Go around, thrust reduction altitude oei
Hi ruddercat,
Imagine the following situation:
-pans-ops 4 chart required 4% for missed app
-LPC says the a/c can do 4,01% (but up to what altitude remains the question!!!)
-MSA is 6000ft, missed app alt is 5000ft, no chart exception (e.g. France: no level accel prior to .....)
-only way to guarantee obstacle clearance is to achieve mnm 4% up to 5000ft
-the LPC says the a/c can achieve 4,01% but can it still guarantee 4% at 5000ft???
The answer is NO! And this is a serious deficiency in our performance considerations!
The LPC landing performance module should include an input for "level acceleration altitude". G/A performance should not stop at 1500ft or with a singular MACG obtained for a nominal height! It should be assessed geometrically up to msa/missed app alt as in line with the assumptions of pans-ops!
Pans-ops 3 previously catered for a 6nm level accel segment at 800ft. This is gone now and is missed by quite a few operators.
Another point:
There is a lot of confusion with regards to 2.1% vs 2.5% macg!
They are two different things!
2.1% is a certification requirement as per EASA CS-25, previously JAR-25. We don't have to worry about that one.
2.5% is an operational requirement as per PANS-OPS to guarantee obstacle clearance! If a chart does not say otherwise: 2.5% is the absolute minimum!
Best regards