# NTSB FTW85LA294: North American AT-6, N4434N, Port Isabel, TX, August 3, 1985

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 3, 1985, 17:30 local (22:30 UTC)
- Place: Port Isabel, TX
- Location: 26.0658° N, 97.3098° W: Placed by OpenAirDocs: center of Port Isabel, TX, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=26.0658&lon=-97.3098&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 21806
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW85LA294
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/21806/pdf
- Page: https://openairdocs.org/ntsb/FTW85LA294

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, approach - vfr pattern - base turn
  - engine assembly,cylinder - cracked (cause)
  - engine assembly,cylinder - separation (cause)
- Forced landing, descent - emergency
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - rough/uneven (cause)
  - terrain condition - none suitable (cause)

## Analysis

THE ACFT WAS SUBSTANTIALLY DAMAGED WHEN IT UNDERSHOT THE RUNWAY AND CARTWHEELED DURING AN EMERGENCY LANDING FOLLOWING AN ENGINE FAILURE IN THE TRAFFIC PATTERN. THE PLT REPORTED THAT INITIAL EXAMINATION OF THE ENGINE REVEALED THAT INITIAL EXAMINATION OF THE ENGINE REVEALED THAT 4 CYLINDER HEADS WERE CRACKED AND SEPARATED FROM THE BARRELS. NO ADDITIONAL INFORMATION HAS BEEN RECEIVED REGARDING THE CAUSE OF THE ENGINE FAILURE.

## Aircraft

- Registration: [N4434N](https://openairdocs.org/aircraft/N4434N), registered now, S/N 88-12044, built 1943 (OpenAirDocs)
- Reported make and model: NORTH AMERICAN AT-6
- Registry model: [North American AT-6C(SNJ-4)](https://openairdocs.org/model/north-american-at-6c-snj-4) (registry code 6400449) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 88-122044
- Airframe hours: 10314
- Engines: P&W R-1340-PC1 600 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Robin F. Diver
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, March 2, 1985, 18 hours before
- Airport: T31, Cameron County, runway 13, 8,000 × 200 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: center; flight hours: 2,815 total, 120 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 140° at 19 knots, gusting 24
- Visibility: 50 statute miles
- Temperature: 90 °F, dew point 73 °F
- Altimeter: 29.00 inHg
- Observed at: BRO, 15 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 19850803038979A](https://openairdocs.org/incident/19850803038979A), Aug 3, 1985: Namer AT6, Port Isabel, TX, Substantial damage. Engine lost power, aircraft vibrated badly. Hit short, cartwheeled. Cylinder heads cracked. Separated from barrels.

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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