Very confused with Engine Out SID

[WhySoTough]

I have a few questions that I am very confused with.

For single engine after take off roll, you are supposed to follow the engine out SID, I understand this.
Are you limited to doing this depending on weight and temperature?
Or do you ALWAYS use the engine out SID in case of engine out after take off?

When coming for an approach after engine out SID and you now want to go around(missed approach), do you use the missed approach on your approach plate, or follow the engine out SID again?

I think I have made this more confusing for myself than it is.
Thanks in advance.

[AerocatS2A]

Your company will have produced take-off performance data for the airfields you operate from. These take-off weights are derived assuming you will follow the engine out procedure in case of an engine failure, therefore yes, you always follow the engine out SID unless you have a compelling reason not to.

In the case of a missed approach you use the published missed approach for the approach you are doing. Once again your company should have produced landing data that gives max landing weights assuming you will follow the published missed approach. In some cases you might have to use a higher DA/MDA in order to meet the missed approach obstacle clearance requirements. All of this should be spelled out in the company's performance manuals.

[STBYRUD]

If you are able (performance-wise) to follow the normal SID and the required climb profile it is advisable to fly that since ATC does not know your EOSID - if that is not possible obviously you can only fly the EOSID. Same thing really in case of a missed approach - if that requires more performance than your airplane can deliver N-1 it is a good idea to fly the EOSID instead (preferrably you inform ATC beforehand what you will do in case of a missed approach).

[cosmo kramer]

Theory:
To put it very simple. All procedures (SID as well at missed approaches) are designed assuming normal operation. To use a certain procedure you have to meet the required climb gradients of the procedures with all engines operating. This decides your MTOW for departure. For landing it decides your MLW and/or the height of your minima, speed additives etc.

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.

In case of an engine failure it's up to the operator to establish contingency procedures (in both cases). No published procedure will cover an emergency.


Practice:
In my company we would never fly the SID with an engine failure. According to surveys of the airports, we will have either a procedure to follow, or if obstacles don't require, we fly runway heading to MSA (Deviating from clearance - declare mayday and inform ATC). This is because the survey is runway specific. It doesn't account for 10 different departure routes where one or more may take you in the opposite direction of the airfield in to a mountain behind the runway.

If doing a single engine approach we use the engine out procedure according to the above.

Finally with an emergency the final responsibility rest with the commander (as always), and the commander may always decide differently (e.g. to continue visually).

Also remember that contingency procedures can't cover every conceivable scenario. You may get your engine failure at 3000' with the engine out procedure behind you... but will you make it above the 12000' peak ahead of you? This is where airmanship, situational awareness and local knowledge (or detailed study of the terrain if first time there) comes into play. Always have a plan.

Remember in an emergency no rules applies anymore. Only rule is that you have to assure the best possible outcome. The Hudson river landing after a double engine failure is a good example of that.

[Checkboard]

To use a certain procedure you have to meet the required climb gradients of the procedures with all engines operating.

Actually procedure designers simply design to a gradient (3.3% for a SID and 2.5% for a missed approach, unless otherwise specified) - they couldn't care less how many engines you have operating.

One of the constraints for the missed approach, however, is that it begins at the Missed Approach point & MDA/DA. A previous company I worked for specified that, should you go-around below the minima for the procedure, you were then to follow the engine out procedure, not the missed approach (as you no longer met the design criteria).

[cosmo kramer]

Actually procedure designers simply design to a gradient (3.3% for a SID and 2.5% for a missed approach, unless otherwise specified) - they couldn't care less how many engines you have operating.

That's not the point. The point is that you only have to meet the gradient from, a legal perspective, as long as you are not having an emergency. With an engine failure you are no longer required to meet the gradient (also in the case of the missed approach) - but the operator has to establish a contingency procedure.

[SidHolding]

If the SID requires a certain climb gradient (eg it specifies 6% to 4000'), then if I am unsure, I will check my performance book for one engine out climb performance at the take off weight (against pressure altitude and temperature) to see if I can archive the gradient if I lose an engine.

