# NTSB LAX96LA023: Great Lakes 2T-1A-2, N3808F, Chandler, AZ, October 26, 1995 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 26, 1995, 16:10 local (23:10 UTC) - Place: Chandler, AZ - Coordinates: 33.24065, -111.779243 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.2407&lon=-111.7792&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report April 1, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 29319 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX96LA023 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29319/pdf - Page: https://openairdocs.org/ntsb/LAX96LA023 ## Probable cause the improper installation of an intake manifold tube assembly during engine overhaul which permitted leakage into the induction system resulting in detonation and piston failure in the associated cylinder. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - mech failure/malf, maneuvering - induction air control,intake manifold - leak (cause) - maintenance,overhaul - improper, company maintenance personnel (cause) - misc,engine pre-ignition and/or detonation (cause) - engine assembly,piston - failure (cause) - Forced landing, emergency descent/landing - On ground/water encounter with terrain/water, landing - roll - terrain condition - ditch - Nose over, landing - roll ## Analysis THE PILOT ELECTED TO MAKE AN OFF-AIRPORT LANDING DUE TO A ROUGH ENGINE, OIL ON THE WINDSHIELD, AND A RADIO REPORT THAT HIS AIRCRAFT WAS TRAILING SMOKE. DURING THE ROLLOUT ON A DIRT ROAD, THE AIRCRAFT STRUCK A DITCH AND NOSED OVER. EXAMINATION OF THE ENGINE REVEALED THAT AN INTAKE MANIFOLD SEAL WAS LEAKING AT THE ATTACHMENT TO THE #4 CYLINDER, AND THERE WAS A BURNED HOLE IN THE #4 PISTON. THE PROPELLER SHAFT SEAL HAD BEEN DISPLACED FORWARD ONTO THE ENGINE PROPELLER SHAFT, AND THE ENGINE OIL SUPPLY HAD BEEN VENTED OVERBOARD THROUGH THE ENGINE BREATHER AND AROUND THE PROPELLER SHAFT. THE ENGINE HAD BEEN OVERHAULED 11 HOURS PRIOR TO THE ACCIDENT. ## Factual narrative On October 26, 1995, at 1610 hours mountain standard time, a Great Lakes 2T-1A-2, N3808F, nosed over while making a forced landing 4.5 miles southeast of Chandler Airport, Chandler, Arizona. The aircraft sustained substantial damage and the commercial pilot was not injured. The aircraft was operated by Chandler Air Service, Inc., and was rented by the pilot for a personal flight when the accident occurred. The local area flight originated from Chandler Airport at 1545. Visual meteorological conditions prevailed at the time and no flight plan had been filed. The pilot reported that the purpose of the flight was to practice an aerobatic sequence three or four times and return to Chandler. However, at completion of the first sequence he felt an abnormal vibration in the engine and terminated his practice. The engine rpm was 200 rpm low and could not be restored with the propeller control, and within a minute engine oil began to appear on the windshield. He turned toward Chandler when the pilot of a nearby aircraft radioed that he was trailing smoke. The pilot identified a suitable dirt road and decided to make a precautionary off-airport landing. During the landing rollout, the aircraft struck a ditch and nosed over. Examination of the aircraft revealed that the engine oil supply had vented overboard through the engine crankcase breather and the propeller shaft. There was engine oil on the exterior of the aircraft aft of the breather tube, and on the exterior of the engine aft of the propeller shaft. The propeller shaft seal was displaced from its normal position and was positioned onto the propeller shaft. The engine had been overhauled by the operator 11 hours prior to the accident. Disassembly of the engine by the operator following the accident revealed that the intake manifold tube flange and flange gasket (Lycoming part numbers 70485 and 71973) on the number four cylinder were leaking due to misalignment. A hole had burned through the number four piston. The hole was located in the perimeter of the piston around the rings and went through to the crankcase side of the piston in vicinity of the wrist pin. ## Aircraft - Registration: [N3808F](https://openairdocs.org/aircraft/N3808F), registered now, S/N 0776, built 1977 (OpenAirDocs) - Reported make and model: GREAT LAKES 2T-1A-2 - Registry model: [Great Lakes 2T-1A-2](https://openairdocs.org/model/great-lakes-2t-1a-2) (registry code 3910101) (OpenAirDocs) - Registry engine: [Lycoming AEIO-360 series](https://openairdocs.org/engine/lycoming-aeio-360-series) (registry code 41522, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 0776 - Airframe hours: 1559 - Engines: LYCOMING AEIO-360-B1G6 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Chandler Air Service, Inc. - Airworthiness certificate: Standard, Aerobatic - Last inspection: Annual, October 22, 1995, 11 hours before - Departed: CHD, AZ ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: rear; flight hours: 3,280 total, 280 in this make and model, 3,050 as pilot in command, 198 in the last 90 days, 86 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 280° at 4 knots - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 84 °F, dew point 25 °F - Altimeter: 29.00 inHg - Observed at: IWA, 10 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 19951026034639A](https://openairdocs.org/incident/19951026034639A), Oct 26, 1995: Grtlks 2T1A2, Chandler, AZ, Substantial damage. Rough engine. Oil on windshield. Nosed over landing. Misaligned intake manifiold. Lean mixture burned hole in piston ## Other investigations on N3808F (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 FTW79FRG05](https://openairdocs.org/ntsb/FTW79FRG05), Oct 21, 1978: Great Lakes 2T-1A (N3808F), Fredericksburg, TX, substantial damage 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.