FCOM 3
Engine Out Taxi
In all cases, two engines shall be started for the initial taxi out. Should a protracted ground delay be expected or occur prior to takeoff, it is permissible to shutdown any or both engines.
The APU should be operating while taxiing with an engine shutdown.
Assess the operational environment and consider possible blast damage from higher than normal thrust requirements when taxiing with one engine at high gross weight.
Engine out Taxi operations should not be conducted when a system that impacts braking or steering capability is not operative.
For restart, when the aircraft is stationary accomplish the BEFORE START and BEFORE TAXI Checklists, together with the associated procedures.