Preliminary Report: Turboprop Accident in Nepal #1
De Havilland Canada DHC-6, Jomsom Airport (VNJS), Nepal, May 16, 2013–The Twin Otter was destroyed while landing at Nepal’s Jomsom Airport, seriously injuring six of 21 people aboard. Operated in regular passenger service by Nepal Airlines, the twin turboprop skidded off the airport’s 1,742-foot runway, traveled down a nearby slope and came to rest on the banks of the Kali Gandaki River.
Preliminary Report: Turboprop Accident in Nepal #2
Cessna C208 Grand Caravan, Simikot Airport (VNST), Nepal, May 27, 2013–A Grand Caravan operated by Goma Air landed hard and burst a tire on the right main landing gear just after touchdown, causing the aircraft to skid off the right side of the runway. The aircraft then struck a nearby ditch, shearing off the right main landing gear and damaging the wing and propeller. None of the 11 people on board was injured.
Preliminary Report: Turboprop Accident in Nepal #3
Dornier Do-228, Simikot Airport (VNST), Nepal, June 1, 2013–A Dornier Do-228 operated by Sita Air was substantially damaged during a landing accident at Nepal’s Simikot Airport. The accident occurred at 7:14 a.m. when the twin turboprop landed hard on the airport’s 1,800-foot runway, shearing off its left main landing gear. The aircraft came to rest on the side of the runway with no injuries to the two pilots or the five passengers. Nineteen people died in September last year when another Sita Air Do-228 crashed on approach to Kathmandu.
Preliminary Report: LongRanger Loses Tail-rotor Control
Bell 206L, near La Junta, Colo., May 7, 2013–The Part 91 helicopter departed La Junta Municipal Airport (KLHX) at noon on an aerial observation flight. Shortly after takeoff, the pilot lost control of the Bell’s tail rotor. During the subsequent hard landing, the tailboom separated, and the fuselage and main rotor were also damaged. Neither the pilot nor the two passengers were injured in the accident. The helicopter was operated by Corporate Aircraft Services.
Preliminary Report: Q400 Damaged in Tail Strike
Bombardier Dash 8-402Q, Sault Saint Marie (CYAM), Ontario, May 26, 2013–A Q400 operated by Porter Airlines was substantially damaged in a tail strike while landing at CYAM. While on final approach, the flying pilot reduced power, and the substantially increased rate of descent was not arrested before impact. The aircraft touched down hard at a high pitch angle, striking the tail and resulting in significant skin and structural damage. The aircraft was able to taxi to the ramp under its own power. None of the 63 people on board was injured in the accident.
Preliminary Report: Learjet Crew Unable to Avert Overrun Accident
Bombardier Learjet 35A, McMinnville Municipal Airport (KMMV), Ore., May 13, 2013–None of the three crewmembers aboard the Learjet was injured when the pilot was unable to stop the aircraft after landing on KMMV’s 5,420-foot Runway 4/22. The aircraft’s wings and fuselage were substantially damaged after the aircraft left the hard surface. The Part 91 aircraft, crewed by Evergreen International Aviation, was completing a post-maintenance positioning flight at the time of the incident.
The pilot reported that upon landing he deployed the spoilers and then pulled the power levers to the thrust-reverser detent position but saw no deployment indicators. He recycled the thrust levers, with the same result. Both pilots attempted to troubleshoot as the airplane continued along the runway. The flying pilot applied the brakes but felt no response and the aircraft did not slow. As the airplane approached the threshold, the pilot engaged the steering lock switch, but the nosewheel steering was also inoperative. He pulled the emergency brake just before the aircraft rolled off the pavement’s end, but the aircraft continued through the ILS antennas and down an embankment. Subsequent examination revealed the mounting screws for both the left and right main landing gear squat switches were loose and that the switches had backed away from their mounting pads.
Preliminary Report: Helicopter Damaged During Spray Operations
Aero Falcon Exporters OH-58A, near Somerton, Ariz., May 4, 2013–The OH-58, operating under Part 137 aerial application regulations, originally departed from Yuma International Airport (KNYL). The helicopter later collided with terrain during the pilot’s 15th crop-dusting run of the day. Visual conditions prevailed at the time of the accident and the pilot escaped unharmed. The pilot stated that he was in a left turn, and continued to apply left cyclic until it hit the stop although the helicopter continued to drift right toward some power lines. The pilot applied up collective and left pedal to maneuver over the power lines when the helicopter started an uncommanded rotation to the right and collided with terrain as the pilot attempted to regain directional control.
Factual Report: JetRanger Collides with Power Line After Takeoff
Bell 206, near Hartford, Ky., May 10, 2013–The helicopter, registered to and operated by Provine Helicopter Service, collided with a power line during an aerial application flight at approximately 6:42 p.m. VMC prevailed at the time of the Part 137 flight. The helicopter sustained substantial damage, but the commercial pilot, the sole occupant, was not injured. The flight had originated five minutes earlier from a location immediately adjacent to the accident site.
