Climb gradient requirement on SID
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Originally Posted by ad319
the company has not bothered to pay for a proper obstacle analysis before starting the route.
Originally Posted by rrat
Perform the EO procedure and routing stored in the secondary flight plan (Air Bus SOP).
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BOAC,
Concur with many of your posts with regards to aviate, and yes, this thread really does appear troubling on many aspects.
There have been many other discussions on pprune regarding OEI procedures and how the criteria and procedures deal with that situation.
EOI in the database? Very, very unlikely.
You will also find, worldwide, a severe lack of obstacles in the survey. Even in the US, the Part 77 surfaces are limited, and there is no proactive effort to gather obstacles. (note that SafeCo Field was built in the flightpath for Boeing Field, and wasnt even lit. It was the Head of the FAA flying in for a meeting, that wondered about this huge dark spot in the middle of the City)
In most other Countries, it is even worse.
Concur with many of your posts with regards to aviate, and yes, this thread really does appear troubling on many aspects.
There have been many other discussions on pprune regarding OEI procedures and how the criteria and procedures deal with that situation.
EOI in the database? Very, very unlikely.
You will also find, worldwide, a severe lack of obstacles in the survey. Even in the US, the Part 77 surfaces are limited, and there is no proactive effort to gather obstacles. (note that SafeCo Field was built in the flightpath for Boeing Field, and wasnt even lit. It was the Head of the FAA flying in for a meeting, that wondered about this huge dark spot in the middle of the City)
In most other Countries, it is even worse.
Last edited by FlightPathOBN; 7th May 2013 at 17:34.
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OBN:
As you certainly know, Part 77 is not designed to provide OEI surfaces. It's up to the operators to provide each runway end OEI survey up to the OEI en route flight path.
Indeed it is as to "normal ops" obstacle data. But, no country has obstacle data for OEI.
You will also find, worldwide, a severe lack of obstacles in the survey. Even in the US, the Part 77 surfaces are limited, and there is no proactive effort to gather obstacles. (note that SafeCo Field was built in the flightpath for Boeing Field, and wasnt even lit. It was the Head of the FAA flying in for a meeting, that wondered about this huge dark spot in the middle of the City)
In most other Countries, it is even worse.
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terpster,
Yes, this is what I meant by Part 77 being limited. Given that this has been discussed ad nauseum on pprune, I didnt even want to get into OEI stuff...
When I said in most Countries, it is even worse, I was referring to virtually ALL obstacle data, not OEI...
Edit: I would add that given the charting standards and adherence to charting standards, I would consider obstacles on a plate as a courtesy, and would absolutely NOT rely on either the lack of obstacles, nor the obstacles shown, to have any relationship to reality.
Yes, this is what I meant by Part 77 being limited. Given that this has been discussed ad nauseum on pprune, I didnt even want to get into OEI stuff...
When I said in most Countries, it is even worse, I was referring to virtually ALL obstacle data, not OEI...
Edit: I would add that given the charting standards and adherence to charting standards, I would consider obstacles on a plate as a courtesy, and would absolutely NOT rely on either the lack of obstacles, nor the obstacles shown, to have any relationship to reality.
Last edited by FlightPathOBN; 7th May 2013 at 21:50.
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IFLY INDIGO
I am sure your operations manual will have something to say on this. Before launching operations from an airfield the company performance engineer using Airbus softwares like PEP or OFP is to ascertain that all these requirements are met. Generally with two engines SID requirements are met. If the gredient is due to terrain issue then OEI perfomance must be checked and OEI SID may have to costructed. There will be company policy on this. If you acedemically want to know then the thumb rules can be used but operationally it is not decision made in the cockpit.
I am sure your operations manual will have something to say on this. Before launching operations from an airfield the company performance engineer using Airbus softwares like PEP or OFP is to ascertain that all these requirements are met. Generally with two engines SID requirements are met. If the gredient is due to terrain issue then OEI perfomance must be checked and OEI SID may have to costructed. There will be company policy on this. If you acedemically want to know then the thumb rules can be used but operationally it is not decision made in the cockpit.
Last edited by vilas; 8th May 2013 at 05:59.
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vilas - see post #20? These 'rules of thumb' are actually useless in this case since they only tell you the required RoC and what is needed is the actual, which is NOT available and is well out of reach of any line pilot until they see it when an engine goes pop - which is a little late if you are then over-weight for the required gradient.
IFLY does NOT need 'Rules of Thumb' - he needs performance charts for each SID at each airfield. a_d319 says they are not available and thus as OBN agrees, OEI procedures will not be adequate.
I find this extremely worrying if true. I am also concerned at the number of questions IFLY has asked (including how to fly a circling approach). It raises questions about the training he/she has received both for licence and type.
IFLY does NOT need 'Rules of Thumb' - he needs performance charts for each SID at each airfield. a_d319 says they are not available and thus as OBN agrees, OEI procedures will not be adequate.
