Preliminary Reports
Balky Engine Preceded Takeoff Failure
Piper PA-46-350P turbine conversion, May 11, 2025, Greenwood, Indiana
When the pilot attempted to increase power to taxi to the runway, the airplane’s PT6A-35 turboprop engine initially did not respond. It did spool up after he let it run a bit, and the pre-takeoff checks appeared normal, but the engine lost all power shortly after takeoff. Both the pilot and passenger suffered serious injuries when the airplane descended into a taxiway from an altitude of about 100 feet and slid into an embankment, incurring substantial damage to the fuselage.
Six Killed in Below-minimums Approach
Cessna S550, May 22, 2025, San Diego, California
The single pilot and all five passengers died when a Citation S550 crashed into a residential neighborhood during an attempted approach to Montgomery-Gibbs Executive Airport (KMYF), and eight people on the ground were injured. The accident occurred at 03:47, well before dawn. Prevailing weather conditions at Marine Corps Air Station Miramar included calm winds with visibility of half a mile and an indefinite ceiling at 200 feet.
The flight from Teterboro, New Jersey, refueled at Colonel James Jabara Airport in Wichita, Kansas, and departed Wichita at 02:36 Central time. Checking in with Southern California Tracon, the pilot acknowledged knowing that KMYF’s ASOS was out of service and requested the RNAV approach to Runway 28R. Weather minimums for that approach include three-quarters of a mile visibility and ceilings from 250 to 500 feet, depending on whether vertical guidance is provided.
The controller cleared the pilot to the NESTY approach fix at 9,000 feet and provided the weather observation from Miramar. He received his approach clearance five miles from NESTY with instructions to cross at or above 3,800 feet. The jet slowed from 200 to 120 knots on the approach course, crossing the PALOS fix 2.9 miles from the threshold 190 feet below the minimum crossing altitude. The last ADS-B data point showed an altitude of 60 feet. The airplane struck the ground 1.8 miles from Runway 28R’s displaced threshold, hitting one residence and 20 vehicles and sparking a post-crash fire.
A cockpit voice recorder was located in the wreckage. FAR Part 91 does not prohibit attempting an instrument approach in weather conditions below the procedure’s minimums, nor does it require current weather data from the destination airport.
Final Reports:
Power Loss Traced to Loose Transmission Locknuts
Bell 206B, Jan. 22, 2023, Itacarė, Bahia State, Brazil
The locknuts securing the bolts holding the inner coupling to the engine-side power shaft flange of the main driveshaft assembly loosened in flight, causing a sudden loss of main rotor rpm. While en route at about 90 knots airspeed and an altitude of 1,000 feet, the pilot observed an abrupt 30% reduction in torque accompanied by an uncommanded left yaw, after which the helicopter began to descend. The pilot executed an emergency autorotation, and although their low altitude prevented them from reaching the intended landing site, both he and his passenger escaped without injury.
Investigators found the boot protecting the transmission’s inner coupling torn on the transmission side. The bolts were bent and showed crush damage to their threads. The bolt holes on the engine side of the flange were elongated, with denting and polishing marks caused by movement of the bolt heads. The excessive play unbalanced the drive shaft; the eventual separation of the inner coupling from the engine-side power shaft flange caused the loss of power to the main rotor system. Investigators were unable to determine whether the locknuts had been overtorqued, undertorqued, or reused during overhaul contrary to the manufacturer’s requirements (which in turn could have caused either over- or undertorquing).
Although the engine produced only 338 of its rated 420 horsepower during a post--accident bench run, this was attributed to a combination of impact damage and uneven spray from the fuel nozzle, which would have been expected to cause a gradual rather than a sudden power loss. Investigators also noted that the pilot’s type rating for single-engine turbine helicopters had expired in February 2021, leaving him legally ineligible to act as pilot in command despite having flown the accident aircraft 17.5 hours in the preceding 90 days. This, too, was not believed to have contributed to the accident.
PC-12 Broke Up after Autopilot Disengaged in IMC
Pilatus PC-12, Feb. 24, 2023, Stagecoach, Nevada
Spatial disorientation following autopilot disengagement led to the in-flight breakup of a Guardian Flight Pilatus PC-12 operating under the Care Flight brand. The pilot, flight nurse, flight paramedic, and two passengers were killed when the aircraft crashed near Stagecoach, Nevada.
The air ambulance flight, a non--emergency medical transport, departed Reno-Tahoe International Airport (KRNO) at 21:00 under IFR in night instrument meteorological conditions. Cloud bases were reported at 1,200 feet agl with tops near FL240. Cleared to climb to 25,000 feet, the PC-12 never reached its assigned cruising altitude.
