You need a specialist broker. I took out a life policy with a company called Sovereign a few years ago which was cheaper including helicopter risk than the big companies were without the flying risk! Sovereign has now been swallowed up by another company (not sure who).
I seem to recall Sovereign's view was that although the possibility of crashing puts up the risk, the frequent medicals and the safety culture of being a pilot made it less likely you would die elsewhere and this offset that extra risk.
Check the flying magazines for brokers.
I Hope this helps.
Phil.