Preliminary Reports:
No Injuries in Oroville Overrun
Cessna 560XL, August 21, 2019, Oroville, California – All 10 occupants evacuated the aircraft without injury after it overran the departure end of Oroville Municipal Airport’s Runway 02. Most of the airplane was subsequently consumed by a post-crash fire. Two pilots and eight passengers were on board the charter flight to the Portland, Oregon International Airport. According to the pilot flying, the airplane accelerated through V1 to VR, but failed to respond to elevator inputs when he tried to lift the nose (see related story on page 14).
No Survivors in Majorca Mid-air
Bell 206L3 LongRanger III and Aeroprakt A22L Foxbat, August 25, 2019, Balearic Islands, Mallorca, Spain – Four members of a German family, the Italian pilot of their sightseeing flight, and two Spanish citizens were killed in a low-altitude collision between a helicopter operated by a German tour company and a locally registered “microlight” airplane (a designation comparable to the U.S. light-sport category). The accident took place around 1:30 p.m. local time in characteristically clear weather.
Press reports described the helicopter passengers as a couple from Munich and their two children, ages 9 and 11. The majority of the wreckage fell onto a private estate, though press photographs show the airplane’s tailcone on a gravel road. The collision was the deadliest accident in the Spanish archipelago in many years. In 1972, 102 perished when an Iberian Airline flight crashed on the island of Ibiza.
Norwegian AS 350 Accident Prompts Emergency AD
Airbus Helicopters AS350B3e, August 31, 2019, in the Skoddevarre Mountains South of Alta, Norway – Airbus Helicopters issued an emergency service bulletin that EASA upgraded into an emergency airworthiness directive following the crash of an almost-new AS 350B3e that killed all six on board. The AD requires a one-time inspection of the main gearbox drive shaft/engine coupling in AS350, AS550, and EC130 helicopters with less than 300 total flight hours. The Accident Investigation Bureau of Norway (AIBN) reports that the accident helicopter “had less than 73 hours since new.”
In a press release issued on September 11, the AIBN reported that on-scene work has been completed, with the wreckage recovered to a facility in Lillestrøm. Among the components retrieved was the helicopter’s recording unit, designed to capture not only flight and voice data but video feeds of the cockpit and outside view, GPS coordinates, attitude in all three axes, and sound signatures from the engine and gearbox. The unit was not hardened to air-carrier impact and thermal standards and suffered severe heat damage. It has been sent to the recorder lab of France’s BEA, which is assisting the AIBN investigation. Fire damage prevented recovery of any information from any of the other data-logging devices in the aircraft.
Three Hurt in Challenger Wake-turbulence Encounter
Bombardier CL600 2B16, August 8, 2019, Lubbock, Texas – The flight attendant and one passenger sustained minor injuries and a second passenger suffered a tibia fracture requiring surgery during an 11-second wake turbulence encounter. The Challenger 600, operated by NetJets on a fractional ownership flight, was en route from Dallas Love Field to Santa Ana, California. While climbing through FL335 for its assigned altitude of FL340 in light and variable winds, the jet encountered a sudden right quartering headwind of 77 knots that imposed a 2.1-g vertical load which reversed to -0.7 g in less than one second. During the same second, it experienced a yaw acceleration from -0.6 (left) to 0.4 (right), causing a simultaneous 10-degree pitch excursion and uncommanded 20-degree right roll. According to the preliminary report released by the NTSB on September 6, “All unsecured objects in the cabin were thrown about including all passengers and the flight attendant…Cabin service items (food, broken plates, and dishware) and the lavatory fluid spilled on the interior of the cabin.”
After assessing damage and injuries, the captain requested an immediate diversion to Lubbock, where the flight landed without further incident. Two passengers and the flight attendant were transported to the hospital; one passenger and the attendant were released after treatment for minor injuries.
Radar track data showed that at the time of the encounter, the Challenger was eight to 10 miles in trail of a FedEx Airbus A300 on a scheduled flight from Fort Worth Alliance to Bob Hope Burbank Airport, level at FL340 on the same assigned route. The Challenger’s flight crew was not made aware of the FedEx flight before the encounter. According to its flight data recorder, variable winds of two to seven knots prior to the accident returned to less than 12 knots afterward.
