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flythere
Topic Author
Posts: 207
Joined: Sat May 22, 2010 3:24 pm

744 Can Stand More Crosswind Than 777 Or 340?

Thu Jul 21, 2011 3:44 pm

Sorry if there is any specific thread having talked about the crosswind problem. Wish some experts here can shed more data for justification.

The background of my question arose from a F-class flight report by a respected a.net member Sam Chui when he talks about departure from SFO. Link here: Cathay Pacific B747-400 First Class Transpacific (by N178UA Jul 21 2011 in Trip Reports)

He quoted from the ground staff that due to the cross-wind at SFO, only B747-400 were able to takeoff without safety breach, while all other B777 and A340 were grounded and delayed until the weather situation improves. It is a surprised to me that 744 can stand more crosswind than 777 or 340 based on the larger lateral area of the 744 fuselage. Of course there are many factors or hardware that could result in this.

Hope some experts here can provide more insight on this. Thank you.

P.S. Another two great J-class trip report up for your grasp.
Cathay Pacific New Business Class Experience (by N178UA Jul 13 2011 in Trip Reports)
Cathay Pacific New Business Class - CX 888 HKG-YVR (by fjiii Jul 19 2011 in Trip Reports)

[Edited 2011-07-21 08:45:23]
 
lowrider
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Thu Jul 21, 2011 3:57 pm

Companies may impose different limitations on how much crosswind is acceptable. We use a 36 knot component for landing, and 40 for take off.
 
migair54
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Joined: Thu Jun 14, 2007 4:24 am

RE: 744 Can Stand More Crosswind Than 777 Or 340?

Thu Jul 21, 2011 4:10 pm

The longer the plane the worse for wind......

Every plane has a different max crosswind limitation and also the company can impose even lower winds.....

Even for same family of planes the max crosswind component could be different (ATR42-ATR72) (A340-200 A340-600).....
 
fcogafa
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Thu Jul 21, 2011 4:57 pm

The A340 series is horrendous in crosswind landings, I've seen many go-arounds because of it. B777s seem solid as a rock!
 
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Zkpilot
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Thu Jul 21, 2011 5:00 pm

Suggest moving to tech ops forum
 
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bikerthai
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Thu Jul 21, 2011 7:16 pm

Don't the 747 have a main landing gear bogey that can "crab"? Would that help with cross wind take-off?

bikethai
 
roseflyer
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Thu Jul 21, 2011 7:20 pm

The 747 has a huge dual rudder. That's why it can take a higher crosswind and stay on centerline.
 
lowrider
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Thu Jul 21, 2011 9:28 pm

Quoting bikerthai (Reply 5):
Don't the 747 have a main landing gear bogey that can "crab"? Would that help with cross wind take-off?

No. The body gear (inboard pair of mains) are steerable on the ground, but they do not crab for crosswind landings.
 
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zeke
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Fri Jul 22, 2011 1:28 am

Quoting flythere (Thread starter):

He quoted from the ground staff that due to the cross-wind at SFO, only B747-400 were able to takeoff without safety breach, while all other B777 and A340 were grounded and delayed until the weather situation improves.

Ground staff had it the wrong way around, when everything else is flying the 744 is on the ground.

Type takeoff/landing

744 30/30
748 30/30
A330 32/40
A340 37.5/41
772 - 38/38
773 - 38/38
77W - 38/38
 
Max Q
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Fri Jul 22, 2011 7:32 am

It's not that simple.



Boeing gives operators guidelines, with crosswinds they will tell them what their maximum demonstrated crosswind component reached in testing was.



It is up to the individual Airline what limits they want to set (they would not set these above max demonstrated)



Not only that there will be different limits for wet and dry or contaminated runways.
 
spencer
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Fri Jul 22, 2011 10:57 am

I believe the size of the fin on the B747 basically turns it into a huge weathercock, resulting in a more "into wind" approach/departure.
Spence
 
lowrider
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Joined: Wed Jun 30, 2004 3:09 am

RE: 744 Can Stand More Crosswind Than 777 Or 340?

Fri Jul 22, 2011 12:57 pm

Quoting zeke (Reply 8):
744 30/30

Interesting, we operate the same type, but allow for more component. I have heard that the Rollers have a little less ground clearance than the Lightbulbs (GE). Do you know if that is true and could be the source of the difference?
 
