# NTSB SEA94LA016: Cessna 180K, N61946, Garfield, WA, October 7, 1993 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 7, 1993, 12:00 local (19:00 UTC) - Place: Garfield, WA - Coordinates: 46.990985, -117.160049 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.9910&lon=-117.1600&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report September 13, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 41841 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA94LA016 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41841/pdf - Page: https://openairdocs.org/ntsb/SEA94LA016 ## Probable cause CONNECTING ROD BOLT FATIGUE. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, cruise - engine assembly,connecting rod bolt - fatigue (cause) - engine assembly,connecting rod - fractured - Forced landing, descent - emergency - On ground/water encounter with terrain/water, landing - roll - terrain condition - rough/uneven ## Analysis WHILE THE AIRPLANE WAS IN CRUISE FLIGHT AT 500 FEET AGL, THE ENGINE BEGAN TO VIBRATE AND SHAKE. THE PILOT SHUT THE ENGINE DOWN AND INITIATED A FORCED LANDING TO AN OPEN AREA. DURING THE GROUND ROLL, THE AIRPLANE COLLIDED WITH THE ROUGH TERRAIN AND GROUND LOOPED. POST-CRASH INVESTIGATION REVEALED THAT THE NUMBER THREE CONNECTING ROD WAS BROKEN. METALLURGICAL EXAMINATION REVEALED THAT THE BREAKING AND DAMAGE OF THE NUMBER THREE CONNECTING ROD WAS THE RESULT OF FATIGUE FRACTURE OF ONE OF THE CONNECTING ROD BOLTS. ## Factual narrative On October 7, 1993, at 1200 Pacific daylight time, a Cessna 180K, N61946, lost engine power during cruise flight. The pilot initiated a forced landing to an open area near Garfield, Washington. During the ground roll, the airplane collided with the rough terrain and ground looped. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the private pilot and his passenger were not injured. The flight had originated from Spokane, Washington, on October 7, 1993, at 1100 and was en route to Grangeville, Idaho, during a personal flight. The pilot reported during a telephone interview and subsequent written statement, that while in cruise flight at 500 feet above ground level, the engine began to vibrate and shake. The pilot stated that he immediately shut the engine down and initiated a forced landing. During the ground roll on the rough terrain, the airplane ground looped before coming to a stop. During the post-crash investigation, it was found that the number three connecting rod was broken. The connecting rod and related assembly were metallurgically examined by the National Transportation Safety Board Materials Laboratory. The metallurgist reported that "The breaking and damage of the No. 3 connecting rod was the result of fatigue fracture of one of the connecting rod bolts." No metallurgical defects could be found to contribute to the initiation of the fracture. Extensive post- separation damage was noted to nearly all of the connecting rod and assembly. ## Aircraft - Registration: [N61946](https://openairdocs.org/aircraft/N61946), registered now, S/N 18052815, built 1977 (OpenAirDocs) - Reported make and model: CESSNA 180K - Registry model: [Cessna 180K](https://openairdocs.org/model/cessna-180k) (registry code 2072624) (OpenAirDocs) - Registry engine: [Continental O-470 series](https://openairdocs.org/engine/continental-o-470-series) (registry code 17026, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18052815 - Engines: CONTINENTAL O-470-U 230 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Chapman, Wallace J. - Registered owner: Chapman, Wallace J. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 6, 1993, 30 hours before - Departed: SFF, SPOKANE, WA - Destination: S80, GRANGEVILLE, ID ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 66; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 7,500 total, 3,400 in this make and model, 30 in the last 90 days, 12 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 30 statute miles - Lowest ceiling: 800 ft broken ## Other investigations on N61946 (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 OAK79FVD15](https://openairdocs.org/ntsb/OAK79FVD15), Mar 7, 1979: Cessna 180 (N61946), Concord, CA, 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.