Inspection below passenger doorstep panel 141 ALF

Effectivity: All Challenger 300/350/3500 series aircraft

ATA:53

By: Serge Robert — Technical Services  

While performing a 48-month inspection on the Challenger 3XX series aircraft, task 53-ZL-00-306 General Visual Inspection of the Forward Fuselage from FS 327.00 to FS 406.00 below WL 80.00 – Internal could get overlooked and corrosion could remain undetected, especially under passenger doorstep panel 141 ALF.

Cleaning the area prior to inspection is the key to detecting early signs of corrosion.

When the door is open, the doorstep can be exposed to rain while passengers are boarding the plane. Water accumulating on the door will end up below the doorstep panel 141 ALF area. This part of the fuselage features a sealed and drained well, which prevents water dripping off the closed door from spilling into the main fuselage.    

Minor undetected corrosion, perhaps hidden by dirt and debris accumulated over time, can lead to costly repairs.  

Bombardier reminds operators to follow the SPM Task 20-70-00-210-801 General Visual Inspection of Aircraft Zone when performing a zonal inspection.