# NTSB FTW88LA142: Beech A36TC, N3707Z, Vega, TX, August 2, 1988

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 1, 1988, 23:17 local (Aug 2, 1988, 04:17 UTC)
- Place: Vega, TX
- Coordinates: 35.240692, -102.420768 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.2407&lon=-102.4208&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report January 16, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 22668
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW88LA142
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/22668/pdf
- Page: https://openairdocs.org/ntsb/FTW88LA142

## Probable cause

UNREPORTED PROPELLER STRIKE.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - engine assembly,crankshaft - fatigue (cause)
  - propeller system/accessories - separation
- Forced landing, descent - emergency
- On ground/water collision with object, landing - roll
  - fluid,oil - loss,total
  - window,flight compartment window/windshield - dirty(foggy)
  - visual lookout - restricted (contributing factor)
  - visual/aural perception (contributing factor)
  - light condition - dark night (contributing factor)
  - object - sign

## Analysis

THE AIRPLANE WAS ON A NIGHT CROSS COUNTRY FLIGHT WHEN ENGINE OIL STARTED TO APPEAR ON THE WINDOWS. THE PILOT WAS UNABLE TO GET THE AIRPLANE TO AN AIRPORT BEFORE THE OIL PRESSURE WENT TO ZERO. AFTER LOSS OF OIL PRESSURE, THE ENGINE STARTED TO VIBRATE, AND THE PROPELLER SEPARATED FROM THE ENGINE. WITH NO FORWARD VISIBILITY AND VERY LITTLE SIDE VISIBILITY, THE PILOT MADE A FORCED LANDING ON A HIGHWAY SERVICE ROAD; HOWEVER, DURING THE LANDING ROLL, THE AIRPLANE IMPACTED HIGHWAY SIGNS AND REFLECTORS. THE PILOT SAID THERE WAS A FIRE ON THE HIGHWAY, BEHIND THE AIRPLANE, BUT IT NEVER REACHED THE AIRPLANE. A TEARDOWN OF THE ENGINE REVEALED A FAILURE OF THE CRANKSHAFT THAT WAS INITIATED BY A PRE-EXISTING FATIGUE CRACK. THERE WAS EVIDENCE THAT OPENING OF THE FATIGUE CRACK LED TO GRADUAL LOSS OF LUBRICATING OIL, THEN SEPARATION OF THE PROPELLER.

## Aircraft

- Registration: N3707Z (not matched to a registry record)
- Reported make and model: BEECH A36TC
- Category: Airplane
- Serial number: EA 150
- Airframe hours: 570
- Engines: CONTINENTAL TSIO-520-UB 300 horsepower reciprocating
- Damage: Substantial damage
- Fire: On-Ground
- Flight: Personal, Part 91
- Registered owner: Petro Jet Aviation, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, April 1, 1988, 76 hours before
- Departed: DEN, DENVER, CO
- Destination: MAF, MIDLAND, TX

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 35; commercial, airline transport; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 5,800 total, 250 in this make and model, 5,500 as pilot in command, 130 in the last 90 days, 30 in the last 30 days, 7 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 170° at 15 knots
- Visibility: 25 statute miles
- Lowest ceiling: none
- Temperature: 72 °F, dew point 61 °F
- Altimeter: 30.00 inHg

## 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 19880801029589A](https://openairdocs.org/incident/19880801029589A), Aug 1, 1988: Beech A36TC, Vega, TX, Substantial damage. Lost oil pressure through a crack in crankshaft at prop flange. Prop separated landed on I40 striking highway signs

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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