Ryanair and 757 'vortex'
 

Wots going on ? - Why are Ryanair (B738) crew increasingly asking for two minutes spacing behind departing B752s, - and other crews are catching the bug. Wake doesn't stop them eating up 757s on final approach though.
All seems a bit 'Irish' to me......

Its because a "wake turbulence" upset is more critical the closer to the ground you get...if your visual on approach all you do is adjust your touchdown point to beyond the preceeding 75..and your fine:ok:

Its more critical on departure..simply because your margins are that much smaller:ok:

Previous discussion here and the 757, particularly when heavy, can generate significant wake turbulence. Captain's discretion as always (and you have to hope they will advise you BEFORE you line them up for an immediate:) )

"All seems a bit 'Irish' to me......"

What do you mean by this exactly???? B757's are catagorised as "Heavy" Aircraft when considering wake turbulence. Thats probably why Ryanair AND other operators ask for 2 mins. I'm an ATCO and whenever take off clearence is issued to a medium behind a heavy I think its good airmanship to just caution the medium a/c that a B757 has just departed. I always take into consideration the space a medium may need behind a 757 when deciding whether or not to give clearance to line-up.

Roger - that is the problem - if you look at my link it appears that it may only be France that does categorise it so. The latest AIP has it as medium. Many disgree with this and as I said, it is Captain's discretion.

Not in the UK, who decided to class them as Upper Mediums.

Therefore here a 737 (Lower Medium in UK) only requires one minute on departure according to our separation tables (and 4nm spacing on final, not five).

Correct! And the thing that really pi*$es me off... someone lines up, cleared to go and its only then they decide to tell you they want 2 minutes! :}

So is the minimising of runway occupancy STILL a problem at Heathrow, then, with resultant go-arounds.......?
Something for the Command Course Facilitators to take up with their 'newbie' captains, I feel.........
Perhaps CRM training should touch on the development of 'external awareness', or is that too much to ask?

Nop! No resultant go-arounds unless we are TEAMing as we use one runway for Deps and one for Arrs. Just a bit annoying when you have good departure splits.

I seem to have to argue with pilots all the time to go behind a 757. Some will, some won't, even within the same company, drives me mad, even asked one are you ready for an immediate behind the 757, answer yes, then lines up and refuses to roll. Result same company go around. Bet that was fun in the crew room later. Pilots say that it is company restrictions, well I don't work for your company therefore I don't know these rules, anyway you went a minute behind yesterday. F***ing pilots :ugh::ugh:

In HongKong we had to give 2 mins vortex behind a 757 for other mediums on departure.
I'm not sure if it's an ICAO requirement or it was just in the HK AIP.757s are nasty things for vortex and if pilots wants 3+ mins behind one,then thats what they will get.After all it's their safety thats the issue.

er.....I remember it well........especially on SRO............alzheimers not quite set in, yet. ISTR it was usually DLH who sprung the unexpected 60 secs after line-up. Not pro.

Well.....I guess some Ryanair pilots have been scared S***less runnin into the wake of a 757 and decided to spread the word!! I can see why they might. A 757's wake vortices, whether it is classed as medium, upper-medium or heavy, are pretty horrific if you fly into them. I agree that it's pilots discretion. Afterall, they know best!

On several occasions I've been asked if the preceeding was a 757 when it infact was an A321. Guess quite a few drivers round are more than a little wary.

Heavy / Medium in Canada
 

In Canada, the 757 is considered a medium when following and a heavy when in front.

A w/t cautionnary is necessary even to a 747 behind a 757. Lately, I've started doing that with A321 although that is not yet a rule.

well i am a pilot and have had situations like above;

i beleive there is a rule that states that if a Pilot deems it nessecary to have increased separation with preceding a/c; he should advice ATC

before he/she accepts the line up clearance e.g. T/O clearance

Therefore if you guys clear an aircraft and he/she does not act on that clearance while he did line up, make him vacate the runway immediately, that'll teach him for the next time!

Pointer :E

True, i did not meant it to be first action but you probably know who it was, you might use this as a last resort to get the point across. but the little people in the big plane should think about this, it is important to know IMHO.

