• Find a nice large open area to place a Hellcat (armed version) on the ground or in the air.
• (Optional) Set its pilot and copilot to 100% skill level.
• Set yourself nearby as a vehicle or infantryman for a hostile faction.
• Give the Hellcat a 'move' or 'seek and destroy waypoint' near your position.
• (Optional) Configure the waypoint with Combat mode: Open fire. Behavior: Combat.
• (Optional) Shoot in its direction occasionally to be absolutely sure it notices you.

This was first reported on the forums this year on March 7th by Mrcurry: WY-55 Hellcat (Armed) will not attack engaged targets. Per his report, it sounds like the Hellcat was previously working and got broken at some point. Mrcurry stated he tested all the other helicopters and AAF vehicles and had no issues with them.

Just to be sure, I tried flying another helicopter against the Hellcat to see if it would shoot at airborne targets. It did actually shoot at me, but didn't hit me even with 100% skill level. It was only one time in a ten minute test, and I think it may have just been random due to how I was positioned in front of it. For contrast, it never shot at me when I was on the ground except for when I walked in front of its weapons while it was sitting on the runway.

The Hellcat's flight was so random that at times I was unsure if it really had spotted me. Just to be certain, I did verify that I really had been detected by using a trigger.

To be thorough, I verified Mrcurry's work by re-checking all the helicopters with built-in weapon systems. The ones with independently-aimed weapons (AH-99 Blackfoot, Mi-48 Kajman, UH-80 Ghost Hawk, CH-67 Huron) killed me almost instantaneously once the weapon was pointed in my general direction. The PO-30 Orca was similar to the Hellcat in that it has to aim its whole body to point its weapons at a target. It was slow to kill me since it was inaccurate even at 100% skill level (aimed to my right pretty consistently), but due to decent spread between its shots it did finally manage to kill me within a few minutes after making 2-3 passes on me.

I checked the new Apex VTOLs as well. The V-44 Blackfish (armed) never fired on me. With 'search and destroy' it flew around seemingly randomly but didn't fire even when the weapons were kinda-sorta pointed in my direction. With 'move' it made repeated flyovers but did not attack me and didn't really get into a position where the weapons could aim at me anyway. With 'loiter' it insisted on a clockwise flight path around the loiter point, even though its weapons are on its left side. I tried positioning it into a counter-clockwise path so it would have the weapons aimed towards the center of the loiter point, but it simply turned and got back on a clockwise path where it couldn't aim at me again. This was at 100% skill level for all crew members.

The Y-32 Xi'an did manage to shoot at me when I put it on a 'search and destroy' waypoint. Unlike other air vehicles with independently-aimed weapon systems, the Xi'an took several minutes and 5-6 passes, and it fired about 5-6 missiles with each pass. Despite the severe inaccuracy it did eventually manage to take out the turret on my NATO AA vehicle. Like my tests above, this was when I set it to 100% skill level.

I searched the forums and this bug tracker for similar issues. The only potentially related issue I found was here: Hellcats cannot lock on to vehicles or infantry. Diesel5187 reported on May 7th this year that a lock-on ability for Hellcats had been removed which broke a mod he had made to change the Hellcat's missiles. I'm not sure if the removed lock-on ability was needed by the AI to aim and fire the guns, but it might be something to test for a possible fix.

As always, any help would be appreciated!