Definition
On an instrument approach, continuing the aircraft below the published Minimum Descent Altitude (MDA) or Decision Height (DH) without meeting the regulatory conditions required to do so. Under 14 CFR 91.175, descent below MDA or DH is only permitted when the aircraft is in a position to land using normal maneuvers and a normal rate of descent, the flight visibility meets or exceeds the value published for that approach, and the pilot has at least one of the specified visual references for the runway environment distinctly visible and identifiable.
Plain English
Going lower than the lowest altitude the approach allows, before you have the runway in sight and the conditions you need to legally and safely land.
Context Anchor
Seen in instrument approach training, approach chart use, accident discussions, and FAA guidance on operational pitfalls.
Why Pilots Care
This action removes the safety buffer designed into the approach and is a frequent factor in controlled flight into terrain accidents.
Grounding Statement
If you reach the MDA or DH and cannot clearly identify the required runway environment, the safe action is to stop descending and go missed.
Intuition Check
Do not think of MDA or DH as a rough suggestion or a place to “take one more look.” They are published safety limits: unless the required visual conditions are met, you do not continue lower.
Example Sentence 1
The pilot reached the MDA, did not see the runway environment, and correctly initiated a missed approach rather than risking a descent below the MDA.
Example Sentence 2
During the approach briefing the instructor stressed that any descent below the MDA or DH without visual contact violates the procedure.