take-off analysis
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take-off analysis
hy
is a must to have aboard the take-off analysis, in order to use a particular rwy? If so,where can I find this requrement writen?
Or ,one can use the performance data from the AFM?
Brgds
is a must to have aboard the take-off analysis, in order to use a particular rwy? If so,where can I find this requrement writen?
Or ,one can use the performance data from the AFM?
Brgds
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One needs the numbers .. regardless whence they come, at the enquiry the aircraft needs to be seen to be not more in mass than the data permits for the takeoff.
Problem with conventional AFM data is that it does not immediately give you the answer and, for most large aircraft, the time taken in doing the sums .. even if you have all the obstacle data, makes AFM use a bit questionable. ... effective solution is to have RTOW tables for each runway in the operation.
Problem with conventional AFM data is that it does not immediately give you the answer and, for most large aircraft, the time taken in doing the sums .. even if you have all the obstacle data, makes AFM use a bit questionable. ... effective solution is to have RTOW tables for each runway in the operation.
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alexban,
Ya gotta be quick to beat the venerable john_tullamarine to the draw.
What john_t has said is absolutely correct, but to address your original question "If so,where can I find this requrement writen?" -
You will be well familiar with the Performance requirements, as well established in the FAR, JAR, CAO etc., depending upon the applicable regulatory authority. In varying words, all say much the same thing with respect to Field Performance, Obstacle Clearance etc. So, as an absolute minimum, you'll need the AFM with all of it's performance data, plus a complete obstacle analysis (which might require the establishment of Special OEI Procedures). Even with a full set of obstacle data, it's not very practical to use the AFM and the obstacle data, by the time that you've finished, the wind, QNH and Temperature have all changed and you have to start again. Some Australian operators (not many) have been able to get away with such a system because of the good quality Obstacle data available in the public domain via the Authority's own publications (ERSA/RDS).
So where is it written? It will be contained within your operator's Air Operator's Certificate (AOC), wherein the operator is required to show procedures and techniques required for Compliance with the relevant regulations. It will then be up to the regulatory authority to accept (or reject) the operator's Compliance statements.
Having said that, the most efficient, and most likely to be approved system of procedures and techniques for Compliance with the regulations, is the Takeoff Analysis / Runway Analysis as we know it. Under the terms of the AOC, therefore, it MUST be aboard.
Of course, the operator may submit some alternative means of compliance with the regulations, and, if approved for the AOC, such applicable documents MUST be aboard the aircraft. An example, if an operator elected to calculate all Takeoff data from a Lap-Top computer (good idea), the Lap-Top, with it's APPROVED programme, including an obstacle database, MUST be aboard.
The AOC is where you will find it, the need for Compliance will be found within the relevant regulatory documents.
Regards,
Old Smokey
Ya gotta be quick to beat the venerable john_tullamarine to the draw.
What john_t has said is absolutely correct, but to address your original question "If so,where can I find this requrement writen?" -
You will be well familiar with the Performance requirements, as well established in the FAR, JAR, CAO etc., depending upon the applicable regulatory authority. In varying words, all say much the same thing with respect to Field Performance, Obstacle Clearance etc. So, as an absolute minimum, you'll need the AFM with all of it's performance data, plus a complete obstacle analysis (which might require the establishment of Special OEI Procedures). Even with a full set of obstacle data, it's not very practical to use the AFM and the obstacle data, by the time that you've finished, the wind, QNH and Temperature have all changed and you have to start again. Some Australian operators (not many) have been able to get away with such a system because of the good quality Obstacle data available in the public domain via the Authority's own publications (ERSA/RDS).
So where is it written? It will be contained within your operator's Air Operator's Certificate (AOC), wherein the operator is required to show procedures and techniques required for Compliance with the relevant regulations. It will then be up to the regulatory authority to accept (or reject) the operator's Compliance statements.
Having said that, the most efficient, and most likely to be approved system of procedures and techniques for Compliance with the regulations, is the Takeoff Analysis / Runway Analysis as we know it. Under the terms of the AOC, therefore, it MUST be aboard.
Of course, the operator may submit some alternative means of compliance with the regulations, and, if approved for the AOC, such applicable documents MUST be aboard the aircraft. An example, if an operator elected to calculate all Takeoff data from a Lap-Top computer (good idea), the Lap-Top, with it's APPROVED programme, including an obstacle database, MUST be aboard.
The AOC is where you will find it, the need for Compliance will be found within the relevant regulatory documents.
Regards,
Old Smokey
The AOC is where you will find it
This isnt always the case, our Operations Specifications state that we must have takeoff performance, but it doesnt state what shape or form it must come in.
We operate using tabulated takeoff data primarily due to the ease of use, however we have operated AOG recovery flights using AFM data with single point calculations.
Mutt
This isnt always the case, our Operations Specifications state that we must have takeoff performance, but it doesnt state what shape or form it must come in.
We operate using tabulated takeoff data primarily due to the ease of use, however we have operated AOG recovery flights using AFM data with single point calculations.
Mutt
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Jurisdictions will vary mutt, the one to which I have to pay homage requires the Airport Analysis pretty much as described in my post for regular operations, with General Chart backup in case of NOTAM (excluding NOTAMs advising new obstacles). The AOC defines this.
