The climb-limited MTOW is the maximum weight at which the airplane meets three EO minimum climb gradient requirements, generally referred to as 1st, 2nd and 4th segment. The 4th segment minimum climb gradient must be met at VFTO in the en-route configuration, maximum continuous thrust on the operating engine(s), at 1500 ft or the EO ACC altitude, whichever is higher.
Just a note of caution: Hazelnut is answering an entirely different question to that posed by the OP. Tat question was about the effect of changing S/E alt in the Mcdu whereas Hazelnut is describing an actual acceleration above 1500ft. You can theoretically insert any altitude you want in the Mcdu without affecting when you choose to accelerate. Hazel it's point is well made though for actual acceleration.
In fact some Aibus performance packages stipulate both a. minimum and maximum acceleration altitude.
Simply a reminder. Can be used in briefing or by PF following actual engine failure by glancing down at the perf page usually displayed on that side. I agree it does seem odd but same in other Airbus a/c.
There is indeed a minimum and a maximum Accel. altitude. The minimum is for obstacle clearance and maximum is equal to the altitude the airplane would attain once the 10 minute TOGA thrust limit is reached.
One debate is whether is what altitude to select for engine out.
I am interested in learning more about the performance implications of selecting different altitudes
I personally prefer to select 2000 feet rather than 1500 as an engine out acceleration altitude.
If I have a engine out with severe damage and engine fire, it gives me more time to complete the Ecam actions before having to push to level off, if we have to push to level off at 1500, we must stop the ecam actions, and cannot discharge the bottle until after cleaning up the aircraft, depending on your SOP and Airbus procedure.
Being lower than maximum engine out acceleration altitude, you delay discharging the bottle.
Delaying acceleration until Engine is secure, Airbus style:
This is an extract from the Airbus (manufacurer's) FCTM following an engine failure after V1.
PROCEDURE INITIATION OF THE PROCEDURE
The PNF will closely monitor the aircraft's flight path. He will cancel any Master Warning/Caution and read the ECAM title displayed on the top line of the E/WD. Procedures are initiated on PF command. No action is taken (apart from cancelling audio warnings through the MASTER WARNING light) until:
• The appropriate flight path is established and,
• The aircraft is at least 400 ft above the runway.
A height of 400 ft is recommended because it is a good compromise between the necessary time for stabilization and the excessive delay in procedure initiation. Priority must be given to the control of the aircraft trajectory. Once the PF has stabilized the flight path, the PNF confirms the failure and the PF orders ECAM actions.
The flight crew should delay the acceleration for securing the engine. An engine is considered as secured when the ECAM actions of the procedures are performed until:
• "ENG MASTER OFF" for an engine failure without damage
• "AGENT 1 DISH" for an engine failure with damage
• Fire extinguished or "AGENT 2 DISH" for an engine fire.
Note: If the decision has been taken to delay the acceleration, the flight crew must not exceed the engine out maximum acceleration altitude. (The engine out maximum acceleration altitude corresponds to the maximum altitude that can be achieved with one engine out and the other engine(s) operating at takeoff thrust for a maximum of 10 min.). END.
Trouble is everyone knows better than the manufacturer or even the previous Chief Pilot and Chief Training Captain etc and impose their personal biases on SOPs. I don't know when this combination of accelerating whilst completing the ECAM procedure started i.e. Stop ECAM Flaps one; Continue ECAM; Stop ECAM Flaps zero but its messy potentially dangerous and quite unnecessary. how long does it take to secure an engine? I work for a company which does it like this but I continue to hope they will see the light of day.