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seasun
2nd Jun 2008, 17:08
Hi guys,
I heard that for some (airlines)theoretical tests they asked a question about crosswind:
Is it better to take off with right or left crosswind? We don't have other info like if it's a turbo prop or jet...
Does anybody have an idea of the good answer?
thank you:ok:

roljoe
2nd Jun 2008, 20:34
Hi,

a simple start for that discussion is,

with propellers, as long as they 're rotating the same way, a critical engine is determined simply because the yaw momentum is different considering the right or left engine...in case of failure of the "critical" one..
In other words the critical one is asking you more aerodynamic force to counteract yaw momentum...

For a jet engines, no critical engine , in that way of thinking exist...but other aspects have to be taken into account..

To answer your question, the critical engine will already consume all the aerodynamic power you get..so adding a crosswind...and you could be out of control..(directionnaly speaking)..

rgds

seasun
2nd Jun 2008, 21:06
thank you for your reply;)

airfoilmod
3rd Jun 2008, 03:05
Since it's theoretical, always make sure the failure is downwind. That way your VS will weathervane into the good one.

Airfoil



(for the journolists: this is a joke, K?)

Creedy Cat
3rd Jun 2008, 03:29
On this subject of crosswind takeoff or for that matter, crosswind landing.....do simulators the necessary fidelity to realistically simulate a real simulator landing? A pal of mind was up in Korea for a B777 sim training and was failed by the check airman because it was claimed that he had insufficient aileron input for drift correction on take off and residual drift during landing. He maintained that to follow the Korean Alteon recommendation during training, he had to employ almost full aileron into the wind for a 30kts crosswind takeoff!!! I have never seen such a massive aileron input for cosswind takeoffs within aircraft certification limit. Likewise during training for landing with decrabbing, he had to use full cross aileron as opposite rudder input was employed to decrab. In his final check he has used reduced aileron input as he felt pretty uncomfortable with such hefty inputs.......as such he employed a combination of wing low and slight decrab on landing, landing with a small crab angle on touchdown which he subsequently removed upon touchdown. The checker failed him, claiming it was a bad and hard landing even though the sim did not show any indication of hard landing or crash landing!

Is the sim so realistic to assess landings like that?

airfoilmod
3rd Jun 2008, 03:43
I'm trying to decipher.... "realistically simulate a real simulator landing". But if I'm right, I think the answer could be Remember, aileron input is dependent on airspeed and strength of xwind. Maximum deflection is a functional limit, so yes, the CA was a little harsh, but what's his testimony?

airfoil

TyroPicard
3rd Jun 2008, 10:12
seasun
I suggest you have a think about what the wind direction does with a gust which increases the wind speed - there may be a topic for discussion there.
TP

DFC
3rd Jun 2008, 23:43
I suggest you have a think about what the wind direction does with a gust which increases the wind speed


Yes and remember that having the 90deg crosswind on the left is only good in the northern hemisphere.

Regards,

DFC

TyroPicard
4th Jun 2008, 15:24
Now you've gone and given it away!:ugh:

woodyspooney
10th Jun 2008, 03:37
Hi Creedy Cat,

I don't suppose your pal had the misfortune of meeting the alteon check airman ' juan killing-ham ' ? Some years ago, this canuck failed a very good pilot friend of mine for a ridiculous reason when that individual decrab on the runway...it seem odd for people who have never flown a plane with a long wheel truck like the triple 7. This checker has never physically flown a 777, only the sim and he thinks the B777 sim behaves exactly like the plane. Strange that Alteon allow people who have never flown a t7 to be a checker on aircraft type!

Bubi352
10th Jun 2008, 04:52
"On this subject of crosswind takeoff or for that matter, crosswind landing.....do simulators the necessary fidelity to realistically simulate a real simulator landing? A pal of mind was up in Korea for a B777 sim training and was failed by the check airman because it was claimed that he had insufficient aileron input for drift correction on take off and residual drift during landing. He maintained that to follow the Korean Alteon recommendation during training, he had to employ almost full aileron into the wind for a 30kts crosswind takeoff!!! I have never seen such a massive aileron input for cosswind takeoffs within aircraft certification limit. Likewise during training for landing with decrabbing, he had to use full cross aileron as opposite rudder input was employed to decrab. In his final check he has used reduced aileron input as he felt pretty uncomfortable with such hefty inputs.......as such he employed a combination of wing low and slight decrab on landing, landing with a small crab angle on touchdown which he subsequently removed upon touchdown. The checker failed him, claiming it was a bad and hard landing even though the sim did not show any indication of hard landing or crash landing! Is the sim so realistic to assess landings like that?"






I have been an examiner in the past and it's always the same story: "The examiner failed me". Yep, it's never "I failed".

oztrekker
10th Jun 2008, 05:51
Do not be so smug my friend; in my many years as a TRI/TRE I have come across many idiots who think that failing another pilot on their whims and fancies are a God given right. I have operated and checked on the most modern B777 simulators and I can tell you that none come close to behaving like the aircraft, especially during landing. Bear in mind in the sim, it's the visuals which are in motion and though the sim structure does move it is certainly not an actual aircraft. The sim is a tool to teach and examine procedures, manoeuvres and correct manipulations of flight controls, etc. However to fail someone for a landing ( unless it is a crash landing, or drift off the runway or an extremely hard landing indicated on the sim operator's panel ) as described by C Cat is definitely unwarranted.

411A
10th Jun 2008, 08:53
I have come across many dickheads who think that failing another pilot on their whims and fancies are a God given right.

Absolutely correct.
As a TRE/IRE for quite sometime, it is my opinion that those who practise failing, just for the sake of 'failing' should be expunged from the profession...forever.
Period.
These malcontents have no place in professional airline flying/checking.

Spooky 2
10th Jun 2008, 15:43
I can assure you that there is no language in the B777 FCTM that suggests the technique that you have described. Boeing x-wind landings are catergorized as folows;

De-crab during flare
Touchdown in crab
Sideslip

None of these involve a full deflection of aileron during the landing phase.

Barney Rock
10th Jun 2008, 19:24
Some sims have fidelity problems, the KAL sims which Alteon uses have those characteristics described. Exaggerated aileron inputs required during cross wind operations during take offs and landings.

Mat Sabo
11th Jun 2008, 18:09
At almost every check for other pilots TREs maintain that the sim is 100% accurate UNLESS IT IS THEIR OWN CHECK when they will argue and swear on their great grandparents' graves that their performance is fine, it's the sim that lacks fidelity!!! Almost always the case!

foustou
11th Jun 2008, 20:57
Speaking of performance it's better to have a left crosswind on a take off because wind turns 30 by the right with altitude(north hemisphere). If you take off with a right crosswind on the ground you might encounter tail wind component after lift off. But that it very theoretic.