It was a dark and stormy night.....................that's exactly what it was, flying out of Bergen after midnight on a three stop shuttle, with ARAs to each deck on minima and no discernible horizon. The third deck was a semi-sub and the wind dictated that it was to be my landing and take-off. For my poor SFO, who was very competent, there was nothing to see outside until we were within the helideck circle.
Our S61 could not be accommodated in the company hangar at Bergen and had suffered several spurious electrical warnings as a consequence of being rained on almost constantly almost every day for a couple of weeks.
I briefed for the final take-off from the semi-sub for the return flight to Bergen, lifted and on rotation was immediately on instruments. Within a second or so of having called "committed", the SFO called "Fire engine one" and I heard the audio warning. Instantly he reached for SSL1 and asked if I wanted it retarded, while I was concentrating on getting a heavy S61 to register a convincing rate of climb on two engines while accelerating slowly through about 50 knots.
Mindful of the large waves just discernible in the landing light beams and having significant doubts about the believability of the fire warning system, I opted to instruct my excellent SFO to leave the SSLs forward and suspend the EOP until we'd passed 500' rad alt. Sure enough, within seconds and as we were passing Vy, the fire warning lights started to fade.
Once checks were completed and the aircraft secured, we reviewed what had just happened and agreed that damp electrics was the most likely cause. An uneventful flight was continued to Bergen, followed by appropriate tech log entries and report writing.
Not my first engine fire warning in flight, but the most dramatic. The others were attributable to hot gas leaks. Never had a real engine fire in a long career and on balance I would think that it's nearly always better to check for visible signs before proceeding through the EOPs.