DUEY!! Fancy meeting you in this place. It's Mark H here. I finally decided to join in.
This is a favourite topic for me.
I began my fire-awareness and research into Nomex while in Moose Jaw in 81/82. Back then, and until recently, our flying clothing was a wool/poly blend generally in the colour of the dress uniform of the period. It was, in fact, the exact same fabric. We were constantly lectured/reminded of the need to wear two layers, with the inner being 100% cotton, and that always struck me as bizarre when the outer layer contained significant quantities of one of the nastiest fabrics imaginable. On the plus side, wool will not support combustion on its own and is a very good insulator. Worn over the cotton, it did give fairly good protection as a result. On the negative side, as it's a good insulator, these suits were not pleasant to wear on a warm day (the dark green ones really soaked up the sun as well) and one smelled like wet dog on rainy days in the field (it hardly stopped at all during my first Fallex). Nomex, if I remember correctly, will not burn at all but chars to an ash about 700F. Unfortunately, it transmits heat quite well, therefore one still needs the cotton layer underneath as Inch, I think, said. Without that, one has the choice of roasting or baking like a foil-wrapped potato depending upon the fabric. Our old flying suits gave about 0.3 seconds less (0.9 vice 1.2 seconds) flame protection than the US ones (both worn over cotton), but that can still make a huge difference especially in an ejection-seat-equipped aircraft. The current Nomex ones, being a heavier weight, should give more but I don't have the info.
Most guys will only wear the long underwear and turtleneck in cooler weather, and switch to T-shirt and gotch of choice in summer, but I've always worn the full lot when flying. Nomex is much cooler and breathes better at least.
We had a lengthy fight to get our two-piece olive green Tac Hel suits. It finally came down to a US Army exchange Major who developed the suit and some senior Army officers tired of seeing Kiowa guys leap out of our hels in almost white tan summer suits to liaise with their heavily-cammed troops on ex. We got our first ones at the beginning of my last year at 444 Sqn - but our CO, the last CDS, refused to let us wear them even in the field for all sorts of dumb reasons: we didn't have all of the badges for them, then we did but one was smaller than the coloured version, then something else. He was all for the stupid blue ones though.
The Herc guys started scrounging our two-pieces when they were flying into Sarajevo - they weren't supposed to leave the aircraft while on the ground but if they absolutely had to they didn't want to be the only idiots wearing bright blue shoot-me suits. The F18 guys got over a hundred US suits for Gulf War I and more for later operations over the former Yugoslavia when they finally wised up to the fact that there was only one colour that really mattered and it wasn't the airshow one.
I wouldn't care less what the air force does if it wasn't for the sad fact that Tac Hel (which originated in the Canadian Army) got sucked into it in 1975. There are still plenty at the top who have no clue what Tac Hel's about or why we exist and what we need - I could rant for hours about that, too - so I am not terribly optimistic about seeing even our two-piece in CADPAT.
A battlefield helicopter is simply a vehicle with a different means of mobility - rotary wing rather than wheels or tracks - and its employment and crew requirements are pretty much the same. Common clothing just makes too much sense, except amongst the decision-makers.
Our current suits (one- or two-piece) would not be suitable for vehicle crews as-is. You'd most likely want to change most, if not all, of the pockets, eliminate the lower leg zippers and go to a more traditional bloused leg, and remove the pen pockets from the shins, and the F18 leg-restraint tunnels as they snag.
"F18 leg-restraint tunnels"?
There is a strap that goes around the mid-calf area of F18 pilots which attaches to an explosive-driven reel that hauls their legs back against the seat a split-second before ejection occurs so that their legs do not catch on the instrument panel or flail. The large lower-leg patch pockets are generally stuffed with maps and flying publications. There was concern that these restraints would not stay in place properly with pockets filled, so there is a flat fabric tunnel between the pocket and underlying leg fabric that these restraints can be passed through. The dumb thing is, aside from adding a few bucks more to the cost of construction and something for us to catch twigs with in the field, F18 guys are not allowed to fly without G-suits over top of their flying suits so these tunnels are covered up and, as far as I know, have never been used since they appeared in the early eighties. No F18 guy that I know of has ever flown in a Tac Hel two-piece suit either, with or without G-suit, yet these tunnels are included in the two-piece suit as well. Such is the mentality that we labour under.
And then there was the aircrew NBC ensemble that they attempted to force us into in the mid-eighties, but that's another two hours of typing - diapers, condoms with hoses, dental adhesive...