Pihero
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Fri Jul 22, 2011 5:14 pm

Quoting fcogafa (Reply 3):
The A340 series is horrendous in crosswind landings, I've seen many go-arounds because of it. B777s seem solid as a rock!

Strange statement... and apparently not from personal experience.
How much credibility should I give it ?.. especially after Zeke's post... and my own experience ?..
 
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zeke
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Fri Jul 22, 2011 7:07 pm

Quoting lowrider (Reply 11):
Do you know if that is true and could be the source of the difference?

I would suggest the difference would be that CX operate under a European certification (JAR) rather than US (FAA) certification. CX have RR/GE/PW engines.
 
flythere
Topic Author
Posts: 207
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Fri Jul 22, 2011 8:55 pm

Quoting zeke (Reply 8):

Ground staff had it the wrong way around, when everything else is flying the 744 is on the ground.

Type takeoff/landing

744 30/30
748 30/30
A330 32/40
A340 37.5/41
772 - 38/38
773 - 38/38
77W - 38/38


So does it mean that CX operates their 744 in a more lenient way regarding the crosswind situation than some other airlines/aircrafts?
 
lowrider
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Fri Jul 22, 2011 9:14 pm

Quoting zeke (Reply 13):
CX have RR/GE/PW engines.

Thought you guys were all Rolls on the 74. Thanks.
 
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zeke
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Joined: Thu Dec 14, 2006 1:42 pm

RE: 744 Can Stand More Crosswind Than 777 Or 340?

Sat Jul 23, 2011 3:30 am

Quoting flythere (Reply 14):

So does it mean that CX operates their 744 in a more lenient way regarding the crosswind situation than some other airlines/aircrafts?

CX would operate to the flight manual limits associated with its certificate of airworthiness, however the 744 has more than one flight manual issued by Boeing depending on the certification basis. CX basically operates under EU OPS, and generally has used the JAR certification basis, however I think the 777 maybe FAA basis.

Quoting lowrider (Reply 15):
Thought you guys were all Rolls on the 74. Thanks.

These are the aircraft covered by the CX manuals

744 RR HOP/R/S/T/V/W/X/Y
744 RR HUA/B/D/E/F/G/I/J
744 PW4056 HKE/F/T/U/V
744F RR HUH/K/L/O/P/Q
744BCF RR HOU/Z/R/S
744BCF PW4056 HKH/J/X
744BCF PW4056 KAE/F/G/H/I
744ERF PW4062A LIA/B/C/D/E/F
748F GEnx 2B LJA/B/C/D/E/F/G/H/I/J
 
tdscanuck
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Joined: Wed Jan 11, 2006 7:25 am

RE: 744 Can Stand More Crosswind Than 777 Or 340?

Sat Jul 23, 2011 4:11 am

Quoting flythere (Thread starter):
It is a surprised to me that 744 can stand more crosswind than 777 or 340

The true crosswind capability on any airliner is usually far in excess of that used in service. The aircraft is almost certainly physically capable of landing in higher than the demonstrated max (it's just the highest number the OEM found during testing and you can't control the wind) and almost no airline will have their operating spec allowing up to the demonstrated max.

Tom.
 
JoeCanuck
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RE: 744 Can Stand More Crosswind Than 777 Or 340?

Sat Jul 23, 2011 5:56 am

It's a huge difference in scale but a 172 has a 15 knot maximum demonstrated crosswind rating. All that means is that's the max it's been tested to...they never do test it to the point it loses control. That gets a bit on the dangerous side. It's also not a recommendation to land in 15 knot crosswinds...just what the plane can safely handle...not necessarily the pilot.

I wouldn't be surprised if the big tin is tested in much the same way.

15 knots in a 172 is very entertaining though...

Now back to your regularly scheduled thread...
 
Kaiarahi
Posts: 1810
Joined: Tue Jul 07, 2009 6:55 pm

RE: 744 Can Stand More Crosswind Than 777 Or 340?

Mon Jul 25, 2011 10:09 pm

Quoting JoeCanuck (Reply 18):
15 knots in a 172 is very entertaining though...

   I got my PPL here (WLG) in 1969 on 152/172s    http://www.youtube.com/watch?v=P_LaAkAyoz0
Never learned how to wheelbarrow though.

[Edited 2011-07-25 15:11:44]

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