# NTSB LAX94LA273: Adams Thorpe T-18, N51079, Stockton, CA, July 3, 1994 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 3, 1994, 07:58 local (14:58 UTC) - Place: Stockton, CA - Coordinates: 37.900161, -121.399581 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.9002&lon=-121.3996&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 December 7, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 28788 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX94LA273 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28788/pdf - Page: https://openairdocs.org/ntsb/LAX94LA273 ## Probable cause A VAPOR LOCK INDUCED ENGINE FAILURE DUE TO INADEQUATE THERMAL SHIELDING OF THE FUEL PUMP AND LINES. SOFT TERRAIN IN THE LANDING AREA WAS A FACTOR. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, takeoff - initial climb - fuel system,line - blocked(total) (cause) - fuel system,pump - blocked(total) (cause) - fluid,fuel - starvation - acft/equip,inadequate design, manufacturer (cause) - Forced landing, descent - emergency - Nose over, landing - roll - terrain condition - soft (contributing factor) ## Analysis The accident flight was the second flight of the aircraft since certification on April 6, 1994. The aircraft has a Mazda NSU wankle rotary automobile engine installed and is operated on automotive gasoline. The pilot was on initial climbout after takeoff when the engine suddenly quit. The pilot was unable to make the runway and executed a forced landing in a field near the airport. The aircraft nosed over after encountering soft, rough terrain. The pilot reported that the fuel lines and fuel pump do not have any thermal shielding and he believes the engine failure was due to vapor lock. ## Factual narrative On July 3, 1994, at 0758 Pacific daylight time, an experimental homebuilt Adams Thorpe T-18 airplane, N51079, nosed over while attempting a forced landing in a field adjacent to runway 29R at Stockton, California. The aircraft was owned and operated by the pilot and was on a local area test flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft incurred substantial damage. The certificated private pilot, the sole occupant, sustained minor injuries. The flight was originating at the time of the accident. According to information provided by an Federal Aviation Administration (FAA) inspector from the Oakland, California Flight Standards District Office, the accident flight was the second flight of the aircraft since certification on April 6, 1994. The aircraft has a Mazda NSU wankle rotary automobile engine installed and is operated on automotive gasoline. The pilot was on initial climbout after takeoff when the engine suddenly quit. The pilot was unable to make the runway and executed a forced landing in a field near the airport. The aircraft nosed over after encountering soft, rough terrain. The pilot reported that the fuel lines and fuel pump do not have any thermal shielding and he believes the engine failure was due to vapor lock. ## Aircraft - Registration: [N51079](https://openairdocs.org/aircraft/N51079), registered now, S/N 988, built 1994 (OpenAirDocs) - Reported make and model: ADAMS THORPE T-18 (THORPE T-1) - Registry model: [Adams T/Adams B/Adams B ADAMS/THORPE T-18](https://openairdocs.org/model/adams-t-adams-b-adams-b-adams-thorpe-t-18) (registry code 05620NX) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 988 - Airframe hours: 1 - Engines: MAZDA NSU WANKLE 153 horsepower reciprocating - Damage: Substantial damage - Flight: Part 91 - Operator: Terry W. Adams - Registered owner: Terry W. Adams - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, April 6, 1994, 1 hours before - Departed: SCK - Destination: SCK - Airport: SCK, Stockton Metro, runway 29R, 8,600 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 351 total, 1 in this make and model, 351 as pilot in command, 3 in the last 90 days, 1 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 15 statute miles - Temperature: 72 °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 19940703017469A](https://openairdocs.org/incident/19940703017469A), Jul 3, 1994: Amtrth THORPT18, Stockton, CA, Substantial damage. Engine quit on climbout. Landed off airport. Nosed over soft soil. Unshielded fuel line and auto fuel vapor locked. 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.