When can both autopilot 1 and autopilot 2 be engaged simultaneously?

The correct option is when LOC (Localizer) and G/S (Glideslope) are armed or engaged because this situation specifically allows for the use of both autopilots simultaneously to enhance safety and precision during an approach. When both autopilots are engaged in this configuration, it enables a more stable approach while minimizing the risk of pilot workload and maximizing aircraft control during critical phases of flight.

During the approach, when capturing both the localizer and glideslope, using dual autopilots facilitates better path tracking. This is particularly important as it provides redundancy; if one autopilot fails, the other can take over, ensuring that the aircraft maintains its intended flight path.

In contrast, engaging both autopilots at other times, such as anytime during the flight, descending via an arrival, or during the go-around phase, does not conform to the operational standards outlined in the aircraft's procedures. Specifically, dual autopilot usage is not permitted during many normal operations outside of approaches, as it may not provide benefits and could complicate pilot interactions with the flight control systems.