Wake Turbulence

[kevindelaney]

Hi All
Listening this evening to Departures at Heathrow and after a BA Boeing took off, the pilot or first officer came over the radio and reported to the ATCO that he received wake turbulence in the take off from the previous aircraft (another BA). He seemed rather miffed at this and I was just wondering what is the seriousness of this incident.

The ATCO just radioed back and informed the pilot to complete the wake turbulence report and that was it.

Can anybody throw some light on this?

Many Thanks
Kevin

[bagpuss lives]

Basically the movement of the aircraft through the air creates dangerous vortices (large swirls usually) that seriously disrupt and impede the flow of air over the following aircraft's flight surfaces.

This can cause anything from heavy buffeting to a stall or even an inversion or loss of the aircraft if not dealt with correctly by an unsuspecting flight crew.

Correct intervals between departing aircraft, monitored by the Tower ATCO involved and of course, the flight crew, are used to prevent such events ocurring. That's why I expect the crew were rather miffed - it's not a good situation to be in.

There have been several accidents related to wake turbulence and I'm sure someone more informed than I will tell you about them.

Hope this helps a tad :)

[bagpuss lives]

Sorry to post again but you may want to read http://www.pprune.org/forums/showthread.php?s=&threadid=71106 which is all wake turbulence related. I'm sure you've heard of the incident.

[Jerricho]

Just as an addition as to maybe the pilot sounded a little miffed.

We have Wake Vortex separation minima to follow for departing and arriving aircraft. But sometimes, certain wind conditions can actually cause the vortex to remain longer.

There have been instances of inbound medium aircraft following heavies, where the standard is 5 miles in trail or crossing the same point, and the following medium has reported being bumped around while a good 7 miles behind.

And not making light of the situation, but when asked if the pilot wishes to file a "Wake Vortex Report", some say yes, some say no. I guess the severity and effect of the vortex determins this.

[Flying Boat]

I was in a PA28 & #2 to a Virgin Express Charter 737, to land.
Had the following instruction:

"G-++++ cleared to final behind the 737, caution wake vortex, minimum separation 6NM. 'KEEP IT TIGHT'"

What was all that about?


:eek:

[Gonzo]

Flying Boat,

Just guessing, but I think the controller was probably trying to encourage you to come in 'high and tight', so you approached 'above' the flightpath of the landing 737, so staying out of the vortex, thus negating the need for 6 miles.

On the subject of the pilot sounding miffed, I've read incident reports where crews are expecting vortex separation between a heavy and another heavy on departure, but there is no such requirement in the UK. I can clear a Heavy for take off as soon as the previous Heavy is off the tarmac.

Gonzo.

[Spank me baby!!!]

Radar Wake Turbulence Separation Minima doesn't always guarantee that an aircraft won't encounter Wake Turbulence.

Once I had a Medivac C441 (twin turbo-prop) maintaining FL180. The preceding B737 on descent passed through FL180, 18NM ahead of the C441 (I know, I measured it at the time). About 4 minutes later the C441 flew through the same air that the B737 had descended through and reported encountering "severe wake turbulence".

Even though I had the minimum Radar Wake Turbulence Separation (5NM) the C441 still encountered severe turbulence. Ever since that day, whenever a light aircraft is going to pass through the same air as a medium or heavy I advise them: "caution wake turbulence".

:8