Missed Approach Climb Gradient question?
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Missed Approach Climb Gradient question?
Hi all,
I will shortly start to fly a twin turbine performance class B aircraft and I have a couple of questions that you most wise of professionals may be able to answer!!
During an IFR approach with two different DA(H), one for a 5.0% and another for a 2.5% missed approach climb gradient, do I have to use the 2.5% on the assumption that I may loose an engine? It will not do 5.0% single engine.
Is there any document that I can find the stipulation that you must use the single engine climb gradient for selecting IFR approaches?
What happens if there are only minimums for a 5% climb gradient? Do i have to calculate an increased DA(H) that will allow a 2.5% climb gradient?
Any help is much appreciated.
I will shortly start to fly a twin turbine performance class B aircraft and I have a couple of questions that you most wise of professionals may be able to answer!!
During an IFR approach with two different DA(H), one for a 5.0% and another for a 2.5% missed approach climb gradient, do I have to use the 2.5% on the assumption that I may loose an engine? It will not do 5.0% single engine.
Is there any document that I can find the stipulation that you must use the single engine climb gradient for selecting IFR approaches?
What happens if there are only minimums for a 5% climb gradient? Do i have to calculate an increased DA(H) that will allow a 2.5% climb gradient?
Any help is much appreciated.
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A multi-variant question indeed...
First off..the criteria assumes all engine for the missed. EO procedures are custom. There are NO calculations assumes with any criteria for EO.
Not sure what you reference is, either FAA or ICAO...but neither address EO in design criteria.
EO procedures are emergency only.
Remember, and most forget, these are MINIMUMS. If the chart states an MDA, then you must calc you DA depending on your real time performance.
First off..the criteria assumes all engine for the missed. EO procedures are custom. There are NO calculations assumes with any criteria for EO.
Not sure what you reference is, either FAA or ICAO...but neither address EO in design criteria.
EO procedures are emergency only.
Remember, and most forget, these are MINIMUMS. If the chart states an MDA, then you must calc you DA depending on your real time performance.
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As flight path states, those gradients are for all-engines operating only. With all engines operating you have to determine whether your aircraft can comply with the steeper climb gradient. If not, you are required to use the higher minimums predicated on the less demanding climb gradient.
With an engine inoperative you need to have a one-engine inoperative "escape route."
As to normal ops, no one provides the performance data so it is mostly an exercise in politics rather than performance.
A lesson in aircraft instrument flying procedures: It is a lot easier for the government lackies and manufacturers to determine how an airplane will descend on an instrument flight procedure than climb on an instrument flight procedure.
With an engine inoperative you need to have a one-engine inoperative "escape route."
As to normal ops, no one provides the performance data so it is mostly an exercise in politics rather than performance.
A lesson in aircraft instrument flying procedures: It is a lot easier for the government lackies and manufacturers to determine how an airplane will descend on an instrument flight procedure than climb on an instrument flight procedure.
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You assume that you will be flying the MAP with one engine and therefore you need to know your OEI climb gradient to be able to choose which minima to use. If you have an escaperoute for departure from the same runway, perhaps once in a while it could be accepted to use that procedure and then use a lower minima, but remember that the GA performance calculations and TO performance calculations differ in their requirements and that it is not (in a strict world) possible to just decide to use normal departure procedures for GA.
We had this problem in Sarajevo when I flew there. In bad weather it was more advantageous to be as light as possible to get a better climb gradient to be able to choose a lower minima. One good way to keep track is to ask the performance calculating company to produce a speedbook with the gradients stated for each weight.
Edit: I see the two previous posters say that the performance is based on all engines operating. Perhaps it is so for Perf Class B, so be it, I'm only familiar with performance class A. In any case, I for one would not want to be below minima if I didn't have single engine performance to get me out... All takeoffs are based on it so why not have the same reasoning for go arounds?
We had this problem in Sarajevo when I flew there. In bad weather it was more advantageous to be as light as possible to get a better climb gradient to be able to choose a lower minima. One good way to keep track is to ask the performance calculating company to produce a speedbook with the gradients stated for each weight.
Edit: I see the two previous posters say that the performance is based on all engines operating. Perhaps it is so for Perf Class B, so be it, I'm only familiar with performance class A. In any case, I for one would not want to be below minima if I didn't have single engine performance to get me out... All takeoffs are based on it so why not have the same reasoning for go arounds?
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The reference you are looking for is EU OPS 1, subparts G & H.
