Belize, 1980. I was back then a “first tourist” Puma helicopter pilot. Having done a full day’s single crew tasking in the usual very hot and humid jungle conditions, in the late afternoon we set off back up north to Airport Camp with a full load of assorted military passengers; the senior passenger being the Colonel of the Cheshire Regiment.
We got as far as Stann Creek, about 40% of the total distance, when it became obvious that a line of big thunderstorms was in our way, coming off the inland hills to the west. The very angry CB clouds and torrential rain stretched well out over the sea to the east of track. I decided not to attempt to fly over the sea; it wasn’t possible to know how far the storms extended and in any case we didn’t carry any sea safety or survival equipment. Climbing above was out of the question, some of those sub-tropical storms were known to extend to 50,000 feet.
I decided the only way to complete the flight was to maintain our present altitude (about 2,000 feet) and head for the brightest patch of sky (describing it as “bright” was a bit optimistic). We didn’t have a weather radar. As soon as we hit the rain, it was torrential, well beyond my previous experience and I lost all external visual cues. We were reasonably well practiced in instrument flying, but it took a few seconds to get established.
I was wary, not least because there was a concern about how much heavy rain it would take to put out the flame in the Turmo IIIC4 engines back then. The engines had relatively vulnerable, forward facing, open intakes (later retro-fitted with intake protection modules) and due to a serious potential fault with a pair of diodes in the start panel we were at that time not allowed to attempt in flight engine re-lights. If both diodes had failed (and we had no way of knowing), closing one engine control switch would switch off both engines!
I quickly realised that we were descending. I applied full power but it made little difference, the rate of descent increased until the VSI needle hit the bottom stop. I briefly looked at the engine gauges, thinking that I might have a flame out. They were both working as advertised and in any case, the rotor rpm was normal. I used my only remaining option - I flared the aircraft, in an attempt to trade speed for height from cruise speed to minimum power speed. We were still descending! I knew we were getting very low and was about to call “Brace, Brace!” because I no more options and really thought we were going to hit the trees!
However, a second later, we popped out into relatively clear sky, not far above the jungle tree tops. The torrential rain stopped as rapidly as it had started. Instantly, the aircraft climbed as it should have done in that configuration, like a cork out of a bottle. I checked the instruments and realised we had been below 400 feet. My mouth was as dry as a bone! We’d had a very close shave.
Ahead, the weather looked just as bad as before and I’d had enough for one day. We found a better gap in the clouds, away from rain did a 180 degree turn and went back to the Punta Gorda army camp. I had to explain why to the Colonel. He was really quite good about it, bearing in mind that he was travelling north for an important briefing. We stayed overnight and returned north to base the following morning.
I later realised that we’d probably hit what was then a relatively unpublicised phenomenon now known as a “microburst”. This is caused when updrafting air over a very wide area returns to earth in a much more violent form, in a very narrow piece of sky.
Once seen, never forgotten.
Last edited by ShyTorque; 6th Jan 2021 at 16:49.