# NTSB FTW93LA184: Cessna 172, N6446B, Canyon Lake, TX, June 9, 1993 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: June 9, 1993, 11:12 local (16:12 UTC) - Place: Canyon Lake, TX - Coordinates: 29.870532, -98.260757 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.8705&lon=-98.2608&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report September 13, 1994 - Report: Approved by Office Director - ADs cited in the narratives: [AD 87-20-03 R2](https://openairdocs.org/ad/87-20-03-R2) (OpenAirDocs) - NTSB case key (mKey): 18771 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW93LA184 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18771/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=18771 - Page: https://openairdocs.org/ntsb/FTW93LA184 ## Probable cause THE MOVEMENT OF THE PILOT'S SEAT AFT WHICH RESULTED IN HIS LOSS OF CONTROL, HIS INABILITY TO REGAIN CONTROL, AND THE ENSUING INADVERTENT STALL. A FACTOR WAS THE INADEQUATE INSPECTION OF THE AIRPLANE. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, takeoff - initial climb - fuselage,seat - disengaged - stall - inadvertent, pilot in command (cause) - remedial action - not possible, pilot in command (cause) - maintenance,annual inspection - inadequate, other maintenance personnel (contributing factor) - In flight collision with object, descent - uncontrolled - object - tree(s) ## Analysis THE PILOT STATED THAT DURING THE RUN UP, HE MOVED HIS SEAT BACK TO SECURE ONE OF THE DOORS AND THEN READJUSTED HIS SEAT TO ITS ORIGINAL POSITION. SHORTLY AFTER LIFTOFF, THE SEAT TRAVELED AFT AND THE PILOT LOST CONTROL OF THE AIRPLANE. IT SUBSEQUENTLY IMPACTED TREES IN A NOSE DOWN ATTITUDE OFF ONE SIDE OF THE RUNWAY. EXAMINATION OF THE SEAT LATCHING MECHANISM REVEALED THAT IT WAS INTACT, AS WERE THE SEAT TRACKS. EXAMINATION OF THE LATCHING HOLES INDICATED THAT THEY WERE ELONGATED AND SCRAPE MARKS WERE EVIDENT BETWEEN THE HOLES. THE END OF THE LATCHING PIN WAS ROUNDED. THE SEAT LATCHING MECHANISM SUBSEQUENTLY OPERATED NORMALLY. THE SEAT LATCH AD INSPECTION HAD LAST BEEN PERFORMED TWO YEARS PRIOR TO THE ACCIDENT. ## Factual narrative On Wednesday, June 9, 1993, at approximately 1112 central daylight time, a Cessna 172, N6446B, was substantially damaged when it collided with trees following a loss of control on initial climb out from the Canyon Lake, Texas, airport. The airplane, owned and operated by the ATP rated pilot, was departing on a local personal flight. There was no flight plan filed and visual meteorological conditions prevailed. The pilot, the sole occupant, received minor injuries. The pilot stated that during the engine run up, he noticed that one of the doors was not properly secured and he adjusted his seat in order to reach the door. He stated that after securing the door, he readjusted his seat to its original position and took off. He further stated that shortly after liftoff, the seat pin broke and the seat traveled aft. He lost control of the airplane and it subsequently impacted the trees off the left side of the runway in a nose down attitude. The airplane remained suspended in the trees. Examination of the airplane revealed that the seat latching mechanism was intact, as were the seat tracks for the pilot's seat. Examination of the latching holes indicated that they were elongated and scrape marks were found between the holes. The end of the latching pin was worn and rounded. Following the examination, the seat was re-installed and the seat locking mechanism operated normally. A review of the airplane's maintenance records indicated that the recurring seat latch airworthiness directive (AD 87-20-03) had last been performed on January 1, 1991. ## Aircraft - Registration: [N6446B](https://openairdocs.org/deregistered/N6446B-2013-04-29), registration cancelled 2013-04-29, S/N 29646, built 1956 (OpenAirDocs) - Reported make and model: CESSNA 172 - Registry model: [Cessna 172](https://openairdocs.org/model/cessna-172) (registry code 2072402) (OpenAirDocs) - Registry engine: [Continental 0-300 series](https://openairdocs.org/engine/continental-0-300-series) (registry code 17022, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17229646 - Airframe hours: 6161 - Engines: CONTINENTAL O-300A 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Beal, Thomas W. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 13, 1993, 1 hours before - Departed: 34TS - Destination: 34TS - Airport: 34TS, Canyon Lake, runway 19, 2,600 × 45 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 72; airline transport, flight instructor; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 20,505 total, 360 in this make and model, 15,012 as pilot in command, 48 in the last 90 days, 43 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 130° at 12 knots - Visibility: 15 statute miles - Lowest ceiling: 3,400 ft broken - Temperature: 82 °F, dew point 63 °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 19930609017689A](https://openairdocs.org/incident/19930609017689A), Jun 9, 1993: Cessna 172, Canyon Lake, TX, Substantial damage. Lost control on climbout when seat slid backwards. Seat pin and hole worn but still serviceable. ## Docket (3 files) The files NTSB released with the investigation on June 3, 1995, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=18771. 2.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40423421&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - FAA Inspector's Statement (item 2, .PDF, 31 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40423422&FileExtension=.PDF&FileName=FAA%20Inspector%27s%20Statement-Redacted.PDF - Maps or Charts of Accident Area, Wreckage Diagrams (item 3, .PDF, 88 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40005111&FileExtension=.PDF&FileName=Maps%20or%20Charts%20of%20Accident%20Area,%20Wreckage%20Diagrams-Master.PDF 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.