Climb gradient requirement on SID
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Jaja,
We're not talking about one engine out situation phase and it's phases. And I didn't talk about delaying thrust reduction. Just saying that in a normal climb-out, you could delay the accelerating needed to retract the flaps.
Also the SID IFLY_INDIGO mentioned does not mention the word average. If I were to depart from an unfamiliar airport in mountainous area In IMC with a sid mentioning a required climb gradient of 7 %, I would make sure to stay above the required slope all the time!
Of course, by day in CAVOK or at an airport I know, I'd be happy to retract the flaps as per SOP.
We're not talking about one engine out situation phase and it's phases. And I didn't talk about delaying thrust reduction. Just saying that in a normal climb-out, you could delay the accelerating needed to retract the flaps.
Also the SID IFLY_INDIGO mentioned does not mention the word average. If I were to depart from an unfamiliar airport in mountainous area In IMC with a sid mentioning a required climb gradient of 7 %, I would make sure to stay above the required slope all the time!
Of course, by day in CAVOK or at an airport I know, I'd be happy to retract the flaps as per SOP.
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IFLY_INDIGO,
I've just had a look at some VIDP and VABB charts.
At VIDP I found several Rnav SIDs requiring a 7 % climb gradient uo to 3600' (Alija, Bipan, Hinda etc) Our VIDP company charts (LIDO) all show a table with required V/S versus groundspeed.
Now if you're asking, if somewhere in the FCOM, you will find the answer to the question as to whether you'll be able to get that V/S in specific conditions, the answer is no. If you're looking for a practical answer to the question my reply is: don't worry, even at MTOW in hot conditions, you'll make it! (assuming thrust reduction at 1500' AGL and acceleration at 3000' AGL)
I've just had a look at some VIDP and VABB charts.
At VIDP I found several Rnav SIDs requiring a 7 % climb gradient uo to 3600' (Alija, Bipan, Hinda etc) Our VIDP company charts (LIDO) all show a table with required V/S versus groundspeed.
Now if you're asking, if somewhere in the FCOM, you will find the answer to the question as to whether you'll be able to get that V/S in specific conditions, the answer is no. If you're looking for a practical answer to the question my reply is: don't worry, even at MTOW in hot conditions, you'll make it! (assuming thrust reduction at 1500' AGL and acceleration at 3000' AGL)
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Vilas,
IndiGo use PEP, (version 5.3 if you want specifics!) However, PEP is only as good as the data you enter into it. The surveys that have been (or have not been conducted) at some of the IGO destinations is the problem.
Just look back a few years to the NE when they were departing from certain airports with no obstacle data... The answer given was it wasn't published.
As has been said on here many times before - a simple ICAO obstacle chart is not always enough.
Also, for reasons unknown (cost) IGO won't have the EO procedures coded into the navigation database.
It used to amaze me to see the guys diligently calculating the speeds and FLEX
for an airport where the airline had not conducted a survey! Those numbers then become meaningless!
IndiGo use PEP, (version 5.3 if you want specifics!) However, PEP is only as good as the data you enter into it. The surveys that have been (or have not been conducted) at some of the IGO destinations is the problem.
Just look back a few years to the NE when they were departing from certain airports with no obstacle data... The answer given was it wasn't published.
As has been said on here many times before - a simple ICAO obstacle chart is not always enough.
Also, for reasons unknown (cost) IGO won't have the EO procedures coded into the navigation database.
It used to amaze me to see the guys diligently calculating the speeds and FLEX
for an airport where the airline had not conducted a survey! Those numbers then become meaningless!
Beau_Peep
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question arises, why airbus could not provide any chart/table that could state the possible climb gradient in various conditions, all engine/single engine? what is the difficulty in designing such a chart? too many variables? lets consider what all factors, climb angle depends upon. IAS, weight, OAT, PA, tailwind/headwind. One thing I noticed is that varying IAS during takeoff climb and acceleration would make it difficult to publish a single climb angle figure. Also the changes in the wind direction from ground above would also make it impossible to state a single climb angle.
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Hi IFLY_INDIGO,
Do you mean like the charts contained in:
Performance, Take Off, Take Off Data, 50 Net Take Off Path, Close and Remote obstacle clearance for all the take off flap settings, showing the climb gradient V the take off weight?
Do you actually read your manuals?
why airbus could not provide any chart/table that could state the possible climb gradient in various conditions, all engine/single engine?
Performance, Take Off, Take Off Data, 50 Net Take Off Path, Close and Remote obstacle clearance for all the take off flap settings, showing the climb gradient V the take off weight?
Do you actually read your manuals?
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Well I guess the Quote feature doesn't work. From another member -
'Anyone else concerned a pilot flying an A320 is only just learning about this now?'
-----------------------
I stopped railing about this a while back. Let the planes crash. If the chief pilots don't care, The FAA doesn't care, the passengers don't care, the insurance companies don't care, the pilots don't care, the forum membership doesn't care then it's an industry of hucksters pretending to be concerned about safety and professionalism.
