# NTSB ANC94LA044: Piper J3, N37932, Denali Nat'L Pk, AK, April 10, 1994 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 9, 1994, 17:00 local (Apr 10, 1994, 01:00 UTC) - Place: Denali Nat'L Pk, AK - Coordinates: 63.780075, -148.51918 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=63.7801&lon=-148.5192&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report January 12, 1995 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 2493 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC94LA044 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/2493/pdf - Page: https://openairdocs.org/ntsb/ANC94LA044 ## Probable cause THE FAILURE OF THE LANDING GEAR BOLT ATTACHMENT FITTING DUE TO FATIGUE. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Gear collapsed, landing - flare/touchdown - landing gear,main gear attachment - failure,total (cause) - landing gear,main gear attachment - fatigue (cause) ## Analysis THE PRIVATE PILOT, ALASKA HUNTING GUIDE, WAS FLYING SUPPLIES TO CLIENTS IN THE FIELD LANDED ON REMOTE SNOW COVERED TUNDRA. UPON LANDING, THE RIGHT LANDING GEAR BOLT ATTACHMENT FITTING FAILED AND THE PLANE GROUND LOOPED. PREEXISTING FATIGUE WAS NOTED ON ATTACHMENT FITTING. THE FITTING IS NORMALLY ENCLOSED IN FABRIC RENDERING IT INACCESSIBLE FOR VISUAL INSPECTION. ## Factual narrative On April 8, 1994, at 1645 Alaska daylight time, a ski equipped Piper J-3 Cub airplane, N37932, owned and operated by the pilot- in-command, crashed during landing at a remote landing site near the Tokositna River in the Denali National Park. The private certificated pilot, an Alaska registered hunting guide, the sole occupant, was not injured and the airplane sustained substantial damage. The business flight, conducted under 14 CFR Part 91 for the purpose of resupplying a hunting camp, last departed Trapper Creek, Alaska and the intended destination was the accident site. The pilot reported that at the time of the accident, visual meteorological conditions prevailed and there was no filed flight plan in effect. On the evening of April 09, 1994, the NTSB investigator-in-charge conducted a telephone interview with the pilot-in-command. The pilot reported that he was delayed in getting into the camp earlier in the day due to reduced visibility from a mixture of light rain and snow and there was poor contrast with the surrounding terrain which produced a flat light condition. Upon landing, was reported normal in every way, the right landing gear collapsed due to a gear bolt attachment failure. The right ski tipped forward and dug into the snow causing the right wing tip to collide with the snow resulting in a ground loop. The pilot forwarded the failed bolt attachment fitting to the NTSB investigator-in-charge. The fitting evidenced preexisting fatigue in the form of darkened discoloration along the fracture surface. The fitting is normally enclosed in fabric rendering it inaccessible for visual inspection. ## Aircraft - Registration: [N37932](https://openairdocs.org/deregistered/N37932-2015-05-19), registration cancelled 2015-05-19, S/N 6709, built 1941 (OpenAirDocs) - Reported make and model: PIPER J3 - Registry model: [Piper J3C-65](https://openairdocs.org/model/piper-j3c-65) (registry code 7100510) (OpenAirDocs) - Registry engine: [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series) (registry code 41505, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: 6709 - Airframe hours: 10110 - Engines: LYCOMING O-235-C1-TC 115 horsepower reciprocating - Damage: Substantial damage - Flight: Business, Part 91 - Operator: Hutcheson, Calvin W. - Registered owner: Hutcheson, Calvin W. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 4, 1993, 146 hours before - Departed: TRAPPER CREEK, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; private; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: front; flight hours: 2,511 total, 2,151 in this make and model, 2,511 as pilot in command, 112 in the last 90 days, 30 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: 1,500 ft overcast - Temperature: 37 °F, dew point 34 °F - Altimeter: 29.00 inHg ## 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 19940409000119A](https://openairdocs.org/incident/19940409000119A), Apr 9, 1994: Piper J3C65, Denali National, AK, Substantial damage. Bolt holding right ski broke landing. Ski dug in. Dragged a wing on remote strip and ground looped. 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.