# NTSB ANC95LA174: Piper PA-18-150, N3991Z, Big Delta, AK, September 12, 1995 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 11, 1995, 19:00 local (Sep 12, 1995, 03:00 UTC) - Place: Big Delta, AK - Coordinates: 63.699748, -144.890853 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=63.6997&lon=-144.8909&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report April 29, 1996 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 2743 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC95LA174 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/2743/pdf - Page: https://openairdocs.org/ntsb/ANC95LA174 ## Probable cause The pilot's selection of an unsuitable step taxi/takeoff area. The submerged object was a related factor. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - On ground/water collision with object, taxi - to takeoff - object - submerged object (contributing factor) - unsuitable terrain or takeoff/landing/taxi area - selected, pilot in command (cause) ## Analysis The pilot stated he was hunting in the area and was returning to his base camp. He stated the lake was small, so he was step taxiing as close to shore as possible to gain the greatest amount of takeoff area. He felt the left float hit something submerged. The front of the float came up and struck the left wing struts and the left wing struck the water. ## Factual narrative On September 11, 1995, at 1900 Alaska daylight time, a float equipped Piper PA-18-150 airplane, registered to and operated by the pilot, struck a submerged object, collapsed the left float, and dragged the left wing, during step taxi for takeoff. The personal flight, operating under 14 CFR Part 91, was departing an unnamed lake located 30 miles on the 160 degree radial of the Big Delta VORTAC. The destination was Birch Lake located 7 miles away from the departure point. No flight plan was filed and visual meteorological conditions prevailed. The airline transport certificated pilot, the sole occupant, was not injured and the airplane was substantially damaged. During a telephone conversation with the pilot on September 26, 1995, he stated that the lake was small and he was step taxiing close to shore to gain as much takeoff area as possible. He felt the left float bump something. The nose of the left float than came up and bent the left wing struts and the airplane's left wing struck the water. The airplane stopped in 3 feet of water. The pilot stated that the float's wire braces and float struts were broken. He stated he was sure that the left float struck the bottom of the lake or a submerged object. He did not see any objects floating on the water prior to step taxiing. ## Aircraft - Registration: [N3991Z](https://openairdocs.org/aircraft/N3991Z), registered now, S/N 18-7936, built 1963 (OpenAirDocs) - Reported make and model: PIPER PA-18-150 - 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: 18-7936 - Airframe hours: 4000 - Engines: LYCOMING O-360-A1A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: John A. Bachner - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 25, 1995, 60 hours before - Departed: UNNAMED LAKE, AK - Destination: BIRCH LAK3E, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; airline transport, flight engineer, flight instructor; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 19,000 total, 4,000 in this make and model, 15,000 as pilot in command, 60 in the last 90 days, 30 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 90° at 7 knots - Visibility: 99 statute miles - Lowest ceiling: none - Temperature: 61 °F - Altimeter: 30.00 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 19950911032779A](https://openairdocs.org/incident/19950911032779A), Sep 11, 1995: Piper PA18150, Big Delta, AK, Substantial damage. Struck submerged log during step taxi for water takeoff. Float came up and bent wing. Stopped in 3FT water depth. ## Other investigations on N3991Z (2) 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 ANC70DAA13](https://openairdocs.org/ntsb/ANC70DAA13), Jun 1, 1970: Piper PA-18 (N3991Z), Fairbanks, AK, substantial damage - [NTSB ANC70A0030](https://openairdocs.org/ntsb/ANC70A0030), Oct 6, 1969: Piper PA-18 (N3991Z), Fairbanks, AK, minor damage, 1 fatal 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.