What will be the impact of using a stopway without a clearway on the take-off mass and V1?

Utilizing a stopway without a clearway impacts the take-off performance of an aircraft significantly. A stopway is an area beyond the runway that is designed to provide additional distance for an aircraft to stop if necessary. However, having no clearway (which is an area beyond the runway that can assist in the take-off phase) implies that the take-off distance required cannot be reduced, as a clearway would normally allow higher mass operations with shorter distances.

When an aircraft is taking off, V1 is the decision speed beyond which the pilot must continue the take-off even if an engine fails. If a stopway is available and there is no clearway, the pilot needs to consider that the aircraft will lack additional take-off distance above the runway length, which generally leads to lower maximum allowable take-off mass. This is because, without the clearway, the required length of the take-off run is greater when considering possible engine failure scenarios.

In this scenario, the significant consequence is that the allowed take-off mass reduces due to the increased distance required to achieve a safe take-off given the potential for an aborted take-off. Meanwhile, V1 will also decrease since a lower mass will necessitate a lower speed for decision-making during take-off. Thus,