# NTSB ANC98LA054: Piper PA-18, N8578D, Glennallen, AK, May 23, 1998 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: May 23, 1998, 09:00 local (17:00 UTC) - Place: Glennallen, AK - Coordinates: 62.100257, -145.529235 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=62.1003&lon=-145.5292&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report April 6, 2001 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 44118 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC98LA054 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/44118/pdf - Page: https://openairdocs.org/ntsb/ANC98LA054 ## Probable cause The pilot's inadequate preflight of the airplane's fuel system, and presence of water in the fuel system. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - nonmechanical, cruise - fuel system - contamination,water (cause) - aircraft preflight - inadequate, pilot in command (cause) - fuel system - contamination,water (cause) - aircraft preflight - inadequate, pilot in command (cause) - Forced landing, emergency descent/landing - In flight collision with object, emergency descent/landing - object - tree(s) ## Analysis The certificated commercial pilot was conducting an aerial moose survey for the State of Alaska. The passenger was a wildlife biologist employed by the State of Alaska. The pilot said that while in cruise flight, about 500 feet above the ground, all engine power was lost. Attempts to restore engine power were unsuccessful, and he turned the airplane to avoid rising terrain. During the subsequent forced landing, the airplane collided with trees. The airplane received substantial damage to the wings and fuselage. A Federal Aviation Administration (FAA) airworthiness inspector, inspected the airplane wreckage, and obtained a fluid sample from the fuel system gascolator. The sample exhibited two obvious layers of separated liquid. The top layer consisted of a bluish liquid, consistent with the color of 100LL aviation fuel. The lower layer consisted of a clear liquid which appeared to be water. The NTSB investigator-in-charge tested the clear fluid with water finding paste. The sample tested positive for water. ## Factual narrative On May 23, 1998, about 0900 Alaska daylight time, a tundra tire equipped Piper PA-18 airplane, N8578D, sustained substantial damage during a forced landing, about 40 miles west of Glennallen, Alaska. The airplane was being operated as a civil government flight under Title 14 CFR Part 135 when the accident occurred. The certificated commercial pilot, and the sole passenger aboard, received minor injuries. Visual meteorological conditions prevailed, and company flight following procedures were in effect. The flight originated from a private airfield about 35 miles west of Glennallen about 0800. During a telephone conversation with the National Transportation Safety Board investigator-in-charge, on May 27, 1998, at 1000, the pilot reported that he was conducting an aerial moose survey for the State of Alaska. The passenger was a wildlife biologist employed by the State of Alaska. The pilot said that while in cruise flight, about 500 feet above the ground, all engine power was lost. Attempts to restore engine power were unsuccessful, and he turned the airplane to avoid rising terrain. During the subsequent forced landing, the airplane collided with trees. The airplane received substantial damage to the wings, and fuselage. The pilot related he was not sure why the engine lost power, but he suspected the fuel may have been contaminated with water. He said it had been raining hard the day before the accident flight, and that during the preflight inspection preceding the accident flight, he noticed some water in one of fuel samples taken from a wing sump. A Federal Aviation Administration (FAA) airworthiness inspector, inspected the airplane wreckage, and obtained a fluid sample from the fuel system gascolator. The sample exhibited two obvious layers of separated liquid. The top layer consisted of a bluish liquid, consistent with the color of 100LL aviation fuel. The lower layer consisted of a clear liquid which appeared to be water. The NTSB investigator-in-charge tested the clear fluid with water finding paste. The sample tested positive for water. ## Aircraft - Registration: [N8578D](https://openairdocs.org/aircraft/N8578D), registered now, S/N 18-6236, built 1958 (OpenAirDocs) - Reported make and model: Piper PA-18 - Registry model: [Piper PA-18](https://openairdocs.org/model/piper-pa-18) (registry code 7101802) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-6236 - Airframe hours: 3950 - Engines: Lycoming O-320-A2B 150 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Registered owner: Terry M. Webb - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 3, 1998, 50 hours before - Departed: AK - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 43; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 5,000 total, 2,000 in this make and model, 4,900 as pilot in command, 200 in the last 90 days, 100 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 5 knots - Visibility: 50 statute miles - Lowest ceiling: none - Temperature: 50 °F, dew point 30 °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 19980523010519A](https://openairdocs.org/incident/19980523010519A), May 23, 1998: Piper PA18, Gulkana, AK, Substantial damage. Aerial moose survey. Lost power low altitude. Struck trees. Water in fuel. Had sat out in all night rain. (.4)the certificated commercial pilot was conducting… 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.