Final Reports:
Snow Ingestion Brought Down Powerline Patrol
MD Helicopters 369HM, January 15, 2018, Perrysburg, Ohio – In a probable cause report released on September 10, the NTSB attributed the loss of the aircraft to a low-altitude engine flameout precipitated by the ingestion of ice or snow. Both the pilot and the powerline inspector were killed when the helicopter crashed onto a snow-covered field after a near-vertical descent. Recovered GPS data showed that for most of the preceding hour it had operated between 180 and 220 feet agl at forward airspeeds below 10 knots, making a series of right turns consistent with powerline inspection.
Witnesses reported moderate snowfall at the time of its departure from the Wood County Airport in Bowling Green, Ohio as well as at the accident scene, the latter confirmed by police photographs showing “falling snow and flat light or white-out conditions at the time of the accident.” Visibilities as low as 1.25 miles were reported throughout the area, including at the Bowling Green airport when the helicopter took off. (Federal regulations require only a half-mile visibility for daytime VFR operations in Class G airspace below 1,200 feet msl.) The pattern of vertical crushing on the bottom of the fuselage suggested that the helicopter struck the ground in a nose-level attitude not consistent with an in-flight loss of control. There was also no evidence of contact with the power lines or transmission towers. Stretch signatures on the filament of the instrument panel’s RE-IGN lamp indicated that a gas generator speed below 55 percent had activated the engine’s re-ignition system, required by the manufacturer for operation in falling or blowing snow.
Airport surveillance footage confirmed witness accounts that the helicopter sat on the ramp in falling snow for more than an hour after arriving to pick up the inspector. The surveillance camera captured an image of two people walking around it before boarding but did not provide sufficient resolution to determine whether they removed accumulated snow from the engine air inlet. Low-airspeed operation would also facilitate accumulation of snow in the inlet, and a 1968 study cited by Rolls-Royce found that ingestion of as little as 30 grams (1.07 ounces) of snow or slush could cause a flameout in the Allison 250 engine, which had a filter to strain ice particles from the fuel but no system to prevent snow ingestion at the air inlet.
Damage to the main rotor hub was consistent with excessive coning and downward flapping of the blades, suggesting a loss of main rotor rpm. The flight was conducted in the shaded area of the MD 369’s height-velocity diagram, a condition in which limited potential energy (altitude) and kinetic energy (airspeed) combine to make both engine restart and successful autorotation unlikely or impossible. Flat light conditions would also have impeded efforts to land from an autorotation.
Spatial Disorientation Implicated in Ontario R66 Accident
Robinson R66, March 4, 2019, Timmins, Ontario, Canada – In its final report issued on August 22, the Transportation Safety Board of Canada concluded that the helicopter’s pilot and owner lost visual references while flying over “remote areas with almost no ambient or cultural sources of light” on a dark, moonless night. Because he had not filed a flight plan or flight itinerary, the aircraft was not reported missing for another 36 hours, and searchers did not locate the snow-covered wreckage until the afternoon of March 11, nearly one week after the crash. The emergency locator transmitter was found turned off and consequently did not activate. The pilot and his wife, the only passenger, had been ejected from the cockpit, neither having apparently been wearing their safety harnesses. However, the TSB judged the crash to have been unsurvivable in any case.
The accident site was in a previously cleared section of forest 36 nm south-southeast of its destination, the pilot’s private helipad near Fauquier-Strickland, Ontario. Tree damage and impact signatures in the wreckage indicated that the helicopter struck the ground in a steep nose-down, left-bank attitude. A weather report filed six minutes earlier at the Timmins airport, 18 miles southeast of the scene, included 15 miles visibility under a 4,000-foot overcast, but visibilities as low as one mile in light snow showers were reported in the area earlier that evening.
The accident flight was the last of four legs spanning eight flight hours and nearly 11 hours of clock time that began with the couple’s departure from Nashville’s John C. Tune Memorial Airport at 9:24 a.m. They stopped for 40 minutes at the Springfield-Beckley Municipal Airport in Ohio and one hour 14 minutes at London, Ontario. Their final stop at Sudbury, Ontario, was just 15 minutes, taking off two minutes before the end of civil evening twilight at 6:42 p.m. The crash is believed to have occurred at 8:06, though unlike the three preceding legs, the accident flight was not tracked by radar.
The pilot held a private pilot helicopter certificate with night rating and a Category 1 medical certificate but no instrument rating, and the helicopter was not certified for IFR flight. He had logged 925 hours of flight time, 585 of them in the R66 including 157.5 in the preceding year. However, the TSB noted that he was not legally current to transport passengers at night, having made no night takeoffs or landings in the previous six months. Canadian Aviation Regulations require five of each.