# NTSB LAX96LA173: Cessna 150K, N6466G, Mojave, CA, April 17, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 17, 1996, 09:15 local (16:15 UTC) - Place: Mojave, CA - Coordinates: 35.070129, -118.180313 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.0701&lon=-118.1803&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 20, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 29423 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX96LA173 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29423/pdf - Page: https://openairdocs.org/ntsb/LAX96LA173 ## Probable cause the pilot's failure to clear the engine during an idle power descent, as required by the engine manual. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - nonmechanical, approach - vfr pattern - base leg/base to final - procedures/directives - not followed, pilot in command (cause) - Forced landing, emergency descent/landing - weather condition - high wind - Nose over, emergency landing ## Analysis The pilot descended into the airport traffic pattern from 4,200 feet AGL with the engine idled, mixture rich, and carburetor heat on. When engine power was added to adjust the landing approach, the engine failed to respond. Because of high surface winds, the pilot was unable to glide to the runway and an off-airport landing was made and the aircraft nosed over. Inspection of the engine revealed carbon buildup under the intake and exhaust valves and low compression. After staking the valves compression returned to normal. The second pilot said they had not cleared the engine during the descent as required by the engine Operator's Manual. ## Factual narrative On April 17, 1996, at 0915 hours Pacific daylight time, a Cessna 150K aircraft, N6466G, was substantially damaged during an off-airport landing 1 mile east of the Mojave, California, airport. The airline transport pilot and one passenger were not injured. Visual meteorological conditions prevailed for the instructional flight. The second pilot, who holds a commercial pilot license, told an inspector from the FAA Van Nuys, California, Flight Standards District Office that the flight was part of the training syllabus of a private test pilot school. After descent from 7,000 feet (4,200 feet AGL) with the engine idled, carburetor heat on and mixture rich, the engine failed to produce power when the throttle was advanced during landing approach to runway 25. The first pilot took control of the aircraft at this point; however, because of 20- to 30-knot surface winds, he was not able to glide to the runway. An off-airport landing was made in the desert and the aircraft nosed over. The second pilot stated that they had not "cleared" the engine during descent. The Teledyne Continental Motors Operator's Manual for the O-200 engine, dated January 1975, states on page 19: "If a long glide is made, apply power at short intervals to clear the cylinders and retain engine temperatures in the event that instant power is required." Inspection of the engine by the FSDO inspector revealed heavy carbon buildup under the intake and exhaust valves and low compression. After staking the valves compression returned to normal. The fuel supply was clear and the magnetos and spark plugs sparked normally. ## Aircraft - Registration: [N6466G](https://openairdocs.org/deregistered/N6466G-2003-04-22), registration cancelled 2003-04-22, S/N 15071966, built 1970 (OpenAirDocs) - Reported make and model: Cessna 150K - Registry model: [Cessna 150K](https://openairdocs.org/model/cessna-150k) (registry code 2071822) (OpenAirDocs) - Registry engine: [Continental 0-200 series](https://openairdocs.org/engine/continental-0-200-series) (registry code 17020, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 15071966 - Airframe hours: 4458 - Engines: Continental O-200-A 100 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Sean Roberts - Airworthiness certificate: Standard, Utility - Last inspection: Annual, September 11, 1995, 76 hours before - Departed: MHV - Airport: MHV, Mojave, runway 25, 7,040 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 4,702 total, 112 in this make and model, 3,955 as pilot in command, 92 in the last 90 days, 30 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 280° at 20 knots, gusting 30 - Visibility: 25 statute miles - Lowest ceiling: 20,000 ft broken - Temperature: 54 °F - Altimeter: 29.00 inHg - Observed at: MHV, 1 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 19960417007949A](https://openairdocs.org/incident/19960417007949A), Apr 17, 1996: Cessna 150K, Mojave, CA, Substantial damage. Failed to clear engine during descent. It failed respond when needed on approach. Nosed over in desert short runway ## Other investigations on N6466G (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 CHI73FEP17](https://openairdocs.org/ntsb/CHI73FEP17), Aug 25, 1972: Cessna 150K (N6466G), Janesville, WI, 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.