# NTSB LAX90LA338: Mooney M-20-M, N9161D, Flagstaff, AZ, September 29, 1990

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: September 28, 1990, 17:55 local (Sep 29, 1990, 00:55 UTC)
- Place: Flagstaff, AZ
- Coordinates: 35.230934, -111.720504 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.2309&lon=-111.7205&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report March 12, 1993
- Report: Approved by Office Director
- ADs cited in the narratives: [AD 91-08-07](https://openairdocs.org/ad/91-08-07) (OpenAirDocs)
- NTSB case key (mKey): 26933
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90LA338
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26933/pdf
- Page: https://openairdocs.org/ntsb/LAX90LA338

## Probable cause

ENGINE FAILURE DUE TO A RUPTURED FUEL PUMP DIAPHRAGM. A FACTOR IN THE ACCIDENT WAS THE UNSUITABLE NATURE OF THE TERRAIN TO MAKE A FORCED LANDING.

## 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, approach - vfr pattern - downwind
  - fuel system,pump - ruptured (cause)
  - maintenance,inspection - inadequate, manufacturer
  - acft/equip,inadequate aircraft component, manufacturer
- Forced landing, descent - emergency
  - terrain condition - none suitable (contributing factor)
- In flight collision with object, descent - emergency
  - object - tree(s)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PILOT OF A MOONEY M-20-M EXPERIENCED ENGINE FAILURE WHILE APPROACHING THE AIRPORT FOR LANDING. THE PILOT STATED HE HAD JUST SWITCHED TO THE FULLEST TANK AND ACTIVATED THE BOOST PUMP. AT THAT POINT THE ENGINE QUIT. EXAMINATION OF THE 18 HOURS SINCE NEW AIRCRAFT FUEL SYSTEM, DISCOVERED A RUPTURED FUEL PUMP DIAPHRAGM. AIRWORTHINESS DIRECTIVE 91-08-07 AND SEVERAL TEXTRON/LYCOMING SERVICE BULLETINS ADDRESS THIS EVENTUALITY.

## Aircraft

- Registration: [N9161D](https://openairdocs.org/aircraft/N9161D), registered now, S/N 270071, built 1990 (OpenAirDocs)
- Reported make and model: MOONEY M-20-M
- Registry model: [Mooney M20M](https://openairdocs.org/model/mooney-m20m) (registry code 5870222) (OpenAirDocs)
- Registry engine: [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series) (registry code 41533, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 27-0071
- Engines: LYCOMING TIO-540-AF1A 270 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: R. T. Dilley
- Departed: ELP, EL PASO, TX
- Airport: FLG, Flagstaff, runway 21, 6,999 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; flight hours: 2,500 total, 8 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- 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 19900928043459A](https://openairdocs.org/incident/19900928043459A), Sep 28, 1990: Mooney M20M, Flagstaff, AZ, Destroyed. Lost power on approach. Unable to make runway. Crashed in trees. Fuel pump diaphram had ruptured. New aircraft.

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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