Preliminary Reports
Series of Autopilot Engagements, Disengagements Preceded Crash
Daher TBM 700, March 30, 2024, Truckee, California
The single-engine turboprop was maneuvering in instrument meteorological conditions to land at Truckee Tahoe Airport (KTRK) in California and crashed following a series of autopilot activations and deactivations, according to the NTSB preliminary report. The accident claimed the lives of the pilot and passenger.
Flying under Part 91 IFR, the aircraft was returning to KTRK from Denver’s Centennial Airport. The flight was uneventful until the airplane reached the final approach fix. The TBM 700 passed over the final approach fix, and FAA ADS-B data showed that, immediately thereafter, the autopilot’s approach mode was turned on and the altitude hold (ALT Hold) was turned off. Some 20 seconds after passing over the visual descent point at about 121 knots and 6,475 feet msl, ADS-B data shows the aircraft passed over the missed approach point at 6,200 feet msl and 100 knots and continued until abeam the runway identifier numbers (about 1,300 feet east).
At this point, the autopilot was turned off. As the airplane began a gradual 180-degree turn to the right and climbed to about 6,750 feet during the turn, the following autopilot selections were made: ALT Hold on, ALT Hold off, lateral navigation (LNAV) on, autopilot on, LNAV off, several altitude selections (ending with 9,300 feet), and lastly, the autopilot was turned off as the airplane passed over Runway 11.
The airplane then climbed to about 6,850 feet (1,075 feet agl) while making a left turn. The turn tightened, and the final ADS-B returns showed a rapid decrease in altitude and speed. The last return indicated the airplane was at about 280 feet agl and 170 knots. That return was about 200 feet northeast of the first impact point.
An aviation weather report for KTRK issued about two minutes before the accident stated: wind calm, visibility three--quarters of a mile in light snow, ceiling overcast at 900 feet agl, and temperature/dewpoint 30/30 (deg F).
Evidence of Fire in Virginia Crash
Rockwell International 690A, May 5, 2024, Palmyra, Virginia
The condition of the wreckage suggested both a fire in the left wing and an inflight break-up that scattered debris over a 3.5-mile track in a rural Virginia forest. The pilot and only passenger were killed.
A witness who was across the road from the accident scene described a sound “like thunder.” He went outside and saw the airplane flying “on its left side and on fire in the middle” as it descended into the trees.
Investigators found the left wing and left engine still attached to the fuselage but “heavily burnt;” the right wing, also fire-damaged, was separated and found about one-quarter of a mile north. The right engine and propeller were not located; the horizontal and vertical stabilizers were found three-quarters of a mile north of the main wreckage.
The personal flight was en route from Manassas (Virginia) Regional Airport to Rock Hill, South Carolina at FL200 when the pilot reversed course, telling the controller, “We have lost…we need to climb…we have lost autopilot.” No further communications were received.
Weather data indicated cloud layers rising above 30,000 feet with “potential for rime and mixed icing from 12,000 to 25,000 feet.”
Two Killed in Arkansas Break-up
Piper PA-46-500TP, May 12, 2024, Marianna, Arkansas
The pilot and only passenger perished when the single-engine turboprop entered an abrupt spiraling descent that reached an estimated rate of 17,000 fpm. The fuselage came to rest 0.1 nm from the last point recorded in its flight data track; “the left horizontal stabilizer, vertical stabilizer, rudder, elevator, right aileron, right flap, and the outboard portion of the right wing were not located at the accident site” and were not subsequently found by search efforts that included use of a state police drone.
The accident occurred about 10 minutes after the private flight from Pensacola, Florida to Batesville, Arkansas initiated a descent from FL280. Airmets for occasional moderate turbulence between FL210 and FL410 were in effect, and sounding data suggested strong vertical wind shear between 12,000 and 24,000 feet “with a high probability of moderate or greater turbulence around the time of the accident.”
Helicopter Destroyed in Taxi Accident
Sikorsky S-58T, May 15, 2024, Burlington, Ontario, Canada
While taxiing the wheel-equipped helicopter onto an inactive runway during a training exercise, the pilots allowed its tailwheel to drift off the pavement into the grass. The resulting shock triggered nearly instantaneous ground resonance that caused the main rotor to sever the tail boom, then strike the ground.
The craft rolled onto its side after the right gear strut collapsed. Both crew members escaped, though one suffered minor injuries.
