# NTSB CHI87LA200: Aero Commander 690, N9168N, Appleton, WI, September 2, 1987

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 2, 1987, 12:15 local (17:15 UTC)
- Place: Appleton, WI
- Coordinates: 44.260501, -88.389915 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=44.2605&lon=-88.3899&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 5 uninjured
- Status: Completed, report October 25, 1988
- Report: Approved by Office Director
- NTSB case key (mKey): 13815
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI87LA200
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/13815/pdf
- Page: https://openairdocs.org/ntsb/CHI87LA200

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - hydraulic system,line - ruptured (cause)
  - hydraulic system,bypass valve - binding(mechanical) (cause)
- Main gear collapsed, landing - flare/touchdown
  - emergency procedure - attempted
  - gear down and locked - not possible
  - wheels up landing

## Analysis

THE PLT RPRTD THAT AFTER THE ACFT WAS AT CRUISE FLT, THERE WAS A RAPID LOSS OF HYDRAULIC PRESSURE. HE RETURNED TO THE DEP ARPT, BUT WAS UNABLE TO GET THE LEFT MAIN GEAR TO LOCK DOWN. SUBSEQUENTLY, THE LEFT MAIN GEAR COLLAPSED WHEN THE ACFT WAS LANDED. AN INVESTIGATION REVEALED A HYDRAULIC LINE IN THE LEFT WING HAD FAILED WHICH HAD ALLOWED A LOSS OF HYDRAULIC FLUID & PRESSURE. ALSO, THERE WAS A STICKING PRIORITY VALVE. WITH THESE PROBLEMS, THE GEAR COULD NOT BE EXTENDED WITH EITHER THE NORMAL OR EMERG SYS.

## Aircraft

- Registration: [N9168N](https://openairdocs.org/deregistered/N9168N-2000-05-25), registration cancelled 2000-05-25, S/N 11068 (OpenAirDocs)
- Reported make and model: AERO COMMANDER 690
- Registry model: [Aero Commander 690](https://openairdocs.org/model/aero-commander-690) (registry code 0141720) (OpenAirDocs)
- Category: Airplane
- Serial number: 11068
- Airframe hours: 5632
- Engines: AIRESEARCH TPE-331 718 horsepower turbo prop
- Damage: Substantial damage
- Flight: Part 135
- Operator: Maxair
- Registered owner: Maxair, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, August 25, 1987
- Departed: ATW
- Destination: STL, ST. LOUIS, MO
- Flight plan: IFR
- Airport: ATW, Outagamie County, runway 3, 7,001 × 150 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; airline transport; airplane ratings: single-engine sea, multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 10,000 total, 2,405 in this make and model, 105 in the last 90 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 330° at 6 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 63 °F, dew point -0 °F
- Altimeter: 30.00 inHg
- Observed at: ATW, 5 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 19870902054399A](https://openairdocs.org/incident/19870902054399A), Sep 2, 1987: Gulstm 690, Appleton, WI, Substantial damage. Lost hydraulic pressure. Returned. Unable to lock gear in down position. Left main gear collapsed on landing.

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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