FAA Instrument Flight Instructor (FII)IFR Procedures and ApproachesMedium
On a nonprecision approach chart, the FAF crossing altitude is 2,000 feet MSL, a step-down fix altitude is charted as 1,400 feet MSL, and the MDA is 900 feet MSL. After crossing the step-down fix at or above 1,400 feet, to what altitude may the pilot descend prior to the missed approach point?
- A900 feet MSL, the published MDA
- B1,400 feet MSL only, until reaching the MAP
- CAn altitude midway between 1,400 and 900 feet MSL
- DNo further descent is authorized until reaching the FAF again
Show answer & explanationAnswer & explanation
Correct answer: A. 900 feet MSL, the published MDA
A step-down fix identifies a point beyond which additional descent is authorized because obstacle clearance has been verified for that segment; after crossing it at or above the charted altitude, the pilot may continue descent to the published MDA.
Why the other options are wrong
- B. This ignores that the step-down fix authorizes further descent to the MDA, not a level-off there.
- C. There is no rule authorizing descent to an arbitrary altitude between the step-down fix and MDA.
- D. The FAF is behind the aircraft and not re-crossed; this ignores the purpose of a step-down fix.
Step-Down Fix
A fix that permits additional descent to a lower altitude (down to MDA) within a segment of a nonprecision approach once the aircraft has passed that fix, based on verified obstacle clearance.
- Located between the FAF and MAP
- Descent below the step-down altitude is not authorized until the fix is crossed
- Allows a lower MDA than would otherwise be published without it
- Identified by DME, GPS waypoint, or crossing radial/fix on the chart
Memory trick: Step down like stairs — one fix, one lower floor