Accidents: August 2021

 - August 2, 2021, 9:05 AM

Preliminary Reports

Four Killed in Firefighting Training Accident

BHI H60 Helicopters UH-60A Blackhawk, May 25, 2021, Leesburg, Florida – All four crew members died and the helicopter was destroyed when an unsecured snorkel assembly contacted the main rotor during water-drop training. The snorkel and water tank had been installed eight days earlier under a supplemental type certificate.  The accident occurred on the first post-installation test flight after several days of ground testing and calibration.

Witnesses at the airport reported that the crew made six uneventful runs, picking up water from a lake adjacent to the Leesburg airport. One described the water being dropped as “very dirty.” At the beginning of the seventh pass, two employees of the helicopter’s operator saw the snorkel swinging “violently,” its end coming close to the main rotor blades. One telephoned the airport’s control tower and asked the controller to have the pilot slow down and land immediately. The other ran alongside the helicopter waving her arms but failed to get the pilots’ attention. As the helicopter accelerated into forward flight and began to climb, she heard a loud bang “and saw multiple main rotor blades separate and hit the tail section.” The tail cone separated and the helicopter spun into the trees. A “loud explosion” and plume of smoke followed.

The main wreckage was found one-quarter mile east of Runway 3. The tail cone was 78 feet farther north. Half of one main rotor blade was found 600 feet to the south; half of another was 1,500 feet west. The snorkel’s stainless-steel suction cage was next to the runway with another section of main rotor blade, and the water-pump housing from the snorkel inlet was “heavily fragmented.”

Turbine Lancair Destroyed in Ohio

Lancair Evolution, May 28, 2021, McDermott, Ohio – The pilot and passenger were killed when the amateur-built airplane crashed in circumstances suggestive of an in-flight breakup. The airplane climbed to FL 250 and accelerated to a groundspeed of 215 knots on an IFR flight from Bellefontaine, Ohio, to Charleston International Airport, South Carolina. Over the course of one minute and 43 seconds, it gradually slowed to 146 knots groundspeed, then turned left and descended rapidly. A stuck microphone transmitted “a distressed conversation between the pilot and passenger.” Air traffic control was unable to contact the pilot before radar contact was lost.

A witness who saw the airplane spiral down told investigators that “it may have been missing a wing.” It crashed into a forest in a near-vertical nose-down attitude, starting a fire. An outboard nine-foot section of the right wing was found about half a mile from the main wreckage. The airplane was equipped with a ballistic parachute that was not deployed during the descent; its propulsive charge ignited in the post-crash fire. AIRMETs for icing up to 22,000 feet and moderate turbulence from 25,000 to 42,000 feet were in effect over an area that included both Bellefontaine and the accident site.

Gear-Up Landing at Odds with Pilot’s Account

Beech 1900, June 2, 2021, Denver – The Part 135 freighter touched down with its landing gear fully retracted, resulting in damage to both propellers and the bottom fuselage lateral bulkhead and stringers. Airport surveillance footage showed that all three legs of the gear were up when the Part 135 freight flight crossed the threshold of Denver International Airport’s Runway 17R and stayed up as the airplane descended to the runway. Radar data showed that it crossed the threshold and passed taxiway EC at 196 knots. Post-accident photographs showed its flaps fully retracted.

The pilot told investigators that on final approach he lowered the landing gear, confirmed three green indicator lights, and felt the increase in drag from the gear extension, though the airplane didn’t seem to slow as expected.  After hearing another pilot and the tower controller advise him to check the gear position, he “confirmed three green lights while the airplane was touching down,” which was “smooth and normal” until “the propellers impacted the ground.”

Final Reports

Night Crash Attributed to Spatial Disorientation

Bell UH-1H, September 6, 2019, Anna Bay, New South Wales, Australia – The pilot’s decision to continue flying past last light, then attempt an overwater route devoid of visual references despite not being trained for night or instrument flight, led directly to spatial disorientation and loss of control. All five on board were killed when the helicopter crashed into the ocean about five km (three miles) southwest of Anna Bay 12 minutes after the published end of evening twilight. The accident occurred on the last leg of a flight from Archerfield Airport in Queensland with a planned destination of Bankstown Airport, New South Wales. The 1,440-hour pilot held private and commercial helicopter licenses with a gas turbine endorsement but had no night or instrument experience, which were not required at the time he trained.

