# NTSB MIA87LA238: Aero Commander 680FL, N111UA, St Thomas, September 2, 1987

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 2, 1987, 15:25 local (19:25 UTC)
- Place: St Thomas
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 7 uninjured
- Status: Completed, report January 11, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 31958
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA87LA238
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/31958/pdf
- Page: https://openairdocs.org/ntsb/MIA87LA238

## Sequence of events

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

- Airframe/component/system failure/malfunction, approach
  - hydraulic system,relief valve - inoperative (cause)
  - landing gear,normal retraction/extension assembly - overload (cause)
  - gear extension - not possible
- Main gear collapsed, landing - flare/touchdown

## Analysis

AFTER A LOSS OF HYD PRESSURE, THE RGT MAIN GEAR WOULD NOT FULLY EXTD WHEN THE PLT TRIED TO LOWER THE GEAR FOR LNDG. ALL ATMTS TO LOCK IT INTO PLACE WERE UNSUCCESSFUL. WHEN THE ACFT TOUCHED DOWN DRG THE LNDG, THE RGT MAIN GEAR COLLAPSED.THE ACFT SLID TO A STOP & THE OCCUPANTS WERE EVACUATED. AN INSPN OF THE RGT MAIN GEAR ASSY REVEALED THE HYD ACTUATING CYL HAD FAILED AT THE SNAP RING GROOVE & THE PNEUMATIC ACTUATING CYL HAD FAILED AT THE ROD END. BOTH FAILED FM OVERLOAD.THIS WAS THE 2ND OVERLOAD FAILURE OF THE HYD ACTUATING CYL IN 26 FLT HRS OF OPN. ACCORDING TO A MECHANIC, WHO WAS FAMILIAR WITH THE ACFT, THIS FAILURE WAS CONSISTENT WITH EXCESSIVE PRESSURE IN THE SYS DUE TO A PRESSURE RELIEF/UNLOADERVALVE MALFUNCTION.

## Aircraft

- Registration: [N111UA](https://openairdocs.org/deregistered/N111UA-2014-12-17), registration cancelled 2014-12-17, S/N 1370-43 (OpenAirDocs)
- Reported make and model: AERO COMMANDER 680FL
- Registry model: [Aero Commander 680FL](https://openairdocs.org/model/aero-commander-680fl) (registry code 0141608) (OpenAirDocs)
- Category: Airplane
- Serial number: 1370-43
- Airframe hours: 9769
- Engines: LYCOMING IO-720-B1B 400 horsepower reciprocating
- Damage: Substantial damage
- Flight: Part 135
- Registered owner: Clint Aero, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, May 31, 1987, 73 hours before
- Departed: MKPD, DOMINICA,UK, OF
- Flight plan: VFR
- Airport: STT, Cyril E. King, runway 9, 5,358 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; commercial, 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: 2,986 in this make and model, 89 in the last 90 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 60° at 10 knots
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 84 °F, dew point 77 °F
- Altimeter: 29.00 inHg
- Observed at: STT

## 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 19870902083269A](https://openairdocs.org/incident/19870902083269A), Sep 2, 1987: Gulstm 680FL, Charlotte Amali, U.S. Virgin Islands, Substantial damage. Unable lock down right main gear which collapsed on landing. Actuating cylinder failed from defect in relief valve.

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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