There is no specific requirement to ensure that a performance class B aeroplane can meet the requirements of a non standard (i.e. greater than 2.5%) missed approach gradient. This requirement only applies to class A aeroplanes.
Class B aeroplanes are only required to demonstrate an arbitary minimum level of go around performance. This is a steady gradient of 0.75% in the approach climb (going around from 1500ft with one engine inoperative, gear and flaps retracted), and 2.5% in the landing climb (a baulked landing from below DA/MDA with the gear and landing flap extended). For a twin engined class A aircraft, the required gradients are 2.1% in the approach climb and 3.2% in the landing climb. Note that single engine performance is not necessarily guaranteed in either class, even on a standard missed approach.
So using the 5.0% minima is not expressely prohibited, but I would seriously question the wisdom of doing it without checking your aircraft's performance manual first. As 2.5% is the standard missed approach procedure gradient, airfields with a steeper gradient will always publish higher minima for aircraft unable to meet it. If in doubt use the 2.5% minima.
There is no specific requirement to ensure that a performance class B aeroplane can meet the requirements of a non standard (i.e. greater than 2.5%) missed approach gradient. This requirement only applies to class A aeroplanes.
Class B aeroplanes are only required to demonstrate an arbitary minimum level of go around performance. This is a steady gradient of 0.75% in the approach climb (going around from 1500ft with one engine inoperative, gear and flaps retracted), and 2.5% in the landing climb (a baulked landing from below DA/MDA with the gear and landing flap extended). For a twin engined class A aircraft, the required gradients are 2.1% in the approach climb and 3.2% in the landing climb. Note that single engine performance is not necessarily guaranteed in either class, even on a standard missed approach.
So using the 5.0% minima is not expressely prohibited, but I would seriously question the wisdom of doing it without checking your aircraft's performance manual first. As 2.5% is the standard missed approach procedure gradient, airfields with a steeper gradient will always publish higher minima for aircraft unable to meet it. If in doubt use the 2.5% minima.
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Cheers for the pointers.
I just found the below paragraph in EU Ops for performance class A aircraft.
My understanding is that for performance class A if the climb gradient is greater than 2.5% then you must check that you can achieve it OEI, would that be correct?
I then found this for Performance class B aircraft
It looks as if there is no requirement to consider a OEI missed approach climb gradient with performance class B aircraft. That seems odd....
I just found the below paragraph in EU Ops for performance class A aircraft.
OPS 1.510
Landing — Destination and alternate aerodromes
(b) For instrument approaches with a missed approach gradient greater than 2,5 % an operator shall verify that the expected landing mass of the aeroplane allows a missed approach with a climb gradient equal to or greater than the applicable missed approach gradient in the one-engine inoperative missed approach configuration and speed (see applicable
requirements on certification of large aeroplanes). The use of an alternative method must be approved by the
Authority.
Landing — Destination and alternate aerodromes
(b) For instrument approaches with a missed approach gradient greater than 2,5 % an operator shall verify that the expected landing mass of the aeroplane allows a missed approach with a climb gradient equal to or greater than the applicable missed approach gradient in the one-engine inoperative missed approach configuration and speed (see applicable
requirements on certification of large aeroplanes). The use of an alternative method must be approved by the
Authority.
I then found this for Performance class B aircraft
OPS 1.545
Landing — Destination and alternate aerodromes
An operator shall ensure that the landing mass of the aeroplane determined in accordance with OPS 1.475
(a) does not exceed the maximum landing mass specified for the altitude and the ambient temperature expected for the estimated time of landing at the destination and alternate aerodrome.
Landing — Destination and alternate aerodromes
An operator shall ensure that the landing mass of the aeroplane determined in accordance with OPS 1.475
(a) does not exceed the maximum landing mass specified for the altitude and the ambient temperature expected for the estimated time of landing at the destination and alternate aerodrome.
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Balkanhawk,
Yes that's the way I understood it. What makes even less sense is that for performance A the minimum approach climb gradient for certification is 2.1%, yet the standard MAP gradient is 2.5%, there is no guarantee in either class that you'll be able to achieve the MAP gradient with one engine inoperative. That said, these figures are certification minimums and the performance of your aircraft could be considerably better - there are some performance class B aircraft with higher performance margins than some performance class A aircraft.
The point I'm trying to make is, study the performance data for the aircraft you'll be flying and understand what it can do, especially if you'll be flying into somewhere performance limiting.