This will determine my take off brief.... In the event of an engine failure after V1, I will.... follow the SID (and cancel any noise abatement) or follow an engine out procedure.

I would also commend looking at a topo chart if you'd be unable to meet the gradient, especially if you're unfamiliar or it's IMC.

Happy flying,

Sid.

[Piltdown Man]

There is no requirement to follow a SID N-1, so I wouldn't worry about that. But where does the topo. chart come in on a Perf. A operation when IMC? What you really need is the location of nav. aids vs MSA so you can work out where you can safely climb during the 4th segment. For that a radio nav. chart is a pretty reasonable device. When visual a Mk I eyeball is also a useful tool.

PM

[Notso Fantastic]

Oh do get rid of this dreadful expression N-1 please! Who invented this? They need a kicking.

[de facto]

This will determine my take off brief.... In the event of an engine failure after V1, I will.... follow the SID (and cancel any noise abatement) or follow an engine out procedure
If you have an N-1:cool: take off procedure ,i suggest you drop the perf book and follow it ,if not,follow runway track until MSA in the sector.If N-1 :cool: happens during your SID and you are not provided with SID deviation point ,i suggest you turn towards the lowest terrain in the area.

Advise ATC ASAP as they dont know your n-1:cool: procedure.

Oh do get rid of this dreadful expression N-1 please! Who invented this? They need a kicking.

WASNT ME :E

[SidHolding]

No need to drop the perf book, it's all part of the planning. I've got 4 engines and a MTOW of 146.5T, and if it's a short sector I could easily be less than 120T at take off. If I can make the climb gradients, then no need to follow an engine out SID (2 engines is an entirely different situation).

I would always study the topo at heavy weights, especially if I'm unfamiliar with the area and it's IMC (yes, the engine out procedure will be flown using nav aids). If you're operating in mountainous terrain (say some Norweigen airfields), you may realise by study of the topo that the engine out procedure is taking you down a valley for example.

Being CFIT aware (especially IMC or night from an unfamiliar airfield) in a Perf A aircraft is commonplace on my flight deck :)

[de facto]

, you may realise by study of the topo that the engine out procedure is taking you down a valley for example.

Having flown into Innsbruck many times in a 737, i concur:E

[cosmo kramer]

If the SID requires a certain climb gradient (eg it specifies 6% to 4000'), then if I am unsure, I will check my performance book for one engine out climb performance at the take off weight (against pressure altitude and temperature) to see if I can archive the gradient if I lose an engine.

Well good luck with that.

Are you aware that your gradient diminishes in turns? So when you SID takes you in the opposite direction of departure runway, what is you gradient during the 180 deg turn which will take at least a couple of minutes?

[SidHolding]

Yes. Look at the SID, perf, topo etc and have a plan. If you've thought about it and it doesn't happen, enjoy your day. If it does happen, hopefully you've answered some difficult questions already thereby freeing up some important capacity!

[Slasher]

Oh do get rid of this dreadful expression N-1 please!

Never heard it before except here. Whats it supposed to
mean anyway? :confused:

[Piltdown Man]

...you may realise by study of the topo that the engine out procedure is taking you down a valley for example.

So what do you do then?

PM

[SidHolding]

It's called "situational awareness".

I've not drank enough water for a pissing contest.

Sid, out.

[5LY]

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.

It boils down to never go anywhere in an a/c that your brain hasn't been first.

[cosmo kramer]

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. ;)

[5LY]

Cosmo.

So, you don't like climb gradients.

To your first point in the thread: The required gradient is an average over the procedure, so yes it may drop off in the turns.

Where is the misunderstanding that my post underlines so well. A gradient can be translated into a rate of climb which is a ball park way of learning if we might survive our plan to follow a certain procedure in the event of a contingency. It's not perfect, but just because you don't like it doesn't invalidate it. Please explain. I don't pretend to know everything about this, but it's what we do. Looking out the window is great, when you can, but for other days I need a hook.

[mutt]

The calculations are much too complicated. That's why you have a group of geniuses on the ground, their role is to calculate the gradient and limit your weights if required.

