Replanning after a NOTAM closes the destination
You are planning a 1 h 50 min flight to an airport whose runway 09/27 will be closed for works from 10:00 to 14:00 local. Your estimated time of arrival is 11:20 local. The only other suitable airport is 40 minutes away, with a runway 1 400 m long and a 300 ft displaced threshold. Your aircraft needs 1 250 m landing distance at the forecast mass and conditions. The NOTAM also states that the alternate's VOR is unserviceable and that a crane 180 ft AGL is erected 2 km short of the threshold. The weather at the alternate is 2 000 m visibility with a 700 ft ceiling, and the approach minima are 500 ft and 1 500 m.
1. Assess whether the alternate is usable and what the NOTAMs change.
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The destination is unusable at the ETA because the runway closes at 10:00 and you arrive at 11:20; no landing is possible there. The alternate's landing distance available becomes 1 400 - 300 = 1 100 m, which is less than the required 1 250 m, so the alternate is not usable at the planned mass. The crane 180 ft AGL at 2 km short of the threshold lies under the approach path and may require a steeper approach or a higher minima; it must be checked against the obstacle clearance surface.
The unserviceable VOR affects the approach type; a different approach or a visual approach may be needed. The weather is above the 500 ft and 1 500 m minima, so weather alone does not prohibit the approach. The plan must change: reduce mass, select another alternate, or delay departure so the destination reopens after 14:00.
2. What is the correct planning action and what must be filed?
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Because no usable alternate exists at the ETA, the flight cannot be dispatched as planned. Options are to delay departure so arrival is after 14:00, reduce landing mass to meet the 1 100 m distance, or find a third airport. If a delay is chosen, the flight plan must show the revised ETA and the destination must be open at that time. If a diversion alternate is used, the flight plan must name it and the fuel must cover the diversion. The commander must confirm the runway closure times in local time against the flight plan times in UTC, and check that the crane and VOR NOTAMs are still current at the time of flight.