Take Off Performance
 

Could somebody please explain:
1.Why is a 1.2% climb gradient required on the level 3rd segment.
2.Can you accelerate flying level on the 3rd segment.
3.Why are most turns limited to 15*angle of bank during a Special Engine Out Procedure.

Thanks

1) The regulations require it.
2) Yes (it is a capability requirement not a gradient requirement. the wording in cs-25 is "available gradient of climb")
3) Don't know your specific procedures so my best answer would be due to the speed scheduled at the time of the turns and therefore the load factor/stall margin.

An available climb gradient capability (read I could climb at that rate if I wanted to) converts to an available acceleration capability if I fly level.

Not much point flying level if there is not enough spare grunt to accelerate ?

Turn bank angle considerations are

(a) associated loss of climb capability. This principally is due to the increased load factor (think a bit like being heavier) and associated drag. Typical gradient loss is around 0.6 or so percent and will be scheduled in the relevant Type flight manual for calculation purposes

(b) turn radius for track made good and terrain clearance. The general rule adopted is that 15 deg is a good balance so that angle is adopted routinely. On occasion, one schedules a lesser bank angle for radius considerations.

The turns aren't limited to 15 deg AoB, they are designed for it. You're AoB limit is the manoeuvring capability of your aircraft at the time.