'Anyone else concerned a pilot flying an A320 is only just learning about this now?'
-----------------------
I stopped railing about this a while back. Let the planes crash. If the chief pilots don't care, The FAA doesn't care, the passengers don't care, the insurance companies don't care, the pilots don't care, the forum membership doesn't care then it's an industry of hucksters pretending to be concerned about safety and professionalism.
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IFLY INDIGO
What you are asking has so many variables. No manufacturere gives charts for all contigencies.That is why Airbus has software programmes like LPC. PEP, TLO, ADAS etc. where you can put in the factors affecting the performance and you get the answer. Your company ops executives will have entry to Airbus world website. Read 17th Performance and Operations conference Dubai you will get all your answers. I cannot produce it here.All i can say is SID gradient by definition average gradient and with all engines at TOW of 77000 from sea level you will get above 7.5 upto 5000ft.in flex of 40or 50 degrees.
What you are asking has so many variables. No manufacturere gives charts for all contigencies.That is why Airbus has software programmes like LPC. PEP, TLO, ADAS etc. where you can put in the factors affecting the performance and you get the answer. Your company ops executives will have entry to Airbus world website. Read 17th Performance and Operations conference Dubai you will get all your answers. I cannot produce it here.All i can say is SID gradient by definition average gradient and with all engines at TOW of 77000 from sea level you will get above 7.5 upto 5000ft.in flex of 40or 50 degrees.
Last edited by vilas; 8th May 2013 at 16:20.
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Originally Posted by Vilas
All i can say is SID gradient by definition average gradient
I see the required climb gradient as an imaginary steady climb path that you should always stay above.
I will be glad to stand corrected, but I want to see an official reference.
edited for spelling
Last edited by sabenaboy; 8th May 2013 at 16:37.
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EO procedures are not cheap to design.
The SID OIS surface begins at the end of the runway, goes out for 10,200 feet at a 40:1 slope, with ICAO being the same 2.5% for 2nm. This is the limit of the area surveyed for obstacles. Remember, this is the OIS, NOT the re'd min climb gradient of 3.3% If there is an obstacle in the OIS, then the required climb gradient is raised from the min 3.3%
The aircraft performance is a significant issue in the procedure design and configuration. There are usually many iterations of the procedure, especially if there are turns, as those factor heavily in the EO climb.
Once the desktop SIM has been run, using terrain and available obstacles, an obstacle field assessment must be done. This will be done along the flightpath and as wide as the procedure containment area. All obstacles found are loaded into the procedure, and it is run again, and more often than not, there is a new controlling obstacle.
After all of this has been approved, a flight validation is required with the same aircraft type as the procedure is designed for. This brings up another expensive issue, EO procedures are per aircraft type and even aircraft/engine type. (unless you want to limit the entire class, such as 737NG to the lowest common (worst case) scenario. This is why there are no public EO procedures.
Most Countries do not even maintain obstacle databases, the obstacle standards vary, as does the foundation of the datum. AIP information is hit/miss. New airports seldom have any data. (especially in China)
The SID OIS surface begins at the end of the runway, goes out for 10,200 feet at a 40:1 slope, with ICAO being the same 2.5% for 2nm. This is the limit of the area surveyed for obstacles. Remember, this is the OIS, NOT the re'd min climb gradient of 3.3% If there is an obstacle in the OIS, then the required climb gradient is raised from the min 3.3%
The aircraft performance is a significant issue in the procedure design and configuration. There are usually many iterations of the procedure, especially if there are turns, as those factor heavily in the EO climb.
Once the desktop SIM has been run, using terrain and available obstacles, an obstacle field assessment must be done. This will be done along the flightpath and as wide as the procedure containment area. All obstacles found are loaded into the procedure, and it is run again, and more often than not, there is a new controlling obstacle.
After all of this has been approved, a flight validation is required with the same aircraft type as the procedure is designed for. This brings up another expensive issue, EO procedures are per aircraft type and even aircraft/engine type. (unless you want to limit the entire class, such as 737NG to the lowest common (worst case) scenario. This is why there are no public EO procedures.
Most Countries do not even maintain obstacle databases, the obstacle standards vary, as does the foundation of the datum. AIP information is hit/miss. New airports seldom have any data. (especially in China)
Last edited by FlightPathOBN; 8th May 2013 at 17:59.
I see the required climb gradient as an imaginary steady climb path that you should always stay above.
I will be glad to stand corrected, but I want to see an official reference.
I will be glad to stand corrected, but I want to see an official reference.
In my semijet we can't always make the SID climb gradients AEO and just have to use experience and common sense to decide whether we can accept a particular SID or not. If there is no alternative radar SID we might have to request a waver on the height requirements (obviously not an option if it is due terrain.)
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Originally Posted by Vilas
It is mentioned in the same presentation which I have referred.
A quote from an official document including chapter + paragraph, perhaps?
A link to it?
