# NTSB ANC00LA133: Piper PA-31-350, N4105D, Emmonak, AK, September 15, 2000 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 14, 2000, 19:10 local (Sep 15, 2000, 03:10 UTC) - Place: Emmonak, AK - Coordinates: 62.789661, -164.549835 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=62.7897&lon=-164.5498&mi=10 - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report July 10, 2001 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 50360 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC00LA133 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/50360/pdf - Page: https://openairdocs.org/ntsb/ANC00LA133 ## Probable cause The pilot's continued operation of the airplane on unsuitable terrain, and the subsequent failure of the main landing gear torque link. Factors in the accident were rough and uneven runways, and inadequate surveillance of airport facilities/runway conditions by company management. ## Analysis The airline transport certificated pilot was landing a twin engine airplane on a rough, gravel runway that contained potholes. The commuter flight had just departed a similar, rough runway. During the landing roll, the airplane rolled down the runway for about 600 feet. The right main landing gear wheel then rotated about 90 degrees in its landing gear strut housing, and slid along the surface of the gravel runway for several hundred feet. The lower landing gear strut and wheel then broke away from the upper strut housing. The right wing settled onto the runway. The right propeller tips, and the trailing edge of the right flap were damaged. The right wing attach points for the landing gear were not damaged. Upon inspection of the airplane, a torque link, installed on the right main landing gear strut, was found fractured at the outer pivot bolt hole. An metallurgical examination of the torque link revealed a fracture through the pivot point of the link with features typical of overstress separation. No evidence of preexisting conditions, such as crack arrest marks, or corrosion damage was found. ## Factual narrative On September 14, 2000, about 1910 Alaska daylight time, a Piper PA-31-350 airplane, N4105D, sustained substantial damage during landing at Emmonak, Alaska. The airplane was being operated as Flight 166 on a visual flight rules (VFR) scheduled domestic flight under Title 14, CFR Part 135, when the accident occurred. The airplane was operated by Grant Aviation Inc., Anchorage, Alaska. The airline transport certificated pilot, and the three passengers, were not injured. Visual meteorological conditions prevailed. VFR company flight following procedures were in effect. The flight originated at the Alakanuk Airport, Alakanuk, Alaska, at 1900. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on September 14, 2000, the company's vice president for airline operations reported that the runway surface at Alakanuk is rough with several potholes. The runway at Emmonak is also rough with several potholes. When the pilot landed at Emmonak, the airplane rolled down the runway for about 600 feet. The right main landing gear wheel then rotated about 90 degrees in its landing gear strut housing, and slid along the surface of the gravel runway for several hundred feet. The lower landing gear strut and wheel then broke away from the upper strut housing. The right wing settled onto the runway. The right propeller tips, and the trailing edge of the right flap were damaged. The right wing attach points for the landing gear were not damaged. Upon inspection of the airplane, a torque link, installed on the right main landing gear strut, was found fractured at the outer pivot bolt hole. The vice president said that the loss of the torque link allowed the right landing gear wheel to rotate within the upper landing gear strut housing. On September 25, 2000, the director of maintenance for the company reported that the airplane received damage to the aft fuselage bulkhead, and the leading edge of the right horizontal stabilizer. Additionally, the leading edge of the right wing was damaged when it struck a runway light fixture. The fractured torque link was sent to the National Transportation Safety Board's Materials Laboratory for examination. The examination revealed a fracture through the pivot point of the link with features typical of overstress separation. No evidence of preexisting conditions, such as crack arrest marks, or corrosion damage was found. ## Aircraft - Registration: [N4105D](https://openairdocs.org/aircraft/N4105D), registered now, S/N 31-8252027, built 1981 (OpenAirDocs) - Reported make and model: Piper PA-31-350 - Registry model: [Piper PA-31-350](https://openairdocs.org/model/piper-pa-31-350) (registry code 7103110) (OpenAirDocs) - Registry engine: [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series) (registry code 41533, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 31-8252027 - Airframe hours: 9340 - Engines: Lycoming TIO-540-J2BD 350 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Registered owner: Grant Aviation Inc. - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, September 5, 2000, 25 hours before - Departed: AUK, ALAKANUK, AK - Destination: PAEM - Flight plan: Company VFR - Airport: PAEM, Emmonak, runway 16, 4,400 × 75 ft, gravel ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 5,500 total, 600 in this make and model, 5,200 as pilot in command, 250 in the last 90 days, 70 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 225° at 7 knots, gusting 12 - Visibility: 7 statute miles - Lowest ceiling: 3,000 ft overcast - Temperature: 63 °F ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20000914038749A](https://openairdocs.org/incident/20000914038749A), Sep 14, 2000: Piper PA31350, Emmonak, AK, Substantial damage. (.19) On September 14, 2000, about 1915 Alaska daylight time, a Piper PA-31-350 airplane, N4105D, sustained substantial damage during landing at Emmonak,… ## Other investigations on N4105D (2) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB ANC04LA059](https://openairdocs.org/ntsb/ANC04LA059), May 23, 2004: Piper PA-31-350 (N4105D), Goodnews, AK, substantial damage. Probable cause: The pilot's inadequate weather evaluation which resulted in an in-flight encounter with severe turbulence, and his exceedence of the design stress limits resulting in overstress of the wings. A… - [NTSB ANC97LA041](https://openairdocs.org/ntsb/ANC97LA041), Mar 27, 1997: Piper PA-31-350 (N4105D), Nome, AK, substantial damage. Probable cause: a fuel leak from an engine driven fuel pump which initiated an engine fire, and the fuel pump manufacturer's inadequate quality control of the fuel pump. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.