# NTSB LAX93IA029: Piper PA-31T-620, N131AF, Medford, OR, November 5, 1992

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: November 5, 1992, 02:30 local (10:30 UTC)
- Place: Medford, OR
- Coordinates: 42.279537, -122.900764 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.2795&lon=-122.9008&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 24, 1993
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 27836
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX93IA029
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27836/pdf
- Page: https://openairdocs.org/ntsb/LAX93IA029

## Probable cause

FATIGUE FAILURE OF THE ELEVATOR CONTROL TUBE ROD END BEARING RESULTING IN A LOSS OF ELEVATOR CONTROL.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - flt control syst,elevator control - fatigue (cause)
- Loss of control - in flight, cruise - normal
  - flt control syst,elevator control - disconnected (cause)

## Analysis

DURING CRUISE FLIGHT AT FLIGHT LEVEL 230, THE AIRPLANE SUDDENLY PITCHED UP AND THE AUTOPILOT DISENGAGED. THE PILOT WAS UNABLE TO CONTROL THE AIRPLANE WITH THE CONTROL YOKE. USING POWER AND TRIM CONTROL, HE FINALLY REGAINED CONTROL OF THE AIRPLANE AND MADE AN EMERGENCY LANDING AT SACRAMENTO WITHOUT FURTHER INCIDENT. INVESTIGATION REVEALED THAT THE THREADED PORTION OF THE ROD END BEARING, P/N 49261-02, HAD SEPARATED AT THE POINT WHERE THE THREADS ARE INSERTED INTO THE AFT END OF THE ELEVATOR CONTROL TUBE ASSEMBLY, P/N 40847-07. THE ELEVATOR CONTROL TUBE CONNECTS TO THE ELEVATOR PITCH HORN. METALLURGICAL EXAMINATION SHOWED THAT THE SEPARATION WAS DUE TO A FATIGUE FAILURE. THE AIRCRAFT HAD BEEN INSPECTED AT 37 HRS AND 134 HRS BEFORE THE INCIDENT IN ACCORDANCE WITH AN APPROVED AIRCRAFT INSPECTION PROGRAM. NEITHER INSPECTION SPECIFICALLY ADDRESSED AN INSPECTION OF THE ELEVATOR CONTROL TUBE ASSEMBLY.

## Aircraft

- Registration: [N131AF](https://openairdocs.org/deregistered/N131AF-2005-10-14), registration cancelled 2005-10-14, S/N 31T-7820005, built 1977 (OpenAirDocs)
- Reported make and model: PIPER PA-31T-620
- Registry model: [Piper PA-31T](https://openairdocs.org/model/piper-pa-31t) (registry code 7103124) (OpenAirDocs)
- Registry engine: [U/A Canada PT6A-27-28](https://openairdocs.org/engine/u-a-canada-pt6a-27-28) (registry code 61504, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 31T-7820005
- Airframe hours: 12097
- Engines: P&W PT6A-28 620 horsepower turbo prop
- Damage: No damage
- Flight: Part 135
- Operator: Ameriflight Inc.
- Registered owner: Ameriflight Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, October 26, 1992, 37 hours before
- Departed: PDX, PORTLAND, OR
- Destination: OAK, OAKLAND, CA
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 25; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 4,813 total, 280 in this make and model, 4,588 as pilot in command, 301 in the last 90 days, 100 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 340° at 20 knots
- Visibility: 75 statute miles
- Lowest ceiling: none
- Temperature: 18 °F

## 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 19921105056809I](https://openairdocs.org/incident/19921105056809I), Nov 5, 1992: Piper PA31T, Sacramento, CA. Experienced loss of elevator pitch control in flight. Diverted. Rod end bearing had separated due to fatigue

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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