I find this extremely worrying if true. I am also concerned at the number of questions IFLY has asked (including how to fly a circling approach). It raises questions about the training he/she has received both for licence and type.
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I seems there is some misunderstanding here regarding SID climb requirements.
The performance manual from your company will take care of ENGINE OUT climb requirements + a specific procedure to fly in case of an engine failure on that specific SID.
What you see on the SID chart, is a requirement for ALL ENGINES climb gradient, and that is a pilot responsibility to adhere to these. These restrictions are normally due to noise restrictions or for ATC purposes, but can of course also be because of obstacles.
You can NOT use "Rate of Climb thumb rules" here, as you have a segment where you are accelerating.
Instead you need a point, where you have to be at a certain altitude.
You can use this formula :
Required height (ft) = Distance (NM) X (req climb gradient 0,0x) X 6000
Let`s say you need a 4 % climb gradient to 13 NM.
Which altitude at 13 NM ? :
altitude = 13 X 0,04 X 6000
altitude = 3120
3120`
If you do not have a waypoint at 13 NM, create one in your Flightplan and see what altitude the FMS predicts there.
or another example. The SID asks for a 7 % climb gradient to 8000`
At what distance from departure do I need to be at 8000´ ? :
8000 = distance X 0,07 X 6000
8000 = distance X 420
8000/420 = distance
19 NM
again, create a waypoint at 19 NM, and see if the FMS predicts to be at or above 8000`there.
Easy
The performance manual from your company will take care of ENGINE OUT climb requirements + a specific procedure to fly in case of an engine failure on that specific SID.
What you see on the SID chart, is a requirement for ALL ENGINES climb gradient, and that is a pilot responsibility to adhere to these. These restrictions are normally due to noise restrictions or for ATC purposes, but can of course also be because of obstacles.
You can NOT use "Rate of Climb thumb rules" here, as you have a segment where you are accelerating.
Instead you need a point, where you have to be at a certain altitude.
You can use this formula :
Required height (ft) = Distance (NM) X (req climb gradient 0,0x) X 6000
Let`s say you need a 4 % climb gradient to 13 NM.
Which altitude at 13 NM ? :
altitude = 13 X 0,04 X 6000
altitude = 3120
3120`
If you do not have a waypoint at 13 NM, create one in your Flightplan and see what altitude the FMS predicts there.
or another example. The SID asks for a 7 % climb gradient to 8000`
At what distance from departure do I need to be at 8000´ ? :
8000 = distance X 0,07 X 6000
8000 = distance X 420
8000/420 = distance
19 NM
again, create a waypoint at 19 NM, and see if the FMS predicts to be at or above 8000`there.
Easy
Last edited by jaja; 8th May 2013 at 09:18.
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Originally Posted by jaja
The performance manual from your company will take care of ENGINE OUT climb requirements + a specific procedure to fly in case of an engine failure on that specific SID.
While your use of the FMS is good, it does not tell IFLY what RTOW he/she can use on a particular day and SID, does it? By the time the boys and girls get their stickies on the FMS and start making new waypoints the a/c will have been loaded.
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BOAC
Off course you need the correct GMC for your specific RWY of DEP, to satisfy the ENGINE OUT climb requirement. You can NOT calculate that yourself !
My input were for the ALL ENGINE SID climb requirement, which is the responsibility of the pilot to comply with.
Even though many pilots are not aware of that, and do not know how to make that simple calculation, which is very easy and fast to make (even for an old man like me ;-)
Off course you need the correct GMC for your specific RWY of DEP, to satisfy the ENGINE OUT climb requirement. You can NOT calculate that yourself !
My input were for the ALL ENGINE SID climb requirement, which is the responsibility of the pilot to comply with.
Even though many pilots are not aware of that, and do not know how to make that simple calculation, which is very easy and fast to make (even for an old man like me ;-)
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so what's the answer?
So irrespective of what analysis airline has done, there is no way for a pilot to ascertain on the ground (using chart/table) that he would be meet the climb gradient requirement of SID? experience or FMGS prediction (magenta/amber as suggested by rudderrudderrat) is the only way out?
using the formula GS * % climb gradient, does not sound the right way to ascertain the climb performance on ground. it doesn't include the available thrust, OAT, PA, actual takeoff weight in the calculation, which my common sense tells should be the part of calculation. After all, we can be flying level with any of the GS mentioned on the chart!
using the formula GS * % climb gradient, does not sound the right way to ascertain the climb performance on ground. it doesn't include the available thrust, OAT, PA, actual takeoff weight in the calculation, which my common sense tells should be the part of calculation. After all, we can be flying level with any of the GS mentioned on the chart!
Last edited by IFLY_INDIGO; 8th May 2013 at 10:48.
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Unless there are particular obstacle problems on a particular SID, you can pretty well assume that as long as you are below WAT limits you will achieve normal climb gradients on all engines. It is engine out that is the governing consideration for which you need an airfield analysis.
