# NTSB LAX01LA195: Schweizer G-164B, N6902K, Butte City, CA, May 31, 2001 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: May 31, 2001, 07:00 local (14:00 UTC) - Place: Butte City, CA - Coordinates: 39.766666, -121.983329 - Nearby events: https://openairdocs.org/map.md?lat=39.7667&lon=-121.9833&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report April 25, 2006 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 52368 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX01LA195 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/52368/pdf - Page: https://openairdocs.org/ntsb/LAX01LA195 ## Probable cause a fatigue failure of a propeller bolt. ## 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, maneuvering - aerial application - miscellaneous,bolt/nut/fastener/clamp/spring - fatigue (cause) - miscellaneous,bolt/nut/fastener/clamp/spring - fractured (cause) - miscellaneous,bolt/nut/fastener/clamp/spring - separation (cause) - Forced landing, emergency descent/landing - On ground/water encounter with terrain/water, emergency landing - terrain condition - high vegetation ## Analysis The airplane collided with high vegetation when the pilot made an off airport forced landing following a loss of engine power. The local aerial application flight departed a private strip. The pilot reported that a heavy vibration developed in the engine, and he shut it down. He tried to return to a nearby dirt strip, but had to land in a hay field. On the landing roll, the airplane encountered tall vegetation, which damaged the wings and landing gear attachment points. A Federal Aviation Administration inspector examined the airplane, and found a fractured bolt on the propeller. Metallurgical examination of the bolt indicated that the part failed in fatigue at a region of increased stress (stress concentration), though the part overall was not highly stressed (small overstress region). ## Factual narrative On May 31, 2001, about 0700 Pacific daylight time, a Schweizer G-164B, N6902K, collided with terrain following a loss of engine power near Butte City, California. Chuck Jones Flying Service was operating the airplane under the provisions of 14 CFR Part 137. The commercial pilot sustained serious injuries; the airplane sustained substantial damage. The local aerial application flight departed a private strip about 0615. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that a heavy vibration developed in the engine and he shut it down. He tried to return to a nearby dirt strip, but had to land in a hay field. On the landing roll, the airplane encountered tall vegetation, which damaged the wings and landing gear attachment points. A Federal Aviation Administration (FAA) inspector examined the airplane. He found a fractured bolt on the propeller. A specialist from the National Transportation Safety Board Materials Laboratory examined the fractured bolt. He determined that it fractured at the base of the transition radius between the shank and the minor diameter of the threads. The fracture was on a flat plane normal to the surface, though the fracture was at a slight angle from the circumferential direction. The fracture surface contained arrest marks, which propagated through approximately 90 percent of the cross-sectional area. The origin area was at the surface where the specialist observed two ratchet marks. However, he observed no obvious material defects at the origin, and no defects such as nicks or scratches at the surface. The bolt contained the markings "FAA-PMA-MWA 50001." ## Aircraft - Registration: [N6902K](https://openairdocs.org/deregistered/N6902K-2014-05-28), registration cancelled 2014-05-28, S/N 517B (OpenAirDocs) - Reported make and model: Schweizer G-164B - Registry model: [Grumman Acft ENG Cor-Schweizer G-164B](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164b) (registry code 3952802) (OpenAirDocs) - Category: Airplane - Serial number: 5178 - Airframe hours: 10465.84 - Engines: Pratt & Whitney R-1340 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Chuck Jones Flying Service - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, May 1, 2001, 10 hours before - Departed: Butte City, CA - Destination: Butte City, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 26; injuries: serious; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; last flight review January 1, 2001; seat: center; flight hours: 1,150 total, 718 in this make and model, 1,087 as pilot in command, 335 in the last 90 days, 275 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 60 statute miles - Lowest ceiling: none - Altimeter: 29.88 inHg - Observed at: CIC, 24 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 20010531014509A](https://openairdocs.org/incident/20010531014509A), May 31, 2001: Scwzer G164B, Oroville, CA, No damage. (-23) Aircraft propeller began to vibrate violently. The engine was cut and pilot attempted an emergency landing at the nearest airport. Aproximately 100 yards… ## Other investigations on N6902K (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 CEN13LA191](https://openairdocs.org/ntsb/CEN13LA191), Mar 8, 2013: Grumman Acft ENG Cor-Schweizer G-164B (N6902K), Beech Grove, AR, substantial damage. Probable cause: The pilot’s failure to maintain control of the airplane during the takeoff roll. 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.