# NTSB LAX86LA059: Mooney M20E, N5516Q, Selma, CA, December 8, 1985

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: December 8, 1985, 15:20 local (23:20 UTC)
- Place: Selma, CA
- Coordinates: 36.529678, -119.639762 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=36.5297&lon=-119.6398&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 25033
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX86LA059
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/25033/pdf
- Page: https://openairdocs.org/ntsb/LAX86LA059

## 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,cylinder - loose (cause)
  - engine assembly,cylinder - undertorqued (cause)
  - maintenance,major repair - improper, fbo personnel (cause)
- Forced landing, descent - emergency
  - terrain condition - high vegetation (contributing factor)
  - terrain condition - none suitable (contributing factor)
- On ground/water collision with object, landing - roll

## Analysis

DURING CRUISE ON A VFR X-COUNTRY FLT, THE PLT STATED THAT THE ENG BECAME ROUGH WITH MODERATE VIBRATION LEVELS. AFTER SHUTTING DOWN THE ENG, THE PLT MADE A FORCED LANDING IN A FLD, COLLIDED WITH GND OBSTRUCTIONS & COLLAPSED ALL 3 LANDING GEAR. EXAMINATION OF THE ENG REVEALED THAT THE NUTS ON THE HOLD DOWN STUDS FOR THE #3 CYLINDER HAD BACKED OFF WHICH OVERSTRESSED THE REMAINING NUTS & CAUSED THEM TO FAIL. THE #3 CYLINDER WAS FOUND SEPARATED FROM THE CASE. ACCORDING TO THE IA WHO EXAMINED THE ENG, THE NUTS ON THE NUMBERS 3 & 4 CYLINDERS WERE UNDERTORQUED DURING A PRIOR MAINTENANCE PERIOD. THE IMPROPER TORQUE LEVELS ALLOWED SOME OF THE NUTS TO LOOSEN & EVENTUALLY BACK OFF, PRECIPITATING THE SEQUENCE OF EVENT.

## Aircraft

- Registration: N5516Q (not matched to a registry record)
- Reported make and model: MOONEY M20E
- Category: Airplane
- Serial number: 611
- Airframe hours: 2528
- Engines: LYCOMING IO-360-A1A 200 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: John I. Crawford
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, February 6, 1985, 81 hours before
- Departed: RHV, SAN JOSE, CA
- Destination: BFL, BAKERSFIELD, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 46; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 835 total, 107 in this make and model, 641 as pilot in command, 21 in the last 90 days, 15 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 360° at 4 knots
- Visibility: 7 statute miles
- Lowest ceiling: 3,000 ft overcast
- Temperature: 54 °F
- Altimeter: 30.00 inHg
- Observed at: VIS, 22 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 19851208076079A](https://openairdocs.org/incident/19851208076079A), Dec 8, 1985: Mooney M20E, Selma, CA, Substantial damage. Engine shutdown due to severe vibration. Struck grape vines during landing in a field. Undertorqued cylinder nuts.

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.

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