# NTSB LAX89FA314: Piper PA-31-350, N70PE, Ontario, CA, September 15, 1989

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: September 15, 1989, 06:52 local (13:52 UTC)
- Place: Ontario, CA
- Coordinates: 34.070106, -117.619384 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=34.0701&lon=-117.6194&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report September 9, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26251
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX89FA314
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26251/pdf
- Page: https://openairdocs.org/ntsb/LAX89FA314

## Probable cause

FAILURE OF THE RIGHT PROPELLER HUB DUE TO METAL FATIGUE WHICH RESULTED IN CATASTROPHIC SEPARATION OF THE PROPELLER. CONTRIBUTING TO THE ACCIDENT WAS DAMAGE DONE TO THE AIRCRAFT AIRFRAME IN FLIGHT BY THE SEPARATING PROPELLER MAKING THE AIRCRAFT UNCONTROLLABLE.

## Sequence of events

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

- Airframe/component/system failure/malfunction, takeoff - initial climb
  - propeller system/accessories,hub - fatigue (cause)
  - propeller system/accessories,hub - fractured (cause)
  - propeller system/accessories - separation (contributing factor)
  - maintenance,overhaul - improper, other maintenance personnel
- Altitude deviation,uncontrolled, descent - emergency
  - remedial action - attempted, pilot in command
  - aircraft control - not possible, pilot in command
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PROPELLER SEPARATED FROM THE RIGHT ENGINE DURING THE INITIAL CLIMB. EXAMINATION OF THE WRECKAGE REVEALED THE PROPELLER HUB FRACTURE RESULTED IN ONE OF THE THREE PROPELLER BLADES DETACHING FROM THE HUB. THE REST OF THE PROPELLER HUB THEN SEPARATED STRIKING THE RIGHT FRONT OF THE FUSELAGE. OIL WAS SPREAD ACROSS THE AIRCRAFT NOSE AND WINDSHEILD. THE FUSELAGE RIGHT SIDE DAMAGE INCREASED AERODYNAMIC DRAG. WITNESSES REPORTED THE ENGINE COWLING WAS TORN. THE AIRCRAFT ENTERED A RIGHT TURN AND DIVE. IT IMPACTED THE GROUND IN A NEAR INVERTED ATTITUDE. METALLURGICAL EXAMINATION OF THE FAILED PROP HUB REVEALED METAL FATIGUE EMANATING FROM THE THREADED HOLE FOR THE GREASE FITTING. THE THREADS HAD BEEN DEFORMED BY SHOT PEENING, RESULTING IN INCREASED STRESS CONCENTRATIONS AT THE THREADS.

## Aircraft

- Registration: [N70PE](https://openairdocs.org/deregistered/N70PE-1992-11-19), registration cancelled 1992-11-19, S/N 318052137 (OpenAirDocs)
- Reported make and model: PIPER PA-31-350
- Registry model: [Piper PA-31-350](https://openairdocs.org/model/piper-pa-31-350) (registry code 7103110) (OpenAirDocs)
- Category: Airplane
- Serial number: 31-805 2137
- Airframe hours: 3118
- Engines: LYCOMING TIO-540-J2BD 350 horsepower reciprocating
- Damage: Destroyed
- Fire: On-Ground
- Flight: Part 135
- Operator: Ameriflight
- Registered owner: Jack Wall Aircraft Sales Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, August 22, 1989, 39 hours before
- Departed: ONT, ONTARIO, CA
- Destination: SBA, SANTA BARBARA, CA
- Flight plan: VFR
- Airport: ONT, Ontario Int'L, runway 0R

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 24; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 1,916 total, 89 in the last 90 days, 49 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 7 statute miles
- Lowest ceiling: none
- Temperature: 70 °F, dew point 45 °F
- Altimeter: 29.00 inHg
- Observed at: ONT, 2 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 19890915035099A](https://openairdocs.org/incident/19890915035099A), Sep 15, 1989: Piper PA31350, Ontario, CA, Destroyed, 1 fatal. Right prop hub fractured on climbout separating prop assembly.

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.