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Wake Turbulence - Did you know...?

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Wake Turbulence - Did you know...?

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Old 6th Nov 2008, 22:42
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Wake Turbulence - Did you know...?

I fly a 747-200 in my "normal life" - and sometimes moonlighting as Learjet pilot.
So, I know about wake turbulence, and how it feels in a Lear following a "metal overcast"...
But did you know this...?
xxx
Many of us are bad guys in the 747 and other similar planes.
No more than you dislike wake turbulence, we have the same opinion.
If I follow a MD-11 on ILS, I often fly the approach above the glide slope.
At least one half dot, sometimes a dot above to avoid the wake turbulence of the guy up front.
xxx
I do not get to fly often, so I never "couple the ILS" (unless low visibility).
My landing runways are generally the 10 or 12,000 feet long "variety".
If that MD-11 up front touches down at 2,000 feet down, I might go for a point further down.
Even with very little braking, I can stop and still have plenty of concrete left.
Is it me only...? No... many other idiots do like me.
xxx
Where does that leave you...? - Well, first, now, you know about it.
Then, your Citation is also landing on that 12,000 feet long boulevard.
So you can fly an approach "1 dot above" and touch down 3,000 feet beyond threshold.
Still leaves you with 9,000 feet to "attempt" to stop your "Gucci Jet".
With a LR-31 or 35, I only need 4,000 or less to stop with only idle reverse.
So, be careful if too close behind.
xxx

Happy contrails
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Old 7th Nov 2008, 00:02
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Amazing what you can do with Microsoft Flight sim and no one gets hurt

Pace
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Old 7th Nov 2008, 03:20
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Pace...... look at the posters other posts and you will probably discover that he doesn’t know what MSFS is! In fact he was flying for PanAm when i was in diapers!

BelArgUSA, Interested procedure for the 747, but if you want to avoid the wake, why don’t you slow down sooner? Why plan to waste 1500 feet of runway?

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Old 7th Nov 2008, 04:06
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ATC will probably have told you what speed to fly and squeeze you in so seperation may be down to minimums.

BelArgUSA is making his point about wake down the ILS so you will have set the bug speed by then for landing. if he lands behind the touchdown point of the aircraft before him, its wake will still be there as it would have sunk down onto the ground.

to avoide the wake of the aircraft before you, you land after its touchdown point therefore being above its wake turbulance all the way down the ILS as your alwase higher than it.
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Old 7th Nov 2008, 04:32
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He's making a point that he flies a dot high; fly the glideslope and you'll be in his wake. He may also land a little longer, just like anyone else does in a light airplane. It's a courtesy message to educate others that the large airplane ahead may very well be doing the same thing that many light airplane pilots do.

When I fly an approach in a Lear behind a heavy aircraft, I tend to fly a little high, too. I land a little long.

In a 747, I tend to fly with the needles centered and if I land long it's simply because I'm a poor pilot. BelArgUSA does it becuase he's avoiding wake turbulence. Regardless, his point is valid; stay heads up for wake. Don't assume that it's settled below if flying on the glideslope, and be aware that even large airplanes take measures to avoid wake...which might include landing past the touchdown point of the preceding aircraft, in some cases.
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Old 7th Nov 2008, 06:50
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Gracias Sr. Guppy -
xxx
Just thought about wake turbulence because of that Lear accident in Mexico.
Once got behind a ??? at LAX in a Lear... We got beyond 90º bank...
Passengers not too happy.
xxx

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Old 7th Nov 2008, 06:59
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...... and be particularly wary of any B757 ahead of you.

It's becoming an increasingly rare aircraft in the Euro/Mid East context meaning there's a whole new generation of Biz pilots who might not have first hand knowledge of exactly what that aircraft can do to those following.

That's not some anti Boeing mini rant. I've 4000 hours on the 75 and is my career favourite transport aircraft. Be very careful - your own personal checklist of wake turbulence conditions and mitigation simply isn't good enough.

Rob
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Old 7th Nov 2008, 07:15
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I do not get to fly often, so I never "couple the ILS" (unless low visibility).
My landing runways are generally the 10 or 12,000 feet long "variety".
If that MD-11 up front touches down at 2,000 feet down, I might go for a point further down.
Even with very little braking, I can stop and still have plenty of concrete left.
Is it me only...? No... many other idiots do like me.
xxx
Not landing on or near the numbers especially in a heavy is surely a high risk practice to get into especially if you use the same techique on runways which are not quite so length generous.

