# NTSB ANC04LA033: Piper PA-15, N4492H, Big Lake, AK, February 29, 2004 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: February 29, 2004, 12:00 local (16:00 UTC) - Place: Big Lake, AK - Coordinates: 61.707778, -150.516662 - Nearby events: https://openairdocs.org/map.md?lat=61.7078&lon=-150.5167&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report September 1, 2004 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA-AL-ANC FSDO 03 - NTSB case key (mKey): 58840 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC04LA033 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/58840/pdf - Page: https://openairdocs.org/ntsb/ANC04LA033 ## Probable cause An in-flight loss of control for an undetermined reason, which resulted in a forced landing and in-flight collision with trees. ## Analysis The private certificated pilot reported he was in cruise flight, about 800 feet agl, when the ski-equipped airplane began an uncommanded left turn. He applied right aileron control in an attempt to straighten the airplane, but the airplane's left bank became increasingly steep. He also applied right rudder to prevent the airplane from becoming inverted. He said the airplane was in a left descending spiral, and he decided to land as soon as possible. He selected an emergency landing area on a small frozen lake, but was unable to achieve his selected spot. He then selected a stand of trees, and during the landing, the airplane's wings, landing gear, and fuselage received extensive damage. The pilot said that the entire emergency event lasted about one minute. The airplane was rebuilt about 5 months before the accident, and had accrued about 2 hours of operation since the rebuild. The airplane skis were installed just prior to the accident flight. The airplane was disassembled and recovered from the accident site. The airplane fuselage and components were examined by NTSB and FAA personnel. No evidence of a flight control system malfunction was found. The ski retention cables and springs exhibited no anomalies. ## Factual narrative On February 29, 2004 about 1200 Alaska standard time, a ski-equipped Piper PA-15 airplane, N4492H, sustained substantial damage when it collided with trees during an emergency landing, about 18 miles west of Big Lake, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The private certificated pilot, the sole occupant, received minor injuries. Visual meteorological conditions prevailed. The flight originated about 1130 from a cabin on a small frozen lake, about 5 miles west-northwest of Skwentna, Alaska, and was en route to Merrill Field, Anchorage, Alaska. No flight plan was filed, nor was one required. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on March 1, and during an interview on March 8, the pilot reported that after departure from his cabin, he observed areas of sleet near Beluga Mountain. He deviated east of his normal route of flight around areas of low visibility by following the Skwentna River to the Yentna River. While in cruise flight, about 1,200 feet msl, or about 800 feet agl, the pilot said the airplane began a gentle, uncommanded left turn. He applied right aileron control in an attempt to straighten the airplane, but there was no change, and the airplane's left bank became increasingly steep. The pilot applied right rudder to prevent the airplane from becoming inverted. He said the airplane was in a left descending spiral, and he decided to land as soon as possible. He selected an emergency landing area on a small frozen lake, but was unable to achieve his selected spot. He then selected a stand of trees, and during the landing, the airplane's wings, landing gear, and fuselage received extensive damage. The pilot said that the entire emergency event lasted about one minute. The pilot indicated that he made a radio call to an over-flying aircraft to report the accident, but he was unsure of his exact position. No emergency locator transmitter (ELT) was installed in the airplane. The pilot was reported overdue by relatives on February 29, at 2034. Search personnel located the accident site on March 1, about 0830. The closest official weather observation station to the accident location is Skwentna, which is about 26 nautical miles west of the accident site. At 1150, an Aviation Routine Weather Report (METAR) was reporting, in part: Wind, 330 degrees (true) at 4 knots; visibility, 1.5 statute miles in light snow and mist; clouds and sky condition, 1,000 feet broken, 1,800 feet overcast; temperature, 30 degrees F; dew point, 29 degrees F; altimeter, 30.27 inHg. The pilot reported that in the area of the accident, he was flying under 2,000 foot overcast to broken sky conditions, with calm wind conditions. He said the visibility was VFR with low visibility to the south of his position, but clear toward the southeast. The pilot indicated that the airplane was rebuilt, and had an annual inspection in September, 2003. Since the inspection, the airplane had accrued about 2 hours of operation. The pilot also said that airplane skis were installed on the airplane just prior to the accident flight. The installation date was not recorded in the airplane maintenance logs. The airplane was disassembled and recovered from the accident site by friends of the pilot. The wings, ailerons, horizontal stabilizers, elevators, and the rudder, were stored at the home of the pilot. The fuselage was recovered and stored at the pilot's parking spot at Merrill Field. On March 19, the airplane fuselage and components were examined by NTSB and FAA personnel. No evidence of a flight control system malfunction was found. The ski retention cables and springs exhibited no anomalies. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, cruise - reason for occurrence undetermined (cause) - Forced landing, descent - emergency - In flight collision with object, emergency landing - object - tree(s) ## Aircraft - Registration: [N4492H](https://openairdocs.org/aircraft/N4492H), registered now, S/N 15-280 (OpenAirDocs) - Reported make and model: Piper PA-15 - Registry model: [Piper PA-15](https://openairdocs.org/model/piper-pa-15) (registry code 7101502) (OpenAirDocs) - Registry engine: [Continental C85 series](https://openairdocs.org/engine/continental-c85-series) (registry code 17008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 15-280 - Airframe hours: 2810 - Engines: Continental C-85F 85 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Ted W. Greene - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, September 14, 2003, 2 hours before - Departed: Skwentna, AK - Destination: PAMR, Anchorage, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 74; injuries: minor; private; airplane ratings: single-engine sea, single-engine land; medical: class 3, expired; last flight review April 30, 2000; seat: left; flight hours: 4,500 total, 4,300 in this make and model, 4,325 as pilot in command, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 306° at 4 knots - Visibility: 1.5 statute miles - Lowest ceiling: 1,000 ft broken - Temperature: 30 °F, dew point 28 °F - Altimeter: 30.27 inHg - Observed at: PASW, 26 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 20040229005559A](https://openairdocs.org/incident/20040229005559A), Feb 29, 2004: Piper PA15, Skwentna, AK, Substantial damage. (-23) According to the pilot, while in cruise flight the aircraft suddenly went into a left bank and nose down attitude. When the pilot reduced power the bank… ## Other investigations on N4492H (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 ANC95LA026](https://openairdocs.org/ntsb/ANC95LA026), Jan 6, 1995: Piper PA-17 (N4492H), Dutch Harbor, AK, substantial damage. Probable cause: THE PARTIAL FAILURE OF THE RIGHT BRAKE DUE TO A LEAKY BRAKE LINE. 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.