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Take-Off Performance


David Katona

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8 hours ago, koen meier said:

ATOW is actual takeoff weight.

Thanks Koen, now by searching "actual takeoff weight" on search engines we can find some precise explanation, in fact the weight... minus taxi fuel.

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Michael Avallone

Hi,  I entered the intersection data for KJFK but accidentally added intersection PA and PC to 13L could you please delete those, I could not find a way to delete intersections once uploaded.   could you please unlock KEWR, its missing the intersection take off data.     

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TH0R5T€N KlRCHH€lM

Howdy Michael ... Done ... PA and PC were removed ... Thanks for the information and have an awesome 2019 ... 

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  • 4 weeks later...
Patrick Hildebrand

Is there some new info About A319 CFM and A321?

When I use the A320 CFM for A319 is this right because the W/B of an A319 is lower than A320 so it is unrealisic, isn't it?

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  • 1 month later...
Errais abdeljalil
2 minutes ago, Ryan Alliy said:

Could someone tell me what I put into the RTOW [PRI] I can't find it out.

nothing just put the ATOW

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Lane Bumgardner

The first 2 paragraphs explain it but if you want more with an example read on:  Hope this gives you some background.

RTOW is Reduced Takeoff Weight.  We can't just load up and go as we have limiting weights both structural and performance that need to be checked to determine our max takeoff weight.

Most flights you will be limited by your Max Landing Weight which is 66.0 Tons in the FSL A320 version.   So at our destination we must be 66 Tons or less at touchdown.  I think if you exceed any of the structural limits then his software will alert you (MZFW, MTOW, MLW).  Also if you use SimBrief and have set up the aircraft properly it will take care of these 3 for you.

 

If you need More Detail?  then Read On.

 

Max Landing Weight Limit Check.

So if your Trip Fuel is 4.0 Tons your RTOW would be 70 Tons (66.0 + 4.0)  If you released brakes exactly at 70 Tons and burned exactly 4 Tons of fuel en-route, you would  land with 66 Tons.  I like to base it off of MLW - 500 (65,500).  This gives me a buffer and allows me to take a short cut or two en-route as well as some flexibility with altitude and of course unforecast winds aloft.  Once you get in the air you might find your close to MLW or sometimes above and have to fly a lower altitude en-route to burn down below MLW.

Another important one is Performance Takeoff Weight or Max Runway TOW.  I believe the online TO performance calculator does this generically so it would let you know if you are Runway Limited.  This is your ability to accelerate on takeoff, lose an engine and stop on the runway or continue and meet your obstacle clearance requirements for departure.  You may also have an Engine out Departure Procedure at some airports with high terrain or restricted airspace like KDCA (RWY 01).

Enroute (Drift Down):

If you are planning on flight over very high terrain 15,000 or higher you would also consider looking at your drift down performance for OEI operations.  Then you could determine the TOW that would allow you to clear all terrain on your route should you loose an engine anywhere during your flight and have to drift down to an altitude that you can maintain with OEI.  We also have escape routes and decision points for this but beyond the scope of what you're asking just giving you some background.

Many other things are factored in which is why you should have a computerized performance calculator.  We used to have the LPC which was the less paper cockpit but we've moved to the EFB (Fly Smart).  If both of those fail then you are in the paper takeoff charts and have fun with those :-).

 

Applicability:

In the flight sim world we don't care what passengers or bags are put on the plane.  However in the RW we actually have a certain amount of folks that want to get somewhere and arrive with their baggage.  Some of our destinations we leave bags or cargo behind even in the A320.  So if you endeavor to do some calculations like this on your own, then it might go something like this.

  • 42842  (OEW)
  • 7500 (Trip)
  • 375 (Cont)
  • 2500 (Alternate)
  • 1000 (Hold) expecting holding at destination
  • 11375 (minimum fuel)
  • 200 (taxi)
  • 11575 (Ramp Fuel)
  • _______ (Extra Fuel)  With no hold fuel or extra fuel built in you will be taking off with minimum fuel so without any extra you have just your 375 for a buffer.
  • 54417 Total Weight No Payload

So from here I would calculate the Max Payload I can take.

Structural:  77.0 - 54.4 = 22.6 ( I personally don't subtract the taxi fuel because sometimes you burn 100 kg on Taxi and other times 300)

Zero Fuel: 62.5 - 42.8 = 19.7

Max Landing: 66.0 + 7.5 = (73.5) - 54.4 = 19.1

So your max payload in this case would be 19.1, since any payload higher than that would make you over your MLW on arrival.

