Episode # 108

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pilot_ngb
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Episode # 108

Postby pilot_ngb » Tue Nov 18, 2008 9:37 am

Hello everyone

Just some comments on the ON the field landing - It was a C182. The distance between 'where he was when it happened' versus 'where the scrambled aircraft came from' is probably <30nm. He landed at the field where the srambled aircraft took off from.

Over in the U.K., Mililtary controllers (and therefore pilots) practice PAR approaches all the time (you are talked down to 1/4nm I believe). Therefore the pilot of the scrambled aircraft was probably experienced in such procedures.

http://en.wikipedia.org/wiki/Image:PAR_Scope.jpg

It was reported in the press that the pilot had trouble seeing his instruments and did land 1/2 way down the 6000ft runway.

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jackhodgson
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Re: Episode # 108

Postby jackhodgson » Tue Nov 18, 2008 10:11 am

ngb,

thanks for the info. what's your source on the type of aircraft? The text referred to a "two seat cessna" but the pic was a 182. The press get this kind of thing confused all the time. We were wondering which was which.

Also, there remains a lot of confusion as to the extent of his vision loss. Do you have any new, add'l info on that? How "blind" was he really.

Nevertheless, kudos to the impaired pilot, and all the folks helping him. Good job!

-- Jack

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Tracy
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Re: Episode # 108

Postby Tracy » Wed Nov 19, 2008 7:32 pm

I seem to remember a discussion about the 747-400 and it's maximum take-off weight. The version I fly has a Maximum Start of Takeoff weight of 870,000 lbs, thought it can start it's taxi at 873,000, assuming it will burn off the difference getting to the runway. A couple of days ago we left the eastern U.S. bound for Japan with a planned flight time a little over thirteen and a half hours. Our take-off weight was about 863,000, as I remember, with about 360,000 lbs of fuel. We generally land with about 30,000 lbs. in the tanks. A rough guess on fuel burn is 25,000 lb./hr or around 3600 gal/hr. Not the kind of plane you (and 400 friends) would take to a pancake breakfast...

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Damia
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Re: Episode # 108

Postby Damia » Thu Nov 20, 2008 8:41 am

I would like to contribute with some facts about the wake turbulence. I refer to Spanish regulations, but to my understanding they closely follow ICAO recomendations, so they should be about the same everywhere.

Wake turbulence is a by-product of lift, so the most important factor that influences it is weight. Wake turbulence categories are as follows:

Heavy: MTOW of 136.000 Kg (300.000 lbs) and up
Medium: 7.000 Kg (15.400 lbs) to 136.000 Kg (300.000 lbs)
Light: 7.000 Kg (15.400 lbs) and less

Controllers aply a number of separations based on these categories. A typical one is waiting 2 minutes after a take-off/landing of a heavier ACFT.

But the importance of wake turbulence varies greatly with the shape of the wing. That's why some Medium weight ACFT are actually considered Heavy for wake turbulence. The most known of them is the B757, but others have been added to the list recently, like the B737-800.

Recently they have also added a new category "Super Heavy" for the A380. I am inclined to believe Airbus' claims that the A380 wake turbulence is no worse than the B747, because this was one of the requirements they set before they even started to design the new airplane.

So, what is wake turbulence?

Wake turbulence is composed mainly of jetwash and wingtip vortices. Jetwash is strong but has low range, so it is a hazard in the Apron, when you walk or taxi behind a jet. When in flight, we are speaking about the wingtip vortices. They are generated by the pressure gradients between the intrados and extrados of the lifting surfaces, and form a counter-rotating vortex pair that can persist for over three minutes. A small airplane caught inside one of these vortexes can be easily put upside-down, and full aileron deflection will not be enough to counter it.

Vortices are stronger with heavier weight, slower speeds and clean configurations. Helicopters generate stronger vortices proportional to their weight. They depend on lift, so they start with the rotation and end with the front gear touchdown. They move with the air mass and tend to dissipate quiclky in strong winds, but they will persist for a long time in calm wind. They descend at 400-500 fpm and stabilize about 1.000 ft behind the flight path.

So what should pilots do? Take off and land always 2 minutes after heavier aircraft, more if the wind is calm (controllers will understand) or if taking off from an intersection (more forward than the previous ACFT). Take off before the point where the previous ACFT did and with a higher climb angle. Land beyond the point of the previous ACFT and with a higher glide angle. Try to be higher and/or upwind of the flight path of the previous heavier aircraft.

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P.S. Dave, I am a fan of you. You know a lot about airplanes, you take beautiful pictures, you definitely can write, I laugh out loud listening to you irony and you pass on your joy of life. I want you to be around for a long time. So please, don't try to land behind a heavy aircraft. Always fly higher than their path. Take off behind and land beyond where they did.
Damià - LEMH

_____________________________________________________________________
There are three things you never turn down: a ride on an airplane and a free meal.
Burt Rutan

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PilotBillFromTexas
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Re: Episode # 108

Postby PilotBillFromTexas » Thu Nov 20, 2008 10:16 am

Good description of wake turbulence.

Is wake turbulence a factor for using parallell runways? Would the vortices stick around long enough for it to come into play or would a wind strong enough to blow the vortices sideways also dissipate those vortices in the process?

