# NTSB LAX94LA133: Schweizer G-164B, N36265, Clarksburg, CA, February 23, 1994 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: February 23, 1994, 15:10 local (23:10 UTC) - Place: Clarksburg, CA - Coordinates: 38.370025, -121.579727 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.3700&lon=-121.5797&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 14, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 28672 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX94LA133 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28672/pdf - Page: https://openairdocs.org/ntsb/LAX94LA133 ## Probable cause THE TOTAL FAILURE OF THE NO. 1 CYLINDER DUE TO FATIGUE RESULTING FROM AN IMPROPERLY ADJUSTED MIXTURE CAUSING DETONATION. THE SOFT, WET PLOWED FIELD WAS A FACTOR IN THIS ACCIDENT. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - mech failure/malf, cruise - engine assembly,connecting rod - failure,total - engine assembly,cylinder - failure,total (cause) - engine assembly,cylinder - fatigue (cause) - mixture - improper, company maintenance personnel (cause) - maintenance,adjustment - improper, company maintenance personnel (cause) - Forced landing, descent - emergency - Nose over, landing - roll - terrain condition - wet (contributing factor) - terrain condition - soft (contributing factor) ## Analysis THE AIRPLANE SUSTAINED A TOTAL LOSS OF ENGINE POWER SHORTLY AFTER DEPARTING A PRIVATELY OWNED AIRSTRIP. THE PILOT EXECUTED AN EMERGENCY LANDING ON A PLOWED FIELD. THE AIRPLANE NOSED OVER DURING THE LANDING ROLL. THE ENGINE EXAMINATION REVEALED THAT THE NO. 1 CYLINDER FAILED IN FATIGUE ORIGINATING AT ITS SPARK PLUG HOLES. THE CYLINDER HEAD COMBUSTION SIGNATURES SHOWED THAT THE ENGINE HAS BEEN EXPOSED TO THIS OPERATING CONDITION FOR SOME TIME. THE DETONATION RESULTED FROM TOO LEAN OF A MIXTURE. ## Factual narrative On February 23, 1994, at 1510 hours Pacific standard time, a Schweizer G-164B, N36265, sustained a total loss of power shortly after departing a privately owned airstrip about 3 miles southwest of Clarksburg, California. The airplane nosed over in the plowed field during emergency landing. The pilot was en route to a farm area to begin a local visual flight rules aerial application flight under Title 14 CFR Part 137. The airplane, operated by Growers Air Service, Woodland, California, sustained substantial damage. The certificated commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The flight originated at the Heringer Ranch Airstrip, Clarksburg, California, at 1508 hours. National Transportation Safety Board investigators examined the engine at Aero Engines, Los Angeles, California, on March 31, 1994. The engine did not display major ground impact damage. Safety Board investigators found about a 2-inch by 3-inch hole on the side of the No. 5 cylinder skirt. The upper area of the cylinder skirt was torn in an upward direction. The No. 1 cylinder head was found split in half. The fracture surfaces displayed a 45-degree angle plane consistent with an overload fracture. The fracture surface also displayed two, 1/4-inch diameter combustion signatures. The examination revealed evidence of detonation in the cylinder head over a period of time. The No. 1 cylinder head contained a 1/4-inch mark around its circumference. This mark corresponded with the piston's outer circumference. The Nos. 1 and 5 cylinder rods separated near their respective piston pins; the remaining connecting rods separated from their respective retaining bushings. All of the connecting rods displayed massive internal rotational impact damage. The remaining No. 5 connecting rod was found at the No. 7 cylinder position. The fracture surfaces of the Nos. 1 and 5 connecting rods sustained massive impact smudging. This smudging prevented any metallurgical analysis from being conducted to detect the origin(s) of their failure. ## Aircraft - Registration: [N36265](https://openairdocs.org/aircraft/N36265), registered now, S/N 725 B, built 1983 (OpenAirDocs) - Reported make and model: SCHWEIZER G-164B - Registry model: [Schweizer G-164B](https://openairdocs.org/model/schweizer-g-164b) (registry code 8059055) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 725B - Airframe hours: 5871 - Engines: P&W R-1340-AN-1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Growers Air Service - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, January 6, 1994, 192 hours before ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 32; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 5,700 total, 3,000 in this make and model, 5,600 as pilot in command, 190 in the last 90 days, 140 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 35 statute miles - Lowest ceiling: none - Temperature: 63 °F ## 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 19940223002829A](https://openairdocs.org/incident/19940223002829A), Feb 23, 1994: Scwzer G164B, Clarksburg, CA, Substantial damage. Total engine failure. Nosed over landing . Cylinders and connecting rods broken. Evidence detonation. Lean mixture. ## Other investigations on N36265 (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 LAX97LA121](https://openairdocs.org/ntsb/LAX97LA121), Mar 11, 1997: Grumman G-164B (N36265), Winters, CA, substantial damage. Probable cause: the failure of the engine cylinder head assembly due to operational fatigue. 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.