85 KG per pax (15.3) allows you 19.1 - 15.3 = 3.8 tons of bags and cargo.

So in the Calculator you would enter 73500 as your RTOW which if you plan on taking the full load would also be your ATOW.

 

Most of the time you're ok but sometimes with weather and atc delays you might take quite a bit of extra fuel, 1 ton is about 30 minutes and of course your contingency will give you a bit more but there are certain destinations where I have had 4 tons of baggage and I just can't take it all due to the fuel requirements.  Gotta have the gas so if were over weight I start removing cargo, then bags, then pax to get down under weight. 

NOTE:  The other consideration would be your Performance Limiting Weight (Runway).  Not really a factor unless you have a short runway, high terrain, wet or contaminated, obstacles etc...  Typically where I fly I see Performance weights in the 80.0 ton range which is well above structural.

For the sim I simply prefer to let the calculator generate a payload for me and off we go.  If you fly with a Virtual Airline then you'll have to insert the Payload data and go from there.

If it shows you over weight then drop off the extra and off you go.

Sim Brief or PFPX is the way to go and gets you in the air quickly as time is precious in this hobby.

 

Cheers.

L.

 

 

 

 

 

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  • 2 weeks later...
Max Vargas
On 6/20/2018 at 4:46 PM, M_i_k_e_V_o_g said:

I'd *assume* virtually is right.

As he has no access to the code, he can't determine how the A/C redistributes the load and that's probably something the FSL bus is doing on its own.

What I don't understand is, how exactly do YOU expect it to work? If you wait a bit longer and enter your figures AFTER the boarding is finished, then you'll get what you wish for...

YES! Virtuali or GSX is not the culprit. It is in fact FSlabs. I tested it:

1. You set the pax distribution and CP1/5 loads first on MENU/OPTIONS/PAYLOAD.

2. DO NOT LOAD A FLIGHT PLAN OR ENTER ANY DATA INTO INIT2 yet

3. GSX: Board passengers. GSX will board almost exactly the passengers you have in the PAYLOAD page, distribution will vary a little bit.

4. Now you can enter the flight plan and/or modifying the INIT2 page and DISPRIF flow while the passengers are boarding.

Regards

MV

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John Price

BTW, my understanding is that RTOW is not 'reduced' takeoff weight but the Regulated Takeoff Weight; that is to say, the maximum permissible takeoff weight for the particular runway you're operating on in the particular conditions you are operating in. These things aren't hugely pressing in normal weather at Heathrow, for example, but if you're taking off from EGJJ on a very hot day and possibly a few deferred MEL items that affect aircraft performance, suddenly the difference between the RTOW for that particular runway and the aircraft's MTOW may well be quite large.

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  • 2 weeks later...
Lane Bumgardner
On 3/24/2019 at 11:40 AM, John Price said:

BTW, my understanding is that RTOW is not 'reduced' takeoff weight but the Regulated Takeoff Weight; that is to say, the maximum permissible takeoff weight for the particular runway you're operating on in the particular conditions you are operating in. These things aren't hugely pressing in normal weather at Heathrow, for example, but if you're taking off from EGJJ on a very hot day and possibly a few deferred MEL items that affect aircraft performance, suddenly the difference between the RTOW for that particular runway and the aircraft's MTOW may well be quite large.

You are correct, this is the definition of Regulated Takeoff Weight.  I was using RTOW in general as there are other limiting factors that may "Reduce" or limit the takeoff weight below Max Structural.  On longer runways especially dry you will most likely be limited by Max Landing Weight or Structural.  When operating off of long runways, I see Max RWY TO weights well above Max Structural so the runway or the Regulated Takeoff Weight is not limiting however you still might be limited by Max Landing Weight so in the end your takeoff weight is reduced below Max Structural. 

Some stations we operate out of such as Dubai calculate the weight and balance for you and they need to know your MAX Takeoff Weight which is listed as (RTOW).  So we need to let them know what our Max TOW is be it (Regulated, Max Landing, Structural, etc...) this way they can adjust the load accordingly.  Not an issue if we do it all with Fly Smart or Runway Performance Charts.

I believe the web based calculator for FSL A320 does all of this for you, to include a basic calculation for the runway if I remember the forum posts correctly, so it's all really nice to know for the most part especially for flight simulation. 

Interestingly enough one of the airports we operate out of is at 6800' MSL and is repairing the runway so they have turned the taxiway into a temporary runway,  45 M  wide and 2800 M Long but the Landing Distance Available is only 2200M. 

