Definition
A threaded fastener with a cross-shaped recess in its head, designed to be driven by a matching cross-tip (Phillips) screwdriver. The recess is tapered so that excessive torque causes the driver to cam out (lift out of the recess), which helps prevent over-tightening and damage to the screw or surrounding structure.
Plain English
A screw with a plus-sign-shaped slot in its head that you turn with a matching cross-tip screwdriver. The slot shape lets the driver pop out when you tighten too hard, so you don't strip the screw or crack what it's holding.
Context Anchor
Seen on aircraft inspection covers, interior panels, fairings, and other light attachment points during preflight or maintenance.
Derivation
Named after Henry F. Phillips, the American businessman who promoted and patented the design in the 1930s. It was developed for early automotive assembly lines, where the cam-out feature prevented workers from over-torquing screws on production cars.
Why Pilots Care
Correct use avoids damaging screw heads, which maintains the integrity of critical aircraft fasteners.
Intuition Check
A Phillips screw is not just any screw that looks roughly cross-shaped. It should be turned with the correct size Phillips screwdriver so the tool fits fully and does not damage the head.
Example Sentence 1
The mechanic removed the inspection panel by backing out four Phillips screws.
Example Sentence 2
The avionics technician replaced several Phillips screws when reinstalling the instrument panel after maintenance.