17:36 and about 400 ft agl, showed an airspeed of 135 knots and slowing. The aircraft's airspeed was slower than the listed low-speed limitation without flaps (160 knots) for the final 14 seconds of flight, and it continued to slow below the limitation for flaps extended. The flight manual advises landing at 195–215 knots if flaps fail to lower. The aircraft continued descending in the final turn with a bank angle exceeding 40°. The pilot ejected but was fatally injured. Shortly after, the aircraft struck terrain in a residential area southwest of the runway approach end; a post-crash fire consumed the wreckage.
Preflight checks revealed that during the slat and flap operational check, the leading-edge slats operated correctly, but the flaps did not initially extend on the first cycle. The pilot corrected the issue and completed two more cycles without further problems.
Pilot Information
The pilot held a commercial pilot certificate with airplane single- and multi-engine land and instrument ratings, along with an experimental aircraft authorization for the DA-F1. He was issued an FAA second-class medical certificate on January 19, 2021, without limitations. He had logged 2,859 total flight hours, including 152 hours in the F-1. A former U.S. Air Force fighter pilot, he had completed company training and was qualified for the mission flown. He appeared to be in good spirits and rested on the accident day and the previous workday.
Aircraft Information
The F-1 Mirage is a French fighter and attack aircraft imported into the United States and registered in the experimental category. It is a single-engine, swept-wing, supersonic airplane capable of Mach 2+ with a maximum takeoff weight over 35,000 lbs.
High-lift devices include two types of leading-edge slats and double-slotted flaps on each wing. Manual control is via an electronic “SLATS-FLAPS” lever with three positions: fully retracted (guarded), ½ flaps with slats fully extended, and flaps and slats fully extended. The slat control system and flap actuating jacks are supplied by hydraulic system 1, ancillary subsystem. An emergency retraction position overrides other functions. Combat flaps increase lift performance by 25% up to about 18° nose up.
The flight manual’s checklist for “Landing High-Lift Devices Fail to Extend” specifies checking the slats/flaps circuit breaker, utility hydraulic pressure, and ensuring the high-lift device selector switch is not in emergency retract; the slats/flaps light should be off. If failure is confirmed, set the lever to IN and land without high-lift devices at an angle-of-attack (AOA) incidence of about 11°. No-flap landing speeds are 195–215 knots depending on weight; at landing weight, the speed would be about 195 knots, assuming straight and level flight with gear extended. Draken International procedures call for no-flap patterns from a straight-in approach.
Normal F-1 break pattern procedures specify initiating the break at about 350 knots with 60° of bank, throttle below 6,500 rpm, and airbrakes as needed. Abeam the runway, speed should be about 215 knots with airbrakes in, gear down, and flaps down. The pilot should extend downwind to stabilize speed before the final turn. At the 45° approach point, speed should be about 160 knots with AOA incidence about 10° and RPM about 7,300. During the final turn, speed should be about 150 knots with AOA ≤13° (12–13° average). Draken flies normally configured F-1s at a minimum of 165 knots in the final turn. After touchdown and aerobraking, 13° AOA corresponds to about 135 knots at typical landing weight.
The incidence indicator on the left windshield post displays AOA. A horn activates at >17° incidence and cuts off at 14°. Maximum permissible incidence is 17°. The flight manual notes that behavior at high incidence is sound, but the limit is easily exceeded without monitoring the indicator; control forces are light, buffeting low and constant, and the stick often reaches the pitch travel limit without obvious anomaly, especially with combat flaps.
The aircraft was on an Other Approved Inspection Program (AAIP) with organizational, intermediate, and depot levels. The last intermediate and depot inspections were completed on November 9, 2020, at an airframe total time of 4,589.7 hours. A daily inspection was performed before the accident flight.
Wreckage and Impact
The aircraft impacted flat desert terrain in the backyard of a residence about 1.5 miles southwest of the threshold of runway 3R. All major components were at the main wreckage site; the fuselage came to rest by a flatbed semi-trailer on a heading of about 195° magnetic. Small debris fragments scattered several hundred feet. The site elevation was about 1,791 ft mean sea level. A post-impact fire consumed most of the wreckage. The ejection seat and parachute were found about one block east-southeast.
Postaccident examination revealed the aircraft configuration was consistent with slats extended and flaps retracted. The engine showed significant impact damage consistent with high rotational velocity at impact; no evidence of internal catastrophic damage was found. The engine rpm gauge indicated about 7,100 rpm, consistent with break pattern procedures. The variable exhaust nozzle position aligned with engine observations. The Master Failure Warning light filament indicated the amber portion likely illuminated, which on the Failure Warning Panel signifies specific system failures or cautions requiring delayed action. The Flight Data Recorder’s memory chips had likely failed, preventing data extraction. Due to the post-crash condition and lack of recorded data, the nature of the reported flap issue could not be determined. No evidence of preimpact mechanical failures or malfunctions that would preclude normal operation was observed.
Additional Information
Draken International conducted an assessment of the accident aircraft’s final turn performance by replicating flight parameters in similarly equipped F-1 aircraft at a safer altitude, assuming a configuration of gear up, flaps up, and slats down. The assessment noted that the accident aircraft’s overhead pattern was tighter than normal. During final turns at various power settings, the aircraft required an additional 1,000–1,300 ft to recover from the end of the turn and tended to continue turning at 180–190 knots and 17° AOA. Pilots needed to unload to roll wings-level to regain airspeed; afterburner light-off took about 5 seconds. All test runs except one resulted in excessive AOA of 17° or greater; one low-power run prevented turns beyond 110°. Performance charts indicated that the no-flap configuration would deplete energy even at maximum afterburner during the final turn, resulting in incidence at or above the 17° limit.
Failure of the flaps to extend would require additional airspeed and AOA to compensate for lost lift, increasing the turning radius. The organization’s assessment and performance charts showed insufficient thrust to overcome the no-flap configuration while flying a final turn profile designed for flaps extended.