How to know if you can make required climb gradient?
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Each aircraft has a different weight/CG, performance factor due to aging etc. and also different engine models some time.
These tables are for:
ALL ENG.OPERATIVE, Thrust Rating: Max.Climb, A/C ON, A/I OFF, Landing Gear Retracted, climb at given CAS/Mach
You have different ISA conditions, speeds, weights and altitudes so that you can figure out your gradient moe accurately.
Hope it helped.
These tables are for:
ALL ENG.OPERATIVE, Thrust Rating: Max.Climb, A/C ON, A/I OFF, Landing Gear Retracted, climb at given CAS/Mach
You have different ISA conditions, speeds, weights and altitudes so that you can figure out your gradient moe accurately.
Hope it helped.
Last edited by guclu; 31st Oct 2012 at 19:56.
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Climb Performance
I really can't believe that some of you guys are airline pilots and don't know squat about your aircraft's climb gradients. Are you guys relying solely on your performance department? It doesn't give me a warm feeling about sometimes riding in the back of the tube. If you accept a SID that has a specific climb gradient: 1, yes you better know that your aircraft can meet that gradient if you are IMC (in VMC you can maintain obstacle clearance visually); 2, you better make sure that the aircraft can do this with OEI (one engine inoperative). You can not rely on the FMS predictive altitudes because those are for all engines operating (yes you can go into the performance page and manually input feet/NM up to the charts specified obstacle clearance safe altitude). These charts are in your aircraft's performance manual and will give the gradient your aircraft can climb: OEI, OAT, at that airport altitude, to the minimum safe obstacle clearance altitude, with a given weight, with specific flap settings. Please be aware that these charts exist. If you fly to the same airports day in and day out you may never need to look at them. But it you find yourself on a charter one day and ATC issues a SID that your "performance department" didn't expect, or an obstruction has cropped up overnight (building crane, etc...) you better know and not guess that your aircraft can maintain the gradient before you accept the SID.
Last edited by g450cpt; 1st Nov 2012 at 03:15.
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g450cpt
Let's begin by examining some authoritative references.
By all means, feel free to cite your own.
FAA AIM 5-2-8:
FAA AC 120-91:
The AC is quite clear -- Thus, one-engine-inoperative obstacle clearance requirements and the all-engines-operating TERPS requirements are independent, and one- engine-inoperative procedures do not need to meet TERPS requirements.
`
Without a performance engineering analysis, how would you determine the maximum allowable takeoff weight for your G450 (if that is indeed your current ride) at KLAS:
350'/nm to 11,000 MSL.
Per the AC, "...any gradient requirement, specified or unspecified, will be treated as a plane which must not be penetrated from above until reaching the stated height, rather than as a gradient which must be exceeded at all points in the path."
If you are going to insist that it's necessary to fly the COWBY4 with OEI -- and without using a performance engineering analysis:
I really can't believe...
By all means, feel free to cite your own.
FAA AIM 5-2-8:
FAA AC 120-91:
The AC is quite clear -- Thus, one-engine-inoperative obstacle clearance requirements and the all-engines-operating TERPS requirements are independent, and one- engine-inoperative procedures do not need to meet TERPS requirements.
`
Without a performance engineering analysis, how would you determine the maximum allowable takeoff weight for your G450 (if that is indeed your current ride) at KLAS:
350'/nm to 11,000 MSL.
Per the AC, "...any gradient requirement, specified or unspecified, will be treated as a plane which must not be penetrated from above until reaching the stated height, rather than as a gradient which must be exceeded at all points in the path."
If you are going to insist that it's necessary to fly the COWBY4 with OEI -- and without using a performance engineering analysis:
- How would you calculate the correct acceleration height and know with certainty that the airplane would not penetrate the plane from above?
- How would you propose to comply with time limits on takeoff thrust?
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aeroncaman:
No pilot can decide that for OEI without very specific information provided to him by his performance and engineering department for that exact SID.
