RYR depart 1 min 20 behind a heavy.....

[kick the tires]

Yesterday I heard someone warn a RYR that he was starting his take off just 1 min and 20 secs after an Iberia A-340. Then a second warning, but he continued anyway!

I know that the Spanish class the -800 as HVY for landing separation, but is this the case for take-off; surely not??

[HEATHROW DIRECTOR]

Then it was an ATC error in clearing him for take-off too soon.

[Henri737]

Wake can kill.
Eventually they will find out the hard way.

[Microburst2002]

You are right about the xwind, imho, but, where is that pilot discretion written?

[goldeneaglepilot]

Having instructed GA (PPL / CPL) pilots at a busy international airport (in the good old days when they encouraged GA at the same airfield) you become accutely aware of wake turbulence both on takeoff and landing. Its rate of disipation does vary according to external factors (wind strength, direction, ground features) and yes sometimes you would be offered a takeoff earlier than you might expect, but it is always the pilots discretion as to accepting that clearance.

The thread does bring back memories of doing "clover leaf" circuits when the wind was light so as to avoid the turbulence (takeoff 33, touch and go onto 24 back to 05 - keeps a student mentally active !!)

[Serenity]

Several times from non uk airports i have been given take off clearance with the
" caution wake turbulance, cleared take off"

i take this to mean i am cleared to go but separation is down to me. if i want to wait, i say and tell them when im rolling, dont take it to mean you have to go regardless!!

[Checkboard]

You are right about the xwind, imho, but, where is that pilot discretion written?
I know Unhooked, at 61N, isn't in Australia but the Australian regs allow a pilot to "accept a waiver" on the separation. I have to say I never heard a single pilot use that particular rule in many years operating there!

[Doug E Style]

At a major European airport that I go to frequently, they often clear you to line up in sequence and if the preceding aircraft is a heavy, once it's airborne they say something like, "take all the time you need for the wake turbulence, cleared for take off". This puts the onus on us to decide when we will start the take off roll but as it is common practice for us to start a stopwatch when the preceding aircraft is a heavy, it seems a reasonable practice to me. After all, we are trusted to do plenty of other things ourselves.

[bad bear]

My understanding is that the wake separation is " recomended" not compulsory.
If the air is unstable or there is a strong wind / cross wind wake is unlikely to be a problem. I did read that a system for detecting wake is being developed and I would assume it will increase the departure flow rate when wake is not an issue
b b

[WaterMeths]

At the end of the day guys - covering your ar*e is the nature of the beast - so that when for that inexplainable reason you find the aircraft has smacked down on the ground - the lawyers are not going to be able to point the finger at wake separation rules.

Waiting an extra 40 seconds (in this case) is it really going to screw up the on time performance for the day?

The other scenario certainly would.

Fly Safe...

WM

[kick the tires]

wind was calm, slight tailwind when airborne.

I've taken off behind a heavy at +2 mins and still had some uncomfortable encounters.

Madrid ATC weren't interested, they even acknowledged the 1.20 warning!

[arem]

Could have been a case of a very heavy A340 rotating a long way down the runway and RYR not so heavy and knowing he was going to be airborne way before where the A340 rotated,and would be above the 340's flight path during the climb out - its called exercising one's discretion!!!

[Basil]

Could have been a case of a very heavy A340 rotating a long way down the runway and RYR not so heavy and knowing he was going to be airborne way before where the A340 rotated,and would be above the 340's flight path during the climb out - its called exercising one's discretion!!!
Unless, of course, one has a donk stop apres V1 :ooh:
Yes, I know, I must be getting to be a boring old woman.

Not wishing to teach egg sucking but remember that a slight x-wind could hold the vortex on the runway.

I posted on another thread about tiles being removed from roofs that we'd been having a beer close to an airport one evening when a vortex arrived on the terrace - quite invigorating.

[Zoso]

Just cos he rotated a long way down the runway doesn't necessarily mean the A340 is very heavy.

[Basil]

Zoso, Don't be cruel!

[stator vane]

'i heard' ....

it starts right there!

how about some more specific information before coming to any conclusions!

did you hear it? you were on the frequency? the same runway? they have parallels don't they?

who gave the clearance? who gave the warnings? same controller-pilots are starting now to add in some information on the frequency? sounds questionable.

[General_Kirby]

This is a total non event.
If he was CLEARED for take off after 1.20, then give or take a few seconds, he would have become airborne exactly 2minutes behind the heavy. Which is correct.

What some pilots fail to understand is that vortex is timed from rotation of the 1st departure to the rotation of the 2nd. So the take off roll is included in this calculation. Of course you may want extra time in certain situations which is never a problem, as long as you tell us before you line up.

I speak only for the UK, but this is how controllers here are trained.

[Firestorm]

And do you start the watch when the preceeding aeroplane begins it's take off roll, or at it's rotation point?

[HEATHROW DIRECTOR]

>>What was the wind at the time? With a strong x-wind the time seperation may be reduced at the pilots discretion. >>

Where I worked ATC provided the time separation, which was rigidly enforced even if a pilot said "we're happy to go".

[General_Kirby]

"vortex is timed from rotation of the 1st departure to the rotation of the 2nd"

And yes, thats where we use our judgement of the length of the 2nd's take off run.

[safelife]

I wonder no one mentions Rome. In FCO departing runway 25 they clear you to take off as soon as the preceeding lifts off.
However I have witnessed that only with medium behind medium (but mind you that can mean rather small bizjet behind A321).

[kick the tires]

Stator,

We were no 3 for 15R, RYR 7764 was the aircraft in question, taking off on 15R immediately behind an A-340, also on 15R. A pilot gave the 'warning'. ATC said "ok' or words to that effect.

Heathrow Director,

Does your timing start from take off roll or rotation point? I've never heard of the later being a criteria. I do, however, always witness aircraft releasing brakes at the 2 min point in the UK...... (not that wake turbulence knows which nation it is about to bite!!)

[BusBoy]

if you tell BCN that you require 2 mins they cancel t/o clearance and slot a couple of Spanish in ahead of you.
I'll sit there all day rather than busting 2 mins!!

[sarah737]

Maybe everybody was happy because it was 2 min and the policeman simply timed it wrong...
Probably the same policeman who always sees 10 or 20 knots more than he actually flies!

[411A]

Get a grip here, folks.
If the concerned FD crew were quite happy with their clearance, as was ATC, it is hardly anyone elses business...now is it?

I would suggest for those that are so quick to criticise...none of your business.:rolleyes:

[gatbusdriver]

Too many people here like to be judge, jury and executioner. Lets not hang these guys yet until there is concrete evidence. Although it does sound like we have a very good eye witness account.

I've been on a flight (as pax) where the captain used his discretion and did not apply sensible wake separation for T/O. We ended up with approx 15 degrees right wing down followed immediately by approx 25 degrees left wing down, this all happened just after rotation. Not pleasant at all!

[Bearcat]

yawn.......anything else goin on?

[ray cosmic]

Heathrow Director, some years ago I flew into LHR as well and seem to recall often distance separation was used as well instead of time separation. On take off. Do I recall correct, or is this impossible?

[Nicholas49]

gatbusdriver - out of interest what aircraft type were you flying in as a passenger? An A320 / B737? Sounds terrifying!

[HEATHROW DIRECTOR]

ray cosmic. Distance separation on landing, time on take-off. Distance on take-off was rarely used when I left there, nearly 20 years ago so doubt if it's used now. Occasionally, with a fast following a slow we would contact the TMA if time was going to be excessive and they'd agree to 4nm, or something similar.

Standby for someone current who knows what he's talking about!