Vilas, all the documents I have seen, including "getting to grips with aircraft performance" show climb gradient requirements as a CONSTANT flight path, not an average one over a certain distance.
So a "7 % climb gradient to 3600 ft" is NOT the same as "cross 8,465 DME at 3600 ft or above" (= average climb gradient of 7 %)
Once again: I do not mind to be corrected on this, but until you come up with a verifiable trustworthy source I respectfully dare to say that you are just wrong!
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sabenaboy
Am I right or wrong is not important. What I quoted is from Airbus 17th Performance and operations conference Dubai. Climb gradient varies from when you put the gear up to thrust reduction, after thrust reduction to acceleration point, and where you reach 250 kts. On a graph of altitude vs diastance if you draw lines from origin to these points, there will be three gradients. Average of these gradients is the climb gradient. You can read it for yourself. If you differ from Airbus you can send them a query. This is not same as missed approach gradient. Missed approach gradient is not average gradient but the minimum gradient upto the limiting obstacle, a plane below which it is forbidden to fly. This is also given in a presentation on Go around. I said SID gradient in the original post I stand corrected I am talking about all engine climb gradient.
Am I right or wrong is not important. What I quoted is from Airbus 17th Performance and operations conference Dubai. Climb gradient varies from when you put the gear up to thrust reduction, after thrust reduction to acceleration point, and where you reach 250 kts. On a graph of altitude vs diastance if you draw lines from origin to these points, there will be three gradients. Average of these gradients is the climb gradient. You can read it for yourself. If you differ from Airbus you can send them a query. This is not same as missed approach gradient. Missed approach gradient is not average gradient but the minimum gradient upto the limiting obstacle, a plane below which it is forbidden to fly. This is also given in a presentation on Go around. I said SID gradient in the original post I stand corrected I am talking about all engine climb gradient.
Last edited by vilas; 9th May 2013 at 13:59.
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It's not that difficult.
Pans ops has the details and it's free to download.
SIDs are predicated on a 3.3% gradient. This is based on 2.5% OIS + .8% for error.
If during the survey an obstacle penetrates the 2.5% gradient the the gradient required to that obstacle is calculated and .8% is added. This gradient is then stated on the SID i.e. 7% required until 3000'. above that height then 3.3% is assumed.
SIDs are written for AEO and it's up to the operator to come up with a OEI procedure.
OEI gradients are published in the AFM. (Some also include AEO gradients)
If you don't have AEO look at the OEI gradient and if it's above the SID gradient or 3.3% if no gradient is stated then it's safe to fly the SID with or without an engine failure.
If it's less than the stated gradient and no company OEI SID is published or you don't have AEO gradient data call your chief pilot and ask him to provide the required data to safely operate.
Pans ops has the details and it's free to download.
SIDs are predicated on a 3.3% gradient. This is based on 2.5% OIS + .8% for error.
If during the survey an obstacle penetrates the 2.5% gradient the the gradient required to that obstacle is calculated and .8% is added. This gradient is then stated on the SID i.e. 7% required until 3000'. above that height then 3.3% is assumed.
SIDs are written for AEO and it's up to the operator to come up with a OEI procedure.
OEI gradients are published in the AFM. (Some also include AEO gradients)
If you don't have AEO look at the OEI gradient and if it's above the SID gradient or 3.3% if no gradient is stated then it's safe to fly the SID with or without an engine failure.
If it's less than the stated gradient and no company OEI SID is published or you don't have AEO gradient data call your chief pilot and ask him to provide the required data to safely operate.
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This is how climb gradients for missed approaches and SIDs are calculated in the U.S.
https://www.dropbox.com/s/welgvm6j8u...ia.pdf?v=0mcng
https://www.dropbox.com/s/welgvm6j8u...ia.pdf?v=0mcng
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Originally Posted by Vilas
Am I right or wrong is not important.
Originally Posted by Vilas
You can read it for yourself.
That's just the problem! You keep talking about something you (think) you heard or read about in a conference in Dubai. I think you're misinterpreting something you heard or read! When I read that a SID requires a 7 % climb gradient up to 3600 ft, I am pretty sure that means that you're NOT supposed to go below a 7 % imaginary slope extending up from the runway end up to an altitude of 3600 ft.
So, once again, please provide a link (URL or document with chapter, paragraph or page) to what you're saying so that I CAN read it for myself. I'm not happy with a statement such as "that what has been said at certain conference somewhere...
"
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sabenaboy:
There shouldn't be an iota of doubt in your mind.
When I read that a SID requires a 7 % climb gradient up to 3600 ft, I am pretty sure that means that you're NOT supposed to go below a 7 % imaginary slope extending up from the runway end up to an altitude of 3600.
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Sabenaboy
I have made a correction to my statement. I am talking about definition of all engine climb gradient. In the original post wrote SID gradient by mistake. That caused the confusion. Sorry about that.
I have made a correction to my statement. I am talking about definition of all engine climb gradient. In the original post wrote SID gradient by mistake. That caused the confusion. Sorry about that.