Not an airbus pilot. However the information must be there in one form or another. Being able to determine a climb gradient is a fundamental part of performance planning.
Zeffy, best you know whether you can make the SID OEI, otherwise you need a contingency plan(emergency turn).
Zeffy, best you know whether you can make the SID OEI, otherwise you need a contingency plan(emergency turn).
Last edited by aterpster; 1st Nov 2012 at 13:06.
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zeffy:
That is the "baseline" maximum climb gradient. Proposed gradients in excess of 500'/nm must be submitted by the FAA's procedures design office to Flight Standard's Performance Review Board. That Board has a giant rubber stamp that says, "Approved, the Skies the Limit." (ala KTVL Runway 18, et al.)
In the USA, the maximum climb gradient for ODP's/SID's is only 500'/nm -- typically not a problem for jets.
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aeroncaman
Mostly agree, however...
Pilots do not have all of the obstacle data required to perform their own analyses.
For example SID gradients do not include consideration of low, close-in obstacles which may become very significant in OEI situations.
The notes accompanying the COWBY4 contain a listing of groups of obstacles, but these are not specified with sufficient precision for a pilot to make her/his own calculations.
As you say, the pilot MUST know whether or not it is possible to remain on the SID, but the answer has to come from a performance engineering entity that has access to the requisite obstacle surveys.
As pilots we must have that information so that we know whether we can stay with the SID or need to take up the emergency turn/contingency procedure.
It either needs to come from the manuals (which it has done in the aircraft I have flown), or be provided in the form of performance analyses from commercial companies or airline performance planning departments.
It either needs to come from the manuals (which it has done in the aircraft I have flown), or be provided in the form of performance analyses from commercial companies or airline performance planning departments.
Mostly agree, however...
Pilots do not have all of the obstacle data required to perform their own analyses.
For example SID gradients do not include consideration of low, close-in obstacles which may become very significant in OEI situations.
The notes accompanying the COWBY4 contain a listing of groups of obstacles, but these are not specified with sufficient precision for a pilot to make her/his own calculations.
As you say, the pilot MUST know whether or not it is possible to remain on the SID, but the answer has to come from a performance engineering entity that has access to the requisite obstacle surveys.
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To G450CPT, Aeroncaman, Zeffy, and aterpster...
Whether it is TERPS or PANS-OPS, IFR departure procedures are developed based on normal airplane operation and performance. Contingency procedures addressing engine failure and non-normal operations are addressed outside of these criteria. It states this fact this both documents. The FAA has stated the same in AC 120-91 and now again in a new series of performance planning videos that will be made available soon.
The 1st and 2nd segment OEI climb gradient data provided in the AFM does not allow for independent assessment of obstacle clearance without application with the close-in and distance takeoff flight path/obstacle clearance charts that are also published in the AFM. Only in the case of the final segment OEI climb gradient may a “rise v. run” analysis of obstacle clearance be accomplished. The reason for this are many, but they were eloquently explained by Mr. Rob Root from Boeing’s performance engineering & operations training group at this week’s Transport Airplane Performance Planning Working Group’s workshop at the NBAA 2012 convention. Simply put, limiting the takeoff weight to that which allows an OEI climb gradient (e.g. OEI 2nd segment) to meet or exceed the SID climb gradient is not an acceptable solution to the OEI takeoff obstacle analysis.
The OEI takeoff climb gradient and OEI flight path performance data that is published in the AFM is used for the takeoff obstacle avoidance analysis required by 121.189(d) and 135.379(d), respectively. The procedure used to conduct this analysis is contained in AC 120-91. This OEI takeoff obstacle avoidance analysis is not a pilot function. The FAA fully expects this analysis to be performed by a trained performance engineer or furnished through a performance engineer services provider, both of which should have the requisite training and airport & obstacle data resources to complete this analysis. FAA has now stated this fact in the previously mentioned videos.
