Story ID: 004
Accidents: August 2022
By: David Jack Kenny
Caption: Preliminary and final accident reports, August 2022
Word Count: 1596
Preliminary Reports
Twenty-Two Perish in Nepali Airline Disaster - De Havilland DHC-6-300 Twin Otter, May 29, 2022, Sanosware, Nepal

All three crew members and 19 passengers were killed when Tara Air Flight 197 struck a mountainside about 15 minutes into a scheduled 20-minute flight from Pokhara to Jomsom. Originally scheduled for 06:15, the flight was delayed nearly four hours due to cloud cover obscuring Lete Pass. It eventually departed at 09:55 following two of another operator’s aircraft. Contact with air traffic control was lost 12 minutes later.

Continued low weather and failing light hampered search efforts, which required some 20 hours to locate the wreckage at an elevation of 14,500 feet on a steep, rocky slope accessible only by one helicopter at a time. The smell of fuel helped villagers searching for yarsagumba fungus find the site. Press accounts indicate that 16 of the victims, including the crew, were Nepali nationals; four were from India, and two from Germany.

Six Survive Crash into Lava Field- Bell 407, June 8, 2022, Kalea, Hawaii

The pilot and two passengers suffered serious injuries when the air tour helicopter crashed into a lava field after an apparent loss of yaw control. The remaining three passengers escaped with minor injuries. The accident occurred about 25 minutes after departure from the operator’s base at Ellison Onizuka Kona International Airport. ADS-B track data showed that the aircraft proceeded southeasterly at altitudes of 500-600 feet and airspeed between 122 and 127 knots before abruptly slowing and entering a rapid descent. The pilot recalled that the flight progressed normally until “the helicopter experienced a violent upset, followed by an uncontrolled spin (yaw) to the right.” The passenger in the left front seat reported that “she observed something fall off the helicopter; however, she was not able to identify a specific part.” A passenger reported the accident by telephone after the ship spun down into “an area of rough, uneven, lava-covered terrain” and rolled onto its left side.

NTSB investigators found the tail boom 762 feet northeast of the main wreckage, having separated from the fuselage at the tail boom attach point. The upper left attachment fitting and its fastener were missing. The fasteners for the other three attachment fittings were present, but the lower left fitting was fractured and showed fatigue signatures. The tail boom had been installed on August 23, 2009 and had not been removed since, accumulating more than 17,000 flight hours. The most recent torque check of the attachment fasteners was carried out on May 4, 2022, 114.2 flight hours before the accident, and no subsequent maintenance was performed on the attachment location.

No Survivors in Learjet Approach Accident - Learjet 55C, June 22, 2022, 3.8 nm SSE of Charallave-Oscar Machado Zuloaga Airport, Venezuela

Two pilots and four passengers were killed when the twin-engine jet crashed while turning from base to final on its second approach to Runway 10. The flight from Puerto Cabello to Caracas appeared routine until the pilots aborted their initial approach and declared an emergency, citing a problem with the thrust reversers. After initiating a new traffic pattern for the same runway, the airplane initially turned to a heading of 110 degrees to align with the runway, then turned right to a southerly heading while continuing to descend into a forested hillside.
Final Reports
Low-Altitude Stall Claimed Experimental Turboprop Epic LT, March 31, 2019, near Frankfurt-Egelsbach, Germany

The pilot’s attempt to reverse course at low altitude rather than flying a standard traffic pattern triggered an unrecoverable stall, resulting in his death and those of both passengers. The final report of Germany’s Bundesstelle für Flugunfalluntersuchung (BFU) also called attention to the pilot’s non-standard arrival to airspace tightly constrained by that of the adjacent Frankfurt-Main international airport and the lack of any stall-warning equipment in the airplane, originally certified in the U.S. amateur-experimental category in 2008 and exported to Russia in 2014.

The accident flight originated at Cannes, France at 13:57 local time on an IFR flight plan with a filed altitude of FL 260. At 15:19 the pilot contacted Langen Radar to report descending to 6,000 feet, was given the local altimeter setting, advised to expect Runway 08, and cleared to descend to 4,000 feet on a direct course to the DELTA waypoint. Two minutes later the pilot cancelled IFR. The airplane was 16 nm south of the airport at 5,000 feet and a groundspeed of 240 knots.

At 15:22, the flight was handed off to the controller coordinating Egelsbach traffic, who provided runway information and an altimeter setting the pilot acknowledged and a new transponder code he neither read back nor set. Radar track data showed that twice during the descent the Epic penetrated the Class C airspace of the Frankfurt-Main airport. Rather than following the traffic pattern’s base leg parallel to the Bundesautobahn A5 highway, the pilot turned right on a diagonal toward the threshold at the pattern altitude of 1,300 feet and 140 knots groundspeed. Responding to the controller, the pilot acknowledged “not yet” having the airport in site and was advised, “I suggest to reduce, you are now on right base.”

