Ryanair and 757 'vortex'

[throw a dyce]

The 757 should always have been put in the heavy cat once the problem was identified (20 years ago).
I'm sure the CAA baulked because it would have had a drastic impact on the movement rate at the flagship Heathrow.BA had nothing but 757s some years ago.Different now that they have been replaced with Airbus.
I treat them as a Heavy inbound and outbound.Ok it's covering your back,but you get skilled at that after 3 years in HongKong.

[Gonzo]

Dyce,

Shouldn't have mattered. An exception could have been made. As we all know, the air around the UK's busier airports is different than the air around the rest of the UK. We only need 7 miles Heavy-Light rather than 8, etc etc...

[throw a dyce]

Yup, 2 and a half miles down final on a sunny day as well. Maybe it's the right kind of light or something.ICAO you only need 6 miles for Heavy/Light behind.
It's not the first time there has been strange classifications.Anyone that ever saw a Chinook knows that it isn't a small.It's horrific.Reckon that the BAA wasted a fortune with snow clearing equipment.Just get that thing to fly down the runway.Now thats a snow blower.
Anyway I digress again.A 744 skipper friend said the vortex off a 757 at LL spacing was enough to bounce a Jumbo around.I think that the 757 should be treated with utmost caution.

[BOAC]

I have received this from a source I trust well and offer it (edited) for serious consideration on this topic. The first point being made is that without reports to ATC, or ASRs, you CANNOT expect to get any change in the grading of a particular type, regardless of 'what you think of the CAA'. The second clarifies why we have separation.

If a pilot experiences a significant wake encounter, the appropriate response should be to report the incident to ATC at the time to permit the circumstances to be subsequently investigated. It's not much use making an assertion that the problem has been around for years and yet not acknowledged by the CAA et al, if there is a lack of substantive evidence of the problem as a result of, for whatever reasons, pilots electing not to report such encounters.

There would appear to be a misunderstanding among some of the contributors to the thread as to the purpose of the wake vortex separation standards; these are not to eliminate the possibility of an encounter but to limit the roll accelerations/bank angles generated by an inadvertent penetration of the vortex. The transient characteristics of a wake encounter, whilst being disconcerting for a pilot who might not have anticipated one, are such that they rarely result in roll rates/bank angles close to those considered to be acceptable.

Following my post I have received more information, again edited:

AIC 17/99 (still extant) Para. 6 references the importance of wake vortex reports in that they “allow an assessment of the effectiveness of the current standards in providing a satisfactory level of safety” [my underlining], and explains their use in research and the availability of wake vortex report forms. If you don’t have access to the AIC, the procedure is that if a verbal report is made to an ATSU in the UK a report form will be normally made available to the pilot concerned and, where possible, the pilot of the aircraft believed to have caused the wake. Report forms are also available from the Flight Briefing Unit at LHR. You should also be able to ask your Safety Officer for the forms.

[Pointer]

2 min's from when?

Reading some comments on why a F100 takes only 1 min and some 738 takes 2 min; Maybe there are different ways these people take a timing?

The correct way: timing starts from the moment of rotation, however my experience is that some people take it from the time they line up... eg that could be quite a bit longer then.

Pointer

[GuruCube]

Originally Posted by throw a dyce

The 757 should always have been put in the heavy cat once the problem was identified (20 years ago).

Erm.... that would enable a neat 1min split behind a 777.....!

Im not doubting the effects of them, nor previous comments, but referring back to my previous remarks; 90% of the time its no problem and look at the regular situation with a Dash 8 going wheels up behind a 757 from an intersection. Yet classing it as a Heavy would be a nightmare and could lead to significantly worse situations!
I think we should all be aware it is M+ and of the possibility of extra time needed, and crews should be aware of the minimum requirements in the country they are operating!

[clicker]

Slightly off topic

Albeit taken on an approach but this pictures a good one for the disturbed wake.

http://www.airliners.net/open.file?i...v_id=&next_id=