On January 12, 1985, a Cessna T210L (registration N4691Q) was involved in an aviation accident near San Jose, CA. Investigators recorded the probable cause as: A one-half inch piece of packing in the nose gear manifold near the door close valve, and a thermal relief valve stuck in the open position by a build-up of dark colored greasy residue on the spring. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During a flight, the pilot discovered landing gear would not extend. After a temporary fix using the emergency hand pump, both normal and emergency systems failed on return to San Jose, resulting in a gear-up landing with substantial damage. Investigation revealed hydraulic system issues.
Incident Details
During the first leg of a flight, the pilot discovered that the landing gear would not extend. By pressurizing the 'down side' with the emergency hand pump, the landing gear was able to operate normally. On the return flight to San Jose, the pilot attempted to extend the landing gear, but the system would not work with either the normal or emergency system. The aircraft landed with the gear up and incurred substantial damage.
Hydraulic System Examination
Subsequent examination of the hydraulic system disclosed a one-half inch piece of packing in the nose gear manifold near the door close valve. Additionally, a thermal relief valve was found stuck in the open position by a build-up of 'dark colored greasy residue' on the spring.
Probable cause
A one-half inch piece of packing in the nose gear manifold near the door close valve, and a thermal relief valve stuck in the open position by a build-up of dark colored greasy residue on the spring.
What happened in the 12 Jan 1985 Cessna T210L accident near San Jose, CA?
During a flight, the pilot discovered landing gear would not extend. After a temporary fix using the emergency hand pump, both normal and emergency systems failed on return to San Jose, resulting in a gear-up landing with substantial damage. Investigation revealed hydraulic system issues.
What aircraft was involved and where did it happen?
The accident on 12 Jan 1985 involved a Cessna T210L, registration N4691Q, at San Jose, CA.
What was the probable cause of the accident?
A one-half inch piece of packing in the nose gear manifold near the door close valve, and a thermal relief valve stuck in the open position by a build-up of dark colored greasy residue on the spring.
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