Always understood the difference in HERO and EMC between AF and Navy was due to operating environment. The flight deck of an aircraft carrier is a much higher and stronger RF environment than a 10,000 acre airfield. The hardening of support equipment for the environment was always an issue.
Exactly. Back when I was involved in RADHAZ/HERO testing for USN, we had a "rush job" to certify the then-new Apache with it's various weapon loads for USN flight deck operations. Needed in the Persian Gulf asap at the time. We conducted the testing at Dahlgren's ground plane facility for the better part of a week, nonstop including Sundays. Boy howdy..once we got up to keying higher field powers, we lit everything up and off on that bird including the rubber tire on the tail wheel. I think they (Army) ended up operating them off of barges or commercial vessels instead... ;-p