One more item, the OEI takeoff obstacle clearance requirements for US part 121 and part 135 operators applies to any takeoff regardless of whether the conditions are IMC or VMC, or the whether the airplane is operating under instrument flight rules (IFR) or visual flight rules (VFR). OEI visual obstacle avoidance is permitted under the limitations prescribed in AC 120-91, which typically requires that the operator identify the critical obstacle(s) to be avoided and provide any instructions that are to be used in the event of an engine failure. It is not acceptable to just say, “since it’s VMC, we will just see and avoid any obstacles after an engine failure”.
Regarding compliance with a SID climb gradient, there is not an easy question to answer. Depending on the aircraft manufacturer, all-engine-operating (AEO) climb performance data may be available. However, this AEO climb data is not simply a “climb gradient”. Rather, there is an AEO flight path that must be assessed. To illustrate what this AEO path might look like we can say that the climb profile begins with a V2+10 climb to 1000’ AAE followed by an acceleration to 250 KIAS at a nominal rate of climb (e.g. 500 FPM). The profile continues at climb speed of 250 KIAS to 10,000 ft. MSL. During this segment of the profile, the data must account for climb degradations resulting from thrust lapse rate and TAS increase. Once above 10,000 ft., the climb speed increases to enroute climb speed, which for many airplanes using COST INDEX will be a variable speed as altitude increases. The same climb degradations must be considered in the climb above 10,000 ft. The entire profile must also account for wind factors, which may switch around 180 degrees or more in the climb out.
So as you can see, the AEO climb profile does not equate to the constant “gradient” the presented on the SID chart. Only very sophisticated programs, for example Boeing’s Climb Out Program, are capable of analyzing the AEO climb profile against a SID climb gradient requirement. Many airlines use the BCOP and Airbus’s equivalent tool to assess SIDs at various airports. The output of these programs may furnish weight limits to the crew for various conditions or the airline’s engineering department may run the analysis for a wide-ranging set of variables for their fleet to see if there are any AEO performance issues with a particular SID. If performance issues arise, they will address them at time of dispatch or will simply not allow permit their pilots to use the SID. In some cases, they will remove the SID for the nav-database.
Even with the FAA review of SID climb gradients greater than 500’/NM, there still can be performance issues with some transport airplanes. FAA has reported issues with A340s on SIDs at DFW and PHX and with A319s at PHL in meeting the altitude restrictions published on SIDs and ergo, the AEO climb gradient since these gradients were established to meet these ATC –required altitude restrictions. No offense to Airbus airplanes.
For those airplanes without performance tools like the BCOP, it really comes down to your knowledge of the airplane’s capabilities and your best estimate of whether you can make the climb gradient that published on the SID. The OEI case is different since as part 121 or part 135 operator, the pilot/operator must depart with an established takeoff obstacle avoidance procedure. That procedure may follow the SID’s track or may differ.
For US pilots, the FAA will be providing additional information to pilots and operators on this subject. The information will be available from the FAA website and from other websites. More to come soon.
Best regards,
Rich Boll
Co-Chair, Transport Airplane Performance Planning Working Group.
Whether it is TERPS or PANS-OPS, IFR departure procedures are developed based on normal airplane operation and performance. Contingency procedures addressing engine failure and non-normal operations are addressed outside of these criteria. It states this fact this both documents. The FAA has stated the same in AC 120-91 and now again in a new series of performance planning videos that will be made available soon.
The 1st and 2nd segment OEI climb gradient data provided in the AFM does not allow for independent assessment of obstacle clearance without application with the close-in and distance takeoff flight path/obstacle clearance charts that are also published in the AFM. Only in the case of the final segment OEI climb gradient may a “rise v. run” analysis of obstacle clearance be accomplished. The reason for this are many, but they were eloquently explained by Mr. Rob Root from Boeing’s performance engineering & operations training group at this week’s Transport Airplane Performance Planning Working Group’s workshop at the NBAA 2012 convention. Simply put, limiting the takeoff weight to that which allows an OEI climb gradient (e.g. OEI 2nd segment) to meet or exceed the SID climb gradient is not an acceptable solution to the OEI takeoff obstacle analysis.