Yes that's the way I understood it. What makes even less sense is that for performance A the minimum approach climb gradient for certification is 2.1%, yet the standard MAP gradient is 2.5%, there is no guarantee in either class that you'll be able to achieve the MAP gradient with one engine inoperative. That said, these figures are certification minimums and the performance of your aircraft could be considerably better - there are some performance class B aircraft with higher performance margins than some performance class A aircraft.
The point I'm trying to make is, study the performance data for the aircraft you'll be flying and understand what it can do, especially if you'll be flying into somewhere performance limiting.
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You are correct Balkanhawk (funny name, in the balkans this discussion highly relevant).
Performance class B aircraft have relaxed performance requirements in take off and as it seems, also in go around. With this in mind, most things will be legal but I would seriously question going into lets say Sarajevo in ****ty weather and going below the 2.5% minima. If it doesn't work out and you net to get yourself out of there, it's a long way up to MSA if your flying a piston twin on one engine...
But that was perhaps not the question. Anyhow, take care.
Performance class B aircraft have relaxed performance requirements in take off and as it seems, also in go around. With this in mind, most things will be legal but I would seriously question going into lets say Sarajevo in ****ty weather and going below the 2.5% minima. If it doesn't work out and you net to get yourself out of there, it's a long way up to MSA if your flying a piston twin on one engine...
But that was perhaps not the question. Anyhow, take care.
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That is why all OEI procedures are all custom. Nothing in the criteria supports OEI, especially the obstacle clearance surfaces.
Even if you can make 2.5% OEI, you still must have a custom procedure design approved by the regulator.
Even if you can make 2.5% OEI, you still must have a custom procedure design approved by the regulator.
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FlightPath:
Alas, the regulator in this country is incapable of determining whether the operator's OEI procedure will work. So, it's all in the hands of the operator's performance engineering department.
The FAA does have to ostensibly approve carrier deviations from public departure procedures, which the carrier represents as meeting both TERPs and Part 25 OEI takeoff flight path requirements.
Thank goodness for the reliability of modern jet engines, at least above V1 and for awhile after that.
That is why all OEI procedures are all custom. Nothing in the criteria supports OEI, especially the obstacle clearance surfaces.
Even if you can make 2.5% OEI, you still must have a custom procedure design approved by the regulator.
Even if you can make 2.5% OEI, you still must have a custom procedure design approved by the regulator.
The FAA does have to ostensibly approve carrier deviations from public departure procedures, which the carrier represents as meeting both TERPs and Part 25 OEI takeoff flight path requirements.
Thank goodness for the reliability of modern jet engines, at least above V1 and for awhile after that.
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Concur!
As actively designing EO procedures, it is certainly enlightening, and a quite a bit worrisome.
as you say..."thank goodness for the reliability of modern jet engines"
As actively designing EO procedures, it is certainly enlightening, and a quite a bit worrisome.
as you say..."thank goodness for the reliability of modern jet engines"
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Balkanhawk is correct
The operator should provide the pilot with a table with Field Alt vs Temp= LW for several climb gradients in order to comply with approach climb performance.
In the airbus you only can find it until 2,5% for CAT I and 2,1% for CAT II/III.
FCOM 3.05.35
Any climb gradient greater than that , refer to the table that you should be provided.
In the airbus you only can find it until 2,5% for CAT I and 2,1% for CAT II/III.
FCOM 3.05.35
Any climb gradient greater than that , refer to the table that you should be provided.
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Of course while everyone is quoting regs, calling their chief pilot, digging though the FARs, the question remains...do you shoot an approach that should you lose an engine you can't outperform the terrain on the missed?
Not sure if everyone here is really solid on the reasons why we fly twins instead of singles.
Not sure if everyone here is really solid on the reasons why we fly twins instead of singles.
Ficklefinger
Many of the posters on this thread are professional procedure designers and performance engineers discussing the "whys and wherefores" of doing what you make sound so simple, pray tell us, how do you determine that every missed approach you fly will result in terrain clearance OEI.
References to ICAO documents, TERPS, Advisory Circulars or Kentucky Windage, greatly appreciated. We use an APG report, by the way.
Many of the posters on this thread are professional procedure designers and performance engineers discussing the "whys and wherefores" of doing what you make sound so simple, pray tell us, how do you determine that every missed approach you fly will result in terrain clearance OEI.
References to ICAO documents, TERPS, Advisory Circulars or Kentucky Windage, greatly appreciated. We use an APG report, by the way.
