The Sumburgh-based coastguard helicopter was called out last night to airlift a sick oil worker from the Thistle Alpha platform.
The call was taken at about 5.30pm and the aircraft headed to the platform, which is about 142 miles northeast of Sumburgh.
The man was landed at Tingwall Aiport later in the evening and transferred by ambulance to the Gilbert Bain Hospital in Lerwick.
Earlier yesterday afternoon the coastguard helicopter was seen hovering for quite some time over Breiwick near Lerwick, just off the Tesco supermarket. The coastguard confirmed today that it had been a training exercise.
Meanwhile the relief Aith lifeboat was called out yesterday to search for a small boat which was overdue.
The Roger and Joy Freeman, which is standing in while the Charles Lidbury is away for a refit, left at just after 7.30pm.
The missing boat had apparently left Walls at around lunchtime and not been heard from since. However, the boat turned up safe and well shorly afterwards and the lifeboat crew was stood down.
Crew member Ivor Moffat said he was just thankful that the shout ended with a good outcome, as this reflected the purpose of the charity, to save lives at sea.