We limit the landing weight based on the Missed Approach Gradient for certain airports.

Mutt

[john_tullamarine]

A few thoughts ..

(a) Your company will have produced ...

Most do, some don't .. it is good practice for the commander to know which sort of company it is for which he/she flies.

(b) If you are able (performance-wise) to follow the normal SID and the required climb profile it is advisable to fly that since ATC does not know your EOSID

Fair comment - but the ops eng folk need to have looked at this topic in detail to make sure that tracking is feasible from the approach and that net profiles, especially third segment acceleration and turn radius is OK. That is to say, not appropriate for the commander to figure out on the fly.

(c) To use a certain procedure you have to meet the required climb gradients

Do keep in mind that gradients are only part of the problem. Configuration changes, gross/net decrements, and turn gradient delta/radius complicate things.

(d) .. the commander may always decide differently ..

But do make sure you have a good story for the Enquiry. Be very wary of continuing visually in tiger country areas - the gradients are very shallow and not amenable to winging it as we go.

(e) You may get your engine failure at 3000' with the engine out procedure behind you... but will you make it above the 12000' peak ahead of you?

A good ops engineer will have looked at ALL the possibilities until you are above all relevant terrain. Unfortunately, not all ops engineers are operationally savvy and, if this is the case, the exercise should involve a joint ops eng/flight standards liaison.

(f) The point is that you only have to meet the gradient ..

Not adequate. Please do keep configuration changes and turn deltas/radius in mind.

(g) I would also commend looking at a topo chart if you'd be unable to meet the gradient

Topos give useful background - particularly in respect of the big picture stuff. They are not too bad at telling you that there is a BIG hill here or there ... however, they are NOT terribly accurate or useful when it comes to figuring critical net clearances.

Further the sorts of errors which creep into the topo world are legion.

In the real world of ops engineering we use the topo to figure out where the difficult bits might be and then, if it is really critical, a couple of fine chaps/chapesses draw the short straw and have a fun day out in the bush with a theodolite and associated kit.

(h) When visual a Mk I eyeball is also a useful tool.

So long as it is limited to staying away from big hills in the same way that we eyeball staying away from thunderstorms. Mk I eyeball is pretty useless for scraping over ridges and such like OEI.

(i) Are you aware that your gradient diminishes in turns

Something similar to operating at higher weights (load factor effect). The specific sums might vary a bit but, typically, expect something in the region of 0.6 - 1.0 percent decrement, give or take.

(j) It boils down to never go anywhere in an a/c that your brain hasn't been first.

That's not a bad philosophy ..

(k) The required gradient is an average over the procedure, so yes it may drop off in the turns

.. but how are you intending to allow for such things ? The main problem with the real world is that the pointy bits of the profile have a nasty habit of sticking through the gradient surface and hitting a hard bit ... averages give some guidance but don't hack it at close quarters.

Also, before we get too anxious, keep in mind that the gross/net decrement gives a fairly big delta the further we get away from the runway so it's not all gloom and doom .. but once the lawyers get a hold of it, they do tend to get introspective about black and white, rather than the real world of shades of grey.

[bubbers44]

Since 90% of all approaches are in VMC conditions rather than spending 5 minutes going over every possible missed approach with one engine I just say right turn to downwind and land. Bogota is a good example of that. Their missed approaches change constantly depending on where you are so if is VMC just keep it simple and don't bore your FO with BS that doesn't matter.

[john_tullamarine]

I just say right turn to downwind and land

Have no problem with that idea if you actually land.

Now, if the runway becomes blocked while you are on late final (reason doesn't matter, nor does the consideration that such things are not commonplace) and, for whatever reason, you can't land .. what are you intending to do ? ... hovering on the glidepath for a while to think things over isn't an option in an airliner.

Not much different philosophically to saying that, given the reliability of modern engines, why bother with all this EFATO stuff .. just go ahead and takeoff AEO.

[framer]

I would have thought that if you briefed the circuit visually for the initial landing then it would also be ok for a s/e missed approach proceedure. Am I missing something there?

