# NTSB FTW82IA331: Cessna 421B, N1969J, El Paso, TX, August 16, 1982

- Type: NTSB incident investigation
- Classification: Incident · Minor injuries · Incident investigation · Final report
- Date: August 16, 1982, 14:20 local (20:20 UTC)
- Place: El Paso, TX
- Coordinates: 31.799053, -106.360771 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=31.7991&lon=-106.3608&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report August 16, 1983
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 70569
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW82IA331
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/70569/pdf
- Page: https://openairdocs.org/ntsb/FTW82IA331

## 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
  - accessory drive assy - loose (cause)
  - maintenance,installation - improper, manufacturer (cause)
  - acft/equip,inadequate design, manufacturer (contributing factor)
  - accessory drive assy,drive gear - fatigue (contributing factor)
  - accessory drive assy,drive gear - failure,total (contributing factor)
  - turbine assembly,turbine blade - overspeed
  - turbine assembly,turbine wheel - disintegrated

## Analysis

N1969J IS A 1974 CESSNA 421B MODIFIED BY A RILEY CONVERSION KIT. THE AIRCRAFT WAS DESCENDING THROUGH ABOUT 1900 FT MSL WHEN, WITHOUT PREVIOUS WARNING, IT YAWED LEFT. THE PILOT REPORTED THAT THE ACFT THEN IMMEDIATELY YAWED SEVERELY TO THE RIGHT AND BEGAN TO PRODUCE A HIGH-PITCHED WHINING NOISE. THE RIGHT ENGINE THEN EXPLODED. ENGINE DEBRIS PENETRATED THE CABIN WALL AND WINDOWS AND STRUCK THE PILOT CAUSING MINOR INJURIES. THE PILOT SECURED THE RT ENGINE, FEATHERED THE PROPELLER AND LANDED AT EL PASO WITHOUT FURTHER INCIDENT. EXAMINATION OF THE ENGINE REVEALED THAT THE POWER TURBINE WHEEL HAD DISINTEGRATED INFLIGHT. INTERNAL EXAMINATION REVEALED A BROKEN N2 ACCESSORY IDLER GEAR WHICH EXHIBITED A FATIGUE FRACTURE. A LOOSE NUT SECURING THE N2 ACCESSORY IDLER GEAR AND N2 SPEED DISC ALLOWED RELATIVE MOVEMENT AND WEAR OF THESE PARTS. FATIGUE OF THE IDLER GEAR CAUSED A LOSS OF DRIVE TO THE OVERSPEED GOVERNOR AND ALLOWED THE ENGINE TO OVERSPEED. THE MANUFACTURER IS REDESIGNING THE ASSEMBLY.

## Aircraft

- Registration: [N1969J](https://openairdocs.org/deregistered/N1969J-2012-08-20), registration cancelled 2012-08-20, S/N 421B0588, built 1974 (OpenAirDocs)
- Reported make and model: CESSNA 421B
- Registry model: [Cessna 421B](https://openairdocs.org/model/cessna-421b) (registry code 2076014) (OpenAirDocs)
- Registry engine: [Continental GTSIO-520-C](https://openairdocs.org/engine/continental-gtsio-520-c) (registry code 17035, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 421B0588
- Airframe hours: 1650
- Engines: LYCOMING LTP101-600A1A 599 horsepower turbo prop
- Damage: Minor damage
- Flight: Business, Part 91
- Operator: J.D. Abrams, Inc.
- Registered owner: J.D. Abrams, Inc.
- Departed: AUS, AUSTIN, TX
- Destination: MILWAUKEE, WI
- Flight plan: IFR
- Airport: ELP, El Paso Int'L, runway 26, 9,008 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 44; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; flight hours: 5,535 total, 43 in this make and model, 3,750 as pilot in command, 125 in the last 90 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 130° at 8 knots
- Visibility: 50 statute miles
- Lowest ceiling: 25,000 ft overcast
- Temperature: 212 °F
- Altimeter: 30.00 inHg
- Observed at: ELP

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 19820816038409I](https://openairdocs.org/incident/19820816038409I), Aug 16, 1982: Cessna STC421, El Paso, TX, Substantial damage. N1 gear drive failed. Caused engine turbine section to explode. Debris from engine penetrated cockpit injured 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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