@toung I suggest to use the following two step method to convince your flight ops engineers into a higher ACC ALT
1) safelife's calculation (put your own time values as appropriate)
- a: I assume it takes 1 minute from setting the TO POWER to the start of the first segment (V2 + positive climb);
- b: then you will climb at no less than 2,4%, which is the regulatory minimum;
- c: I assume after reaching the EO ACC ALT, it takes 45 seconds to reach the clean speed with flaps up.
So 5'00''- 1' - 45" = 3'15" is the climb time in second segment you have.
Those 3'15" at groundspeed 140 kt with gradient 2,4% give you ascent to 1105 feet AFE, 5 mins TOGA limit observed.
Or a reversed calculation: To climb up to 800 ft with 140 g.s. on a 2,4% gradient, you only need 2'17". There are still remaining 2 mins and 33 seconds left for the ground roll and acceleration, before hitting the 5 mins limit!
2) Mach E Avelli's perspective.
Use the opinion of your TREs, if necessary TRE from CAA who flies with a more realistic operator, to explain that accel. at 400 feet is interfering with duties for engine malfunction handling. The way you have it now is completely upside down.
Force the FLT OPS ENG to give you room for working by the code of industry's best practice. Own solutions bring own problems. No need for that.
400 - EFATO drill actions
800 - accelerate if ready,
1100 - accelerate the latest to observe the 5 mins limit.