# NTSB ANC09LA064: Douglas DC-3C, N777YA, Skwentna, AK, July 7, 2009 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 7, 2009, 12:00 local (20:00 UTC) - Place: Skwentna, AK - Coordinates: 61.983333, -152.083053 - Nearby events: https://openairdocs.org/map.md?lat=61.9833&lon=-152.0831&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Defining event: [Taxi-from runway: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report May 11, 2010 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration (Airworthiness) - NTSB case key (mKey): 74287 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC09LA064 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74287/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74287 - Page: https://openairdocs.org/ntsb/ANC09LA064 ## Probable cause A fracture of the airplane's tailwheel shock absorber linkage during taxi, resulting in the collapse of the tailwheel. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: nose/tail landing gear](https://openairdocs.org/ntsb-findings/01023220): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Douglas DC3C, 1 case](https://openairdocs.org/ntsb-findings/01023220/cases.md?model=3021457), [All aircraft, 185 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Taxi-from runway: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Douglas DC3C, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=3021457), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The crew of a tailwheel-equipped airplane landed on a gravel-covered, off-airport site at the completion of a Title 14, Code of Federal Regulations Part 135 cargo flight. The captain said that while taxiing to parking after an uneventful landing, he and the other pilot heard a loud “thump”, and he stopped the airplane. The crew’s inspection revealed that the airplane’s tailwheel had collapsed, and as a result, the fuselage adjacent to the tailwheel sustained substantial damage. A postaccident examination revealed a fractured shock absorber linkage, which was part of the tailwheel swivel assembly. ## Factual narrative On July 7, 2009, about 1200 Alaska daylight time, a tailwheel-equipped Douglas DC-3C airplane, N777YA, sustained substantial damage while taxiing after landing on a gravel-covered, off-airport site, about 24 miles west of Skwentna, Alaska. The airplane was being operated by Bush Air Cargo, Inc., Anchorage, Alaska, as a visual flight rules (VFR) on-demand charter flight, under the provisions of Title 14 Code of Federal Regulations (CFR) Part 135. The airline transport captain, the commercial first officer, and the sole passenger, were not injured. Visual meteorological conditions prevailed, and company flight following procedures were in effect. The flight departed the Palmer Airport, Palmer, Alaska, about 1100. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on July 7, the captain reported that after an uneventful landing on the gravel-covered site, he elected to roll to the end, turn around, then back-taxi to parking at the opposite end of the site. He said that after completing the 180 degree turn, he and the other pilot heard a loud “thump”, and he stopped the airplane about mid-way along the site. The crew’s inspection revealed that the airplane’s tailwheel had collapsed, and as a result, the fuselage adjacent to the tailwheel sustained substantial damage. On July 10, a Federal Aviation Administration airworthiness inspector from the Anchorage Flight Standards District Office traveled to the operator’s maintenance facility in Girdwood, Alaska, and examined the airplane after it was recovered. The inspector reported finding a fractured tailwheel shock absorber linkage, part number 2115849-1, which was part of the tailwheel swivel assembly. ## Aircraft - Registration: [N777YA](https://openairdocs.org/deregistered/N777YA-2018-03-20), registration cancelled 2018-03-20, S/N 25634, built 1944 (OpenAirDocs) - Reported make and model: DOUGLAS DC-3C - Registry model: [Douglas DC3C](https://openairdocs.org/model/douglas-dc3c) (registry code 3021455) (OpenAirDocs) - Registry engine: [Pratt & Whitney R-1830-92](https://openairdocs.org/engine/pratt-whitney-r-1830-92) (registry code 51627, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 25634 - Airframe hours: 25950 - Engines: Pratt & Whitney 1830-92 1200 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Operator: Bush Air Cargo Inc - Registered owner: Bush Air Cargo Inc - Airworthiness certificate: Standard, Transport - Departed: PAQ, Palmer, AK - Destination: Skwentna, AK - Flight plan: Company VFR - Airport: runway 30, 3,500 × 100 ft, gravel ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 51; injuries: none; airline transport, flight engineer; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: left; flight hours: 8,000 total, 400 in this make and model, 5,000 as pilot in command, 60 in the last 90 days, 2 in the last 24 hours - Co-pilot; age 59; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane, helicopter; medical: class 2, with waivers/limitations; last flight review January 21, 2009; seat: right; flight hours: 13,000 total, 300 in this make and model, 69 in the last 90 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 25 statute miles - Lowest ceiling: none - Temperature: 64 °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 20090707047609A](https://openairdocs.org/incident/20090707047609A), Jul 7, 2009: Douglas Acf DC3, Hayes River, AK. After landing on an unimproved strip there was a bump during taxi to the parking area. The lower link from the tailwheel damper assembly to the tailwheel fork… ## Other investigations on N777YA (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 ANC06LA032](https://openairdocs.org/ntsb/ANC06LA032), Mar 1, 2006: Douglas DC-3 (N777YA), Beluga, AK, substantial damage. Probable cause: The pilot's failure to maintain altitude/clearance from trees on final approach, which resulted in an in-flight collision with trees. - [NTSB ANC86LA015](https://openairdocs.org/ntsb/ANC86LA015), Dec 16, 1985: Douglas DC-3C (N777YA), Dillingham, AK, substantial damage ## Docket (2 files) The files NTSB released with the investigation on April 1, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74287. 788 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 754 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40327921&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Telephone Conversation - FAA Inspector (item 2, .PDF, 34 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40327923&FileExtension=.PDF&FileName=Record%20of%20Telephone%20Conversation%20-%20FAA%20Inspector-Master.PDF 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.