Summary
We propose to adopt a new airworthiness directive (AD) for M7 Aerospace LLC Models SA227-AT, SA227-AC, SA227-BC, SA227-CC, and SA227- DC airplanes equipped with a bayonet shear pin main cabin door latching mechanism. This proposed AD was prompted by fatigue cracks found in the internal door surround doubler, the external skin fuselage skin, and the door corner fittings at the fuselage upper forward corner of the main cabin door cutout. This proposed AD would require repetitively inspecting the four corners of the main cabin door cutout for cracks, making necessary repairs, and reporting inspection results to M7 Aerospace LLC. We are proposing this AD to correct the unsafe condition on these products.