LiveATC Discussion Forums
Air Traffic Monitoring => Listener Forum => Topic started by: rekno13 on July 18, 2009, 07:59:27 PM
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Hey folks,
I am looking at airport diagram and I have a question about one of the symbols.
It is three oval shapes connected in a line, at the end of a runway. But its not on every runway at the airport, so I am a bit confused as to its meaning.
Thank you for your input!
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It indicates a displaced threshold.
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Ah ok, so when there is no such diagram, then pilots can use the entire runway to land?
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Basically, yes, when there is no indication of a displaced threshold, the runway is usable for the entire length.
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It is not on every runway either. Check out the diagram of KMIA I linked to. Note that only 7, 27, and 30 have the marking being referenced.
http://media.photobucket.com/image/Airport%20Diagram/Rob_canada/Miami_airport_diagram-1.png
When talking about the "Touchdown Zone", see this day time pic of a runway. You'll see at the end of the runway, is the threshold. The touchdown zone is after the numbers, marked by a series of lines. Most runways have three lines, then two, then one line on both sides of the center line, marking the end of the "touchdown zone".
http://www.terragear.org/docs/scenery-tutorial/ksyr-runway.jpg
http://www.boston.com/news/local/breaking_news/emas-1.jpg
In this night pic, the threshold is marked by green lights at the end of the runwan, and the touchdown zone is marked be the two rows of white lights on either side of the center line.
http://homepage.mac.com/benorloff/ExtraFiles/runway-lights.jpg
Enjoy! :-D
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A displaced threshhold is also in use at LAX on the 25's.
In my opinion, busy Airport Blvd. would be much too close to for landings, if if the runway east of Foxtrot were used. Only take offs are aloud.
http://maps.google.com/maps?hl=en&q=lax&um=1&ie=UTF-8&split=0&gl=us&ei=IsZjSse3MJSksgOip8jxAQ&sa=X&oi=geocode_result&ct=title&resnum=1
It is also used at runway 6R just east of echo 17. In this case I believe it is because of the proximity to Pershing Ave. and the dunes/knoll to the west, which actually used to be houses back in the day.
Rob
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Thanks for the pictures and all the info everyone! Those pictures are great illustrations of the threshhold.
I always wondered about those houses, would have been nice to be able to stand on that hill and watch planes take off. Too bad they fence the whole thing off.
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Hadn't realized that LAX has only E-W runways. Here's a wind rose:
http://www.epa.gov/ttn/naaqs/ozone/areas/windr/23174.gif
Life must get interesting during those unusual days when it's from N or S.
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Hadn't realized that LAX has only E-W runways. Here's a wind rose:
http://www.epa.gov/ttn/naaqs/ozone/areas/windr/23174.gif
Life must get interesting during those unusual days when it's from N or S.
As you can see by the graphic you posted that is very rare. Even more rare are when the winds are N or S and greater then 5 kts. The when the winds are less then 5kts the runway that is designated the "calm wind runway" is used. Though winds are only allowed to be called "calm" when less then 3 kts (don't ask me why).
Since we're talking about displaced thresholds I can't help but mention SAN.
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=san+&sll=13.444304,144.793731&sspn=1.076525,1.577911&ie=UTF8&ll=32.730704,-117.178266&spn=0.007274,0.012327&t=h&z=17
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Yeah there is very little N-S winds here. : )
That is a huge displace threshold. What is on the approach to that runway?
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Parking garages, homes, hills, the I-5, you name it.
http://www.airliners.net/photo/0493224/&sid=a19d982406277e9ed1598ad01c18c014
(http://files.getdropbox.com/u/152429/san_dept_27.jpg)
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aha! ok, thanks for the wonderful shot.
I need to install google earth at work... : )