Lost Communications in Controlled Airspace
You are on an IFR flight at FL240 in controlled airspace under radar control when your VHF radio fails completely. You have a transponder with mode C. Your last clearance was "proceed direct to the ABC VOR, maintain FL240, expect further clearance at 12:34". It is now 12:20. Your flight plan shows an en-route time of 40 minutes to the destination and a filed alternate. The aircraft has a second VHF radio that also fails when selected.
1. State the lost-communication actions you will take and the altitude you will fly.
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The standard lost-communication procedure applies: squawk 7600, maintain the last assigned altitude (FL240) and route, and continue to the destination via the flight plan. Because the last clearance included "expect further clearance at 12:34", you hold the assigned level until that time, then continue at the last assigned level or the minimum en-route level, whichever is higher, along the cleared route.
You should also try the second radio, try the emergency frequency 121.5, and attempt contact through other aircraft or the ground station. If the destination is in a radar environment, ATC will see 7600 and protect your route. The examiner wants the sequence: squawk, maintain last clearance, comply with the expect-further-clearance time, then follow the flight plan and commence descent at the destination as close as possible to the estimated time of arrival.
2. What do you do at the destination, and how does the presence of the filed alternate change your plan?
Read the worked answer
At the destination you descend according to the published lost-communication procedure for that aerodrome, which normally means descending to the approach minimum and landing within a defined period after the ETA. You must be prepared for the possibility that the aerodrome is IMC and that other traffic is being vectored around you.
The filed alternate matters because if you cannot land at the destination within the lost-communication window, you proceed to the alternate and fly the published procedure there. The decision is driven by fuel: you must not hold indefinitely waiting for radio contact. The judgement point is that the alternate is part of the lost-communication plan from the start, and that the expect-further-clearance time is a clearance limit, not a suggestion.