About 11 minutes into the flight, the aircraft deviated from its assigned routing and entered a series of altitude and heading changes. Investigators concluded that the flight path was consistent with a graveyard spiral—a type of spatial disorientation where the pilot misperceives a descending turn as level flight and, in attempting to arrest an apparent descent, further tightens the spiral, potentially leading to structural failure.
“The pilot’s loss of control due to spatial disorientation while operating in night instrument meteorological conditions…resulted in an in-flight breakup,” the NTSB found. Contributing factors included “the disengagement of the autopilot for undetermined reasons, as well as the operator’s insufficient flight risk assessment process and lack of organizational oversight.”
The PC-12’s autopilot disengaged twice during the flight. The second event occurred two to four minutes before the crash. The autopilot was not reengaged, requiring manual control in IMC. No anomalies were found with the autopilot, trim servos, or other control systems.
After climbing to about 19,400 feet msl, the aircraft entered a steep descending right turn. Descent rate exceeded 13,000 fpm before radar contact was lost at approximately 11,100 feet msl. The distribution of wreckage and structural damage was consistent with in-flight breakup due to aerodynamic overstress.
The pilot, classified as a float pilot, had been employed for only five months and had limited recent time in type and in the region. Both medical crew members had less than six months’ tenure with the company.
No risk assessment form was found for the accident flight. The operator’s fixed-wing division lacked the crew pairing protocols required for its rotorcraft operations. Other operators had declined similar missions earlier in the day due to weather, but this was not communicated to the accident crew.
An autopsy revealed a 3-centimeter brain tumor in the pilot’s right parietal lobe, an area linked to sensory and navigational processing. While the NTSB could not determine its effect on performance, it noted that the tumor “may have impacted the pilot’s ability to synthesize and respond to sensory interpretation.”
The aircraft was not equipped with a cockpit voice or flight data recorder. However, onboard systems and GPS data enabled investigators to reconstruct the flight path. No mechanical failure was found that would have prevented normal flight.
Wet Runway Overrun Destroys HondaJet
HondaJet HA-420, May 18, 2023, Summerville, South Carolina
Improper landing speed and distance calculations by the pilot caused a HondaJet HA-420 to overrun a wet runway at Summerville Airport (KDYB) in South Carolina, according to the NTSB’s final report. The aircraft, registered as N255HJ, was destroyed by fire after sliding down an embankment beyond the end of the runway, but the pilot and five passengers escaped without injury.
The jet departed Wilkes County Airport (KUKF) at 23:29 on an IFR flight and landed at KDYB at approximately 00:14 in night visual meteorological conditions. The pilot, flying under Part 91, told investigators he used the cockpit display unit (CDU) to calculate a landing reference speed (Vref) of 119 to 120 knots and believed the 5,000-foot asphalt runway provided sufficient length for landing.
ADS-B data showed the jet crossing the runway threshold at 120 knots groundspeed and 119 knots calibrated airspeed. However, Honda Aircraft engineers later determined that the appropriate Vref under the accident conditions was closer to 112 knots, with a wet runway landing distance requirement of about 4,829 feet. With those parameters, the CDU would have issued a warning: “LANDING FIELD LENGTH INSUFFICIENT.”
The aircraft touched down before the 1,000-foot runway markers, and the pilot applied full braking. He reported that the antiskid system cycled more slowly than expected and produced minimal braking force. A sudden grab from the left brake caused the aircraft to yaw and skid, prompting the pilot to abandon thoughts of a go-around. The aircraft overran the runway, descended an embankment, and came to rest 360 feet beyond the paved surface on a rocky berm. A post-impact fire consumed the cockpit, right wing, and center fuselage.
Investigators found no mechanical faults with the brake system that could explain the performance discrepancy. Initial bench testing of the power brake and antiskid valve revealed anomalous hysteresis, or delayed response, but certified testing at the manufacturer’s facility showed no irregularities. While such hysteresis “may lead to braking performance degradation,” the NTSB could not confirm a link to the overrun.
At the time of the accident, the operator had not installed Honda’s 2022 update that incorporated revised performance data and advisory functions for wet and contaminated runways. The free software supplement was recommended but not required under Part 91.
The aircraft was not equipped with a cockpit voice or flight data recorder, nor was one required. The investigation relied on ADS-B data and witness accounts to reconstruct the accident sequence.
—Amy Wilder contributed to this report