On September 2, 1987, an Aero Commander 690 (registration N9168N) operated by Maxair was involved in an aviation accident near Appleton, WI. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot reported a rapid loss of hydraulic pressure at cruise, leading to a left main gear collapse upon landing. Investigation found a failed hydraulic line and a sticking priority valve.
Event Summary
During cruise flight, the pilot experienced a rapid loss of hydraulic pressure. The decision was made to return to the departure airport. Upon approach, attempts to extend the left main landing gear were unsuccessful; the gear would not lock into position. When the aircraft landed, the left main gear collapsed.
Investigation Findings
Examination of the aircraft revealed that a hydraulic line in the left wing had failed, resulting in the loss of hydraulic fluid and pressure. Additionally, a priority valve was found to be sticking. These two issues combined prevented the landing gear from being extended using either the normal or emergency extension systems.
Frequently asked questions
What happened in the 2 Sept 1987 Aero Commander 690 accident near Appleton, WI?
A pilot reported a rapid loss of hydraulic pressure at cruise, leading to a left main gear collapse upon landing. Investigation found a failed hydraulic line and a sticking priority valve.
What aircraft was involved and where did it happen?
The accident on 2 Sept 1987 involved an Aero Commander 690, registration N9168N, operated by Maxair, at Appleton, WI.
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