The OEI takeoff climb gradient and OEI flight path performance data that is published in the AFM is used for the takeoff obstacle avoidance analysis required by 121.189(d) and 135.379(d), respectively. The procedure used to conduct this analysis is contained in AC 120-91. This OEI takeoff obstacle avoidance analysis is not a pilot function. The FAA fully expects this analysis to be performed by a trained performance engineer or furnished through a performance engineer services provider, both of which should have the requisite training and airport & obstacle data resources to complete this analysis. FAA has now stated this fact in the previously mentioned videos.
One more item, the OEI takeoff obstacle clearance requirements for US part 121 and part 135 operators applies to any takeoff regardless of whether the conditions are IMC or VMC, or the whether the airplane is operating under instrument flight rules (IFR) or visual flight rules (VFR). OEI visual obstacle avoidance is permitted under the limitations prescribed in AC 120-91, which typically requires that the operator identify the critical obstacle(s) to be avoided and provide any instructions that are to be used in the event of an engine failure. It is not acceptable to just say, “since it’s VMC, we will just see and avoid any obstacles after an engine failure”.
Regarding compliance with a SID climb gradient, there is not an easy question to answer. Depending on the aircraft manufacturer, all-engine-operating (AEO) climb performance data may be available. However, this AEO climb data is not simply a “climb gradient”. Rather, there is an AEO flight path that must be assessed. To illustrate what this AEO path might look like we can say that the climb profile begins with a V2+10 climb to 1000’ AAE followed by an acceleration to 250 KIAS at a nominal rate of climb (e.g. 500 FPM). The profile continues at climb speed of 250 KIAS to 10,000 ft. MSL. During this segment of the profile, the data must account for climb degradations resulting from thrust lapse rate and TAS increase. Once above 10,000 ft., the climb speed increases to enroute climb speed, which for many airplanes using COST INDEX will be a variable speed as altitude increases. The same climb degradations must be considered in the climb above 10,000 ft. The entire profile must also account for wind factors, which may switch around 180 degrees or more in the climb out.
So as you can see, the AEO climb profile does not equate to the constant “gradient” the presented on the SID chart. Only very sophisticated programs, for example Boeing’s Climb Out Program, are capable of analyzing the AEO climb profile against a SID climb gradient requirement. Many airlines use the BCOP and Airbus’s equivalent tool to assess SIDs at various airports. The output of these programs may furnish weight limits to the crew for various conditions or the airline’s engineering department may run the analysis for a wide-ranging set of variables for their fleet to see if there are any AEO performance issues with a particular SID. If performance issues arise, they will address them at time of dispatch or will simply not allow permit their pilots to use the SID. In some cases, they will remove the SID for the nav-database.
Even with the FAA review of SID climb gradients greater than 500’/NM, there still can be performance issues with some transport airplanes. FAA has reported issues with A340s on SIDs at DFW and PHX and with A319s at PHL in meeting the altitude restrictions published on SIDs and ergo, the AEO climb gradient since these gradients were established to meet these ATC –required altitude restrictions. No offense to Airbus airplanes.
For those airplanes without performance tools like the BCOP, it really comes down to your knowledge of the airplane’s capabilities and your best estimate of whether you can make the climb gradient that published on the SID. The OEI case is different since as part 121 or part 135 operator, the pilot/operator must depart with an established takeoff obstacle avoidance procedure. That procedure may follow the SID’s track or may differ.
For US pilots, the FAA will be providing additional information to pilots and operators on this subject. The information will be available from the FAA website and from other websites. More to come soon.
Best regards,
Rich Boll
Co-Chair, Transport Airplane Performance Planning Working Group.
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Awroncaman:
I presume that means you agree with my Post #30 to you.
As pilots we musthave that information so that we know whether we can stay with the SID or needto take up the emergency turn/contingency procedure.
It either needs to come from the manuals (which it has done in the aircraft Ihave flown), or be provided in the form of performance analyses from commercialcompanies or airline performance planning departments.