Landing ahead of another aircraft which itself has landed long must mean that you are estimating the available runway still available visually?

I am not a large jet pilot but know that in those aircraft the technique expected is not to even go for a smooth touchdown nowadays. Rather to plant it on the numbers and not risk any float thus maximising the available runway length.

Lighter aircraft where there is loads of runway is a different matter and landing late can even be used for waiting for an aircraft to clear that has landed ahead as well as for wake turbulence but dont think such operating mode would go down too well as a principal with large passeneger jets especially by a Captain who doesnt fly too often and doesnt couple on the ILS to get some hands on practice

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Old 7th Nov 2008, 07:59
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He flies by hand to keep in practice. I will happily swap my hours for his 10s of thousands
Spunky Monkey

I dont know everyone here or their hours Maybe he is of the old set who do things differently but dont think that advice would go down to well with the airline nowadays

What has happened with ATC spacing and the pilots own speed control and spacing to be in that position anyway?

Pace

Last edited by Pace; 7th Nov 2008 at 09:12.
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Old 7th Nov 2008, 08:09
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As far as I know wake turbulences tends to go down with a 500ft/min Vz which means that if the guy in front of you is on the GS and that you follow the same path, you should be 500 ft above its wake when passing a minute after him.
In addition, should you be landing facing the wind (which is generally recommended), the wake should be little bit pushed back thus increasing its clearance from the glide path.

Does this make sense ?
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Old 7th Nov 2008, 10:16
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so if you fly one dot above and I´m behind you, how much above should I fly to avoid your wake turbulence? Be serious, no one in a 747 flies one dot above, I fly a Lear60 with a proportion of 1 Lb trust = 2 Lb weight and my Vapp is 150-160 knots, I need runway to stop and if I can I always go to the numbers. Don´t f..k us and fly your needles or you will end f...ing someone behind and then be sorry because he crashed for flying one dot behind a heavy.
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Old 7th Nov 2008, 11:23
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I do fly the G/S "right on" when not following another heavy.
If behind another heavy, no wind, I will be slightly above, up to 1 dot.
I merely get 1 or 2 landings monthly... being relegated to check captain.
Selecting "LAND" with the autopilot is not a form of practice.
I always fly at Vref+5 as speed, which is generally 140-145 knots.
It is rare that I do have less than a 10,000+ft long runway.
And yes, it is also rare, that the RVR is less than basic visual conditions.
xxx
Plenty of practice in simulators... I still love to be in the "real machine"...
Besides, I hang my hat for good at the end of the month.
So I will be out of your airspace. Share it with other nerds and geeks.
That beach in Brazil sounds better every day that goes by.
xxx
This thread was to inform bizjet pilots as to how 747s are sometimes flown.
Sadly, a Lear just "bought the farm" in MEX, 2 days ago.
Wake turbulence was likely in their case. They were behind a 767.
But, you know better than me... I am from a third world nation airline.
I fly an airplane nearly 30 years old, soon to be retired as well.
xxx

Happy contrails, from the "old fart" -
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Old 7th Nov 2008, 11:33
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BelArgUSA

Good post and thanks for bringing our attention again to the continuing hazards of wake turbulence. I go along with what you say.

I am especially vigilant when I am landing on a runway, behind other aircraft in slight tail wind/drift conditions. These conditions bring the wake of preceding aircraft "forward" of course. Wake from an aircraft of the same weight category can be unpleasant enough.

As an addition I always carry an extra 5 to 10 knots* above bug (money in bank) on approach and in some cases, until touchdown. I can easily and soon get rid of that extra 10 knots if and when I want to. Much easier than trying to gain 10 knots lost, when even more "behind the drag curve". get "slow in a Lear" and you die, as I am sure anyone who flies or has flown one will agree.

* I can't fly within +/- 5 knots at my age!

Last edited by weido_salt; 7th Nov 2008 at 11:53.
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Old 7th Nov 2008, 12:02
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BelArgUsa

I am not knocking your advice as you are obviously a thinking pilot rather than a computer mentality pilot.

