If the field-length-limited take-off mass and V1 were calculated with balanced field-lengths, how does the inclusion of additional clearway affect these calculations?

When calculating the field-length-limited take-off mass and V1 using balanced field lengths, the inclusion of an additional clearway provides an extended runway length available for takeoff. This addition allows for a longer distance available for the aircraft to achieve necessary speed and performance requirements before reaching the end of the runway.

As a result, the take-off mass that can be safely carried during a field-length-limited scenario increases because the aircraft can use the additional length to accelerate to take-off speed while still having a safety margin in case of an engine failure. Consequently, V1 – the decision speed – is reduced because the aircraft now has more distance to reach the required speed and maintain safe performance despite an engine loss.

This understanding holds true within the context of the balanced field length concept, where the take-off distance required under certain conditions matches the distance available, including the clearway. Therefore, the additional clearway's effect leads to an increased field-length-limited take-off mass along with a corresponding reduction in V1, making this interpretation the most accurate in relation to the problem posed.