I was the Chief S-76 Test Pilot back then and recall the reason for the limit as -34 degrees C. The limit is based on the qualification and demonstration tests done back in the beginning, where we set -34 as a market acceptable number. There is no fundamental difference between the S-76 and other Sikorsky machines regarding cold capability except for that, even though I do see some interesting sidelights in the above posts. The aircraft will not fail to do anything critical if taken to lower temperatures, but you as PIC will not be legal. The fuel reasons for the limit listed in the posts above are not reasons for the original limit, but they quite well could be true, even so. I do know that we took the Jet A down to -34.4, and that the aircraft flight manual limits should override the engine operator's manual, but a quick call to RR customer service should answer the question.. .The limit is both cold soak/start-up and operating, although the start-up is always the worst condition, since most systems warm up as they turn up. Seals are always the issue, transmission, hydraulic and landing gear.
Regarding wind chill, there really is no such thing, be careful not to get caught in "TV weatherman hype." As defined, wind chill is the temperature you have to take still air down to so that you equal the cooling power of the current temperature/wind conditions. It is semi bulls**t, based on exposed flesh, and is of no use for anything else, like if you have clothes on, or if you are out of the full effect of the wind. It is impressive when quoted on the news, however.
If it is -40 degrees, and 50 knots of wind, a thermometer will read -40. If you shelter the thermometer from the wind, it will read -40. If you take the thermometer from a warm house and hang it in the -40 with 50 knots of wind, it will more quickly get to -40 than if there is no wind (that is all wind chill means).
[ 30 January 2002: Message edited by: Nick Lappos ]</p>