FAA Instrument Rating Airplane (IRA)IFR Procedures and ChartsHard
A nonprecision approach chart depicts a step-down fix between the FAF and the MAP, identified using DME. A pilot's aircraft has no DME and cannot identify the step-down fix by any other means authorized on the chart. What MDA must the pilot use?
- AThe higher MDA published for the segment prior to the step-down fix, since the pilot cannot verify passing it
- BThe pilot may not fly this approach under any circumstances without DME installed
- CThe lower MDA published for the segment after the step-down fix, since it allows a quicker descent
- DThe average of the two published MDAs for the approach segment
Show answer & explanationAnswer & explanation
Correct answer: A. The higher MDA published for the segment prior to the step-down fix, since the pilot cannot verify passing it
If a pilot cannot identify a charted step-down fix, the lower MDA applicable beyond that fix cannot be used because the pilot cannot verify safe passage of the fix. The pilot must use the higher MDA that applies to the segment before the step-down fix for the remainder of the approach.
Why the other options are wrong
- B. The approach may still be flown using the higher MDA; lacking DME doesn't automatically prohibit the approach if other means aren't required and the higher MDA is used.
- C. Using the lower MDA without confirming the step-down fix would remove required obstacle clearance margin.
- D. Averaging minimums has no basis in TERPS design or regulatory guidance.
Step-Down Fix Without Identification
If a pilot cannot identify a charted step-down fix on a nonprecision approach, the higher MDA applicable before that fix must be used for the remainder of the approach.
- Step-down fixes allow a lower MDA once safely identified
- Inability to identify the fix removes eligibility for the lower MDA
- Applies commonly when required DME or RNAV equipment is unavailable
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