Scheduled performance, be it JAR 25 or FAR 25, enables one to define theability of the aircraft throughout all stages of flight, in black and white andnumerical terms. In a court of law a lawyer could ask the operator todemonstrate the complete performance calculation. A wet finger in the wind orblind hope is not what the travelling public want to hear!
Scheduled performance, be it JAR 25 or FAR 25, enables one to define theability of the aircraft throughout all stages of flight, in black and white andnumerical terms. In a court of law a lawyer could ask the operator todemonstrate the complete performance calculation. A wet finger in the wind orblind hope is not what the travelling public want to hear!
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Climb Performance
@Zeffy
Yes it is indeed the aircraft I am currently flying. And yes, before I accept a SID that requires a specific climb gradient I look at my performance charts which tell me at what weight I can take off on that day at that airport and meet that climb gradient with OEI. And yes it takes into account the 10 minutes max at TOGA on the operating engine(s). I don't want to sit here and argue whether Terps is AEO, because that is not what I meant in my previous post. All I am saying is that if you accept a SID and there are obstacles that you need to avoid and you enter IMC then you lose an engine, your aircraft better be able to meet that SID gradient or you may find yourself face to face with a piece of granite. I'm not sure what kind of corporate flying you did before you retired but I know my principles don't want me "rolling the dice" and hoping we don't have an engine failure after V1 in mountainous terrain and can't avoid the "obstacle".
Yes it is indeed the aircraft I am currently flying. And yes, before I accept a SID that requires a specific climb gradient I look at my performance charts which tell me at what weight I can take off on that day at that airport and meet that climb gradient with OEI. And yes it takes into account the 10 minutes max at TOGA on the operating engine(s). I don't want to sit here and argue whether Terps is AEO, because that is not what I meant in my previous post. All I am saying is that if you accept a SID and there are obstacles that you need to avoid and you enter IMC then you lose an engine, your aircraft better be able to meet that SID gradient or you may find yourself face to face with a piece of granite. I'm not sure what kind of corporate flying you did before you retired but I know my principles don't want me "rolling the dice" and hoping we don't have an engine failure after V1 in mountainous terrain and can't avoid the "obstacle".
Last edited by g450cpt; 2nd Nov 2012 at 03:16.
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g450cpt:
TERPS presumes all engines operating.
The problem with an assessment of a SID by other than a professional engineering department is two-fold:
1. Ths SID requires a constant gradient (slope) to a specified altitude, the Part 25 OEI takeoff flight path requires a clean-up segment, which may or may not "bump" into the SID's constant slope.
2. The SID's lateral airspace splays to an area wider than required by AC120-91, which invokes an unneccsary, sometime onnerous penality with OEI and by using a SID rather than a special OEI procedure. Then, in other cases the SID's wider lateral splays may not make a difference. Only a performance specialist can determine that and only if he/she is very conversant in TERPS and PANS-OPS.
I don't want to sit here and argue whether Terps is AEO, because that is not what I meant in my previous post.
The problem with an assessment of a SID by other than a professional engineering department is two-fold:
1. Ths SID requires a constant gradient (slope) to a specified altitude, the Part 25 OEI takeoff flight path requires a clean-up segment, which may or may not "bump" into the SID's constant slope.
2. The SID's lateral airspace splays to an area wider than required by AC120-91, which invokes an unneccsary, sometime onnerous penality with OEI and by using a SID rather than a special OEI procedure. Then, in other cases the SID's wider lateral splays may not make a difference. Only a performance specialist can determine that and only if he/she is very conversant in TERPS and PANS-OPS.
