Is it permissible to take off with a configuration of M/6/6?

In the context of aviation operations, a configuration of M/6/6 indicates a multi-engine setup where the aircraft can operate safely and efficiently with the number of engines it has available. When considering whether it is permissible to take off with this configuration, the rule of thumb is that as long as there are two operational engines, the aircraft is typically capable of initiating takeoff.

This is because aircraft are often designed with certain redundancy, allowing them to continue flying safely even if one engine fails. Therefore, with two engines operational in a configuration that allows for their use, the aircraft can achieve the necessary performance during takeoff and through initial climb while maintaining adequate safety margins.

In contrast to other choices, which suggest needing three engines or imposing restrictions that do not align with common multi-engine operational procedures, the correct answer recognizes the flexibility and capability of the aircraft with two engines functioning properly. Thus, it is entirely permissible to take off when two engines are operational, provided that other operational parameters, such as weight and balance, are also taken into account.