# NTSB SEA95LA155: Cessna 172P, N52139, Vashon, WA, July 13, 1995 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 12, 1995, 19:00 local (Jul 13, 1995, 02:00 UTC) - Place: Vashon, WA - Coordinates: 47.419673, -122.449363 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.4197&lon=-122.4494&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report December 4, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 42197 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA95LA155 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42197/pdf - Page: https://openairdocs.org/ntsb/SEA95LA155 ## Probable cause THE LOSS OF ENGINE POWER DUE TO CONNECTING ROD BOLT OVERLOAD FAILURE. THE ROUGH, UNEVEN TERRAIN IN THE EMERGENCY 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(total) - mech failure/malf, cruise - engine assembly,connecting rod bolt - overload (cause) - Forced landing, emergency descent/landing - On ground/water encounter with terrain/water, landing - roll - terrain condition - rough/uneven (contributing factor) - Nose gear collapsed, landing - roll - landing gear,nose gear - overload ## Analysis WHILE IN CRUISE FLIGHT, THE ENGINE SUDDENLY MADE A LOUD SOUND, BEGAN TO SHAKE, THEN LOST POWER. THE PILOT INITIATED A FORCED LANDING TO AN OPEN FIELD. THE AIRPLANE TOUCHED DOWN, BOUNCED AND BECAME AIRBORNE BEFORE TOUCHING DOWN THE SECOND TIME. THE NOSE GEAR COLLAPSED AND THE AIRPLANE SLID TO A STOP. POST CRASH EXAMINATION REVEALED HOLES IN THE CRANKCASE. A TEARDOWN OF THE ENGINE FOUND THAT THE NUMBER THREE AND FOUR CONNECTING ROD CAP BOLTS SEPARATED. A METALLURGICAL EXAMINATION OF THE FRACTURED BOLTS REVEALED FEATURES CHARACTERISTIC OF A PROGRESSIVE OVERSTRESS. THE METALLURGICAL SPECIALIST REPORTED THAT THE SEPARATION MOST LIKELY OCCURRED DUE TO AN INADEQUATELY TORQUED NUT OR LOSS OF PRESTRESS OVER A PERIOD OF TIME. ## Factual narrative On July 12, 1995, at 1900 Pacific daylight time, a Cessna 172P, N52139, collided with the terrain after the engine experienced a loss of power and the pilot initiated a forced landing to Vashon Island, Vashon, Washington. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the flight instructor and private pilot were not injured. The flight had originated from Seattle, Washington, on July 12, 1995, as an instructional flight. During telephone interviews and subsequent written statements, both pilots reported that while in cruise flight at 2,200 feet, the engine made a loud sound, began shaking, then quit. The flight instructor took over the controls while the private pilot secured the cockpit. The flight instructor stated that he initiated a forced landing to an open field. When the airplane touched down, it bounced and became airborne. When the airplane touched down the second time, the nosed gear collapsed and the airplane slid to a stop. Post crash inspection of the engine revealed holes in the top of the crankcase near the number three and four cylinders. After the engine was disassembled, it was found that the number three and four connecting rod cap bolts separated. Both connecting rod assemblies were sent to the National Transportation Safety Board, Materials Laboratory for a metallurgical examination. The specialist reported that "Stereo microscope examination of the fractured bolts revealed features characteristic of a progressive overstress." The specialist further reported that separation of the bolts most likely occurred due to an inadequately torqued nut or loss of prestress over a period of time. The aircraft maintenance logbooks indicate that the number four cylinder and connecting rod assembly had been worked on and signed off on 10/29/93, and had accumulated a total time of 1,066 hours at the time of the accident. The number two and three cylinders and connecting rod assemblies had been worked on and signed off on 6/8/94, and had accumulated a total time of 770 hours at the time of the accident. ## Aircraft - Registration: [N52139](https://openairdocs.org/aircraft/N52139), registered now, S/N 17274421, built 1980 (OpenAirDocs) - Reported make and model: CESSNA 172P - Registry model: [Cessna 172P](https://openairdocs.org/model/cessna-172p) (registry code 2072436) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17274421 - Airframe hours: 5173 - Engines: LYCOMING O-320-D2J 160 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Wings Aloft - Registered owner: Stephen W. Lee - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, July 17, 1995, 27 hours before - Departed: BFI, SEATTLE, WA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 41; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 200 total ## Weather - Conditions: Visual (VMC), Day - Visibility: 25 statute miles - Lowest ceiling: none ## 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 19950712044119A](https://openairdocs.org/incident/19950712044119A), Jul 12, 1995: Cessna 172P, Vashon, WA, Substantial damage. Reported power loss. CFI landed. Collapsed nose gear on bounce. Holes in engine. Rod cap bolts and rods separated. 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.