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@Zeffy
Yes it is indeed the aircraft I am currently flying. And yes, before I accept a SID that requires a specific climb gradient I look at my performance charts which tell me at what weight I can take off on that day at that airport and meet that climb gradient with OEI. And yes it takes into account the 10 minutes max at TOGA on the operating engine(s). I don't want to sit here and argue whether Terps is AEO, because that is not what I meant in my previous post. All I am saying is that if you accept a SID and there are obstacles that you need to avoid and you enter IMC then you lose an engine, your aircraft better be able to meet that SID gradient or you may find yourself face to face with a piece of granite. I'm not sure what kind of corporate flying you did before you retired but I know my principles don't want me "rolling the dice" and hoping we don't have an engine failure after V1 in mountainous terrain and can't avoid the "obstacle".
Yes it is indeed the aircraft I am currently flying. And yes, before I accept a SID that requires a specific climb gradient I look at my performance charts which tell me at what weight I can take off on that day at that airport and meet that climb gradient with OEI. And yes it takes into account the 10 minutes max at TOGA on the operating engine(s). I don't want to sit here and argue whether Terps is AEO, because that is not what I meant in my previous post. All I am saying is that if you accept a SID and there are obstacles that you need to avoid and you enter IMC then you lose an engine, your aircraft better be able to meet that SID gradient or you may find yourself face to face with a piece of granite. I'm not sure what kind of corporate flying you did before you retired but I know my principles don't want me "rolling the dice" and hoping we don't have an engine failure after V1 in mountainous terrain and can't avoid the "obstacle".
The five years previous to retirement were spent "toiling"
in the cockpit of an F900EX EASy, so essentially the same avionics as you're currently flying in the G450.Our principals also desired to operate at very high levels of safety and for that reason the services of a Performance Engineering company (APG) were engaged. A runway analysis was provided for each and every takeoff, irrespective of wx conditions or terrain environment.
It is unfortunate that so many of us corporate aviators had been inculcated by our schoolhouses with well-intended but (now) undeniably incorrect information about takeoff performance planning. However, there are no longer any acceptable excuses for the promulgation of bogus information.
As richjb has noted
This OEI takeoff obstacle avoidance analysis is not a pilot function. The FAA fully expects this analysis to be performed by a trained performance engineer or furnished through a performance engineer services provider, both of which should have the requisite training and airport & obstacle data resources to complete this analysis.
If your training provider is still teaching that pilots are capable of using the AFM charts to roll their own analyses, consider asking them for a refund. They are wrong.
I would respectfully refer you to a web page and article recently posted by NBAA:
Aircraft Climb Performance
The APG web site offers descriptions of a number of products, including Runway Analysis deliverable on an iPad. Their video library may also be of interest to you.
best,
Z
Last edited by Zeffy; 2nd Nov 2012 at 12:47.
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G450 -
Let me help you out....I see your low post count....you think you are talking to pilots, you aren't...trust me, I have been banned here more times then I can count. It's troll heaven here. The concept that airline captains are sitting infront of a bus and having no clue, idea, training, or concept of how to comply with a SID climb gradient is not only stupid, unrealistic, illegal, and beyond retarded, you are being 'sold' on the idea that it's actually SOP. You are dealing with trolls.....I thought I would let you know this before you go down the road I did...shocked, trying to help, trying to figure it out...don't bother...just laugh it off.
Let me help you out....I see your low post count....you think you are talking to pilots, you aren't...trust me, I have been banned here more times then I can count. It's troll heaven here. The concept that airline captains are sitting infront of a bus and having no clue, idea, training, or concept of how to comply with a SID climb gradient is not only stupid, unrealistic, illegal, and beyond retarded, you are being 'sold' on the idea that it's actually SOP. You are dealing with trolls.....I thought I would let you know this before you go down the road I did...shocked, trying to help, trying to figure it out...don't bother...just laugh it off.
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FE Hoppy:
It might as well be for the pilot who tries to get out of an airport with obstacle issues without a very specific performance engineering assessment.
Those who don't understand what is required of performance engineering will usually do just fine so long as they don't lose an engine around rotation at a climb-limited airport.
Every RTOT I've used has had specific instruction on what to do OEI. It's not rocket science!
Those who don't understand what is required of performance engineering will usually do just fine so long as they don't lose an engine around rotation at a climb-limited airport.
