Definition
An informal name for the small, house-shaped marking on the airspeed indicator that highlights the flap operating range. It typically appears as an arc with squared-off ends resembling a doghouse outline, indicating the speed range within which flap extension is permitted.
Plain English
A small marking on the airspeed indicator shaped like a tiny house. It shows the band of speeds where it is safe to use the flaps.
Context Anchor
Seen on heading indicators and other cockpit heading displays when checking or setting the airplane’s direction.
Derivation
Called a 'doghouse' because the shape of the marking — a flat-bottomed arc with two squared shoulders — looks like the outline of a small kennel. The nickname stuck because it is easier to say than 'flap operating range marking.'
Why Pilots Care
Extending flaps above the speed shown by the doghouse can damage the flaps or the airframe. Knowing exactly where the doghouse sits on your airspeed indicator keeps flap use within structural limits.
Intuition Check
Doghouse does not mean an aircraft compartment or a storage box here. It means the fixed heading reference mark on the instrument display.
Example Sentence 1
Slow the aircraft into the doghouse before selecting the first notch of flaps.
Example Sentence 2
During the recovery from an unusual attitude, she leveled the wings once the doghouse was no longer visible.