# NTSB ANC09LA032: Piper PA-14, N4246H, Anchorage, AK, April 15, 2009 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 14, 2009, 19:35 local (Apr 15, 2009, 03:35 UTC) - Place: Anchorage, AK - Coordinates: 61.213611, -149.843887 - Nearby events: https://openairdocs.org/map.md?lat=61.2136&lon=-149.8439&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Runway excursion](https://openairdocs.org/ntsb-events/300) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report July 28, 2009 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 73657 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC09LA032 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73657/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=73657 - Page: https://openairdocs.org/ntsb/ANC09LA032 ## Probable cause The pilot's inability to maintain directional control due to the pilot's seat sliding back during takeoff as a result of maintenance personnel's incorrect installation of the seat's forward track stop. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Fuselage: seat/cargo attach fitting](https://openairdocs.org/ntsb-findings/01035347): Aircraft › Aircraft structures · Incorrect service/maintenance (probable cause) - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause) ## Analysis The private pilot said that his seat slid back when he applied power for takeoff and that he was unable to reach the rudder pedals to maintain directional control, causing the airplane to ground-loop to the left and the right wing to strike the ground. The airplane sustained structural damage to the right wing during the accident. The pilot said that there were no known mechanical problems with the airplane prior to the accident. A Federal Aviation Administration inspector who examined the airplane said that the front seats of the accident airplane had been modified with adjustable seat tracks with FAA field approval. He said that the mechanical seat stop, which was supposed to be installed on the left track, had been installed on the right track. The stop was needed to keep the seat from being pulled too far forward. Because the stop was installed on the wrong track, he said the pilot was able to pull the seat locking pin forward of the last locking hole. The locking pin fell between two screw heads, giving it the feeling of being secured. He said that during acceleration the locking pin jumped over the screw head, and the seat slid back. ## Factual narrative On April 14, 2009, about 1935 Alaska daylight time, a Piper PA-14 airplane, N4246H, sustained substantial damage during takeoff at Merrill Field, Anchorage, Alaska. The airplane was being operated by the pilot as a visual flight rules (VFR) personal local flight under Title 14, CFR Part 91, when the accident occurred. The solo private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on April 15, the pilot said when he applied power for takeoff, the seat slid back as the airplane accelerated, keeping him from reaching the rudder pedals to maintain directional control. He said the airplane ground-looped to the left, striking the right wing on the ground. The pilot said there were no known mechanical problems with the airplane prior to the accident. The airplane sustained structural damage to the right wing. During a conversation with the IIC on May 7, an FAA inspector who examined the airplane, said the front seats of the accident airplane had been modified with adjustable seat tracks. The modification was done with an FAA field approval. He said it appeared that the mechanical stop, which was supposed to be installed on the left track, had been installed on the right track. The stop was designed to keep the seat from being pulled too far forward and preventing it from latching properly. He said because the stop was installed on the wrong track, the pilot was able to pull the seat locking pin forward of the last locking hole. The locking pin fell between two screw heads, and with the pilot's weight forward on the seat, it created the feeling that the seat was locked in position. He said during acceleration, with the pilot's weight on the back of the seat, the pin jumped over the screw head, and the seat slid back. ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - [Takeoff: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - [Takeoff: Runway excursion](https://openairdocs.org/ntsb-events/300) (defining event) ## Aircraft - Registration: [N4246H](https://openairdocs.org/aircraft/N4246H), registered now, S/N 14-49, built 1948 (OpenAirDocs) - Reported make and model: PIPER PA-14 - Registry model: [Piper PA-14](https://openairdocs.org/model/piper-pa-14) (registry code 7101402) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 14-49 - Airframe hours: 2611 - Engines: LYCOMING O-320 SERIES 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Andrews, Tyler E - Registered owner: Andrews, Tyler E - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 25, 2008 - Departed: MRI, Anchorage, AK - Destination: MRI, Anchorage, AK - Airport: MRI, Merrill Field, runway 25, 4,000 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review May 10, 2008; seat: left; flight hours: 421 total, 4 in this make and model, 381 as pilot in command, 4 in the last 90 days, 4 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 250° at 5 knots - Visibility: 10 statute miles - Altimeter: 30.01 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 20090414046919A](https://openairdocs.org/incident/20090414046919A), Apr 14, 2009: Piper PA-14, Anchorage, AK, Substantial damage. During take off at approximately 35 to 40 m.p.h, the pilot's seat slid rearward causing the pilot to loose directional control of the aircraft. The aircraft… ## Docket (2 files) The files NTSB released with the investigation on June 1, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=73657. 807 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 742 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40314059&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Conversation - FAA (item 2, .PDF, 64 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40314060&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20FAA-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date; 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.