When donning the helmet with the AERP system, which locking position is the bayonet inserted into?

When donning the helmet with the Advanced Emergency Recovery Parachute (AERP) system, the bayonet is inserted into the second locking position. This position is crucial for ensuring a secure attachment of the helmet to the AERP, allowing the system to function correctly during an emergency ejection or descent. It provides the optimal balance between security and the ability to detach when necessary.

Understanding the correct locking position is vital for aircrew safety, as an improper connection could lead to malfunction during critical situations. The other positions do not provide the required secure fit needed for effective operation, which is why they are not the correct choice.