Now the Calculated Actual Landing Distance for the A320 generally floats around 1900 - 2100 M with Reversers Selected and Auto Brakes Low for a dry runway, just depends on the landing weight.  We have other restrictions such as brakes and Spoiler MEL's that are no longer allowed for this airport during the temporary runway as well as "Medium Auto brakes Recommended".  So before we leave operations we will need to do a landing distance calculation before we load up to make sure we aren't restricted due to landing distance, something we don't need to do on a 3500M runway.

BTW the software used by the dispatcher will spit out your MTOW on your computer flight plan and can provide runway performance data but again it's all estimated based on when the Flight Release was produced , estimated loads, weather  etc.

OEAB 13.jpg

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Markos Papoutsidakis

Hi all,

I just saw something strange on the t/o speeds calculations...

As you can see below, the speeds are higher when the configuration is 2 instead of 1+F, under the same conditions...

Is this normal??

 

@David Katona

1.png

2.png

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Koen Meier
4 minutes ago, Markos Papoutsidakis said:

No one?

This tool isn’t being developed anymore by the creator. Fslabs are making their own take off performance tool.

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Lee Holdridge

Enlighten me please, I'm new to this. How do you convert the numbers in the Flex box to temperature? Usually the app gives you four numbers and then a number with a plus sign. How do you convert that to a flex number to put in the MCDU?

 

 

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Gerard Beekmans
43 minutes ago, Lee Holdridge said:

Enlighten me please, I'm new to this. How do you convert the numbers in the Flex box to temperature? Usually the app gives you four numbers and then a number with a plus sign. How do you convert that to a flex number to put in the MCDU?

 

 

Lee, the flex number is the temperature. If it shows you a Flex number of +67 as shows in the screenshot example a few posts up from yours, that means 67 degrees Celsius. In the MCDU, you enter '67' on the PERF page under "FLEX TO TEMP"  (LSK 4R on PERF page). See "A320X Basic Tutorial" page 18 for additional info and screenshots.

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  • 1 month later...
Cathal Kavanagh

@David Katona

Hi David can you update the runway identifiers for Cork EICK please from 17/35 to 16/34? Currently PERF REQ returns system error contact ftd I believe this is as I’ve pointed out due to the runway being redesignated.

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Koen Meier
14 minutes ago, Cathal Kavanagh said:

@David Katona

Hi David can you update the runway identifiers for Cork EICK please from 17/35 to 16/34? Currently PERF REQ returns system error contact ftd I believe this is as I’ve pointed out due to the runway being redesignated.

@Cathal Kavanagh unfortunately David stopped developing the performance tool and sadly once an airport is locked users can’t change the info. Fslabs started their own development of a tool but that takes some time after they lost communication with David.

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Cathal Kavanagh
8 hours ago, koen meier said:

@Cathal Kavanagh unfortunately David stopped developing the performance tool and sadly once an airport is locked users can’t change the info. Fslabs started their own development of a tool but that takes some time after they lost communication with David.

Ah well thank you for explaining!

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  • 1 month later...
Tim Vancauwenbergh

What would be truly amazing is a efb alike application you can run on android/ios (as app) or web based like david's. His tool is fantastic and contains the most important stuff.

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Koen Meier
8 minutes ago, Tim Vancauwenbergh said:

What would be truly amazing is a efb alike application you can run on android/ios (as app) or web based like david's. His tool is fantastic and contains the most important stuff.

I said something like that if we get an efb onboard in the future.

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  • 1 month later...
Zsolt Monostori

So right now there is no realistic takeoff performance calculator for the A3XX.

The "ATSU way" of receiving V-speeds via the company datalink is of course available, but if you don't want to mess with the ATSU there is no other way. 

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Koen Meier
37 minutes ago, Zsolt Monostori said:

So right now there is no realistic takeoff performance calculator for the A3XX.

The "ATSU way" of receiving V-speeds via the company datalink is of course available, but if you don't want to mess with the ATSU there is no other way. 

The atsu way goes to wabpro. So you just go to wabpro instead of the atsu menu. If you mean by realistic the airbus app than no.

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Zsolt Monostori
On 9/1/2019 at 6:21 PM, koen meier said:

The atsu way goes to wabpro. So you just go to wabpro instead of the atsu menu. If you mean by realistic the airbus app than no.

The last time I used Wabpro - in April - there was no IAE or CFM for the A319.

