True helicopters are a good arial form of tank busting. But if the tank are well guarded by AA totting infantry and other various AA vehicles, then helicopters would have some difficulty in being able to effictively engage tanks. Afghanistan, during the Soviet invasion, showed how a small groups armed with AA could make life hard for heli pilots. Also, I was watching a documentary on the training ground used by US forces. The guys acting as the opposition, in an example, showed how not setting up proper security could make your tanks quite useless as they used a Kiowa to peek over a ridge and spy on them. Then again, the first Guld War showed how effective helicopters could be when the enemy's radar and AA capabilities are severly handicapped. I think it just depends on the situation.