Blade strike
We had a similar incident when I was with Blackhawks in Townsville....while operating out of Williamtown Airforce base we had 4 Blackhawks operating out of a fighter revetment (bomb arming point) at the Western end of the field...apprently there was no room for us down at air movements section dur to Mil C130 traffic...going in and out....only a matter of time before we had exactly the same incident...main rotor strike on a revement wall, no taxi way markings was a contributing factor along with in appropriate operating areas for helicopters....crew very lucky....