Description :An airplane component is classified as a Principal Structural Element if:
(a) The component contributes significantly to carrying flight and ground loads.
(b) If the component fails, it can result in a catastrophic failure of the airframe.
The monitoring of these PSE's is the main focus of this Supplemental Structural Inspection Program.
Typical Examples of Principal Structural Elements
Wing and Empennage:
Control surfaces, flaps and their mechanical systems and attachments (hinges, tracks and fittings)
Skin or reinforcement around cutouts or discontinuities
Circumferential frames and adjacent skin
Pilot window posts
Skin and single frame or stiffener element around a cutout
Skin and/or skin splices under circumferential loads
Skin or skin splices under fore and aft loads
Skin around a cutout
Skin and stiffener combinations under fore-and-aft loads
Door skins, frames, and latches
Landing Gear and Attachments
Engine Support Structure and Mounts
For Details: Cessna Maintenance Manual TR 05