Definition
Any visible or detectable harm to the load-bearing components of an aircraft — including the airframe, skin, fasteners, control surfaces, landing gear, or attachment points — that may compromise the aircraft's ability to safely withstand normal flight loads.
Plain English
Damage to the parts of the airplane that hold it together and carry the forces of flight. If something is bent, cracked, dented, torn, or loose on a part that takes the strain of flying, that is structural damage.
Context Anchor
Seen during the visual preflight assessment when checking the airplane for cracks, dents, loose parts, bent areas, or signs of a hard landing or other impact.
Derivation
From Latin 'structura' (a building, a putting together) and 'damnum' (loss or harm). The 'structure' is what holds the aircraft together, so structural damage is harm to the parts that give the airplane its shape and strength — not just cosmetic harm to paint or trim.
Why Pilots Care
Undetected structural damage can lead to catastrophic failure during flight.
Intuition Check
Do not assume structural damage means every scratch or paint chip. In this context, it means damage to a part that helps support the airplane or carry flight and landing forces.
Example Sentence 1
During preflight, the pilot noticed wrinkled skin on the wing's upper surface and grounded the aircraft pending an inspection for structural damage.
Example Sentence 2
After a hard landing, the mechanic inspected the fuselage for any signs of structural damage before approving the next flight.