# NTSB LAX90DUJ05: Bell UH-1E, N138US, Mesa, AZ, November 4, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: November 4, 1989, 09:15 local (16:15 UTC)
- Place: Mesa, AZ
- Coordinates: 33.439037, -111.760238 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.4390&lon=-111.7602&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report June 30, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26544
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90DUJ05
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26544/pdf
- Page: https://openairdocs.org/ntsb/LAX90DUJ05

## Probable cause

THE INFLIGHT SEPARATION OF THE TAIL ROTOR DUE TO IMPROPER MAINTENANCE PROCEDURES AND THE INSTALLATION OF INCORRECT ATTACHMENT HARDWARE ON THE TAIL ROTOR BLADE PITCH CHANGE LINKAGES.

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering - aerial application
  - rotor system,tail rotor hub pitch link - separation
  - maintenance,installation - improper, company maintenance personnel (cause)
  - maintenance,inspection - improper, company maintenance personnel (cause)
- In flight collision with terrain/water, descent - uncontrolled
  - aircraft control - not possible, pilot in command

## Analysis

INVESTIGATION DISCLOSED THAT THE TAIL ROTOR SEPARATED FROM THE HELICOPTER IN FLIGHT. THE TAIL ROTOR ASSEMBLY WAS SENT TO THE MANUFACTURER FOR ANALYSIS. ON TAIL ROTOR BLADE 'A' THE BOLT, NUT AND ASSOCIATED HARDWARE THAT ATTACHED THE PITCH CHANGE LINK TO THE BLADE GRIP WERE MISSING. THE BOLT BUSHING WAS WORN BEYOND THE SERVICE LIMITS THAT MANDATED REPLACEMENT. ON BLADE 'B' THE ATTACHING BOLT, NUT AND HARDWARE WERE DETERMINED TO BE THE WRONG SIZE. IN ADDITION, THE WRONG SPACER WAS ATTACHED TO THE BOLT. FOUR MORE WASHERS THAN ALLOWED WERE UNDER THE TRAILING EDGE BLADE RETAINING BOLT NUT. ACCORDING TO THE PREFLIGHT INSPECTION REQUIREMENTS, THE DISCREPANCIES ON THE BLADE 'A' BUSHING AND THE INCORRECT HARDWARE ON THE BLADE 'B' PITCH CHANGE LINK SHOULD HAVE BEEN DETECTED DURING THE DAILY INSPECTION EVENT.

## Aircraft

- Registration: [N138US](https://openairdocs.org/deregistered/N138US-2018-02-12), registration cancelled 2018-02-12, S/N 154944, built 1967 (OpenAirDocs)
- Reported make and model: BELL UH-1E
- Registry model: [Bell UH-1L](https://openairdocs.org/model/bell-uh-1l) (registry code 1181401) (OpenAirDocs)
- Registry engine: [Lycoming T-53 series](https://openairdocs.org/engine/lycoming-t-53-series) (registry code 41552, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 154944
- Airframe hours: 6866
- Engines: LYCOMING T5311 1100 horsepower turbo shaft
- Damage: Destroyed
- Flight: Aerial application, Part 137
- Operator: Gilman D. Christopher, doing business as Chris'S Aviation
- Registered owner: Phillip D. Barnes
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, May 30, 1989, 300 hours before
- Departed: NONE, QUEEN CREEK, AZ
- Destination: NONE

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 46; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 21,020 total, 580 in this make and model, 20,820 as pilot in command, 300 in the last 90 days, 100 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Lowest ceiling: none
- Altimeter: 29.00 inHg

## 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 19891104044199A](https://openairdocs.org/incident/19891104044199A), Nov 4, 1989: Bell UH1E, Mesa, AZ, Destroyed. Tail rotor pitch change bolt failed and rotor assembly tore off. Crashed in uncontrolled turn and rolled over.

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.