# NTSB LAX82FA167: Cessna 172, N78810, Morman Lake, AZ, May 10, 1982

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: May 10, 1982, 09:45 local (16:45 UTC)
- Place: Morman Lake, AZ
- Location: 34.9116° N, 111.4481° W: Placed by OpenAirDocs: center of Mormon Lake, AZ, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=34.9116&lon=-111.4481&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal, 2 serious
- Status: Completed, report May 10, 1983
- Report: Approved by Office Director
- NTSB case key (mKey): 71770
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX82FA167
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/71770/pdf
- Page: https://openairdocs.org/ntsb/LAX82FA167

## Sequence of events

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

- In flight encounter with weather, cruise - normal
  - preflight planning/preparation - inadequate, pilot in command (cause)
  - aircraft weight and balance - exceeded, pilot in command (contributing factor)
  - weather condition - high density altitude (contributing factor)
  - weather condition - turbulence (contributing factor)
  - weather condition - downdraft (contributing factor)
- In flight collision with object, maneuvering - turn to reverse direction
  - terrain condition - high terrain (contributing factor)
  - terrain condition - mountainous/hilly (contributing factor)
  - object - tree(s) (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE ACFT DEPARTED WINSLOW, AZ ON A FLT TO LONG BEACH, CA WITH AN EN ROUTE STOP SCHEDULED FOR PRESCOT, AZ. BEFORE DEPARTING WINSLOW, THE PLT WAS WARNED BY ANOTHER PLT THAT HE HAD ENCOUNTERED EXTREME TURBULENCE IN THE VICINITY OF MORMON MTN. THE PLT AND PAX'S REMAINED OVERNIGHT AT WINSLOW. THE NEXT MORNING THE PLT WAS ADVISED BY THE OTHER PLT THAT THE WX CONDS AT MORMON & MINGUS MTNS WERE STILL HAZARDOUS, HE RECOMMENDED THAT THEY FLY A SOUTHERLY ROUTE TOWARD PHOENIX, AZ TO CIRCUMNAVIGATE THE HIGH TERRAIN. THE PLT TOOK OFF & CONTD WESTBOUND. HE REPORTED THAT AS THEY PASSED OVER MORMON LAKE, THE PLANE BEGAN TO LOSE ALTITUDE. REPORTEDLY, HE STARTED TO CIRCLE OVER THE LAKE TO GAIN ALTITUDE, BUT ENCOUNTERED A DOWNDRAFT AND THE ACFT COLLIDED WITH TREES & CRASHED (7600' MSL). DURING AN EXAM OF THE WRECKAGE, NO PREIMPACT, MECHANICAL DISCREPANCIES WERE FOUND THAT WOULD HAVE CONTRIBUTED TO THE ACCIDENT. A WEIGHT & BALANCE COMPUTATION REVEALED THE GROSS WEIGHT WAS APRX 2474 LBS. THE MAX AUTHORIZE GROSS WEIGHT WAS 2300 LBS.

## Aircraft

- Registration: [N78810](https://openairdocs.org/deregistered/N78810-1984-05-10), registration cancelled 1984-05-10, S/N 17257776, built 1968 (OpenAirDocs)
- Reported make and model: CESSNA 172
- Registry model: [Cessna 172K](https://openairdocs.org/model/cessna-172k) (registry code 2072430) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 17257776
- Airframe hours: 1714
- Engines: LYCOMING O-320-E2D 150 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: Thayer H. Harvey
- Registered owner: Thayer H. Harvey
- Departed: INW, WINSLOW, AZ
- Destination: LGB, LONG BEACH, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 40; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; flight hours: 8 in the last 24 hours

## Weather

- Conditions: Day
- Wind: 200° at 16 knots
- Visibility: 8 statute miles
- Temperature: 138 °F
- Altimeter: 29.00 inHg
- Observed at: PHX, 200 nm away

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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