# NTSB SEA94LA120: Cessna 150L, N6747G, Rio Linda, CA, May 19, 1994 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: May 19, 1994, 03:03 local (10:03 UTC) - Place: Rio Linda, CA - Coordinates: 38.680576, -121.450111 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.6806&lon=-121.4501&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report January 26, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 41926 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA94LA120 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41926/pdf - Page: https://openairdocs.org/ntsb/SEA94LA120 ## Probable cause THE PILOT'S IMPROPER MIXTURE LEANING PROCEDURE. FACTOR(S) WERE: THE DISCONNECTED IGNITION LEAD, DARK NIGHT CONDITIONS, UNSUITABLE TERRAIN AND THE FENCE. ## 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, cruise - normal - ignition system,ignition lead - disconnected (contributing factor) - procedures/directives - improper, pilot in command (cause) - Forced landing, descent - emergency - In flight collision with terrain/water, descent - emergency - light condition - dark night (contributing factor) - terrain condition - none suitable (contributing factor) - object - fence (contributing factor) ## Analysis DURING CRUISE FLIGHT THE ENGINE BEGAN RUNNING ROUGH AND THE PILOT'S CORRECTIVE ACTION WAS TO APPLY FULL THROTTLE AND LEAN THE MIXTURE. HE ATTEMPTED TO DIVERT TO AN AIRPORT SHORT OF HIS DESTINATION AND SHORTLY THEREAFTER HE EXECUTED A FORCED LANDING UNDER DARK NIGHT CONDITIONS. THE AIRCRAFT IMPACTED A FENCE WHILE PASSING OVER ROUGH, OBSTRUCTED TERRAIN DURING THE FORCED LANDING. POST CRASH EXAMINATION REVEALED THE #2 CYLINDER UPPER SPARK PLUG LEAD DISCONNECTED AND EVIDENCE OF DETONATION WITH A HOLE BURNED THROUGH THE #2 PISTON HEAD. ## Factual narrative On May 19, 1994, approximately 0303 hours Pacific daylight time (PDT), a Cessna 150L, N6747G, registered to and being flown by Thomas F. Hinckley, a certificated private pilot, was destroyed during a forced landing following a power loss while in cruise. The aircraft crashed approximately one mile west of the Rio Linda Airport, Rio Linda, California. The pilot was seriously injured. Visual meteorological dark night conditions prevailed at the time, and no flight plan had been filed. The flight, which was personal in nature, was to have been conducted in accordance with 14CFR91, and originated from Auburn, California, and was destined for Hayward, California. While receiving traffic advisories, the pilot reported that he had a rough running engine and was given vectors toward Natomas Airport. Radar contact was lost at 0303 hours. FAA onsite examination revealed that the aircraft had struck a fence, missing several other fences, railroad tracks and a power line before coming to rest against an upsloping embankment (refer to photograph 1). Additionally, fuel was found within the aircraft. Several unsuccessful attempts to contact the pilot were made and the last NTSB Form 6120.1/2 mailed certified to him was returned stamped "Moved, left no address" (see attachment). Post crash disassembly and examination of the aircraft's Continental four cylinder O-200-A engine by the participants revealed that the right magneto failed to produce a spark at lead number three. The ignition harness was tested and the number three lead was found to be open near the spark plug terminal which connects to the number two cylinder upper spark plug. Additional examination revealed a hole burned through the aluminum number two piston (refer to photographs 2/3) and aluminum particles contaminating the oil filter screen. Mr. Michael J. Grimes, representing Teledyne-Continental Engines, reported that pilot Hinckley indicated that "the engine was running rough, as though it had a fouled spark plug" and the pilot "then applied full throttle and leaned the mixture in an attempt to clear the perceived fouled plug" (refer to Powerplant Inspection Report attached). ## Aircraft - Registration: [N6747G](https://openairdocs.org/deregistered/N6747G-1994-08-11), registration cancelled 1994-08-11, S/N 15072247 (OpenAirDocs) - Reported make and model: CESSNA 150L - Registry model: [Cessna 150L](https://openairdocs.org/model/cessna-150l) (registry code 2071826) (OpenAirDocs) - Category: Airplane - Serial number: 15072247 - Airframe hours: 4681 - Engines: CONTINENTAL O-200A 100 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Operator: Hinckley, Thomas, F. - Registered owner: Hinckley, Thomas, F. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 2, 1993, 64 hours before - Departed: AUN, AUBURN, CA - Destination: HWD, HAYWARD, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 3,300 total ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 170° at 11 knots - Visibility: 15 statute miles - Lowest ceiling: 1,200 ft broken - Temperature: 57 °F, dew point 45 °F - Altimeter: 30.00 inHg - Observed at: MCC, 4 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 19940519011409A](https://openairdocs.org/incident/19940519011409A), May 19, 1994: Cessna 150L, Rio Linda, CA, Destroyed. Rough engine, vectored Q94. Crashed short. Beleived fouled plug. Leaned caused detonation damage. Bad ignition wire 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.