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champguy
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Re: Episode # 108

Postby champguy » Thu Nov 20, 2008 11:13 am

Heavies only fly from nasty places. Places full of concrete and glass, controllers and con men, rules and the people who like to enforce them. Not my kind of place.
Dave better join me out in the real world. The world of class "g", uncontrolled airspace, where you may always have a head wind, at least in a Champ, but the rules are lax, the turbulence is light, and there is always someone around to get you to a cheap motel next to a strip club while a front blows over.
Remember, not all who wander, are lost.
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Damia
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Re: Episode # 108

Postby Damia » Thu Nov 20, 2008 6:41 pm

PilotBillFromTexas wrote:Is wake turbulence a factor for using parallell runways?


Good question.

For traffics operating from parallel runways separated less than 760 meters, or when their flight paths will cross, ATC must provide the same separation as if they were operating from the same runway. No separation is required when runways 760m apart or more. That's why you will find many airports with parallel runways separated exactly 760m.
Damià - LEMH

_____________________________________________________________________
There are three things you never turn down: a ride on an airplane and a free meal.
Burt Rutan

pilot_ngb
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Re: Episode # 108

Postby pilot_ngb » Fri Nov 21, 2008 7:54 am

jackhodgson wrote:ngb,

thanks for the info. what's your source on the type of aircraft? The text referred to a "two seat cessna" but the pic was a 182. The press get this kind of thing confused all the time. We were wondering which was which.

-- Jack


I believe it was a C182 T. Media didn't report it too accurate. Believe he had been at FL150 (transition altitude is 6000') and started a decent to for refuel.

There is a recording available on the following link

http://news.bbc.co.uk/2/hi/uk_news/7716703.stm

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lucaberta
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Re: Episode # 108

Postby lucaberta » Sat Dec 06, 2008 8:18 pm

Damia wrote:P.S. Dave, I am a fan of you. You know a lot about airplanes, you take beautiful pictures, you definitely can write, I laugh out loud listening to you irony and you pass on your joy of life. I want you to be around for a long time. So please, don't try to land behind a heavy aircraft. Always fly higher than their path. Take off behind and land beyond where they did.

totally agree with Damià on this one. I have just listened once again to the bit around min 49 of the podcast and I am quite shocked to hear Dave saying to land *before* the touchdown point of the airliner, basically on the piano keys, in case of a landing behind heavy iron of front of us.

NO! NO! NO!

This is what happened a few years ago at Brussels International (EBBR) to a Cessna 182 who landed behind an MD11 on 25R:

Image

Two people died because of this accident. And this article on wake turbulence on Wikipedia:

http://en.wikipedia.org/wiki/Wake_turbulence

mentions something that I did not know; apparently the Learjet 45 that crashed on final approach in Mexico City last month encountered wake turbulence from the preceding B767-300 and the crew was not told they had a heavy before them:

http://www.youtube.com/watch?v=KDwq-qZ1y8o

ATC and radar recoring of the accident are here, very interesting document, audio in spanish but notes are also in english:

http://www.youtube.com/watch?v=XT5lBg8jDL8

The AIM mentions wake turbulence avoidance in Chapter 7, Section 3:

http://www.faa.gov/airports_airtraffic/ ... m0703.html

More specifically saying:

b. The following vortex avoidance procedures are recommended for the various situations:

1. Landing behind a larger aircraft- same runway. Stay at or above the larger aircraft's final approach flight path-note its touchdown point-land beyond it.


At or above, never below nor behind, Dave! And if you're landing on the same runway as a heavy, chances are you can land halfway on the runway and still have plenty to spare, so forget the piano keys and the aiming point, and just go for mid-runway and you're never going to have a problem.

More references to the new "super" heavy definition of the Airbus 380-800 can be found here:

http://www.skybrary.aero/index.php/Airb ... x_Guidance

I saw the A380 a few times when taxiing at London Heathrow lately, Singapore Airlines uses it on the SIN-LHR-SIN route now. Makes the 747-400 look small when they're parked side by side! Took a few pics of F-WWOW, the first A380, in his first public appearance at the Paris Bourget Airshow in 2005:

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Ciao, Luca
Luca Bertagnolio, CPL/ASEL/AMEL/ASES/IR

US States I've overflown or flown in:
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lucaberta
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Re: Episode # 108

Postby lucaberta » Sat Dec 06, 2008 8:50 pm

Last thing, since the paint scheme company owned by Craig was mentioned at the end of the episode...

A very good friend of mine from Italy, by the name of Mirco Pecorari, is the brain behind Aircraftstudiodesign of Modena, Italy, right in the middle of Ferrari-land.

Mirco works most of his with the USA, and I am sure he would love to get in touch with the podcast (maybe starting here on the forum) to tell you some of the things he's been working on for the last few years. Like these ones, for instance:

Nemesis NXT by Jon Sharp, Reno AIr Races winner:

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Bulldog by Jim LeRoy, RIP aviator :cry: :

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More testimonials are here:

http://www.aircraftstudiodesign.com/new ... onials.php

Mirco's website:

http://www.aircraftstudiodesign.com/new/eng/index.php

I know, shameless plug, but I am proud of seeing an italian becoming an important name in the US aviation market, and he's also my friend. :)

Ciao, Luca
Luca Bertagnolio, CPL/ASEL/AMEL/ASES/IR

US States I've overflown or flown in:
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