Very confused with Engine Out SID
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Very confused with Engine Out SID
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.
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.
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.
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.
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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).
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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.
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.
To use a certain procedure you have to meet the required climb gradients of the procedures with all engines 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).
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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.
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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.
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.
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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.
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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
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 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
procedure.
Oh do get rid of this dreadful expression N-1 please! Who invented this? They need a kicking.
Last edited by de facto; 31st Jan 2012 at 11:38.
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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
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
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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.
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?
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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!
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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.
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.
Last edited by 5LY; 2nd Feb 2012 at 18:59.
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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.
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.
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.
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.
Note.— Development of contingency procedures is the responsibility of the operator.
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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.
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.
Last edited by 5LY; 2nd Feb 2012 at 14:58. Reason: sp