Landing gear: Aural warning device

This regulation requires Part 121 airplanes (with certain exceptions) to have a landing gear warning horn that sounds continuously when flaps are extended beyond a certain point but the landing gear isn't down and locked. The trigger point depends on the aircraft: for planes with an established approach flap setting, it's when flaps go beyond that position; for others, it's when flaps extend beyond where you'd normally put the gear down.

The warning system cannot have a manual shutoff switch—pilots can't silence it. This is separate from any throttle-activated warning required during type certification, though the two systems can share components including the same horn.

In practice, this prevents gear-up landings by providing an unmistakable audible alert during the critical landing phase. If you're configured for landing with flaps but forgot the gear, you'll hear about it continuously until the situation is corrected.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*