Story ID: 004
Accidents: October 2020
By: David Jack Kenny
Caption: Preliminary and final accident reports
Word Count: 1616
Preliminary Reports
Two Escape Nevada Helicopter Crash

Aerospatiale SA342J Gazelle, June 21, 2020, Minden/Tahoe Regional Airport, Nevada – The helicopter was destroyed after losing power during a landing approach, but the pilot and passenger escaped the post-crash fire. The pilot told investigators that when he lowered collective to land at an altitude of 25 feet and an indicated airspeed of 10 to 15 knots, “the engine lost all power.” A witness at the airport recalled hearing “four or five pops in rapid succession, followed by a louder, deeper sound.” The pilot entered a hovering autorotation and raised collection to cushion the landing, but the helicopter landed hard and caught fire. Both occupants were able to escape without assistance.

The accident occurred after a flight of about one hour 15 minutes, during which the pilot noticed an exhaust gas temperature reading “about 50 degrees higher than usual.”  The NTSB’s preliminary report does not include any findings from examination of the wreckage.

One Killed in Tennessee River Ditching

Airbus Helicopters EC130B4, Aug. 3, 2020, Knoxville, Tennessee – One passenger was unable to escape from the cabin after the helicopter crashed into the Tennessee River during an approach to a landing zone on the pilot’s property. Two other passengers and the pilot evacuated the aircraft before it sank.

The accident occurred after a 75-minute local flight that originated from the McGhee-Tyson Airport. The pilot made a right circling approach to the landing site, “descending with low power and a 25-degree angle of descent; ever slowing to come to a hover at low speed over the water." When he added power to stop the descent, the helicopter “started to settle” and he “pulled max power to stop the settling,” but the helicopter descended about 75 feet into the water. The left skid struck first, followed by the main rotor blades, and the helicopter rolled onto its left side. Its wreckage was subsequently recovered.

King Air Destroyed in Takeoff Crash

Beech 200, Aug. 20, 2020, Rockford, Illinois – A privately owned King Air 200 rolled left and crashed into the grass immediately after takeoff, killing the sole-occupant pilot. The airplane sustained fire damage and considerable fragmentation from the accident, which occurred at 3:43 p.m. CDT. The flight was intended to return to the pilot’s home base near Wayne, Illinois, following maintenance work at a Part 145 repair station at Rockford. The nature of the maintenance has not yet been reported.
Final Reports
Fractured Fuel Line Downed Air Tour Helicopter

Airbus Helicopters EC130, Jan. 17, 2016, Hanalei, Hawaii – A complete loss of engine power during a Blue Hawaiian air tour was caused by a fractured main fuel injection pipe. The pilot and all six passengers suffered thoracolumbar fractures from a hard landing after an emergency autorotation; one passenger was left paraplegic.  NTSB investigators ascribed the break to sympathetic vibration excited by the starter-generator, whose worn front bearing support allowed the armature to oscillate enough to impart vibrations to the engine frame. In the absence of any specific requirement to examine the bearing, the excessive play would not have been noticed by the operator.

The helicopter was about one-quarter mile offshore at an altitude of 1,450 feet when the low rotor rpm warning sounded. The pilot immediately entered an autorotation and turned toward the shore, but had to make a hard right turn at low altitude to avoid boulders in his intended landing area. The helicopter touched down hard, buckling the tail boom, pushing the tail skid into the fenestron, and displacing the main gearbox right support rod 24 mm (just under one inch). The Board noted, however, that “the crashworthy fuel tank displayed no deformation or leaking of fuel.” Footage recorded inside the cabin by an onboard camera showed that at least four of the six passengers had not adjusted their harnesses correctly, which the Board cited as having contributed to the severity of their injuries.

Overlooked Gust Lock Caused Runway Excursion

Beechcraft 65-A90-1, June 23, 2016, Hannover, Germany – A runway excursion early in the takeoff roll was traced to the pilot’s failure to recognize and remove the gust lock securing the rudder pedals. BFU investigators found that the chain that should have connected the locks on the control column, power control levers, and rudder pedals was missing, and the red paint on the rudder lock pin had faded to near-invisibility. The pilot, whose transition training had not covered the gust locks, hadn’t previously conducted this model’s preflight inspection alone, though he was familiar with the similar system used in the King Air 200.

