It was a stray voltage problem and unless you pulled circuit breakers in the back seat and in the fuselage it was hard to say it was safe...it did not take much...AH-1's always had signs on them in the hanger letting you know if the jettison cartridges were installed are not and if it was any length of time they had to be removed...Also one of the reasons the cover was finally safety wired shut. I seem them blow by simply turning the master arm on...not routine but common enough...