Preliminary Reports
Four Dead in Atlanta Citation Crash
Cessna 560 Citation V, Dec. 20, 2018, Atlanta, Georgia—A Memphis-based Citation V crashed just after taking off from Atlanta’s Fulton County Airport, killing all four on board and igniting a post-crash fire. Press reports indicate that among the victims was Memphis businessman Wei Chen, founder of Sunshine Enterprise and a 1998 graduate of the University of Memphis. The airplane was bound for the Millington-Memphis Airport on an instrument flight plan but went down less than two miles from the runway threshold.
In 2011, Chen gained fame as the first Chinese citizen to fly a single-engine airplane around the world. It is still not clear whether he was at the airplane’s controls at the time of the crash. The jet went down in a park, narrowly missing several nearby homes.
A weather observation recorded five minutes later included seven miles’ visibility in light rain below a 600-foot overcast.
Runway Excursion Closes Sendai Airport
Beechcraft 300 Super King Air 350, Dec. 23, 2018, Sendai, Japan—Twenty-eight commercial flights were canceled and four more had to divert after a landing King Air veered off the left side of Runway 27, causing the closure of the 3,000-meter (9,843-foot) Runway 09/27 for some two and a half hours. Video footage shows the airplane abruptly veering off the left side of the runway following an apparently normal touchdown and ground roll. The U.S.-registered turboprop was arriving for maintenance after a ferry flight from New Chitose. The solo pilot was uninjured, and photographs suggest that any damage to the airplane was minimal.
Rescue Helicopter Destroyed in Collision with Zipline
AgustaWestland AW139, Dec. 29, 2018, Jebel Jais, Ras Al-Khaima, United Arab Emirates—All four crewmembers were killed when their helicopter, operated by the UAE’s National Search and Rescue Center, struck a zipline cable en route to airlift a patient from Jebel Jais, the United Arab Emirates’ tallest peak. The 2,832-meter (1.8-mile) zipline, certified as the world’s longest by the Guinness Book of World Records, is part of the Jebel Jais Flight recreational development. Photographs from the scene suggest that the zipline was not marked with any high-visibility warning devices.
No Injuries in Oklahoma HEMS Accident
Aerospatiale AS 350 B2, Jan. 11, 2019, Ponca City, Oklahoma—Both crewmen escaped injury after their medical helicopter rolled over while landing at the Ponca City Regional Airport. The aircraft, operated by Air Evac EMS of St. Charles, Missouri, was being repositioned at the time.
The circumstances of the accident remain unclear. Photographs show the aircraft lying on its right side with apparent damage to the tailboom; the main and tail rotors were destroyed. The crewmen extricated themselves and departed under their own power.
Factual Report
Nebraska Pilot Never Opened Flight Plan
Mitsubishi MU 2B-40, Sept. 23, 2017, Ainsworth, Nebraska—The pilot of a twin-engine turboprop that crashed just after takeoff from the Ainsworth, Nebraska Regional Airport had filed an instrument flight plan but never activated it, instead departing into instrument conditions without a clearance. The airplane came down 3.5 miles northeast of the airport, killing the 69-year-old solo pilot. Local conditions cited in the NTSB’s factual report include visibility of 1.75 miles in mist under a 500-foot overcast. Active alerts along the route included “a convective SIGMET for embedded thunderstorms, a Center Weather Advisory for an area of heavy rain showers, and AIRMET Sierra for an extensive area of IFR conditions,” but a review of National Weather Service composite radar imagery showed “no significant echoes in the immediate vicinity of the accident site.”
The pilot contacted the Fort Worth Flight Service Station less than 15 minutes before the accident to file an IFR flight plan to the Bottineau, North Dakota Municipal Airport at a requested altitude of 16,000 feet. He declined a briefing on adverse weather conditions along his route of flight. Notams in effect at Ainsworth that day advised that the remote communications outlet and hazardous in-flight weather advisory service frequency were out of service; however, the pilot had filed his flight plan via his mobile telephone, which he presumably could have used to obtain an IFR clearance.
Based on the pilot’s most recent application for a medical certificate and interviews with the airplane’s co-owner, investigators estimated that he had about 3,775 hours of flight experience that included approximately 2,850 in type. He had completed recurrent training at SimCom in June, three months before the accident. The co-owner reported that the two had jointly owned several MU-2Bs since 2000.
The airplane was reported missing at noon after failing to arrive at Bottineau. The wreckage was not located until 6 p.m. No primary or secondary targets on air traffic control radar could be associated with the flight, but low-altitude radar in the area was also out of service.
