# NTSB FTW90LA103: Beech BE-35M, N1ZY, Tomball, TX, April 28, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: April 28, 1990, 14:41 local (19:41 UTC)
- Place: Tomball, TX
- Coordinates: 30.089567, -95.609802 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=30.0896&lon=-95.6098&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report September 28, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 23127
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW90LA103
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/23127/pdf
- Page: https://openairdocs.org/ntsb/FTW90LA103

## Probable cause

AN ENGINE FAILURE DUE TO DETONATION AND SUBSEQUENT PISTON OVERTEMPERATURE AND EROSION. A FACTOR RELATED TO THE ACCIDENT WAS THE LACK OF SUITABLE TERRAIN.

## 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, descent - normal
  - engine assembly,piston - eroded (contributing factor)
  - engine assembly,piston - overtemperature (cause)
- Forced landing, descent - emergency
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - none suitable (contributing factor)

## Analysis

THE AIRPLANE WAS DAMAGED WHEN IT COLLIDED WITH A FENCE AND A DITCH DURING A FORCED LANDING FOLLOWING A COMPLETE ENGINE FAILURE. INVESTIGATION REVEALED THAT THE NO. 5 PISTON WAS SEVERELY HEAT ERODED WITH PIECES MISSING. THE EROSION ALLOWED EXHAUST VENTING (BLOW BY) INTO THE CASE. THERE WAS SOME EVIDENCE OF PRE-IGNITION ON THE OTHER PISTONS' BUT NOT TO THE EXTENT AS ON NO. 5. IT WAS DETERMINED THAT THE ENGINE WAS 17 HOURS OUT OF A MAJOR OVERHAUL AND HAD BEEN USING AUTO GAS AT THE TIME OF THE ACCIDENT. IT APPEARED THAT THE PISTON EROSION HAD OCCURRED OVER A LONG PERIOD OF TIME.

## Aircraft

- Registration: [N1ZY](https://openairdocs.org/deregistered/N1ZY-1993-01-27), registration cancelled 1993-01-27, S/N D6362 (OpenAirDocs)
- Reported make and model: BEECH BE-35M
- Registry model: [Beech M35](https://openairdocs.org/model/beech-m35) (registry code 1151526) (OpenAirDocs)
- Category: Airplane
- Serial number: D-6362
- Airframe hours: 2630
- Engines: CONTINENTAL IO-470-C 250 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Davis, Harold E.
- Registered owner: Davis, Harold E
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, July 12, 1989, 64 hours before
- Departed: DWH
- Destination: DWH
- Airport: DWH, David Wayne Hooks, runway 17, 4,000 × 100 ft, dirt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 814 total, 335 in this make and model, 756 as pilot in command, 17 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 210° at 10 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 84 °F, dew point 54 °F
- Altimeter: 29.00 inHg
- Observed at: DWH, 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 19900428012909A](https://openairdocs.org/incident/19900428012909A), Apr 28, 1990: Beech M35, Houston, TX, Substantial damage. Engine seized near airport. Crash landed. Auto fuel used. Detonation damage. New engine recent installed by pilot.

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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