Final Reports
Stick Pusher Contributed to Prop Strike
Pilatus PC-12-47E, July 19, 2021, La Môle Aerodrome, Provence-Alpes-Côte d’Azur, France
During a training flight to obtain certification to operate at the La Môle airport, the pilot under instruction—also the airplane’s owner—made an abrupt nose-up input on short final to Runway 06.
Data retrieved from the Pilatus’ lightweight data recorder showed that the sudden increase in angle of attack triggered the stall protection system to activate the stick pusher; the resulting nose-down moment forced the propeller into contact with the runway. The pilot initiated a go-around; once he established a positive rate of climb, the instructor took the controls and made an uneventful landing on Runway 24.
La Môle’s relatively short runway (3,514 feet) is surrounded by higher terrain that requires both angled final approach paths and unusually steep descent profiles to land in either direction. The regional government requires pilots to obtain on-site training and a signoff from a specifically authorized instructor to operate there as pilot-in--command. The accident pilot, whose 381 hours of flight experience included 38 hours and 14 takeoffs and landings in the PC-12, was one of three the instructor was attempting to certify that day.
Fatal Sightseeing Accident Attributed to LTE
Bell 206B, Dec. 30, 2021, Livingston, Texas
The NTSB concluded that a loss of tail rotor effectiveness (LTE) in a 150-foot hover led to a failure of yaw control, resulting in the helicopter’s main rotor striking trees. The sightseeing flight was the prize from a charity auction; the winning bidder, in the front passenger seat, and the pilot were killed when the aircraft sank into a pile of brush. The two rear-seat passengers escaped with minor injuries.
The winner’s initial request was to overfly his childhood home, but low cloud cover en route prevented this. Instead, he asked the pilot to fly over his current residence, which they approached on a west-southwesterly course.
Footage captured by one of the surviving passengers showed an airspeed of about 40 knots at an altitude of 150 feet. The aircraft began a slow right circuit of the property and came to a hover facing south. It then started rotating to the right, completing two turns before the main rotor blades contacted a tree. After the strike the helicopter fell into a “slash pile” of timber left over from clearing operations.
The 73-year-old airline transport pilot had reported 1,679 hours of “civil flight experience” on his most recent medical certificate, obtained in July 2016. After it expired, he flew under BasicMed. His personal records indicated that he’d logged just over 200 hours in helicopters, including 71.7 in the accident make and model.
LTE is a purely aerodynamic phenomenon in which some combination of prevailing winds and vortices produced by the main rotor prevent a mechanically functional tail rotor from producing enough thrust to counter the torque of the powerplant and main rotor. Though winds near the accident scene were generally light, the NTSB concluded that “[LTE] can be affected by numerous factors that could not be conclusively eliminated,” leading to “the pilot exceeding the yaw capability of the helicopter for the flight conditions, resulting in a non--mechanical loss of tail rotor effectiveness.”
Maintenance Errors Cited in Fatal Crash
Robinson R44, Nov. 22, 2022, Charlotte, North Carolina
Missing hardware led the NTSB to conclude that maintenance personnel did not properly inspect the accident helicopter before it crashed during a training mission in Charlotte, North Carolina, killing the pilot and a local staff meteorologist.
According to the Safety Board, the probable cause was “the inadequate inspections of the forward left control rod end attachment hardware to the stationary swashplate by the pilot and by maintenance personnel, resulting in an eventual loosening and backing out of the hardware and subsequent loss of helicopter control.”
About five minutes before the accident, the meteorologist and the R44’s pilot took off for simulated news scene training. After conducting left 360-degree orbits over a highway, the helicopter went out of control, descended steeply, then crashed onto a grassy area. According to the NTSB, “The pilot made a radio call on the local helicopter common frequency before impact stating that ‘Three’s going down, Sky Three’s going down.’ There was no post-accident fire.”
Following the accident, investigators found that connecting hardware was missing from a control rod end that attaches to the helicopter’s stationary swashplate. A metallurgical examination of the remaining components suggested that the missing connecting hardware was loose and backed out during the flight.
“It is unlikely that the hardware was secure before the flight and may have been loose for multiple flights before the accident,” according to the NTSB. “Additional examination of the remaining hardware revealed that one of the two spacers was installed backwards, most likely during the field overhaul of the helicopter about three years before the accident.”
The helicopter had flown 26 flights after the most recent 100-hour inspection, which was completed on October 16. The field overhaul in August 2019 included the replacement of three rod ends, including the forward left control rod end that was implicated in the accident, as well as the lower rod ends.