On a non-precision approach, the clearance between the jet and the ground/obstruction may be as little as how many feet when level at the MDA?

In non-precision approaches, pilots must follow specific minimum descent altitudes (MDAs) during their approach to ensure safe flight operations, especially in relation to terrain and obstacles. The clearance required between the aircraft and the highest obstacle in the approach path is crucial for safe navigation.

When leveling off at the MDA during a non-precision approach, the minimum vertical clearance over obstructions is typically 250 feet. This standard is set to provide an adequate margin for safety and to ensure that pilots have sufficient reaction time to execute a missed approach or maneuver if necessary.

The 250-foot standard is based on the assumption that the aircraft may encounter rising terrain or other obstructions, and this altitude allows for a buffer that helps accommodate any potential discrepancies between the aircraft's navigation system and the actual terrain. Thus, maintaining a minimum of 250 feet clearance guarantees a safer margin during the critical phase of the approach.

In contrast, the other options do not meet the established requirement for non-precision approaches, thereby confirming that the correct minimum vertical clearance is indeed 250 feet when leveled at MDA.