Definition
A final approach flown at a glidepath angle shallower than the recommended descent angle for the runway, typically resulting in a low approach path, reduced descent rate, and the need for higher power to reach the runway threshold.
Plain English
An approach where the airplane comes in too shallow — not descending at the proper angle — so the pilot ends up flying low and using extra power to stretch the descent to the runway.
Context Anchor
Used when judging and correcting the airplane’s path to the runway during final approach for landing.
Derivation
Flat' here describes the shape of the descent path — closer to horizontal than the proper sloped approach. The word is used in the same sense as a 'flat' road or 'flat' trajectory: not steep enough.
Why Pilots Care
A flat approach often leads to excessive floating, increased landing distance, or loss of airspeed control, raising the risk of runway overrun or hard landing.
Analogy
It is like walking down a ramp that is too shallow to reach the floor where you planned; unless you change something, you will not meet the target point correctly.
Intuition Check
Flat does not mean the airplane is level. Here it means the descent path toward the runway is too shallow.
Example Sentence 1
Seeing all four red lights on the PAPI, the pilot realized the approach had become flat and added power to climb back onto the proper glidepath.
Example Sentence 2
Strong headwinds can tempt a pilot into a flat approach that leaves the airplane too high and fast over the threshold.