There's dissatisfaction among some Air Force jet pilots over the flying helmets they are issued. Complaints have been made following investigations into the deaths of several pilots who have been catapulted from their planes onlandings and takeoffs.The catapult is intended to eject the pilotfrom his cockpit and throw him clear of the plane when he wants to bail out after an accident in flight. But there have been a number of ejections while planes were on the ground.No one has discovered whether the ejection mechanism has been accidentally touched off by plane vibration, or whether the pilot has done it intentionally to get free of fire in possible crashes. Whatever the cause, no pilot has ever survived a ground ejection. They always land on their heads, and the helmets aren t strong enough to protect their skulls.