Following a stop at Coffs Harbour, NSW to refuel the helicopter from an onboard 400-liter (105-gallon) storage tank and 205-liter (54-gallon) drum, the helicopter lifted off at 4:48 p.m. At 5:55, the pilot contacted the control tower at Williamtown, requesting clearance to transit its airspace on the published VFR coastal route and a climb to a higher altitude for more favorable winds. The tower controller referred him to approach control, which identified the helicopter on radar and provided the requested clearance at a block altitude of 3,000 to 3,500 feet. This exchange took place at 5:57, four minutes before the published time of last light at Anna Bay.

At 6:02, the pilot was cleared to “track as required” to the Bankstown Airport. At 6:05, he attributed a descent to 2,700 feet to turbulence and was given a block altitude between 2,400 and 3,500 feet. The helicopter then turned left out to sea. ADS-B data showed that it flew southwest for about 90 seconds at GPS-derived altitudes between 2,568 and 3,168 feet, then entered a rapidly descending left turn. The last ADS-B data point was recorded at an altitude of 93 feet at 6:13:18, eight seconds before radar coverage was lost.

Despite an extensive sea and aerial search by the NSW police and, later, the Australian Navy, the wreckage was not located until September 25. The bodies of the pilot and two passengers were not recovered. The investigation discovered that the pilot was being treated for “significant health conditions” with four prescription medications, three of which were “absolutely incompatible” with Australia’s Civil Aviation Safety Authority (CASA) medical guidelines, “as were the underlying conditions.” The fourth would have required an ongoing medical audit after a one-to-three-month grounding before issuance of a restricted medical certificate.

Inspection Procedure Revised Following Sudden Depressurization

Cessna 441, July 22, 2020, Broome, Western Australia - The pilots made a successful emergency descent in response to a rapid loss of cabin pressure, continuing to an uneventful landing. There were no injuries to either crewmember or any of their six passengers. Shortly after the aircraft reached cruising altitude of FL270 on a charter flight from Broome to Browns, a loud noise came from the passenger compartment, the cabin altitude warning light and alarm activated, and the cabin altitude gauge passed 25,000 feet. The pilots immediately donned their oxygen masks, instructed their passengers to do the same, and began their emergency descent.

After reaching 12,000 feet, the pilot monitoring contacted the company’s senior base pilot, who advised them to continue depressurized to Browns Range. During their postflight walkaround, both pilots noticed that the outer skin had separated from the lower aft section of the emergency exit door. With no telephone service, the pilots concluded that the airplane’s Minimum Equipment List permitted them to fly to Halls Creek to meet the senior base pilot, who noticed a 10-mm gap at the bottom of the door. After viewing photographs, company maintenance staff concluded that returning to Broome unpressurized was unlikely to cause further damage. That flight was completed without incident.

Following a structural-failure investigation by the operator’s aeronautical engineer, CASA issued Airworthiness Bulletin 52-004, issue 1, on Aug. 6, 2020, to define a more detailed interim inspection procedure for the Conquest II’s emergency exit door. On Jan. 21, 2021, Textron Aviation issued Conquest Service Letter CQL-99-02 mandating ultrasonic inspection at intervals of 2,000 hours or four years, whichever comes first. Evidence of debonding was subsequently found in two other Australian Conquests operated beyond 22,500 hours total time under Supplemental Type Certificate SVA 528, which defines a life-extension program for the Cessna 441.

Electrical Fire Traced to Storm Window

Beech B200, Oct. 23, 2020, Bournemouth, United Kingdom – Water entering the flight deck through the pilot’s storm window was found to be the likeliest cause of corrosion in the left circuit breaker panel, causing a fire in the back-lighting circuit board. On final approach to Bournemouth in clear weather, a yellow glow and smoke began emanating from the breaker panel after the crew selected approach flaps. Disengaging the electrical master had no effect, so they declared a Mayday, evacuating the airplane on the runway after landing. The airport firefighting crew responded, but the smoke stopped after the engines were shut down.

Inspection showed that moisture had entered the breaker panel. The back-lighting circuit board had sustained heat and fire damage. The panel was underneath the left-side storm window, which had not been retrofitted with the available improved seal. Water tends to collect on the outside of the window and can enter the flight deck when the window is opened—which it frequently is to clear a fogging agent used to sterilize the flight deck during the coronavirus pandemic. While the current operator generally hangared its fleet, this aircraft had been acquired recently and had previously been parked outside.