# NTSB LAX91FA001: Mooney M20K, N231AX, Flagstaff, AZ, October 3, 1990

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: October 3, 1990, 12:46 local (19:46 UTC)
- Place: Flagstaff, AZ
- Coordinates: 35.230995, -111.719963 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.2310&lon=-111.7200&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report August 6, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 26958
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX91FA001
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26958/pdf
- Page: https://openairdocs.org/ntsb/LAX91FA001

## Probable cause

THE PILOT'S DECISION TO OPERATE THE AIRCRAFT WITH A KNOWN DISCREPANCY; INADEQUATE MAINTENANCE PROCEDURES; AND THE PILOT'S INFLIGHT LOSS OF CONTROL DUE TO SMOKE AND FUMES IN THE COCKPIT.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Fire, cruise
  - exhaust system,clamp - failure,total (cause)
  - maintenance,inspection - inadequate, other maintenance personnel (cause)
  - operation with known deficiencies in equipment - intentional, pilot in command (cause)
- Forced landing, descent - emergency
- Loss of control - in flight, descent - emergency
  - fuselage,crew compartment - smoke (cause)
  - aircraft control - uncontrolled, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PILOT HAD RETURNED FROM AN EARLIER DEPARTURE BECAUSE HE HAD SMOKE INSIDE THE AIRPLANE, AND REQUESTED THE ASSISTANCE OF A MECHANIC. UNABLE TO OBTAIN THIS ASSISTANCE, HE BORROWED A PAIR OF PLIERS FROM THE FBO. AFTER INSPECTING THE AIRPLANE HIMSELF, HE RETURNED THE PLIERS AND COMMENTED SOMETHING ABOUT THE EGT PROBE TO THE LINE PERSON ON DUTY. SOON AFTER THE SECOND DEPARTURE, THE AIRPLANE WAS SEEN RETURNING TOWARDS THE AIRPORT TRAILING SMOKE AND POSSIBLY FIRE. THE AIRPLANE ROLLED INVERTED AND DESCENDED INTO TREES. THE AIRPORT MANAGER RESPONDING TO THE ACCIDENT SCENE LOCATED THE EXHAUST TAILPIPE. THE FRACTURED TURBO CLAMP WAS LOCATED AT THE WRECKAGE. METALLURGICAL ANALYSIS REVEALED THAT CRACKING OCCURRED AS A RESULT OF INTERGRANULAR CORROSION. ON 9/26/90 THE TURBOCHARGER WAS REMOVED, REPAIRED AND REINSTALLED.

## Aircraft

- Registration: [N231AX](https://openairdocs.org/deregistered/N231AX-1991-05-21), registration cancelled 1991-05-21, S/N 250114 (OpenAirDocs)
- Reported make and model: MOONEY M20K
- Registry model: [Mooney M20K](https://openairdocs.org/model/mooney-m20k) (registry code 5870220) (OpenAirDocs)
- Category: Airplane
- Serial number: 25-0114
- Engines: CONTINENTAL TSIO-360-GB 210 horsepower reciprocating
- Damage: Destroyed
- Fire: In-Flight
- Flight: Business, Part 91
- Registered owner: Megill, Donald M.
- Destination: UNK, UNKNOWN

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 56; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, expired; toxicology performed; flight hours: 4,800 total, 100 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 310° at 8 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F
- Observed at: FLG, 1 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 19901003050229A](https://openairdocs.org/incident/19901003050229A), Oct 3, 1990: Mooney M20K, Flagstaff, AZ, Destroyed, 1 fatal. Returning to airport saw trailing smoke. Rolled left, hit trees. Tailpipe on runway. AD turbo v clamps not complied.

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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