SDR SFOA447

Service difficulty report · Terminal · Cessna 550

Difficulty date
October 11, 2021
Submitted
October 15, 2021
Operation
Air carrier
Aircraft
N447SF
Make and model
Cessna 550
Aircraft serial
5501020
Aircraft time
5,529 hours, 4,771 cycles
Part
Terminal
Part number
MS25036117
Condition
Broken
Location
Zone 200
Part time
5,529 hours, 4,771 cycles
Stage of operation
IN
How discovered
V
Nature of condition
O
Precautionary procedure
K

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

What was found

WHILE PERFORMING AN INSPECTION ON THE R/H CIRCUIT BREAKER PANEL THE WIRE TERMINALS WERE FOUND BROKEN ON TWO OF THE THREE 75A FEEDER CIRCUIT BREAKERS AND THE THIRD TERMINAL WAS CRACKED AND ABOUT READY TO BREAK. THESE WIRES FEED POWER TO THE R/H CIRCUIT BREAKER PANEL FROM THE AFT POWER JUNCTION BOX. HAD THE LAST TERMINAL BROKEN ALL POWER FROM THE AFT POWER JUNCTION BOX TO THAT BREAKER PANEL WOULD HAVE BEEN LOST AND THE PANEL WOULD BE THEN BE FED SOLELY FROM THE 35A CROSS-FEED BREAKER WITH NO INDICATION TO THE FLIGHT CREW. THE CAUSE OF THE BREAKAGE WAS DUE TO THE WIRE RUNS BEING TOO SHORT CAUSING A STRAIN ON THE WIRES AND TERMINALS. A GENERAL VISUAL INSPECTION IS NOT SUFFICIENT TO LOCATE THIS ISSUE AS EACH WIRE ALSO HAS AN INSULATING BOOT ON EACH WIRE COVERING THE TRERMINAL GIVING A VISUAL EFFECT THAT THE WIRING IS INTACT. SLACK WAS OBTAINED FROM THE WIRE BUNDLE DOWNSTREAM FROM THE BREAKER PANEL AND THE WIRE TERMINALS WERE REPLACED AND REATTACHED TO THE CIRCUIT BREAKERS. OPPOSITE PANEL WAS INSPECTED WITH NO ISSUES FOUND.

More about the Cessna 550