Definition
A machine screw with a rounded, slightly domed head that has a flat underside, used to fasten sheet metal, cowlings, fairings, and other surface components on an aircraft. The flat underside of the head sits flush against the surface being fastened, while the rounded top sits above the surface rather than flush with it.
Plain English
A screw with a low, rounded top that sits on top of the surface it fastens, rather than sinking into it. The bottom of the head is flat so it presses evenly against the part it's holding down.
Context Anchor
Seen in aircraft maintenance manuals, parts catalogs, and inspection or repair work involving panels, covers, fairings, and interior parts.
Derivation
Named for the shape of the head, which resembles an upside-down pan -- flat on the bottom, rounded on top.
Why Pilots Care
Panhead screws are used where a flush surface isn't needed for aerodynamics. Knowing the type helps when ordering replacements or checking that the correct fastener has been used during maintenance -- using the wrong screw type on a flush aerodynamic surface can disturb airflow.
Intuition Check
Do not read “panhead” as a screw brand or a special screw material. It describes the shape of the screw head.
Example Sentence 1
The mechanic replaced a missing panhead screw on the inspection cover before the flight.
Example Sentence 2
Panhead screws hold the radio rack in place without protruding into the airflow.