Hi Rudderrat,
Thanks for your reply.
The FCOM explanatory note is outdated and refers to an obsolete document (JAR-OPS). Let´s assume we talk about the A320 family here.
1.
EASA Air Ops, part CAT does not make any provisions for Performance class A in G/A for AEO nor OEI.
2.
EASA CS-25 contains certification specifications for large aeroplanes and specifies a steady 2.1% for twins OEI. As CS-25 is for certification it is of no direct relevance to our commercial air transport, day to day operation. However it seems that Airbus has included tables in FCOM to show compliance to these certification standards. These tables are of no operational value as we need to ensure compliance with PANS-OPS (2.5% MACG) whenever we fly an instrument approach.
3.
For a DH less than 200ft (CAT2 upwards) EASA CS-AWO states that the aircraft must be able to clear the obstacles as specified in PANS-OPS. Therefore CS-AWO mentions that a WAT table for a 2.5% MACG must feature in the airplane AFM. Again Airbus shows compliance by including a ¨CAT 2 - 2.5% MACG¨ table in FCOM, this coincides with the PANS-OPS requirement even when doing a CAT1 or NPA! (Confused already?)
4.
As an operator we don´t have to worry about CS´s as these are for the manufacturer. As EASA Air Ops does not specify any requirements we only need to ensure compliance with PANS-OPS.
5.
Your method of applying a 1t penalty for every 1000ft above nominal EOAA might be a fair approximation but is hardly academic. Also we are not interested in the singular MACG at EOAA. We need a 2.5% geometric MACG, which is something different. We treat take off performance with great accuracy, why should we treat G/A performance any different?
6.
Airbus only recently changed the default MACG in the LPC from 2.1% to 2.5% which is really strange as the 2.1% has only ever been a certification requirement and never an operational requirement!
7.
Airbus should change the LPC landing module to have an EOAA input-field. This would be for the purpose of defining a geometric MACG up to any EOAA. If unable to comply we should have an ¨emergency turn, EOSID¨. Alternatively we could revert to a constructed ¨emergency turn/EOSID¨ whenever OEI in the same spirit of some operators´ take-off performance.
8.
We consider an engine to fail during any moment of the take-off. However for G/A we allow AEO thr reduction/accel alt routinely to be below our minimum G/A EOAA (MSA/missed app alt). Surely once thrust is reduced and or acceleration has begun we are commited to the AEO scenario. What if the engine fails at this moment? We´ll have to level-off to accelerate and possibly infringe our 2.5% geometric MACG. This is inconsistent with what we do on take-off: normally any prudent operator will not allow EOAA to be higher than AEO AA.
9.
A320 QRH overweight landing checklist includes a G/A WAT table, presumably for 2.1% gradient. This is of no use, unless you intend to do a visual approach anytime you´re overweight.
.
Just my thoughts guys. Happy to be corrected.
Best regards