[de facto]

Bogota is a good example of that. Their missed approaches change constantly depending on where you are so if is VMC just keep it simple and don't bore your FO with BS that doesn't matter.


Je@@@@s chr@@@st bubbers,it is this cowboy attitude that kills people!

[Capn Bloggs]

The required gradient is an average over the procedure, so yes it may drop off in the turns
.. but how are you intending to allow for such things ?
What you need is a chart like this one from the Flight Manual for my twin:

http://i521.photobucket.com/albums/w334/capnbloggs/Gradlossinturn.jpg

[aterpster]

J.T.:

In the real world of ops engineering we use the topo to figure out where the difficult bits might be and then, if it is really critical, a couple of fine chaps/chapesses draw the short straw and have a fun day out in the bush with a theodolite and associated kit.

That is often the only way to sort it all out.

Alas, a popular performance vendor in the U.S. is not even using topos, rather the data derived from the Space Shuttle mission. I have those data as an adjunct on my GIS program. Fairly good for planning, but that is about it. The U.S. 1:24000 topos are generally good (excluding Alaska) but still need at least a Day VFR flight inspection.

It isn't happening with some exceptions.

Also, pilots seem quite confused about visual avoidance providing an "out." OEI flight paths are weather independent as you well know. If they must be flown it is all the same, DAY VFR, Day IMC, etc.

[john_tullamarine]

Am I missing something there?

I think that might be the case.

Picture yourself down low over the runway when you need to go to the miss ... think, for instance, twin perhaps at 2.5-3.0 percent gross on the day. That's not much climb capability. How were you proposing to ensure that your bird misses the hard bits during the miss ?

What you need is a chart like this one from the Flight Manual for my twin

Looking at Capn Bloggs' fine graphic, I should have qualified my previous decrement figures to be relevant to 15 deg bank which is the typical figure for OEI turns.

1:24000 topos are generally good

.. but still far too coarse for detailed work. Best stuff I have found are the occasional very detailed charts down to 1:2000 - 1:5000. Wonderful detail for the ground. HOWEVER, the main problem is that one can't rely on any chart for tree heights and similar .. these it takes a walk in the park to have a looksee.

Sat derived elevations are useful, especially for areas where there are no published survey charts. but they only go so far. Ends up being a case of horses for courses .. if the hill/saddle/etc clearly is not too critical, ROM estimates for vegetation are fine .. if the clearance is critical, a theodolite or inclinometer, depending on the location with respect to the runway and Type, ends up being the only sensible way to cover one's delicate bits for the possible subsequent Enquiry.

still need at least a Day VFR flight inspection

.. often the reasonable cost solution for those intermediate accuracy problems but, again, not much good for critical situations .. although, invariably, great fun.

Can recall a wonderful day, many, many years ago, spent in a largish (and very noisy) four-engined turboprop machine running simulated OEI profiles from the runway head (and from a very low height) at a particular seaside aerodrome only because the Regulator's flight standards representative didn't understand much about what was what.

My mate, Bazza, was driving from the RHS and Dunc (the Regulator man) and I were in the jumpseats. As I recall Denis was in the LHS and beaming widely the whole time.

At one point during proceedings, Dunc observed "I don't really understand why we are doing this", Denis was beaming fondly, while Bazza was having an absolute ball. Me ?, well I was quite bemused as the whole exercise didn't really achieve much at all other than burning lots of kero, would have been far cheaper in an Aztruck or similar ... but it was absolutely great fun and must have annoyed the living daylights out of the locals until we all got bored and flew off back home.

.. I'm not sure if it's a case of all the fun having gone out of life in the present PC world .. or am I just becoming a boring old phart way past his use-by date ?

pilots seem quite confused about visual avoidance providing an "out."

A commonly seen fallacy. Works fine if you have one big hill and you can avoid it by a suitable margin and you are above all other terrain. However, any attempt to play tactical battlefield helicopters OEI in anger is a recipe for disaster - the gradients are too small for the human brain to figure on the fly and, when it comes to figuring differences between small quantities, the brain doesn't appear to have a good track record.