# NTSB SEA95LA058: Mooney M20C, N7836V, Omak, WA, March 3, 1995 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: March 3, 1995, 15:10 local (23:10 UTC) - Place: Omak, WA - Coordinates: 48.359916, -119.270027 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=48.3599&lon=-119.2700&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report October 13, 1995 - Report: Approved by Office Director - ADs cited in the narratives: [AD 73-21-01](https://openairdocs.org/ad/73-21-01) (OpenAirDocs) - NTSB case key (mKey): 42116 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA95LA058 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42116/pdf - Page: https://openairdocs.org/ntsb/SEA95LA058 ## Probable cause THE ELEVATOR PUSH ROD SEPARATION DUE TO FATIGUE. FACTORS CONTRIBUTING TO THE ACCIDENT WERE THE PILOT IN COMMAND'S FAILURE TO INSURE COMPLIANCE WITH THE AIRWORTHINESS DIRECTIVE AND THE FROZEN PUSH ROD BEARING. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - flt control syst,elevator control cable/rod - fatigue (cause) - maintenance,compliance with ad - not performed, pilot in command (contributing factor) - flt control syst,elevator control bearing - frozen (contributing factor) - Loss of control - in flight, approach - flight control,elevator - disconnected - In flight collision with terrain/water, descent - uncontrolled ## Analysis THE PILOT, WHILE ON FINAL APPROACH AT 500 FEET AGL, LOST ELEVATOR CONTROL WHEN THE ELEVATOR PUSH ROD SEPARATED DUE TO BENDING FATIGUE. THE MONOBALL BEARING WAS FOUND TO BE FROZEN AND CORRODED. THE AIRCRAFT HAD UNDERGONE AN ANNUAL INSPECTION WHEN PURCHASED 108 HOURS PRIOR TO THE ACCIDENT, AND THE FLIGHT CONTROLS HAD BEEN SIGNED OFF AS LUBRICATED. NO AD LISTING WAS FOUND, HOWEVER, TO VERIFY WHETHER AD 73-21-01 HAD BEEN COMPLIED WITH AT THE ANNUAL INSPECTION. THE AD, WHICH REQUIRED LUBRICATION OF THE FLIGHT CONTROLS EVERY 100 HOURS, WAS 8 HOURS OVERDUE AT THE TIME OF THE ACCIDENT. ## Factual narrative On March 3, 1995, approximately 1510 hours Pacific standard time (pst), a Mooney M20C, N7836V, being flown by a certificated private pilot, was substantially damaged during collision with terrain following a loss of control while on approach to runway 35 at the Omak Airport, Omak, Washington. The pilot was uninjured. Visual meteorological conditions prevailed and no flight plan had been filed. The flight, which was personal, was to have been operated under 14CFR91, and originated from Electric City, Washington, approximately 1450. The pilot reported that while on approach and at an altitude of approximately 500 feet above ground he lost elevator control and the aircraft began a series of pitch up and nose down maneuvers. The aircraft impacted the ground in a flat, wings level attitude and slid to rest (refer to NTSB Form 6120.1/2 and Okanogan County Sheriff's Report). Post crash examination by FAA Inspector Ken Ziemer revealed a fracture and separation of the threaded end of the elevator push rod eye bolt. Metallurgical examination of the push rod separation surfaces by the NTSB's Material Laboratory revealed topography typical of high stress reverse bending fatigue. Additionally, the monoball bearing at the end of the rod was found to be frozen and corroded (refer to attached metallurgical report). The aircraft's airframe log was examined and an annual inspection was signed off on July 27, 1994, (tach time 1141.4 hours) at which time the pilot purchased and took possession of the aircraft. The annual entry reported among other entries "Lubed all flight controls" (refer to ATTACHMENT I). Two additional airframe log entries followed the annual, the first documenting a transponder test, and the second documenting the replacement of a belly strobe. No list of current Airworthiness Directives could be located and the pilot reported that he never received such a listing. The tach time on the aircraft at the time of the accident was 1249.32 hours as reported by the FAA inspector on site. This yielded a total of 108 hours time transpired since the last annual inspection. FAA Airworthiness Directive 73-21-01, which applies to Mooney M20C, serial number 2871, references the prevention of "corrosion and/or misrigging in the flight control and landing gear systems." Specifically, the AD requires that all flight controls should be lubricated every 12 months or 100 hours time in service, whichever comes first (refer to ATTACHMENT II). It was not known whether this AD was complied with at the July 27th annual. ## Aircraft - Registration: [N7836V](https://openairdocs.org/deregistered/N7836V-2013-05-09), registration cancelled 2013-05-09, S/N 2871, built 1964 (OpenAirDocs) - Reported make and model: MOONEY M20C - Registry model: [Mooney M20C](https://openairdocs.org/model/mooney-m20c) (registry code 5870208) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 2871 - Airframe hours: 3402 - Engines: LYCOMING O-360-A1G6 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Hartman, Calvin, G. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 27, 1994, 108 hours before - Departed: WA21, ELECTRIC CITY, WA - Destination: OMK - Airport: OMK, Omak, runway 35, 4,654 × 150 ft ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 500 total, 100 in this make and model, 400 as pilot in command, 20 in the last 90 days, 7 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 80° at 3 knots - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 46 °F, dew point 19 °F - Altimeter: 29.00 inHg - Observed at: EPH, 69 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 19950303040259A](https://openairdocs.org/incident/19950303040259A), Mar 3, 1995: Mooney M20C, Omak, WA, Substantial damage. Reported lost elevator control on approach. Oscillated. Impacted flat. Elevator push rod broke. Corroded bearing. ## Other investigations on N7836V (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 UNK65X1490](https://openairdocs.org/ntsb/UNK65X1490), Apr 30, 1965: Mooney M21 (N7836V), Freeport, Burkina Faso, 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.