A pilot is filing an IFR flight plan to an airport where the forecast weather for the ETA is a ceiling of 2,500 feet AGL and visibility of 4 statute miles. According to 14 CFR 91.169, when must an alternate airport still be listed on the flight plan despite this favorable forecast?
- AAn alternate is required only if the destination has no instrument approach procedure
- BAn alternate is never required when forecast weather exceeds VFR minimums
- CAn alternate is required if the forecast does not meet the 1-2-3 rule window (1 hour before to 1 hour after ETA)
- DAn alternate is required whenever the destination airport has fewer than two runways
Show answer & explanationAnswer & explanation
Correct answer: A. An alternate is required only if the destination has no instrument approach procedure
Even if the 1-2-3 rule ceiling/visibility criteria are met (2,000 ft ceiling and 3 SM visibility from 1 hour before to 1 hour after ETA), an alternate must still be filed if the destination airport does not have an approved instrument approach procedure, since the pilot could not legally shoot an approach there. In this scenario the forecast (2,500-4) meets the 1-2-3 threshold, so option D describing failure of that rule doesn't apply; the underlying trigger requiring an alternate regardless is lack of an approach procedure.
Why the other options are wrong
- B. Alternates can still be required even with good forecast weather if no approach exists.
- C. The scenario's forecast actually satisfies the 1-2-3 rule, so this is not the controlling factor here.
- D. Runway count is not a regulatory factor for alternate requirements.
Alternate Airport Requirement (91.169)
An alternate must be filed unless the destination has an approved IAP and forecast weather meets the 1-2-3 rule (ceiling 2,000 ft, visibility 3 SM, from 1 hr before to 1 hr after ETA).
- No IAP at destination = alternate always required
- 1-2-3 rule: 2,000 ft ceiling and 3 SM visibility
- Time window: 1 hour before to 1 hour after ETA
Memory trick: '1-2-3': 1 hr window, 2,000 ft ceiling, 3 SM visibility.