When ejecting over terrain exceeding what altitude should the manual override handle be used to deploy the parachute?

The correct choice is based on safety protocols designed to ensure a successful parachute deployment during emergencies. Generally, the recommendation to use the manual override handle when ejecting over elevated terrain is established to provide a greater chance of a successful parachute deployment in varying conditions, including obstacles and increased altitude.

When considering the provided options, the mention of using the manual override handle at 8000 feet MSL reflects a standard procedure that acknowledges the need for immediate action to control the parachute deployment under potentially hazardous conditions. At altitudes higher than 8000 feet, it's crucial for the pilot to maintain control and ensure that the parachute opens adequately before reaching the ground, as the time and distance to altitude may significantly reduce.

Additionally, the altitude above which manual intervention becomes vital typically accounts for the challenges presented by high terrain, which could obstruct free fall and deployment sequences if left solely to automatic systems. Thus, using the manual override handle at this altitude increases the margin for safety in emergency ejections.