FullWings,
Thank you for the compliment, but a performance guru I am not.The only gurus that I know were my mentors and teachers back at Douglas and BAe, I hope to live up to their expectations.
If you're looking for some 'guruship' in the missed approach area, read up
OzExpat's post, on checking his profile he is an Instrument Procedures Designer. My area of expertise is in Takeoff performance, and the OEI procedures that go with it. Naturally, ensuring safe levels of performance in the missed approach phase are also one of my responsibilities, compliant with the PANS-OPS procedures used to design them. I have a few current posts floating around with respect to increasing the standard gradients to comply with the minimum PANS-OPS 2.5%, or greater IF REQUIRED. It does concern me that Gross data is used, as opposed to degraded Gross to Nett data used for the Takeoff case. This degradation continues to much increased vertical obstacle clearances during the acceleration phase.
One of your statements concerns me, just in case you misunderstood -
I know the tech. guys have checked a V1 cut up to MSA on takeoff, so I have no problems following the SID or OEI procedure.
Maybe not everyone does this, I do all the way to MSA, and 'contain' the procedure to within the MSA coverage, but others may well cutoff at a point where the procedure enters a published holding pattern (safely), but well below the MSA. Numerous procedures I've seen from other designers take care of the initial problems, e.g. Right turn at 7.0 DME to Track 270 degrees.......and then what? Some 1st/2nd/3rd segments can take up to 40 to 50 miles - WELL beyond the MSA coverage, now we're concerned with En-route obstacles - Oh my God! One procedure that I saw (no names, but the airline began with "V") had the aircraft taking up a track of 010, to what, infinity? In doing analysis for my own operator from the same airport agreed that that was a good INITIAL route, but a 1620 foot hill lay exactly on the 010 track against an acceleration altitude of 1000 feet and during what would be his 3rd segment. So, when you say "I know the tech. guys have checked a V1 cut up to MSA on takeoff", I worry - DO CHECK the criteria by which your procedure designers have created the procedure. Your statement of "I have no problems following the SID or OEI procedure", OK, I mentioned possible limitations on the OEI procedure, but don't think for a moment that with OEI you can follow the SID. Where reasonable loads are achievable with OEI following the SID, I create secondary data for the SID as the OEI route. This is the exception, and more often than not, actual loads make the optimised OEI procedure the only option.
And finally to your question of "
Yes, but where does this 2.5% gradient with 100' end?. Absolutely no guarantee that it will end at the MSA. Typically, it will take you to a Holding Pattern with it's associated Minimum Holding Altitude. This may well be well below the MSA. On the flight I operated yesterday, the Missed Approach Altitude was 3,000 feet in a Holding Pattern, meanwhile, the MSA was 5,700 feet. Safe for now, climb to MSA/MEA in the holding pattern if you have to divert, or commence another approach. At least you don't have to worry about obstacle clearance in the climb within the holding pattern, only to ensure that you have the aerodynamic performance available for the required further climb. This does have implications in Flight Planning to allow for additional fuel for diversion.
Ozexpat,
In this country, however, if the obstacles have an elevation in excess of 5,000 feet, the MOC is multiplied by 1.5. If obstacle elevation is 10,000 or above, MOC is doubled.
This was always the case in New Guinea (was Port effin Morbid the giveaway?) due to reliability of topographical information. It may well apply in other regions also, but don't forget the factor of Altimeter accuracy as vertical displacement from the QNH source increases.
Said too much already, I'm no guru.
Fly safe,
and check the criteria used to create your data.
Old Smokey