# NTSB ATL92LA038: Beech J-35, N185Y, Knoxville, TN, January 12, 1992

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: January 12, 1992, 14:02 local (19:02 UTC)
- Place: Knoxville, TN
- Coordinates: 35.789512, -83.97026 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.7895&lon=-83.9703&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report August 13, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 8554
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL92LA038
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8554/pdf
- Page: https://openairdocs.org/ntsb/ATL92LA038

## Probable cause

THE MANUFACTURER'S FAILURE TO PROVIDE ADEQUATE TORQUE INFORMATION WHICH RESULTED IN THE LOSS OF TORQUE ON THE CYLINDER HOLD DOWN NUTS AND THE COMPLETE LOSS OF ENGINE POWER.

## 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
  - engine assembly,cylinder - separation
  - engine assembly,cylinder - undertorqued (cause)
  - maintenance,overhaul - inadequate, manufacturer (cause)
  - procedure inadequate, manufacturer (cause)
- Forced landing, descent - emergency
- In flight collision with terrain/water, landing - flare/touchdown
  - airport/facilities - soft

## Analysis

SHORTLY AFTER TAKEOFF, THE PILOT REPORTED A SEVERE VIBRATION IN THE AIRPLANE, FOLLOWED BY A COMPLETE LOSS OF ENGINE POWER. AN EMERGENCY LANDING WAS ATTEMPTED TO RUNWAY 24R AT MCGHEE TYSON AIRPORT, BUT THE AIRPLANE CRASHED A MILE SHORT OF THE RUNWAY. EXAMINATION OF THE ENGINE ASSEMBLY REVEALED THAT NUMBER 1 & 2 CYLINDERS HAD SEPARATED FROM THE ENGINE CASE. THE EXAMINATION ALSO DISCLOSED THAT THE CYLINDER HOLD DOWN STUDS WERE DAMAGED AND THE THREADS WERE BATTERED. THERE WAS AN ACCUMULATION OF METALLIC DUST ASSOCIATED WITH FRETTING ADJACENT TO THE CYLINDER FLANGE AND ENGINE CASE. SEVERAL HOLD DOWN NUTS WERE NOT RECOVERED FOR EXAMINATION. THE ENGINE MAINTENANCE LOG SHOWED THAT THE NUMBER 1 CYLINDER WAS REMOVED AND INSTALLED IN ACCORDANCE WITH CURRENT SERVICE INSTRUCTIONS 314 HOURS PRIOR TO THIS ACCIDENT. SUBSEQUENT TO THIS ACCIDENT CONTINENTAL MOTORS ISSUED A SERVICE BULLETIN INCREASING THE HOLD DOWN TORQUE NUT VALUES FROM 710 INCH POUND TO 810 INCH POUNDS, AND CHANGED EXISTING SIX POINT HOLD DOWN  NUTS TO TWELVE POINT NUTS.

## Aircraft

- Registration: [N185Y](https://openairdocs.org/deregistered/N185Y-2012-08-13), registration cancelled 2012-08-13, S/N D-5333, built 1957 (OpenAirDocs)
- Reported make and model: BEECH J-35
- Registry model: [Beech J35](https://openairdocs.org/model/beech-j35) (registry code 1151522) (OpenAirDocs)
- Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: D5333
- Airframe hours: 4510
- Engines: CONTINENTAL I0-470-C 250 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Webster, Gordon
- Registered owner: Webster, Gordon
- Airworthiness certificate: Standard, Utility; Standard, Normal
- Last inspection: Annual, March 9, 1991, 98 hours before
- Destination: RYY, MARIETTA, GA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 53; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 1,100 total, 90 in this make and model, 1,100 as pilot in command, 10 in the last 90 days, 5 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 250° at 6 knots
- Visibility: 7 statute miles
- Lowest ceiling: 6,500 ft overcast
- Temperature: 39 °F
- Altimeter: 30.00 inHg
- Observed at: TYS, 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 19920112000969A](https://openairdocs.org/incident/19920112000969A), Jan 12, 1992: Beech J35, Knoxville, TN, Substantial damage. Through bolts on 2 cylinders not torqued. Came out causing engine destruction on final. Crashed short of runway.

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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