View Full Version : BA vortex sep. heavy/heavy?
Gonzo
19th May 2001, 16:20
While I was doing delivery the other day I was reading a copy of the ATC occurrance digest for March, and there were three incidents where BA 747/777s had reported wake vortex incidents on departure, and the language used was surprising. ie. "It was alleged that the tower had cleared the reporting a/c for take off only 5 seconds after the previous departing 747 had rotated." Now, my reaction was '5 seconds, it should have been immediately'! So how much separation do BA heavy crews need/want/is required by SOPs? We can launch 'wheels up', no vortex considerations.
Comments?
Gonzo.
chiglet
19th May 2001, 17:41
At EGCC, we have had foreign aircrews go around after a heavy dep.
Best one was a now defunct Turkish mob with mixed UK/Turk crews. [UK flew 757s and Turks flew MD80s]. MD80 at the holding piont, 757 short finals, and 747 rolls. As the 757 flared, the (very) English capain broacast "straight thru his wake" to which the MD skipper said "Roger, line up and wait!"
Air man nearly choked in saying "negative"
HEATHROW DIRECTOR
20th May 2001, 18:50
I know it's a while since I left Heathrow Tower but I'm sure these comments apply just as much now... A lot depends on when crews/ATC start the timing.... I used to time vortex separation from the moment the first guy started rolling. However, some crews start their stop watches when the one ahead lifts off - that can add 40-50 seconds and easily increases the standard vortex 2mins to 3mins. Vortex sep is another area where different crews react differently. Eg Several Lufthansa pilots ask for extra spacing behind 757s. They're obviously entitled to ask.. and get it. However, if everyone wanted extra spacing (time or distance) over the laid down minima we'd never shift anything!
I think your timing is the correct one, director.
Gonzo
20th May 2001, 19:12
Agree with that, HD, but I was wondering what vortex spacing if any BA 747/767/777 crews wanted behind another 747/767/777 etc. I inferred from the ATC Occurrence digest that they wanted some vortex sep., whereas the MATS pt1 says any H after H there is no wake vortex sep. on departure. Not even 1 minute.
Gonzo
BA requirements are as laid down in MATS pt1 - there is no company requirement to increase separation on departure or arrival.
I guess that the individuals concerned on the day just wanted a little more than min separation. You normally get a bit more cautious for a few weeks after an unexpected encounter near the ground!
Gonzo
21st May 2001, 23:54
WOK, that makes sense, thanks.
Gonzo