The airplane veered left off of Runway 09L as it reached an airspeed of 30 knots. The pilot attempted to keep it on the runway with right rudder, exerting enough force to fracture the pedal, but the airplane slewed left some 70 degrees before coming to rest in the grass. The left rudder pedal’s linkage was also bent. The pilot was able to shut down the engines and exit the cockpit without injury. The BFU noted that the preflight and pre-takeoff checklists did not specify the number or location of gust locks that must be removed.

Hard Landing Result of Deficient Systems Knowledge

Embraer EMB-550 Legacy 500, Nov. 27, 2017, Paris Le Bourget Airport, France – The flight crew’s lack of understanding of the anti-icing system and its relation to the angle-of-attack (AoA) limits imposed by the airplane’s stall protection logic led them to fly the final approach segment at an airspeed below the activation threshold of the AoA limiter, which prevented the captain from flaring the airplane to land. The jet touched down nose-first at a descent rate of 1,350 fpm and a load factor of 4 Gs, shearing the upper rear attachment fitting of the right main landing gear and punching it through the upper surface of the wing. No injuries resulted. France’s BEA also faulted the crew for failing to follow the correct reset procedure in response to an apparent failure of the wing and horizontal stabilizer anti-icing system, then choosing to depart from Moscow Domodedovo Airport in icing conditions in violation of the airplane’s Master Minimum Equipment List. 

The apparent fault in the anti-icing system was probably due to the crew’s having set the mode selection switch to ALL rather than AUTO before engine start, as specified by the pre-start checklist. This bypasses the ice-detection system; as the wing and stabilizer anti-ice cannot operate without engine power, the monitoring circuitry registers a failure. The apparent anti-icing failure, in turn, raises the minimum airspeed at which angle-of-attack limitation becomes effective, but the crew did not recognize the significance of the STALL PROT ANTICIPATE annunciation on the instrument panel, the yellow arc on the primary flight display’s airspeed tape, or the yellow pitch limit indication on the PFD’s attitude display. The EMB-550 flight manual specifies increasing the landing reference speed by 30 knots and the minimum landing distance by 70 percent with STALL PROT ANTICIPATE active, but the captain flew the final approach at 120 knots rather than the 144 knots required in this regime. 

The BEA report also notes that the crew unsuccessfully tried to reset the wing/stabilizer protection by turning the WINGSTAB button off and back on with the anti-icing mode selector still set to ALL. The mode selector’s ICE SPEED RESET position reinitializes AoA limitation to the non-icing airspeed, but not knowing that the higher value was in effect, the pilots did not cancel it.

Low Visibility, Wrong Turn Lead to Controlled Flight Into Terrain

Cessna 208B, Aug. 6, 2019, Mayo, Yukon Territory, Canada – The pilot veered left from his intended course and into a box canyon during a scheduled flight from the Rau Airstrip to the Mayo Airport, both in the Yukon Territory. He and the sole passenger were killed when the Grand Caravan flew wings-level into a hillside shortly after entering IMC. The Transportation Safety Board of Canada (TSB) report suggests that the diversion may have been a simple navigational error. Eyewitnesses placed the airplane at just 200 feet agl shortly before the crash and reported cloud bases at treetop level on the hillsides. Visibility was estimated at one statute mile.

The pilot had been upgraded to captain less than three months earlier. Based on flight data logged by a Garmin 296 GPS, the TSB concluded that this was the first time he’d flown the route in marginal weather conditions. The flight was being done under VFR, but the pilot was instrument-rated with a current proficiency check and the airplane was equipped for instrument flight, offering the possibility of making an emergency climb into the clouds. His training records characterized him as “exceptional, well organized, flew above standard, and adapted well,” but there is no evidence that he had ever performed an emergency transition from visual to instrument references either in training or from actual necessity.

Company rules limited new captains to flying in visibilities of at least five statute miles with ceilings no lower than 2,000 feet. The TSB concluded that he probably encountered lower weather during the outbound flight to Rau Strip, but chose to make the return flight on schedule without consulting either more senior pilots or company dispatch. GPS data shows that the airplane was flying at 156 knots groundspeed, leaving barely 20 seconds’ reaction time in one-mile visibility and nearly tripling the diameter needed to reverse course in a 45-degree bank at 90 knots. The airplane was also equipped with a Garmin GTN 750 capable of providing terrain warnings, but investigators were unable to determine the pre-impact position of the “terrain inhibit” switch that silences those warnings.