# NTSB LAX96LA274: Cessna 172N, N738NZ, Daggett, CA, July 16, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 16, 1996, 07:40 local (14:40 UTC) - Place: Daggett, CA - Coordinates: 34.860115, -116.809638 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.8601&lon=-116.8096&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report December 16, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 29510 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX96LA274 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29510/pdf - Page: https://openairdocs.org/ntsb/LAX96LA274 ## Probable cause The fracture and separation of an exhaust valve head for undetermined reasons. ## 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 - normal - engine assembly,valve,exhaust - fractured (cause) - engine assembly,valve,exhaust - separation (cause) - Forced landing, emergency descent/landing - On ground/water encounter with terrain/water, landing - roll - terrain condition - berm ## Analysis The pilot reported that he was in cruise flight when the engine suddenly ran rough and lost power. The pilot attempted to land on a desert road; however, the road curved more than the aircraft could turn at the speed it was traveling after touchdown and the aircraft left the road and hit a berm. During recovery operations an exhaust valve head fell out of the exhaust stack. Maintenance personnel reported that the fracture faces on the head and corresponding stem were obliterated due to peening. The engine was overhauled about 24 hours prior to the accident. ## Factual narrative On July 16, 1996, at 0740 hours Pacific daylight time, a Cessna 172N, N738NZ, collided with a berm while attempting a forced landing on a desert road near Daggett, California. The forced landing was precipitated by a loss of power during cruise. The aircraft was operated by Barstow Aviation of Daggett, and was rented by the pilot for a local area personal 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, was not injured. The flight originated at Daggett on the morning of the accident at 0700. The pilot reported that he was in cruise flight when the engine suddenly ran rough and lost power. The pilot attempted to land on a desert road; however, the road curved more than the aircraft could turn at the speed it was traveling after touchdown and the aircraft left the road and hit a berm. During recovery operations an exhaust valve head fell out of the exhaust stack. Maintenance personnel reported that the fracture faces on the head and corresponding stem were obliterated due to peening. The engine was overhauled about 24 hours prior to the accident. ## Aircraft - Registration: [N738NZ](https://openairdocs.org/deregistered/N738NZ-2004-12-20), registration cancelled 2004-12-20, S/N 17270120, built 1977 (OpenAirDocs) - Reported make and model: Cessna 172N - Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17270120 - Airframe hours: 2739 - Engines: Lycoming O-320-H2AD 160 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Barstow Aviation - Registered owner: Allen Thompson - Airworthiness certificate: Standard, Normal - Departed: DAG ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 81 total, 48 in this make and model, 25 as pilot in command, 20 in the last 90 days, 12 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 8 knots - Visibility: 25 statute miles - Lowest ceiling: none - Temperature: 84 °F, dew point 57 °F - Altimeter: 29.00 inHg - Observed at: DAG, 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 19960716017909A](https://openairdocs.org/incident/19960716017909A), Jul 16, 1996: Cessna 172N, Daggett, CA, Substantial damage. Lost power at cruise. Tried land desert road on curve ran off hit berm. Engine had swallowed a valve. 24HRS tbo. 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.