The pilot said he had just loaded the final tank of chemicals for the day and circled over the field three times looking for power lines, obstructions, houses and people as he tried to develop a plan to spray the field. He successfully completed two spray passes but during the third he heard a “pop” and saw “…the lines” as they contacted the windshield. The helicopter was controllable briefly but then yawed slowly to the right and slightly down, at which point the pilot lost all control. The helicopter continued to rotate clockwise and veered to the right, hitting the ground on the left side. The pilot reported there were no pre-impact mechanical failures or malfunction with the helicopter or its systems.
The Provine policy and procedures manual in effect at the time of the accident specified extensive duties and responsibilities of the pilot, which included a requirement for a conference before application to each field being sprayed. The pre-work conference specifies that the tract representative, ground crew and pilot agree on and understand the weather conditions, locations of the tract and boundaries, products being applied and their rates, landing zones, adjacent landowners and potential for miscommunication. However, nowhere in the manual is it spelled out that potential flight hazards be identified.
As a result of this accident, the operator changed the procedures manual to require that all parties specifically identify flight hazards during the pre-work conference.
Final Report: Helicopter’s Main Rotor Severed Tailboom
Hughes 369D, near Meeker, Colo., March 8, 2011–The NTSB determined that the probable cause of an accident that substantially damaged a Hughes helicopter was the main rotor’s in-flight contact with the tailboom, severing it from the fuselage, according to the NTSB. The pilot was unharmed and the single passenger aboard received only minor injuries.
The accident helicopter, registered to and operated by Quicksilver Air, was being operated as a public-use flight for the Colorado Division of Wildlife as part of a deer capture operation and departed Meeker Airport (KEEO) at noon in marginal VFR conditions.
The pilot reported the crew was conducting its seventh deer capture of the day and was herding a deer toward the road to aid in a clear capture when he felt the first shudder or jolt through the helicopter airframe and controls. The pilot estimated he was 40 feet above the trees and that the airspeed was between 25 and 30 knots when the shudder or jolt occurred. The first jolt was immediately followed by a bang, at which time the helicopter started to rotate to the right. The helicopter then pitched nose down with forward movement as it rotated to the right, and hit the ground.
The empennage was found 70 feet east of where the rest of the helicopter came to rest. Examination of the helicopter, engine and related systems revealed no mechanical anomalies. Metallurgical examination revealed features consistent with overstress separations on all fractures in the tailboom and the driveshaft. The damage and mode of separation of the empennage was consistent with impact from a main rotor blade.
The manufacturer noted that main-rotor contact with the fuselage is possible only with low rotor rpm or flight outside the approved operational envelope. However, the pilot indicated that there were no bells, horns or warnings before the bang and that he did not receive a low-rotor warning or a chip light.
During the post-crash investigation, battery power was applied to the instrument panel to verify correct light sequence. A “press-to-test” functional check of the trim actuators and the power governor “beep” switch revealed no anomalies. Investigators also confirmed cyclic and collective continuity from the stick and lever through to the main rotor hub. Both chip detectors on the engine were noted to be free from contaminants. The investigation was unable to conclude that low rotor rpm or flight outside the approved operational envelope led to separation of the tailboom.
Final Report: Pilot Lost Control of Twin Otter
De Havilland Canada DHC-6-100, Clayton County Airport (4A7), Hampton, Ga., March 8, 2011–The NTSB blamed the Twin Otter crash on the pilot’s inability to regain control of the aircraft after the wing stalled in the traffic pattern for Clayton County’s Runway 6. The two pilots, the only occupants, were killed.
The flight was a local maintenance test after both of the Twin Otter’s 550-shp Pratt & Whitney Canada PT6A-20 engines had been replaced with 680-shp PT6A-27s. The same Hartzell propellers used on the -20 engines had been reinstalled on the -27s. The aircraft had not flown for five months before the accident flight.
Witnesses saw the airplane depart and complete two uneventful touch-and-go landings before they say the aircraft struggled to gain altitude and airspeed while maneuvering for the third landing. One witness, an aircraft mechanic, saw the airplane yawing to the left and heard noises he associated with propeller pitch changes, which he also believed consistent with propeller operation in the “Beta” range. The airplane stalled and hit trees in a wooded marsh area about one mile from the airport and came to rest about 80 degrees vertically.
Weather at the time of the accident was good VFR conditions, with wind from the east at 10 knots gusting to 21 knots. Examination of the wreckage did not reveal any pre-impact malfunctions; however, the lack of flight data and cockpit voice recorders and the condition of the wreckage precluded the gathering of additional relevant information. Damage to both engines and both propellers revealed they were likely operating at symmetrical power settings and blade angles at the time of the impact, with any differences in scoring signatures likely the result of impact damage.
Investigators could not determine the reason for the yawing and the noise associated with propeller pitch changes that were reported before the stall. The autopsy of the pilot also revealed nothing unusual that might explain the accident.