# NTSB LAX86LA076: Mooney M20F, N234GA, San Manuel, AZ, December 28, 1985

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: December 27, 1985, 17:53 local (Dec 28, 1985, 00:53 UTC)
- Place: San Manuel, AZ
- Coordinates: 33.76091, -112.610298 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.7609&lon=-112.6103&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 4 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 25045
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX86LA076
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/25045/pdf
- Page: https://openairdocs.org/ntsb/LAX86LA076

## 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)
  - maintenance,major repair - improper, other maintenance personnel (cause)
- Forced landing, descent - emergency
  - light condition - dark night (contributing factor)
  - airport facilities,runway edge lights - unavailable (cause)
  - proper touchdown point - not identified, pilot in command (contributing factor)
  - go-around - not possible, pilot in command (contributing factor)
- On ground/water collision with object, landing - roll
  - object - tree(s) (contributing factor)
  - ground loop/swerve - inadvertent, pilot in command (cause)

## Analysis

DURING CRUISE AT 10,500 FT MSL ON A NIGHT X-COUNTRY FLT, THE PLT SAID THE ENG RAN ROUGH WITH MODERATE VIBRATION LEVELS. PLT DECLARED AN EMERGENCY WITH ABQ ARTCC, WHO VECTORED THE ACFT TO AN UNLIGHTED AIRSTRIP. THE PLT SAID HE HAD DIFFICULTYIN SEEING THE RWY IN THE DARKNESS. THE ACFT LANDED LONG, BLEW A TIRE, VEERED OFF THE RT SIDE OF THE RWY & STRUCK A TREE.EXAMINATION OF THE ENG REVEALED THAT THE #3 CYLINDER WAS AJAR FROM THE CASE, WITH ALL THE TOP HOLD DOWN STUDS & NUTS IN PLACE BUT BENT UPWARD. THE NUTS WERE MISSING FROM THE LOWER FORE & AFT LARGE HOLD DOWN STUDS, & THE REMAINING CENTER STUDS HAD ALL FRACTURED AT THE CYLINDER FLANGE LEVEL. THE ENG WAS OVERHAULED 6 MONTHS AND 21 HRS PRIOR TO THE ACCIDENT. THE FAA AIRWORTHINESS INSPECTOR WHO EXAMINED THE ENG STATED HIS OPINION THAT THE NUTS ON THE LOWER LARGE STUDS WERE UNDERTORQUED AT INSTALLATION.

## Aircraft

- Registration: [N234GA](https://openairdocs.org/aircraft/N234GA), registered now, S/N 680036, built 1967 (OpenAirDocs)
- Reported make and model: MOONEY M20F
- Registry model: [Mooney M20F](https://openairdocs.org/model/mooney-m20f) (registry code 5870214) (OpenAirDocs)
- Registry engine: [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series) (registry code 41515, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 680036
- Airframe hours: 1510
- Engines: LYCOMING IO-360-A1A 200 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Eugene L. Haggerty
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, May 3, 1985, 21 hours before
- Departed: ELP, EL PASO, TX
- Destination: PHX, PHOENIX, AZ
- Flight plan: VFR
- Airport: E77, San Manuel, runway 29, 4,200 × 50 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 7,600 total, 700 in this make and model, 7,300 as pilot in command, 45 in the last 90 days, 16 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: 270° at 10 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 32 °F, dew point -0 °F

## 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 19851227063849A](https://openairdocs.org/incident/19851227063849A), Dec 27, 1985: Mooney M20F, San Manuel, AZ, Substantial damage. Loss of power in mountainous terrain. Made a runway but tire blew,struck a tree. Cylinder studs improperly torqued.

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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