The Ministry of Defence said the Sea King helicopter, which was carrying four crew members, made a controlled landing in a field near Ardrossan, Ayrshire, at about 11.25 am yesterday.
A spokeswoman said: "We can confirm that a Royal Navy Sea King Mark 5 helicopter from HMS Gannet made a precautionary landing just north of Ardrossan in a field adjacent to the Ardrossan to Largs road at approximately 11.25am after a potential technical issue was identified by duty crew members.
"The landing was smooth and unhurried."
She said the aircraft was en route to training at the time.
The spokeswoman said: "At no time was there any danger to the aircraft, crew or the public.
"The issue relates to observations noted by the crew of fluctuations in a temperature gauge.
"The aircraft is now operational once more."