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A climb gradient requirement is not the same as an altitude restriction at a certain point. When the chart says that a 7 % climb gradient is required up to 7000, that means that you should stay above this slope all the time! Theoretically it could be that you make the restriction at 7000 ft with more then a 7 % average climb rate, BUT you might have gone below the required slope during the acceleration phase to get your flaps up.
So, as I said in my previous post: "In case of doubt when in IMC or by night, you can consider delaying the acceleration and flap retraction until out of the restricting altitude"
So, as I said in my previous post: "In case of doubt when in IMC or by night, you can consider delaying the acceleration and flap retraction until out of the restricting altitude"
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no restricting altitude
There was no restricting altitude in my original post. I am referring to few RNAV SIDs of VABB and VIDP. only climb gradient requirement is mentioned.
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IFLY_INDIGO
We are talking about two things here.
Engine failure
Your company Performance Manual will (hopefully) have a correct calculated max T/O Mass for each RWY you are flying from. This gives you the max T/O Mass + procedure, so you will able to safely fly up to a safe altitude in case of an engine failure = it keeps you away from obstacles
All engine T/O
Here you as a pilot have to calculate and comply with the restriction laid out in the SID. These restrictions can be due to noise restriction, ATC or obstacles. Use the formula I wrote earlier.
You can NOT do what "rudderrudderrat" wrote earlier :
"Your NAV display with Constraints will show the ALT required in magenta to make the required gradient. If they appear in amber, then you will need to speed intervene / delay acceleration etc."
because very often these restrictions are not in your FMS as a waypoint/restriction.
We are talking about two things here.
Engine failure
Your company Performance Manual will (hopefully) have a correct calculated max T/O Mass for each RWY you are flying from. This gives you the max T/O Mass + procedure, so you will able to safely fly up to a safe altitude in case of an engine failure = it keeps you away from obstacles
All engine T/O
Here you as a pilot have to calculate and comply with the restriction laid out in the SID. These restrictions can be due to noise restriction, ATC or obstacles. Use the formula I wrote earlier.
You can NOT do what "rudderrudderrat" wrote earlier :
"Your NAV display with Constraints will show the ALT required in magenta to make the required gradient. If they appear in amber, then you will need to speed intervene / delay acceleration etc."
because very often these restrictions are not in your FMS as a waypoint/restriction.
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climb angle?
Jaja, your method is good. I have noted it down to try.
7% climb gradient turns out to be 3.99 deg of climb angle. of course, we can use FPV one side to be ascertain that we are meeting the requirement, but that is only possible in-flight.
7% climb gradient turns out to be 3.99 deg of climb angle. of course, we can use FPV one side to be ascertain that we are meeting the requirement, but that is only possible in-flight.
Last edited by IFLY_INDIGO; 8th May 2013 at 11:07.
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BOAC
Not to be personal, but considering your post # 7 talking down to AIRBUS pilots, and now # 33, there is no such thing for a professional pilot as to "ASSUME" in cases like these ;-)
BOAC : "you can pretty well assume"
rudderrudderrat
Quote:
"because very often these restrictions are not in your FMS as a waypoint/restriction.
Then insert a "+ALT" restriction"
That is also what I wrote earlier, but you have to make the calculation first, and then create a waypoint.
Sabenaboy
You can NOT just delay the acceleration fase. In your Performance Manual you have a Maximum Acceleration Height (this is to complete the 3rd segment before end of the 10 minute T/O thrust limit). I think also you are mixing things up. Your example with a 7 % climb requirement, is an AVERAGE of 7 %, so it CAN include the acceleration fase. Read the previous posts again, and you will see we are talking about two different things here ;-)
Not to be personal, but considering your post # 7 talking down to AIRBUS pilots, and now # 33, there is no such thing for a professional pilot as to "ASSUME" in cases like these ;-)
BOAC : "you can pretty well assume"
rudderrudderrat
Quote:
"because very often these restrictions are not in your FMS as a waypoint/restriction.
Then insert a "+ALT" restriction"
That is also what I wrote earlier, but you have to make the calculation first, and then create a waypoint.
Sabenaboy
You can NOT just delay the acceleration fase. In your Performance Manual you have a Maximum Acceleration Height (this is to complete the 3rd segment before end of the 10 minute T/O thrust limit). I think also you are mixing things up. Your example with a 7 % climb requirement, is an AVERAGE of 7 %, so it CAN include the acceleration fase. Read the previous posts again, and you will see we are talking about two different things here ;-)
Last edited by jaja; 8th May 2013 at 11:22.
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Originally Posted by jaja
Not to be personal, but considering your post # 7 talking down to AIRBUS pilots, and now # 33, there is no such thing for a professional pilot as to "ASSUME" in cases like these ;-)
Regarding 'assume', I take it you still have not looked at #20? I recommend you do soonest. How else can +IFLY work it out? Any ideas? (non-type-specific, of course
)