A commercial rotorcraft was expected to cover any emergency callouts but with poor visibility forecast, the other aircraft have systems that mean they can operate in worse weather conditions.
Alderney Airport will close in the evening between Tuesday 18 April and Wednesday 26 April to allow for essential runway maintenance work.
Guernsey Airport will also shut in the evening from Monday 24 April until Monday 1 May.
So-called medevac flights from Alderney to Guernsey will temporarily land at either Les Butes or Braye Common whilst repair works are carried out.
When Guernsey Airport closes in the evening, the helicopter will operate from the car park at Port Soif.
This area will be closed to the public between 8pm and 7am from 24 April until 1 May.
Terry Coule from Guernsey's Health and Social Care Department said: "The team involved in the advanced planning would like to thank islanders for their understanding while these alternative measures are in place and to respectfully ask them to avoid these landing sites while they are in use."
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