SDR 99ZZZX2353

Service difficulty report · Valve · Cessna 550

Difficulty date
June 2, 1999
Submitted
March 26, 2000
Operation
General aviation
Make and model
Cessna 550
Aircraft serial
0062
Part
Valve
Part number
385814
Condition
Malfunctioned
Location
Brake
Component
Hydroaire · 385814
Stage of operation
NR
Nature of condition
O
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

THE ANTI-SKID SERVO VALVE WIRES (POSITIVE AND NEGATIVE) WERE CROSSED ON THE REPLACEMENT OF THE POWER BRAKE VALVE. THIS PREVENTED THE ANTI-SKID SYSTEM FROM ACTUATING THE VALVE TO UNLOAD THE BRAKE HYDRAULIC PRESSURE WHEN A SKID OCCURRED ON LANDING RESULTING IN A FLAT TIRE. THE ANTI-SKID SYSTEM DOES NOT MONITOR THIS VALVE CONDITION, THEREFORE, IT DID NOT PROVIDE A WARNING ANNUNCIATION TO THE CREW THAT THE SYSTEM WAS INOPERATIVE. THE WIRE CONNECTORS ARE IDENTICAL AND THE WIRE NUMBERS ARE SIMILAR IN APPEARANCE (G111A22 AND G71A22) CONTRIBUTING TO THE PROBLEM OF CORRECTLY MATCHING THEM. A FUNCTION TEST OF THE SYSTEM WOULD HAVE REVEALED THE PROBLEM.

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