Service difficulty report · Uplock Switch · Cessna 750

Difficulty date
October 17, 2008
Submitted
May 22, 2009
Operation
Air carrier
Aircraft
N960QS
Make and model
Cessna 750
Aircraft serial
7500160
Aircraft time
7,040 hours, 4,276 cycles
Part
Uplock Switch
Condition
Out Of Adjust
Location
Nlg
Stage of operation
CL
How discovered
O
Nature of condition
N
Precautionary procedure
A

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

What was found

UPON DEPARTURE, GEAR RETRACTION, GEAR "UNLOCK" LIGHT ILLUMINATED WITH NO GREEN LIGHTS. FOLLOWED CHECKLIST PROCEDURES AND RETURNED TO DEPARTURE WITH 3 GREEN LIGHTS USING NORMAL GEAR EXTENSION WITH GEAR HANDLE. FOUND NLG UPLOCK SWITCH OUT OF ADJUSTMENT. ADJUSTED AND WORK PERFORMED IAW MM CHP 32-30-05 LANDING GEAR SYS, OPS CHECK WAS NORMAL. COULD NOT CUP IN HANGER, OPERATION OF LANDING GEAR AND DOWN LOCK LIGHTS AND UNLOCK LIGHT NORMAL. C/W MM SER 32-30-00 (REV 35) GEAR BUMP TROUBLESHOOTING. CHECKS OK. SERVICED NLG OLEO IAW MM SEC 12-10-38 (REV 35) INSTALLED DATA MONITORING UNIT (PMU) CYCLED GEAR SEVERAL TIMES, ALL VOLTAGES ARE NORMAL. CHECKED TRAVEL ON ALL UPLOCK SWITCHED, FOUND NORMAL. INSPECTED UPLOCK HOOKS FOR ENGAGEMENT, FOUND NORMAL. OPERATED EMERGENCY GEAR RELEASE WITH GEAR SELECTED UP AND HYDR POWER ON, MAINS OPERATED NORMAL, NOSE WOULD NOT RESET, THE UNLOCK LIGHT REMAINED ILLUMINATED. CHECKED ADJUSTMENT UP NOSE GEAR ACTUATOR, FOUND NORMAL. FOUND UPLOCK SWITCH NOT MAKING CONTACT WITH ROLLERS ON NOSE STRUT. ADJUSTED NOSE UPLOCK SWITCH FOR POSITIVE ACTUATION NORMAL GEAR RETRACTION OPERATION IS NORMAL AND EMERGENCY GEAR RELEASE OPERATION IS NORMAL. WORK DONE IAW CHAPTER 32-30-05.

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