Originally Posted by
hellkitty
Hello Guys,
As I am getting lost with all that gradient mess please be so kind and help me with uderstanding it
I know that certification gradients for MA are 2,1 for approach climb (with OEI, flaps approach, gear up)) and 3,2 for landing climb. I know also that minimum gradient for MA procedures is 2,5%. Let's assume we are flying to Nice, there is ILS Y RWY04L in use (just as an example) where we have such statement: MACG min 3,0% DA: 301 (for B cat a/c) and MACG 2,5% so then DA is 321. This is the point I am getting lost. If they put 3.0% gradient on the map,
AFAIK, that means there is a demand for higher gradient than standard procedural (2,5%). First question - does the gradient from the jeppsen map include OEI? As I know normally procedures are made for AEO, however the name "MACG" makes me think it is missed approach climb hence it takes into account only OEI.
I see that my FMS after computing all the WAT data i put in, gives me approach climb 3,5 and balked landing 4. As 3,5>3,0 I can commence the approach with lower minimas. The question is what about 2,1%. Do I need it somehow? For what exactly I need it or do I even need it at all?
Do i need keep at least 3,0 untill the end of the whole missed approach procedure (end of final segment)?
Is it somehow possible that my a/c will not meet certification requirements for MACG/landing climb under some circumstances (assuming I am operating it within AFM limits)?
The 2.1 approach climb OEI and 3.2 landing climb AEO are ICAO design minimum gradients. All EASA missed approaches are 2.5 unless terrain or ATC procedures dictate a higher gradient.
Whatever gradient is on the chart, you must be able to achieve it from the missed approach point on one engine, as it is assumed to fail at the MAP (just like your takeoff is assumed OEI). So as long as your perf calculation shows your approach climb gradient exceeding (as yours did) you are fine. You must keep the gradient if OEI until above MSA or reaching platform altitude (so don’t accelerate on one engine below MSA or platform as you’re in the unknown). Your company SOP should state this clearly.
If you can’t make the gradient on the perf calc, use the higher minima or try packs or bleeds off. If you still can’t make the gradient then most companies (and the authorities) allow you to use a takeoff engine failure procedure if one exists for that runway. This is because you will definitely exceed the OEI
takeoff minimum gradients when commencing a missed approach from the MAP (you’re higher up and further back). If you baulk the landing (GA below minima) technically you will need to fly the takeoff EFP to assure obstacle clearance if an engine fails as you decide to go around.
Hope that makes sense, I’m typing it quickly over dinner!