EAP
Long time since I was involved. I know the SHAR noise dose was similar to Sea King. 115-120dB(A) if I recall, making the reduction to 73 an astonishing achievement by the Farnborough scientists. The EFA helmet people came to see me in about 1997, but I don't know what they did. You are right about aeromedical. An RAF Gp Capt ran the Applied Research Package in the 80s. Once he delivered the concept (for RAF Harrier, but they had problems with the Mk10 helmet at the time), it was for the aircraft office to 'pull it through'. That is, apply the science. At that point, speech intelligibility and annoying noise was added to the equation; meaning you have to consider the entire comms sub-system. One stumbling block was the early submissions had pages of decibel notation, and scrutineers toppled. Once changed to 'allowable flying hours' it all made sense - along with the realisation just how serious the problem was. FONAC's attitude changed from not interested, to Critical Health and Safety Constraint in the Constraints Document, in the space of a few days. Which is what kicks off procurement, and makes it very easy to sail through scrutiny. One benefit was a/c soundproofing could be removed, helping CofG and increasing fuel load; so you could mention spend to save. I wouldn't say money was no object, because the one thing denied me was new helmet transducers. I wanted superb French ones, but was told to retain the cheap crap that is in the Mk4A, which is like buying a £50k CD player and using a pair of headphones out of Poundland. Yet, I was able to get money for made-to-measure helmets for everyone in the squadron - none of this short/medium long/if it doesn't fit, tough luck nonsense. I was never sure how many took up the offer, but they would have gone to the company and had their head laser-mapped, waited a couple of hours and gone home with two new helmets. My attitude was, if I've got £20M to modify each cab, then a few grand for each pilot and observer was loose change.