# NTSB ANC07LA018: Piper PA-12, N3233M, Glennallen, AK, February 1, 2007 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: February 1, 2007, 09:45 local (13:45 UTC) - Place: Glennallen, AK - Coordinates: 62.522777, -145.976669 - Nearby events: https://openairdocs.org/map.md?lat=62.5228&lon=-145.9767&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report May 29, 2007 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA-AL-ANC FSDO 03 - NTSB case key (mKey): 65384 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC07LA018 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/65384/pdf - Page: https://openairdocs.org/ntsb/ANC07LA018 ## Probable cause The pilot's failure to maintain adequate airspeed to preclude a stall while maneuvering, which resulted in an uncontrolled descent and subsequent collision with terrain. Factors contributing to the accident were variable wind conditions, and an inadvertent stall. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, maneuvering - airspeed(vs) - not maintained, pilot in command (cause) - weather condition - variable wind (contributing factor) - stall - inadvertent, pilot in command (contributing factor) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - snow covered ## Analysis The commercial certificated pilot was maneuvering to land his ski-equipped airplane on a snow-covered lake during a Title 14, CFR Part 91, personal flight. The pilot reported that he and his passenger were scouting the area for a wolf hunt, and decided to land on a remote frozen lake. While making a slight left turn toward the landing area, he said he encountered a windshear about 20 feet above the ground. He said the airplane was configured with 20 degrees of flaps, and the airspeed was about 45 mph. The pilot indicated the left wing stalled, and the airplane descended, colliding with the surface of the lake. The airplane received structural damage to the left wing, fuselage, and landing gear. The pilot described the wind conditions as light and variable winds, with no gusts. He also indicated that the wind shifted several times after the accident. ## Factual narrative On February 1, 2007, about 0945 Alaska Standard time, a ski-equipped Piper PA-12 airplane, N3233M, sustained substantial damage when it collided with snow-covered terrain while maneuvering to land on a remote lake, about 30 miles northwest of Glennallen, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight under Title 14, CFR Part 91 when the accident occurred. The airplane was operated in visual meteorological conditions by the pilot/owner of Copper Valley Air Service, LLC, Glennallen. The commercial certificated pilot was not injured. The sole passenger received minor injuries. The flight originated at the Gulkana Airport, Gulkana, Alaska, about 0920, and no flight plan was filed. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on February 2, the pilot reported that he and the passenger were scouting the area for a wolf hunt, and decided to land on a frozen lake. While making a slight left turn toward the landing area, he said he encountered a windshear about 20 feet above the ground. He said the airplane was configured with 20 degrees of flaps, and the airspeed was about 45 mph. The pilot indicated the left wing stalled, and the airplane descended, colliding with the surface of the lake. The airplane received structural damage to the left wing, fuselage, and landing gear. On the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) submitted by the pilot, the pilot described the weather conditions as clear, visibility unlimited, a temperature of about 15 degrees F, light and variable winds, with no gusts. He also indicated that he observed several wind shifts after the accident. ## Aircraft - Registration: [N3233M](https://openairdocs.org/aircraft/N3233M), registered now, S/N 12-2027, built 1947 (OpenAirDocs) - Reported make and model: Piper PA-12 - Registry model: [Piper PA-12](https://openairdocs.org/model/piper-pa-12) (registry code 7101202) (OpenAirDocs) - Registry engine: [Lycoming O-320-A2B](https://openairdocs.org/engine/lycoming-o-320-a2b) (registry code 42101, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 2027 - Airframe hours: 2910 - Engines: Lycoming O-320-B2D 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, October 1, 2006, 11 hours before - Departed: PAGK, Glennallen, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; injuries: none; commercial; airplane ratings: single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review June 1, 2006; seat: front; flight hours: 7,000 total, 1,500 in this make and model, 6,200 as pilot in command, 15 in the last 90 days, 11 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 60 statute miles - Lowest ceiling: none - Temperature: 16 °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 20070201001599A](https://openairdocs.org/incident/20070201001599A), Feb 1, 2007: Piper PA12, Glennallen, AK, Substantial damage. (-23) The pilot stated while maneuvering for landing on a remote lake, the aircraft controls became ineffective and the left wing dropped and contacted the… ## Other investigations on N3233M (3) 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 GAA17CA511](https://openairdocs.org/ntsb/GAA17CA511), Aug 26, 2017: Piper PA 12 (N3233M), Gulkana, AK, substantial damage. Probable cause: The pilot’s inadequate in-flight fuel planning, which resulted in a loss of engine power due to fuel exhaustion. - [NTSB ANC10LA012](https://openairdocs.org/ntsb/ANC10LA012), Jan 14, 2010: Piper PA-12 (N3233M), Gulkana, AK, substantial damage. Probable cause: The pilot's selection of unsuitable terrain for landing, which resulted in structural damage to the airplane during landing. - [NTSB ANC02LA113](https://openairdocs.org/ntsb/ANC02LA113), Sep 3, 2002: Piper PA-12 (N3233M), Chickaloon, AK, substantial damage. Probable cause: The pilot's failure to maintain control of the airplane during the landing roll, which precipitated a nose over. 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.