# NTSB FTW90LA084: Cessna 172G, N4696L, Rio Hondo, TX, March 17, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: March 17, 1990, 15:11 local (21:11 UTC)
- Place: Rio Hondo, TX
- Coordinates: 26.229024, -97.579933 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=26.2290&lon=-97.5799&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report September 15, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 23117
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW90LA084
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/23117/pdf
- Page: https://openairdocs.org/ntsb/FTW90LA084

## Probable cause

OIL STARVATION INDUCED POWER LOSS DUE TO IMPROPER MAINTENANCE PROCEDURES. CONTRIBUTING TO THE ACCIDENT WERE INADEQUATE MAINTENANCE INSPECTION AND THE SOFT TERRAIN IN WHICH THE FORCED LANDING WAS PERFORMED.

## 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
  - single engine aircraft
  - lubricating system,oil line - separation (cause)
  - lubricating system,oil line - stripped thread (cause)
  - maintenance,installation - improper (cause)
  - maintenance,inspection - inadequate, company maintenance personnel (contributing factor)
- Forced landing, descent - emergency
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - none suitable (contributing factor)
  - terrain condition - soft (contributing factor)
- Nose over, landing - roll

## Analysis

THE PILOT STATED THAT WHILE IN CRUISE FLIGHT AT 2,500 FEET, HE NOTICED AN INCREASE IN ENGINE RPM AND DETECTED SMOKE IN THE CABIN. AFTER REDUCING THROTTLE TO A CONTROLLABLE RPM, HE NOTICED THAT THE ENGINE OIL PRESSURE WAS ZERO. HE SUBSEQUENTLY EXECUTED A FORCED LANDING TO AN OPEN BRUSHY AREA THAT WAS THE BEST AVAILABLE. DURING ROLL OUT THE NOSE GEAR DUG INTO THE SOFT GROUND AND THE AIRPLANE FLIPPED OVER. INVESTIGATION REVEALED THAT THE PROPELLER GOVERNOR OIL LINE FITTING HAD SEPARATED DUE TO STRIPPING OF THE THREADS OUT OF THE GOVERNOR HOUSING AND THAT THE FITTING WAS INCORRECT FOR THE APPLICATION. THE AIRPLANE HAD EXPERIENCED A FORCED LANDING 13 DAYS PRIOR TO THE ACCIDENT DUE TO AN OIL LEAK AND LOSS OF OIL PRESSURE DUE TO THE JAM NUT ON THE FAILED FITTING HAVING BACKED OFF. ON THAT OCCASION, A MECHANIC TIGHTENED THE LINE AND THE AIRPLANE WAS CLEARED FOR FLIGHT.

## Aircraft

- Registration: [N4696L](https://openairdocs.org/aircraft/N4696L), registered now, S/N 17254691, built 1966 (OpenAirDocs)
- Reported make and model: CESSNA 172G
- Registry model: [Cessna 172G](https://openairdocs.org/model/cessna-172g) (registry code 2072420) (OpenAirDocs)
- Registry engine: [Lycoming 0-360-A1D](https://openairdocs.org/engine/lycoming-0-360-a1d) (registry code 41504, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 17254691
- Airframe hours: 3844
- Engines: LYCOMING IO-360-A1D 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Bs Aviation, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, November 17, 1989, 11 hours before
- Departed: HRL, HARLINGEN, TX
- Destination: HRL, HARLINGEN, TX

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 51; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 142 total, 45 in this make and model, 142 as pilot in command, 2 in the last 90 days, 1 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 340° at 7 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 81 °F, dew point 45 °F
- Altimeter: 30.00 inHg
- Observed at: HRL, 18 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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