While planning for your next C Check for your F900B, don’t forget Chapter 5-10 has task 53-40-00-270-801 that instructs you to comply with an ultrasonic inspection for corrosion around the fasteners of the front center panel ahead of frame 10.
Because of the high probability of future corrosion in this area, Duncan Aviation strongly recommends to comply with SB 392, whether corrosion is indicated or not. The conditions of high moisture due to fuel tank condensation with minimal drainage and ferrous metal nut-plates on pressure vessel skin set up an environment where corrosion rapidly grows and repairs could be substantial.
Repairing Pneumatic De-icers
Webinar: Current Events with Cabin Disinfection