(playing a bit the devils advocate here, don't mean to suggest anything unsafe.. :\ )

Pointer :E

You will end up not caring about the lost minutes one day!

It's obvious some pilots want one rule and ATC are applying their rules / procedures.

As previously quoted, it's ok for pilots to ask for extra time, no problem, but as happened to me very recently don't bl**dy tell me you want 2 minutes after you have lined up and especially when you know that I'm trying to depart 2 in a very tight gap on visual splits :ugh:
Sooooo glad we don't have miked up VCRs:mad:

Must say this disease has spread recently at my unit as the associated personnel within a certain blue and white low cost carrier have rotated through.

It's just the lack of consistancy that's difficult to grasp. In my example why did the FK100 ahead in the queue take only one minute separation behind his departing B757 and yet the B738 not?
With this being a repeated thread (every year or so) when is action going to be taken by the standards/authorities?

- and how are they going to know about it?

At least 4 posts mentioning refusal of take-off clearance since my post #2, so if it that bad, report it? Airlines have Ops Departments. You should have the numbers. Put the two together.

If ATCOs occasionally get problems behind 757s, wouldn't best practice be to ask aircraft behind them who you think might need increased separation whether they require it or not before line up ?? And to discuss such with your colleagues and peers so it becomes a SOP.

Use your knowledge, training, initiative, and a bit of common sense ;) and all will be well in the world.

AD 2-EGLL-1-13
Minimum Runway Occupancy Time...........includes......
"Pilots should ensure that they are able to commence the take-off roll immediately take-off clearance is issued."
"Pilots not able to comply with these requirements should notify ATC as soon as possible once transferred to Heathrow Tower Departures Frequency."
Yes, separation standards are minima and may be increased when required. But there is no excuse for not notifying the inability to comply prior to accepting line-up clearance.
ISTR that when I was an LL Tower Sup we had to log every instance when extra separation was requested. ATC Ops would then process the data, identify trends, and take appropriate action. So asking for extra time once on the runway should no longer be happening. No wonder that point 5 gets irritated.

Who said that ?? :)

(PS No :ok: makes note to read whole thread again next time)

Believe me, all of us at LHR can quote the AIP until we're blue in the face, but most of us are more realistic. Hell, half the crews don't listen to the ATIS. We need to work in the real world, unfortunately.

You'd be quite welcome to do my Sup duty on Friday and then tell me if you had enough time to log every instance as you describe. You're also quite welcome while you're in to inform our Ops Department that they should analyse said logs. In fact can I watch? Both they, and the Tower Sup, have far more pressing matters to attend to.

Manchester MATSpt2 states that, in this very situation, with a similar(ish) category aircraft to depart behind a 757, the controller must ask the crew, before lining them up, if they can accept a 1-minute departure interval. Doesn't take many seconds, doesn't cost anything, but certainly helps with a smooth departure order plan and avoids upset on both sides of the R/T.

Like sorting out the breaks...........et ceteraaaaaa

I see even better.... I often get ATR72s and Dash8s going straight behind 757s. Yes, to be fair I always ask them as I can see the obvious effects there, but 90% of the time they say yes, even when asked 'Are you happy to depart immediately behind a 757?'!!! (And the Dashes Im thinking of quite often go from intermediate holds too!).
Anywho... regardless of who is the bravest etc. etc. the issue here is that the crews dont tell us in enough time. Certainly when lining up it is unacceptable. I even find it unacceptable when foreign pilots say '757 is a Heavy' to me - Why aren't they knowledgeable on the AIP for this country? What other risks might they experience if they havent read it? (Yes Gonzo, its the real world sadly :( ).
In fact, for the benefit of the crews reading this... many of us get frustrated when, like point5, we are trying to get maximum runway occupancy and the only double gap we have arranged is that one (And we cant send the 757 second in order). Its even worse if there are a load of inbounds and we have given Approach 3nm packs thinking the 2 deps would be gone (Although its only the crews who suffer for it, I still hate the idea of missed gaps and inbalanced delays!).
Whats my point? Well, just to have a look at the hold and if there are any 757s just advise the AIR controller ahead of time. Our gaps are planned ahead (mostly ;) ) and the sooner we know, the better.
For the record, when Im planning, I try to only ever put a 757 first if there is no choice or if its just part of a larger order... :)

