Service difficulty report · Uplock Hook · Cessna 525A

Difficulty date
November 2, 2023
Submitted
November 8, 2023
Operation
Air carrier
Aircraft
N744CB
Make and model
Cessna 525A
Aircraft serial
525A0223
Aircraft time
5,977 hours, 5,319 cycles
Part
Uplock Hook
Part number
632750117
Part serial
NSN
Condition
Cracked
Location
Zone 700
Part time
5,977 hours
Stage of operation
CL
How discovered
V
Nature of condition
O
Precautionary procedure
A

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

What was found

CLARITY OF DISCREPANCY: "GEAR NOT LOCKED AFTER POSITIVE RATE GEAR UP CALL" MEANING SPECIFICALLY THAT THE GEAR DID RETRACT, AND AFTER ABOUT 30 SECONDS THE CREW EXPERIENCED THE GEAR UNLOCKED LIGHT ILLUMINATING AND THEN FELT THE HYD SYSTEM ACTIVATE. AGAIN. THIS IS WHEN THEY CHOSE TO RETURN TO APA. AGAIN, THERE WERE NO ISSUES WITH THE HYDRAULIC SYSTEM, OR THE GEAR RETRACTION SYSTEM. ROOT CAUSE: WEST STAR AVIATION FOUND THE L/H MLG UPLOCK HOOK HAD CRACKED THROUGH ABOUT 80% OF ITS MATERIAL THICKNESS. THIS ALLOWED THE GEAR TO "DROOP" DOWN AND AWAY FROM THE UPLOCK SWITCH CAUSING THE GEAR UNLOCKED LIGHT TO ILLUMINATE, AND A SUBSEQUENT HYD SYSTEM ACTIVATION TO "RAISE THE GEAR". WEST STAR REMOVED AND INSTALLED A NEW UPLOCK HOOK ASSEMBLY. AND PERFORMED SEVERAL GEAR SWINGS.

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