ground roll on take off - lineup allowances

[flyingdunky]

I have looking for the reference to find out how is calculated the distance necessary for entering the runaway and lining up on the T.O. run, and how this afects the calculations (T.O. dist., ASD, etc.)
thank-you to anyone that can help me.

[BOAC]

Almost certainly defined in JAROPS, the link to which is in the 'sticky' in this forum.

[john_tullamarine]

Probably will be some variation between jurisdictions....

Ignoring the potential value of a CAD layout analysis, the traditional method involves physical taxi trials for 90deg/180deg turns. A suitable clearance allowance is determined from the high strength side and end alignments and the test numbers normalised to account for whatever "standard" clearance is adopted.

It would not normally be necessary to complete the turn and line up on the centreline as that is not the aim of the exercise .. rather to part complete the turn to a point from which a sensible and repeatable takeoff roll can be commenced.

What final figures are assigned to the particular takeoff calculations will depend on the relevant Authority but will be from the runway end (real .. or notional in the case of an intersection departure) either to the mains or nosewheel.

[Fox Alpha]

Varies per aircraft type also, or more correctly, by company published performance figures.

[411A]

Reference, Australia, a long time ago (circa 1979).

B707, all runways in Australia, TODA reduced by 150 feet, due to 90 degree line-up for takeoff.

If a backtrack and a 180 degree turn required, TODA reduced by 300 feet.

FACT, not fiction.

[oldebloke]

Genarally in the 'Airframe'aircraft section of the filght Manual it shows turning Radii and distances....
In discusions about 'contaminated'runway distance for alignment 200' is gen' recognized as the penalty in the Acc/stop distance..Only Australia 'accounted' for Alignment in their 'distances'..
Cheers.....:ok:

[18-Wheeler]

Qantas allow 65 metres for 747's.

[mutt]

Is line up distance used in the takeoff calculation?

For JAA and CASA operators the answer is yes, but for FAA operators it falls to the airline to decide if they want to use it. Older version of Boeing/Douglas takeoff analysis programs do not have the ability to account for LUD.


Mutt.

[Old Smokey]

JAROPS provides an excellent formula / technique for calculating Line-Up Allowance for aircraft. As mentioned by mutt, FAA operators leave it to user discretion. When I've done work with FAR25 aircraft for Australian operations (where it must be considered) the authority (CASA) has been happy to apply the JAROPS derived allowance to apply to the FAR25 aircraft.

Regards,

Old Smokey

[flyingdunky]

Thanks guys,
I appreciated your replies and they meet, roughly, what I tought, but do you have an actual JAR refrence number where to look at it?
(we have a TRE that loves this kind of questions and I would like to be prepared instead of sorry!)
I spent some time (actually a lot!) but I did not have any luck.
Any help is most welcome!!

[MkVIII]

Does this help? From Airbus...

http://www.gunboards.com/forums/uploaded/vulch/20052235588_rwy%20lupa.jpg

[mutt]

Flyingdunky,

You might find that the value is worthless to you unless you do your own takeoff performance before each flight. There is no point in telling your TRE that its 45 meters, unless you can show that it was accounted for!

It would also help if you said what type of aircraft you are operating.


Mutt.

[flyingdunky]

Thank you Mutt,
I forgot about it :) i am flying the a 320, also i pretty sure that in my company the distance is already included in the calculation, just I would like to know how the have come out with it so that if I change bus I still have an idea.