# NTSB ATL91FA077: Cessna 172D, N2936U, Mocksville, NC, April 7, 1991

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: April 6, 1991, 20:00 local (Apr 7, 1991, 01:00 UTC)
- Place: Mocksville, NC
- Coordinates: 35.890872, -80.550949 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.8909&lon=-80.5509&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal, 1 serious
- Status: Completed, report March 24, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 8319
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL91FA077
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8319/pdf
- Page: https://openairdocs.org/ntsb/ATL91FA077

## Probable cause

THE LOSS OF ENGINE POWER DUE TO OPEN CIRCUITS IN THE IGNITION WIRING HARNESS, AND THE PILOT'S FAILURE TO MAINTAIN FLYING AIRSPEED DURING THE FORCED LANDING ATTEMPT. FACTORS IN THIS ACCIDENT WERE THE DARK NIGHT LIGHTING CONDITIONS AT THE TIME OF THE ACCIDENT.

## 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
  - ignition system,ignition harness - open (cause)
- Forced landing, descent - emergency
  - light condition - night (contributing factor)
- Loss of control - in flight, descent - emergency
  - airspeed - not maintained, undetermined (cause)
  - stall - inadvertent, pilot in command
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

DURING CRUISE FLIGHT IN NIGHT, VFR CONDITIONS, THE ENGINE REPORTEDLY QUIT. DURING THE FORCED LANDING ATTEMPT, THE AIRPLANE STALLED, THEN COLLIDED WITH THE TERRAIN IN A STEEP, NOSE-DOWN ATTITUDE.  POST-CRASH INVESTIGATION AND ENGINE RUN REVEALED THAT 6 OF THE 12 IGNITION HARNESS WIRE CIRCUITS WERE OPEN FROM THE MAGNETOS TO THE SPARK PLUGS. THE ENGINE WOULD RUN ON A TEST STAND, HOWEVER THREE CYLINDERS WERE COLD TO THE TOUCH AFTER THE RUN. ENGINE CONTINUITY WAS ESTABLISHED, AND THE MAGNETOS TESTED SATISFACTORILY ON A TEST BENCH. THE IGNITION HARNESS APPEARED OLD AND WORN, AND THE AIRPLANE HAD BEEN FLOWN ONLY 41 HOURS IN THE PREVIOUS 4 YEARS.

## Aircraft

- Registration: [N2936U](https://openairdocs.org/deregistered/N2936U-1994-03-24), registration cancelled 1994-03-24, S/N 17250536 (OpenAirDocs)
- Reported make and model: CESSNA 172D
- Registry model: [Cessna 172D](https://openairdocs.org/model/cessna-172d) (registry code 2072410) (OpenAirDocs)
- Category: Airplane
- Serial number: 17250536
- Engines: CONTINENTAL O-300-D 145 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Robbins, James L.
- Registered owner: Robbins, James L.
- Last inspection: Annual, November 13, 1990, 21 hours before
- Departed: MWK, MT. AIRY, NC
- Destination: EXX, LEXINGTON, NC

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; toxicology performed; flight hours: 250 total

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 220° at 4 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 70 °F, dew point 50 °F
- Altimeter: 30.00 inHg
- Observed at: INT, 23 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 19910406009119A](https://openairdocs.org/incident/19910406009119A), Apr 6, 1991: Cessna 172D, Mocksville, NC, Substantial damage, 1 fatal. Lost power en route at night. Hit tree on forced landing. Recent annual. Ignition harness worn and frayed.

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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