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Wake Turbulence / Wingtip Vortices Speeds

  • brook
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brook created the topic: Wake Turbulence / Wingtip Vortices Speeds

G'day All,

This point has come up a few times, and I'm not going to loose sleep about it but it could possibly be an exam question that throws you.

I did two courses, I did the home study using Bobs great CPL Aerodynamics Book, then I did an instructor led 2 day Aerodynamics course at WA Aviation College.

There was no doubt that Bob's book gave me much more useful information than was imparted in the limited two day course, although the instructor was very helpful at answering my questions (I had a few after having prepared by reading Bobs book).

There were a few questions I had and some comments, I will post a separate topic for the other.

The main one here relates to the Wake Turbulence and Wingtip vortices - which at the bottom of Page 5.6 Bob says "drift laterally outwards at about 3 - 4 knots".

While I'm happy that this is correct for most wake turbulence the CASA supplement "Wake Turbulence Hazards and Characteristics" which came with the instructor led course says (part 2.6) "when the vortices of large aircraft sink close to the ground (within about 200ft), they tend to move laterally over the ground at about 5KT".

So just wondering has anyone experienced an issue with this in the exam (mine is on Monday) did it ask for specific speeds to be input or was it multiple choice in the event it was asked at all, since BT is saying 3-4 KT and CASA 5KT.

Thanks


Brook
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Richard replied the topic: Re: Wake Turbulence / Wingtip Vortices Speeds

Hi Brook,

Don't worry about that too much. I very much doubt they are going to ask you for a precise number especially since in the CASA supplement you mention they only say "about 5kt". Just how much is "about"? Is that a metric or imperial "about"? :P

If you like, just remember the vortices do move laterally at anywhere around 3-5kt and don't forget their movement over the ground will be affected by the surface wind.

Cheers,

Rich
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  • brook
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brook replied the topic: Re: Wake Turbulence / Wingtip Vortices Speeds

Hi Rich,

I send you private message before but I'm not sure it worked - I also sent Bob a copy but if he's like me he will try and avoid computers on the weekend!

I tried to log in to the Cyberexam facility a few times using the info below in the email sent out, but it says to me (login bt4859).

Sorry - The Usercode you have entered does not exist.

Please Click Here to check the information you entered and try again.

I’m fairly keen to log in as my Aerodynamics exam is on Monday at 2.00pm WA time is there anything at all you can do from your end? I am using the correct password as per the email.

Regards

Brook
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Richard replied the topic: Re: Wake Turbulence / Wingtip Vortices Speeds

Hi Brook,

Yeah, I got your message - thanks!. The office isn't manned over the weekend though and Lee is the Cyberexam admin. She'll get on to it first thing Monday morning. We can't change anything remotely before then unfortunately.

Cheers,

Rich
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  • dtrembath
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dtrembath replied the topic: Re: Wake Turbulence / Wingtip Vortices Speeds

Hi
Did Aero recently ...had 3 WT q's. CASA seems to want to work with 'about 5 knots'.
Beware the situation (is stated in CASA document) of landing behind a big jet and you have 'about a 5 knot quarterly tail-wind' .... WT stays 'inline' AND can drift further PAST the landing point of the jet ....
Good luck ...
I'm back to my Law study .. Exam on Tuesday ....
David
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  • brook
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brook replied the topic: Re: Wake Turbulence / Wingtip Vortices Speeds

Hi David,

Thanks for that info and good luck with that Law Exam on Tuesday, hope the exam centre didn't float away anywhere!!

Brook
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