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theficklefinger:
That question doesn't add much to the discussion.
What g.f. is pretty much trying to tell you is that the gradient expressed on either a departure procedure or IAP missed approach procedure is climb performance "apples" and that an OEI profile, whether on a departure or missed approach procedure is climb performance "oranges."
The two appear to some to be related but they are distant cousins, especially when the obstacle environment is critical (aka, "obstacle rich environment" in performance engineering and procedure design parlance).
The obstacle assessment done by the public procedures designers is often of little, or no, use for OEI purposes. It comes down to the specifics of the aircraft you are flying, and the OEI profile your company elects to use. That, in turn, requires a very specific obstacle assessment that is valid for your company's elected profile for each specific type of aircraft.
Galaxy do you fly planes with a flight manual?
What g.f. is pretty much trying to tell you is that the gradient expressed on either a departure procedure or IAP missed approach procedure is climb performance "apples" and that an OEI profile, whether on a departure or missed approach procedure is climb performance "oranges."
The two appear to some to be related but they are distant cousins, especially when the obstacle environment is critical (aka, "obstacle rich environment" in performance engineering and procedure design parlance).
The obstacle assessment done by the public procedures designers is often of little, or no, use for OEI purposes. It comes down to the specifics of the aircraft you are flying, and the OEI profile your company elects to use. That, in turn, requires a very specific obstacle assessment that is valid for your company's elected profile for each specific type of aircraft.
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Your flat out wrong ATERP...you need to see how planes are certified...and how instrument approaches are certified...
Simply put, if your looking at the climb gradient of a MAP or departure, and are responsible enough to your passengers, industry, owner of the aircraft, your family, your profession...then you will pull out the Flight Manual and see if you have the single engine performance to do that procedure.
I don't get how the OEI differs from the IAP procedures...if by that you mean the math that the pilot has to accomplish to get to a climb gradient or feet/nm...that's the pilot's job...
Either way...the numbers need to be crunched if you are actually doing your job.
Simply put, if your looking at the climb gradient of a MAP or departure, and are responsible enough to your passengers, industry, owner of the aircraft, your family, your profession...then you will pull out the Flight Manual and see if you have the single engine performance to do that procedure.
I don't get how the OEI differs from the IAP procedures...if by that you mean the math that the pilot has to accomplish to get to a climb gradient or feet/nm...that's the pilot's job...
Either way...the numbers need to be crunched if you are actually doing your job.
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No, FF, you are.
The obstacle clearance surfaces, either Part 77 or ICAO, are analysed for all engine performance. This is all there is, no matter what your performance is, or what you think it is..
This is all there is for a Part 77 certification on a runway.
Get with the program, NOTHING in the procedure design criteria addresses Engine Out, nothing.
If you really think that you have terrain and/or obstacle clearance Engine out based on either ICAO or Partt 77, ...you are fooling yourself.
The obstacle clearance surfaces, either Part 77 or ICAO, are analysed for all engine performance. This is all there is, no matter what your performance is, or what you think it is..
This is all there is for a Part 77 certification on a runway.
Get with the program, NOTHING in the procedure design criteria addresses Engine Out, nothing.
If you really think that you have terrain and/or obstacle clearance Engine out based on either ICAO or Partt 77, ...you are fooling yourself.
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You guys need to look up Part 25 aircraft certification.
You've dug yourselves into a hole if you want the world to believe that you can fly jets without having single engine performance that meets the departure and MAP profile.
And even if your not flying a Part 25 aircraft it's irresponsible to be flying twins with such reckless abandon.
If your gonna fly your twins like a single engine aircraft, you need to be flying single engine aircraft, well actually you shouldn't be flying at all...
You've dug yourselves into a hole if you want the world to believe that you can fly jets without having single engine performance that meets the departure and MAP profile.
And even if your not flying a Part 25 aircraft it's irresponsible to be flying twins with such reckless abandon.
If your gonna fly your twins like a single engine aircraft, you need to be flying single engine aircraft, well actually you shouldn't be flying at all...
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theficklefinger:
I've been around TERPs a bit, Part 25 a bit, and OEI performance engineering a bit.
Your arrogance is only matched by your closed mind.
Best of luck with your operations. You'll need it.
Your flat out wrong ATERP...you need to see how planes are certified...and how instrument approaches are certified...
Your arrogance is only matched by your closed mind.
Best of luck with your operations. You'll need it.