SID's are designed for min. 3.3% or higher climb gradient. A twin eng. a/c is expected to acheive 2.4% c.g. after an eng. failure. That's what your climb limit is all about. Be very carefull about following a SID on one engine. It may be that on the SID you're on that terrain is not an issue, but do you want to run the experiment on some dark dirty night in IMC? Fly straight ahead or if there's an EOSID follow that.
GA procedures are based on 2.5% c.g. As has been stated in previous posts, check your performance. If you can meet 2.5% c.g. you're good. If you can't, have a plan.
That's
exactly the misunderstanding I was talking about in my first post in this thread. And an excellent example to underline my point:
For some reason the missed approach is cause of a lot of confusion. The missed approach is no different that any other procedure design - it assumes all engines operating.
1) You argue very well
not to follow one kind of procedure with an engine failure due to the inability to establish if you are able to meet the climb gradient. The procedure in question called an SID.
2)
Yet, in the exact same situation, only with a different name (Missed Approach), you advocate that it is safe to do so.
Yes one starts at DER and the other at the MAP, but after that point their purposes are the same and you are pretty much in the same configuration, hence two comparable situations.
Go-arounds will, just as often as SIDs, have higher than standard gradient. You have no guarantee that you will meet the gradient in either the case of the SID or the Missed approach. The calculations are much too complicated. In the real world we fly paths, not gradients. When including turns, acceleration segments decreasing headwind/increasing tailwind during the climb, it will all affect your path. With a variable path you will have a variable gradient as well. How are you going to account for that?
Gradients on a charts are, in my opinion, useless. Nothing is more pointless than when the PF briefs
"okay, today we have a gradient of 4.2%, that shouldn't be a problem for us... arrhh with 200 knots that would be around 900 fpm". Of course it won't be a problem when we always have gradients around 12-15% and rockets out with 2-3000 fpm! A waste of time is what it is.
Tell me about the high MSA, where the mountains are and where our special procedure is going to take us instead. Where are we going to turn to rejoin our special procedure when it's behind us.
For engine out situations forget about the gradient and trust you performance department and follow their directions. If you don't have guidelines in your documentation on how to proceed with regards to single engine missed approach - complain.
On many previous occasions I guess it has been agreed upon that the single engine missed approach is one of the biggest gray areas in aviation regulation. I guess when working out the decades old regulations the prevailing idea must have been that a single engine approach always ends with a landing (not a bad idea I guess
).
P.s.
Checkboard:
ICAO Doc. 8168, Section 2. General principles, Chapter 1. General information:
1.1.2 Procedures contained in PANS-OPS assume that all engines are operating.
Note.— Development of contingency procedures is the responsibility of the operator.