The airplane was equipped with a Chelton electronic flight display as well as two back-up attitude indicators, one on each side of the instrument panel. During a flight the previous Wednesday the pilot had seen what he described as a “transient display” on the Chelton system, which he’d reported to both his partner and the manager of their avionics shop; no further details were provided. Impact damage prevented functional testing of the system after the accident.
While probable cause of the accident has not been determined, the factual report cites the FAA’s Introduction to Aviation Physiology and Airplane Flying Handbook on the subject of spatial disorientation.
Final Reports
Wingtip Strike Traced to Icing During Approach
Embraer EMB-500 (Phenom 100), Feb. 15, 2013, Berlin-Schönefeld Airport, Germany—Investigators for Germany’s BFU have determined that ice accumulated on approach caused the Phenom’s left wing to stall during the landing flare. The airplane rolled left, striking the wingtip, then back to the right, fracturing the right main landing gear. The pilots’ faulty understanding of the interaction between the airplane’s anti-icing and stall warning protection systems was cited as a contributing factor.
The accident occurred at the end of a flight from Belgium’s Kortrijk-Welvelgem Airport with one passenger on board. Although Schönefeld’s ATIS Information Zulu reported moderate icing below 3,000 feet, the captain chose not to activate the pneumatic boots on the wings and horizontal stabilizer during an ILS approach to Runway 07L because he did not see ice on the portion of the left wing visible from the cockpit. (He did turn on the engine and windshield anti-icing systems.) As noted in the BFU’s report, the EMB-500 Airplane Flight Manual calls for the use of all anti-icing systems at temperatures below 5 degrees Celsius when visible moisture is present; the temperature at the time of the accident was 0 Celsius with a 1,400-foot ceiling and three miles’ visibility in mist.
Engaging the wing and stabilizer boots increases landing reference speed by 23 knots and reduces the angle of attack that activates the stall warning system from 21 to 9.5 degrees. The stick pusher is triggered at a 15.5-degree AoA compared to 28.4 degrees with the wing and stabilizer anti-icing turned off.
Loose Bolt Caused Helicopter Drive Shaft Failure
Bell 206B, May 26, 2017, Rockville, Idaho—Fatigue cracks in one of the flexible couplings of the engine-to-transmission drive shaft were traced to a loose bolt whose washer wore a depression in the outside surface of the coupling while the bolt itself gouged the inner surface of its mounting hole. Fatigue cracks propagated, subsequently causing the remainder of the coupling to fail in overstress, according to a probable cause report published on December 19.
During an aerial application flight at about 40 to 50 feet above ground level, the pilot heard a “growling” noise followed by a sudden bang and complete loss of power. The pilot attempted an autorotation and the helicopter landed hard in a marshy field, damaging the tail boom and fuselage. Disassembly of the remaining flexure elements did not identify any similar patterns of damage.
Premature Liftoff, Maintenance Practices Implicated in NWT Accident
Airbus Helicopters AS350B2, Feb. 15, 2018, Tulita, Northwest Territories, Canada—The pilot’s rushed response to a possible episode of ground resonance was the proximate cause, but the TSB also drew attention to the operator’s failure to investigate increased vibration observed after the main rotor blades were removed and reinstalled. Contrary to Canadian Aviation Regulations, the operator did not routinely log blade removal and reinstallation or track vibration levels. The accident occurred near a timber helipad at a remote telecommunications tower at Bear Rock, three miles north-northwest of Tulita.
About 30 minutes after landing, the pilot conducted a ground run in accordance with the cold-weather supplement to the helicopter’s operating manual. During a second ground run, the aircraft began bucking back and forth on its skids, which intensified after the pilot reduced fuel flow. Suspecting ground resonance, he increased power to take off, but did not advance fuel flow completely. The helicopter lifted with main rotor and engine rpm below the flight governing range, descended, and tumbled down a hillside. The pilot extricated himself and was subsequently evacuated with a badly broken arm.
Ground resonance is a phenomenon specific to helicopters with fully articulated main rotor systems. Vibration in the main rotor (sometimes caused by a hard landing that pushes one blade out of phase with the others) sets up a sympathetic vibration in the fuselage; if its frequency is close to the airframe’s natural harmonic frequency, the two vibrations amplify one another until the helicopter shakes itself to pieces. Lifting off allows the vibration to dissipate while the blades realign.
The pilot had been aware of increased vibration levels since the main rotor blades had been removed and reinstalled three days earlier. Though the equipment was available on site, maintenance personnel did not measure vibration levels or check blade track and balance. The helicopter had been flown another six hours at the time of the accident.