It's really quite simple. 400' is the minimum height for the end of the 2nd segment - the 2nd segment can be extended to 1500' or any where in between once you are clear of the dominant obstacle (if any exists). The height is sometimes referred to as HA or height for acceleration and will be different for each airfield depending on obstacle - unless,of course your SOP uses the 1500' figure as standard.
Now, this is basic Schedule A Performance (remember that difficult exam you took, probably as part of your CPL never mind your ATPL) but many operators use 1500' for simplicity.
Also, remember this is about NET performance (i.e. making the required gradient in the 2nd segment) with an engine out. Your GROSS performance should be much better on the day. Incidentally, from the end of the 2nd segment it is assumed that you fly level to accelerate and flap retract: no turns are allowed for in the 3rd segment because of the impossibility of calculating turning radius with changing speed.Once again, based on an engine out.
1106
Last edited by Type1106; 16th July 2010 at 15:37.
Reason: HA comment added