The approval also allows, as described by you for AOG extractions, for an individual calculation to be made by the P/E office for 'oddball' occasions, and the results advised to the crew. No need for a full set of data in this case, just one set for the operational circumstances of the day, and all of this because the regulatory authority has approved the methods used by the P/E office.
Regards,
Old Smokey
The approval also allows, as described by you for AOG extractions, for an individual calculation to be made by the P/E office for 'oddball' occasions, and the results advised to the crew. No need for a full set of data in this case, just one set for the operational circumstances of the day, and all of this because the regulatory authority has approved the methods used by the P/E office.
Regards,
Old Smokey
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Thks
I've been asked if able to use a take-off position ,some 3-4 hundred meters from normal take-off point ,for which I had no take-off analysis.Long rwy,nice weather,no obstacles.I didn't take it.
And also,i've been asked to fly a charter flight to a obstacled ,unfamiliar airport.I've demanded to have the take-off analysis for that particular flight before departing base.
In both cases there was somebody to question my decisions.
I've heard guys that said:"well,we don't have the analysis for XX rwy,2000 m long at 2000' alt? We'll use the analysis for rwy YY from the airport YY...., it's almost the same length and alt.."
I've been asked if able to use a take-off position ,some 3-4 hundred meters from normal take-off point ,for which I had no take-off analysis.Long rwy,nice weather,no obstacles.I didn't take it.
And also,i've been asked to fly a charter flight to a obstacled ,unfamiliar airport.I've demanded to have the take-off analysis for that particular flight before departing base.
In both cases there was somebody to question my decisions.
I've heard guys that said:"well,we don't have the analysis for XX rwy,2000 m long at 2000' alt? We'll use the analysis for rwy YY from the airport YY...., it's almost the same length and alt.."
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I've heard guys that said:"well,we don't have the analysis for XX rwy,2000 m long at 2000' alt? We'll use the analysis for rwy YY from the airport YY...., it's almost the same length and alt
Performance engineers are paid to make the most income they can for the airline, within legal limits. If they don't do their job...
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I would think, alexban, that using a similar, but conservative, Runway Analysis, would be EXTREMELY inadvisable. At the enquiry, you would not have a legal leg to stand on.
What barit1 has said ("If the analysis is clearly and convincingly conservative (regarding altitude, length, slope, obstacles...) ") makes sense on the surface, but you would have to dig much deeper.
To compare runway lengths for example, equal or better lengths would appear to be conservative, but what of the comparison of Stopway and Clearway (OK OK mutt, I know that you don't use them but many do).
In my experience, there is no more conservative Runway Slope against another. What is more conservative, a greater UP slope or a greater DOWN slope? I could show you performance charts (AFM) that within the same Takeoff performance graph demonstrated UP slope to be better in some circumstances, but run your finger down the page and find DOWN slope to be better (Obviously Down slope favours the GO case, but UP slope favours the STOP case, but each of them are similarly affected in the acceleration to Vef.) There is a crossover point where UP/DOWN becomes more/less conservative and this will differ from runway to runway.
Obstacles would be the greatest nightmare, but which ones affect the 1st segment, and which affect the 2nd? And then we get to the highest obstacle in the Takeoff area which determines the 3rd segment acceleration altitude. Lower may appear to be more conservative, but lower also implies lesser gradient, and the margins Gross Vs Net rules imply that the lower gradient requires the higher acceleration altitude.
In summary - DON'T DO IT!
barit1 also makes a noteworthy observation -
True, the P/E's job is to maximise payload, and this requires selection of the OEI route with the lowest obstacles, and herein lies the strange marriage between safety and profit. Both require the lowest possible obstacles, and in this ONE case it is a perfect and unusual union.
And if they don't do their job.......get a new one.
Regards,
Old Smokey
What barit1 has said ("If the analysis is clearly and convincingly conservative (regarding altitude, length, slope, obstacles...) ") makes sense on the surface, but you would have to dig much deeper.
To compare runway lengths for example, equal or better lengths would appear to be conservative, but what of the comparison of Stopway and Clearway (OK OK mutt, I know that you don't use them but many do).
In my experience, there is no more conservative Runway Slope against another. What is more conservative, a greater UP slope or a greater DOWN slope? I could show you performance charts (AFM) that within the same Takeoff performance graph demonstrated UP slope to be better in some circumstances, but run your finger down the page and find DOWN slope to be better (Obviously Down slope favours the GO case, but UP slope favours the STOP case, but each of them are similarly affected in the acceleration to Vef.) There is a crossover point where UP/DOWN becomes more/less conservative and this will differ from runway to runway.
Obstacles would be the greatest nightmare, but which ones affect the 1st segment, and which affect the 2nd? And then we get to the highest obstacle in the Takeoff area which determines the 3rd segment acceleration altitude. Lower may appear to be more conservative, but lower also implies lesser gradient, and the margins Gross Vs Net rules imply that the lower gradient requires the higher acceleration altitude.
In summary - DON'T DO IT!
barit1 also makes a noteworthy observation -
Performance engineers are paid to make the most income they can for the airline, within legal limits. If they don't do their job...
And if they don't do their job.......get a new one.
Regards,
Old Smokey
