Service difficulty report · Downlock Switch · Piper PA44180

Difficulty date
June 12, 2014
Submitted
June 12, 2014
Operation
General aviation
Aircraft
N316PA
Make and model
Piper PA44180
Aircraft serial
4496125
Engine
Lyc O360A1H6
Propeller
Hartzl HCC2YR1
Part
Downlock Switch
Part number
89291003
Condition
Broken
Location
Rt Mlg
Part time
128 hours
Stage of operation
AP
How discovered
O
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

DURING FINAL APPROACH, PILOT LOWERED LANDING GEAR AND RECEIVED NO DOWN AND LOCKED INDICATION ON THE RT GEAR. THIS WAS AFTER 2 SUCCESSFUL TOUCH AND GO MANEUVERS. THE PILOT NOTIFIED TOWER OF THE CONDITION. THE TOWER THEN VERIFIED THAT THE LANDING GEAR WAS DOWN BY VISUAL OBSERVATION. AFTER THE ACFT MADE A SUCCESSFUL LANDING IT WAS BROUGHT IN THE MAINTENANCE FACILITY FOR INSPECTION. UPON INSPECTION BY A MECHANIC, IT WAS DISCOVERED THAT THE DOWNLOCK SWITCH HAD A BROKEN WIRE ON THE SWITCH ASSY. THE WIRES OF THIS SWITCH ARE ENCASED IN SHRINK WRAP FROM THE MOLEX CONNECTOR TO APPROX 1.5" FROM THE SWITCH BODY, WHICH APPEARS TO ENCOURAGE THE WIRES TO FLEX IMMEDIATELY OUTSIDE THE SWITCH BODY DURING THE MOVEMENT OF THE GEAR. THIS REPAIR STATION HAS SEEN AND REPORTED A NUMBER OF SWITCH FAILURES THAT ARE SIMILAR AND HAVE CAUSED INCORRECT GEAR INDICATIONS. THE SWITCH HAD BEEN INSTALLED 2 MONTHS PRIOR.

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