Oh, and it reminds me of a story...
It was fairly recent, when some of our ATR72 ('Small' vortex category) aircraft started requesting 2mins behind 'Medium' aircraft. According to them it was new company policy. They found themselves, especially in busy periods of same route traffic, being delayed more than others. (Obviously this isnt what we intend to do, but if you have a number of jets on the same route behind, they will either all be delayed or just the ATR...). What then happened is that some would still ask for the companies 2mins, but some would be happy to take 1min, aware that it may cost them time if not (Gonzo's forementioned method of asking was useful here! ;) ). After a few weeks we never heard anything else and they tend to take the 1min as usual again.

(Im not sure if it maybe took a negotiation from ATC Ops to Airline Ops to explain the situation, but something made them drop the idea)

MATS Pt 1 section 2 chapter 1 page 9 13.9:
"The pilot of a departing aircraft may request a delay in take-off because of the danger of vortex wake from the preceeding aircraft. There is particular danger for aircraft comencing the take-off run part of the way along the runway"

we've all learned the hard way about this one and it's been covered many many many times before. At the end of the day the safest option for planning purposes is to ask anything going begind a 757 is:

"ARE YOU HAPPY TO ACCEPT 1 MINUTE BEHIND THE 757."

If the answer is yes, then you can line them up or clear them for an immediate take off. If no then adjust the departure plan accordingly and ask for a gap elsewhere should it be required.

Our job and the job of the pilots is all about SAFETY, if you or the pilot doesn't think it's safe then it just isn't done.

And yes i work in a very mixed traffic environment with lots of 757 followed by S/M traffic.

In Germany a B757 has to be treated as heavy as well (in regard to wake turbulence).

Ben

Thanks for that, Bravo - it looks as if UK is out of line!

I have had three wake 'hits' from 757's in the last twenty years. I suppose I have eventually learned from experience; but they were in progressively larger aircraft, the last in an A300 which (when I wear my specs) seems quite a bit bigger than than the culprit.

I do want two minutes behind a departing 757, and a minimum of four miles (preferably five) when following on approach.

This thread obviously started with Stansted, where a few weeks back, as I took off, I heard a Thomson 757 query why he was behind me, seeing he was at the holding point (R) before me (at S). The controller replied to the effect that Ryanair guys like a gap when behind 757's and there was a brief conflab about whether medium or heavy etc.

Well, I don't know about different ATC regs (re: 757 wake) in Germany, UK, France or elsewhere. but it seems rather obvious common sense to make clear one's wishes before the ATC man commits to a particular course of action and maybe baulkes someone else by default.

The SOP in my particular LoCo does say that you should not accept line-up unless you are ready - else check first if it is still ok. If I want a 2 Min wake delay then clearly I am not ready, and I should say so or expect, not unreasonably, some unparliamentary language.

The first wake experience I had ,about 20 years ago, was in a Dash 7 (not 8) about four miles behind a BA 757 on finals to LHR. We used to reckon that the sixteen big paddle prop blades chopped up vortices rather well, and were surprised when it got bumpy. We were well surprised when the wing dropped forty degrees plus at 1100 feet. In fact so surprised we didn't even swear.


Despite that I still think propellors deal with vortices better than jets. Conditions permitting, in a prop, it is possible to to fly a 4 degree slope and escape the problem. Controversial stuff or what.

Just as an aside, and a contribution to thread creep, the only problem I have with approaching Stansted is that the first or second London freq may give you a speed to fly (say 300 kts) which then surprises a subsequent controller who asks you to reduce pronto. Well, I have noticed in the last few weeks that the handing-over controller says 'Call xyz and tell them your speed. It seems the problem has been recognised and is being addressed. It's good here isn't it.

Regards all.

Once again (despite the gainsayers:) ) I have 'Chirped' and asked them to look at the Cat of the 757 in the UK.

Are you a noob??? Lol, what are you doing here? If an a/c report READY to GO,and you cleared him to T/O and it says that he will wait,considering that preceeding A/C was same or lower wake turb. cat.- Vacate rwy immediatelly!!!