FAA Aviation Mechanic Airframe (AMA)Airframe StructuresEasy
A technician is installing a new engine cowling panel that attaches to the adjacent airframe structure along its entire leading edge using a continuous hinge with a single hinge pin running the full length of the joint. What type of hinge is this?
- AKnuckle hinge
- BStrap hinge
- CPiano hinge
- DButt hinge
Show answer & explanationAnswer & explanation
Correct answer: C. Piano hinge
A piano hinge is a continuous hinge with a single long pin running the full length of the joint, commonly used on cowlings, access doors, and control surface attachments because it distributes loads evenly along the entire edge.
Why the other options are wrong
- A. A knuckle hinge refers to the interlocking hinge leaf sections, not a specific continuous hinge type.
- B. Strap hinge is not a standard aircraft hinge classification for cowlings.
- D. A butt hinge is a short, individual hinge, not continuous along the full edge.
Piano Hinge
A continuous hinge consisting of two long leaves joined by a single pin running the entire length, used on cowlings and access panels for even load distribution.
- Continuous full-length hinge pin
- Distributes load evenly along the joint
- Common on cowlings, doors, and control surfaces
Memory trick: Piano hinge = keys in a row, one long pin holding it together