The airplane began descending at a rate that reached 1,400 fpm before turning left and crossing the runway northbound “at very low altitude,” the pilot requesting, “…may I…make an orbit?” He was directed to circle left and avoid overflying the highway westbound. Witnesses, including three in the airport tower and two in a Piper PA-28 trailing its approach, saw the Epic initiate a left turn below 400 feet at a bank angle estimated at 30-45 degrees. Halfway through the turn, it abruptly pitched down and crashed into an asparagus field in a near-vertical attitude, igniting a fire that consumed virtually all of the aircraft and leaving a scar  of  20 meters (63 feet) in diameter.

The 53-year-old pilot held a Russian airline transport pilot license with type ratings for the Boeing 737CL and 737NG and the Gulfstream G550 as well as a single-engine airplane instructor’s certificate. His 11,425 hours of flight experience included 676 as pilot-in-command of the Epic LT.

Autopilot Likely Engaged During Fatal Upset Robinson R66, Jan. 9, 2020, Mechanicsburg, Pennsylvania

Detailed analysis of attitude and engine data recorded during the flight led the NTSB to conclude that the helicopter was probably operating on autopilot when it encountered moderate to severe turbulence in the vicinity of the accident site. After about 20 seconds of “slight pitch and roll oscillations,” the helicopter rolled left into an inverted attitude during which the main rotor struck the tail boom. The pilot and only passenger were killed in the resulting break-up at 2,300 feet.

The VFR flight departed from Martin State Airport in Baltimore, Maryland, at 19:57 local time, requesting traffic advisories to New York’s Buffalo Niagara International Airport at a planned altitude of 3,000 feet. Two minutes after takeoff Martin State tower transferred the flight to Potomac Approach Control, which in turn handed it off to Harrisburg Approach Control at 20:23. The pilot acknowledged and followed instructions to fly a heading of 310 degrees, tracking northwesterly at 107 knots at an altitude of 2,300 feet. Radar contact was lost six minutes later.

No significant attitude excursions were recorded until the last 30 seconds of the flight. Pitch oscillations began between 20:28:46 and 20:29:05, and a left roll reached 10 degrees as the normal acceleration parameter dropped to -1 G and indicated airspeed fell from 107 knots to zero in a single second. Over the next four seconds, the left roll continued through fully inverted to a right bank of 114 degrees, and the engine’s power turbine speed (N2) spiked at 128 percent while torque dropped to 1 percent. The suppression of pitch and roll excursions until the final sequence led NTSB investigators to conclude that the helicopter’s two-axis stability augmentation system  autopilot was “likely” in control of the aircraft until its final upset.

Robinson Helicopters’ Safety Notice 11 warns that low-G flight maneuvers are extremely dangerous, and the R66 rotorcraft flight manual recommends limiting airspeed to 60-70 knots during “significant” turbulence. The NTSB’s weather study indicated 27-knot winds from 190 degrees at 2,300 feet, creating an 87 percent probability of moderate to severe turbulence. Pilot reports confirmed strong to severe windshear and moderate-to-severe turbulence between 2,300 and 3,000 feet at the time of the accident. The 58-year-old private pilot had completed a company R66 safety course in February 2019, shortly after his company acquired the helicopter, and had logged 167 hours in type.

Electrical Anomalies Traced to Water Ingress MD 900, July 25, 2021, London, UK

Inadequate sealant around the right engine’s igniter cables allowed water to seep from the engine bay into the rear fuselage compartment where it reached the symbol generator and the right engine’s electronic engine control unit (EEC).

The air ambulance flight was returning from Royal London Hospital to RAF Northolt Airport after several hours parked on the hospital helipad in heavy rain, and first the commander’s electronic horizontal situation indicator blanked, followed shortly by his electronic attitude indicator. The copilot’s conventional flight instruments were unaffected. The right engine’s EEC then indicated a critical fault while the left indicated a non-critical failure, allowing it to continue under automatic control while the pilot had to switch the right engine to manual control using the twist throttle.

The crew landed safely at RAF Northolt, where maintenance personnel found partial blockage of the drain holes in the rear baggage compartment and visible moisture on the symbol generator and right EEC. Those units were returned to their manufacturers for evaluation, and the EEC was found to have failed permanently due to a moisture-induced short circuit in its power board.    ζ