# NTSB ANC01LA116: Piper PA-18, N4167Z, Anaktuvuk Pass, AK, August 6, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 6, 2001, 14:00 local (22:00 UTC) - Place: Anaktuvuk Pass, AK - Coordinates: 68.711669, -151.886672 - Nearby events: https://openairdocs.org/map.md?lat=68.7117&lon=-151.8867&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 20, 2002 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA-AL-FAI FSDO 01 - NTSB case key (mKey): 53078 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC01LA116 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/53078/pdf - Page: https://openairdocs.org/ntsb/ANC01LA116 ## Probable cause A failure of the landing gear strut assembly due to corrosion. A factor in the accident was the pilot's inadequate maintenance of the airplane. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - flare/touchdown - landing gear,main gear strut - corroded (cause) - maintenance - inadequate, pilot in command (contributing factor) - On ground/water encounter with terrain/water, landing - flare/touchdown - terrain condition - rock(s)/boulder(s) ## Analysis The commercial certificated pilot was landing at a remote airstrip. When the airplane touched down, the right main landing gear strut collapsed. The propeller struck the ground, and the leading edge of the right wing struck a large rock. The pilot activated the airplane's emergency locator transmitter, and a search and rescue helicopter picked up the pilot. A postaccident examination of the airplane revealed extensive corrosion of the landing gear strut. ## Factual narrative On August 6, 2001, about 1400 Alaska daylight time, a tundra tire-equipped Piper PA-18 airplane, N4167Z, sustained substantial damage during a landing at a remote airstrip near Gunsight Mountain, located about 35 miles north-northeast of Anaktuvuk Pass, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country business flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by Arctic North Guiding Inc., North Pole, Alaska. The commercial certificated pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The Federal Aviation Administration (FAA) notified the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on August 6th, that an emergency transmitter locator (ELT) signal had been detected north of the Brooks Mountain Range. A search and rescue helicopter from the North Slope Borough, Barrow, Alaska, responded to the scene and picked up the pilot. The pilot was taken by the helicopter to the pilot's hunting camp. The helicopter crew reported the pilot made a hard landing, and the airplane received damage to the right landing gear strut assembly, the propeller, and the leading edge of the right wing. An FAA inspector, Fairbanks Flight Standards District Office (FSDO), reported that after temporary repairs by a mechanic, the airplane was flown to Fairbanks, Alaska. The inspector examined the airplane on August 20, and reported the landing gear strut assembly had evidence of extensive corrosion. The inspector said that when the landing gear strut failed, the leading edge of the right wing collided with a large rock. About two feet of the leading edge of the wing was crushed aft about 4 inches. The closest official weather observation station is Anaktuvuk Pass. On August 6, 2001, at 1355, an automated weather observation system (AWOS) was reporting in part: Wind, 180 degrees (true) at 5 knots; visibility, 10 statute miles; clouds and sky condition, 3,400 feet scattered, 4,600 feet overcast; temperature, 45 degrees F; dew point, 43 degrees F; altimeter, 29.84 inHg. ## Aircraft - Registration: [N4167Z](https://openairdocs.org/aircraft/N4167Z), registered now, S/N 18-8349, built 1965 (OpenAirDocs) - Reported make and model: Piper PA-18 - Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-8349 - Airframe hours: 4520 - Engines: LYCOMING O-320-B2A 160 horsepower reciprocating - Damage: Substantial damage - Flight: Business, Part 91 - Registered owner: Arctic North Guiding Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 29, 2001, 25 hours before - Departed: PAKP, ANAKTUVUK PASS, AK - Destination: ANAKTUVUK PASS, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; injuries: none; commercial; airplane ratings: single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review September 30, 2000; seat: front; flight hours: 4,680 total, 4,110 in this make and model, 4,668 as pilot in command, 22 in the last 90 days, 22 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 154° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 4,600 ft overcast - Temperature: 45 °F, dew point 43 °F - Altimeter: 29.84 inHg - Observed at: PAKP, 35 nm away ## 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 20010806020259A](https://openairdocs.org/incident/20010806020259A), Aug 6, 2001: Piper PA18150, Anaktuvukpass, AK, No damage. (.19) On August 6, 2001, about 1430 Alaska daylight time, a tundra tire-equipped Piper PA-18 airplane, N4167Z, sustained substantial damage during a landing at… ## Other investigations on N4167Z (1) 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 ANC06LA056](https://openairdocs.org/ntsb/ANC06LA056), May 19, 2006: Piper PA-18 (N4167Z), Naknek, AK, substantial damage. Probable cause: A loss of engine power during cruise flight for an undetermined reason, which resulted in a forced landing and subsequent collision with high vegetation and the ground. 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.