Your flying is real flying compared to the highly regulated and highly automated type of flying today.

Having flown third world ferries in what can only be described as "character" business jets I would identify with you more than the new way. I can think of some hot, high, and heavy takeoffs we made which were not even in the performance graphs but we had massive runways in Africa so more a case of needbe and estimate the takeoff figures.

My son is flying for Easy Jet on a 737 at the age of 22 in the UK. They no longer land aeroplanes but have forced arrivals for fear of using a foot more runway than need be and it made me wonder how they would take such advice? What do you do in the same situation where your runway length is more limited?

Spunky Monkey

The reason I fly corporate is the same as yours It was the ref to landing past a heavy which itself landed long which concerned me not so much on a massive runway but using the same technique on shorter runways, not the dot high on the glide.

BelArgUSA

Good luck with the retirement

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Old 7th Nov 2008, 12:22
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May I humbly suggest that if one flies one dot above the glide and the other one with unreasonable excess speed all the way to touch down, the two combined could lead to disaster or not far from it.
Slippery aircrafts such as modern commercial jets, are not often of the forgiving type.
I do not have BelArgUSA's experience (and he didn't imply he was doing both either) so in my limited view, I can say that whether I flew the 75/76/73 or the smaller Citations, Vref+5 at the threshold (Corrected with half the wind + full gust to a max of 20kts), on the glide has always worked well enough.

But I do take note of other's ways to operate...

Last edited by PPRuNeUser0215; 7th Nov 2008 at 15:34.
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Old 7th Nov 2008, 13:40
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Thumbs down BelArgo

Well Paul, there are some out there Mon Brave

Last edited by merlinxx; 7th Nov 2008 at 13:46. Reason: Post withdrawn
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Old 7th Nov 2008, 13:52
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AMEX,
I don´t know where you fly, where I fly (mostly europe) I´ll be told either by the plate or ATC how quick to fly (yeah I´m the captain, still I like the Idea of complying to instructions). So there is not to much room for straying from speed. (especially not at airports that are served with the heavies -the 57 aside)
The seperation we get here is usually 5 or 6 nm behind heavies (depend on your own weight class)

I had 2 closer shapes with wakes, one in a CJ2 behind a 757 and one in a KingAir behind a Fokker 50. Both have been in weather when by the book, you would not have expected it.

Still I´d like the big fellows at least tell us if they fly high on the GS. I usually fly high as well.

BTW, anyone else noticed that newbies have a real trouble to fliy exactly one dot off whilst they are really good on flying on the glide? Maybe I was the same, but I don´t recall.

BelArgUSA: happy retirement! Wish I would be short before it as well...
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Old 7th Nov 2008, 13:54
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AMEX -
xxx
The way I land a 747 to stop it on a 5,500 ft runway, or 12,000 ft is quite different.
You do not know how the idiot preceding you on the ILS is...
I am teaching constantly how the other stupid guys could be.
Call it teaching "awareness".
Who knows, I am one of them.
xxx
Do not assume that everyone is flying "by the book" in all circumstances.
If you are that perfect, ok. I am not. Just human.
Now that I leave the career, I still want to help the young ones.
I learned from my "seniors" as well, and sometimes from my F/Os or F/Es...
Pprune is great for all of us. Did not exist when I learned to fly.
All the best to all of you, fly safe.
xxx

Happy contrails, always
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Old 7th Nov 2008, 14:15
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Merlinxx

I really will write that book... nobody will believe some paragraphs...
Like going to Tel Aviv for maintenance with a plane in Saudia colors...
Coming from Jeddah, making a touch-and-go in Larnaca.
xxx
Will not forget to send you a print, if I ever publish it...
You will laugh at some of the details, and remember some of the characters.
Who was that guy with "leathers and chains" in his flight kit, passing customs...?
xxx
I raise my glass. The "sadiqi" here is tastier - "caipirinha"...!

Happy contrails
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Old 7th Nov 2008, 14:41
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Wake Turbulence

Good information and good posts.

In my aviation career I found that common sense in any situation was the best method and in particular to keep your thinking ahead of the aircraft you are flying.

Your last landing will then be a good one.

Tmb
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