When is an alternate required?

• A. If you have a flight plan not filed
• B. If winds are calm
• C. If destination is VFR
• D. If weather at destination is less than 2,000 ft ceilings or 3sm visibility from one hour before ETA to one hour after ETA

Answer: (D)

In IFR flight planning you need a backup airport (an alternate) when the forecast at your destination isn’t good enough to assure a safe landing if conditions change. The rule is that you don’t need an alternate only if the forecast at the destination, for the period from one hour before to one hour after your ETA, is at least 2,000 ft ceilings and 3 statute miles visibility. If the forecast falls below those minima during that window, you must designate an alternate. The choice describing weather at the destination being worse than those minima in that critical window matches this requirement exactly. The other scenarios—whether a flight plan is filed, winds being calm, or the destination being VFR—don’t determine the need for an alternate.