UPDATE

Still no CFM only IAE. So the ATSU way is not the same as Wabpro. The ATSU can calculate for all variants. We need a fully fledged non-ATSU app that can do these calculations. Wabpro isn' developed any further and can't calculate the 319 CFM performance.

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Koen Meier
23 minutes ago, Zsolt Monostori said:

The last time I used Wabpro - in April - there was no IAE or CFM for the A319.

UPDATE

Still no CFM only IAE. So the ATSU way is not the same as Wabpro. The ATSU can calculate for all variants. We need a fully fledged non-ATSU app that can do these calculations. Wabpro isn' developed any further and can't calculate the 319 CFM performance.

fslabs has done some trickery to get the a319 cfm data using wabpro. the atsu request goes to wabpro. keep in mind fslabss are developing their own performance tool to replace wabpro but that takes time.

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  • 3 months later...
Kim Ruben Fjeldstad

Is it any weblink for this TOPL as well that we can use as a backup incase our ATSU hangs?

Just as we had the old one, a weblink we could use as a backup.

Rgds

Kim

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Koen Meier
6 hours ago, Kim Ruben Fjeldstad said:

Is it any weblink for this TOPL as well that we can use as a backup incase our ATSU hangs?

Just as we had the old one, a weblink we could use as a backup.

Rgds

Kim

There is no weblink. 

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Norman Blackburn
8 hours ago, Kim Ruben Fjeldstad said:

Is it any weblink for this TOPL as well that we can use as a backup incase our ATSU hangs?

There is no weblink we can supply at this time.

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  • 2 weeks later...
Kim Ruben Fjeldstad

One airport is missing as well..

ESKS the new Scandinavian Mountains Airport is not in the system, where can it be added?

I got the data needed to add/update it if needed.

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Norman Blackburn

Thanks Kim.  When I get home later I will look to adding it.

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Kim Ruben Fjeldstad
2 hours ago, Norman Blackburn said:

Thanks Kim.  When I get home later I will look to adding it.

Hey!

Perfect, if you need anything to get it added, let me know and I can send you what you need.

I also get issues at ENTC as well, just as it is not there at all for the A321..

No Information, even with TOGA and 81tonnes, anyhow wich runway I select.

A321 is flown out from there with Wizzair and Thomas Cook, with weights up to 93 tonnes..So it should be there..

 

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  • 4 weeks later...
Wanthuyr Filho

Are the airports in Asia and Oceania available? I've been flying these continents lately and never got a valid performance response.

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Koen Meier
7 hours ago, Wanthuyr Filho said:

Are the airports in Asia and Oceania available? I've been flying these continents lately and never got a valid performance response.

You mean with wabpro cause this thread should be closed to prevent any confusion regarding the performance system.

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Wanthuyr Filho
7 hours ago, Koen Meier said:

You mean with wabpro cause this thread should be closed to prevent any confusion regarding the performance system.

I mean the performance calculation within the ATSU.

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Koen Meier
1 minute ago, Wanthuyr Filho said:

I mean the performance calculation within the ATSU.

I know but for me this thread is associated with wabpro. I think for the new system it is best to use the atsu section of the forum. Ideally we need a new thread in the atsu section for the current performance system.

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Wanthuyr Filho
9 minutes ago, Koen Meier said:

I know but for me this thread is associated with wabpro. I think for the new system it is best to use the atsu section of the forum. Ideally we need a new thread in the atsu section for the current performance system.

Ahhh, I see. I didn't pay attention to this, and I agree.

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  • 1 month later...
Curt Söderberg
On 1/17/2020 at 2:43 PM, Norman Blackburn said:

Thanks Kim.  When I get home later I will look to adding it.

What happened to this problem?

METAR for via ATSU does not work.

/Curt

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Koen Meier
11 minutes ago, Curt Söderberg said:

What happened to this problem?

METAR for via ATSU does not work.

/Curt

Which provider are you using?

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Curt Söderberg

Answer from Daveo at HiFi: The METAR/weather works correct but not the route display from a flightplan on the map.

/Curt

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Koen Meier

But what is your actual question. Also this thread is about the wabpro calculator which isn’t used anymore in the fslabs 

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Curt Söderberg
On 1/17/2020 at 2:36 PM, Kim Ruben Fjeldstad said:

One airport is missing as well..

ESKS the new Scandinavian Mountains Airport is not in the system, where can it be added?

I got the data needed to add/update it if needed.

 

On 1/17/2020 at 2:43 PM, Norman Blackburn said:

Thanks Kim.  When I get home later I will look to adding it.

/Curt

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