Why is x-wind an engine limitation?
Thread Starter
Joined: Feb 2012
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From: hong kong
Why is x-wind an engine limitation?
The Airbus A330 manual states the following:
"Wind for takeoff:
‐ Maximum certified crosswind................................................... ......................... 32 kt (gust included)
Note: The maximum certified crosswind value is an Airplane Flight Manual (AFM) limitation. It is an engine limitation."
I understand that the placement of an engine may limit the angle of bank allowable to compensate for x-wind. However, I doubt they mean this by saying "engine limitation", so what factor is actually limiting?
The Max demonstrated x-wind is 40kts, and is stated as not being an AFM tlimitation. I assume this means we know it will go past 32kts, but your insurance ends there. So why is it called an "engine limitation?"
"Wind for takeoff:
‐ Maximum certified crosswind................................................... ......................... 32 kt (gust included)
Note: The maximum certified crosswind value is an Airplane Flight Manual (AFM) limitation. It is an engine limitation."
I understand that the placement of an engine may limit the angle of bank allowable to compensate for x-wind. However, I doubt they mean this by saying "engine limitation", so what factor is actually limiting?
The Max demonstrated x-wind is 40kts, and is stated as not being an AFM tlimitation. I assume this means we know it will go past 32kts, but your insurance ends there. So why is it called an "engine limitation?"
Joined: Feb 2001
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From: Milkway Galaxy
PARADOG ,
Any Reference to that statement?
My Manual states (LIM-12 P 1/2)
Any Reference to that statement?
My Manual states (LIM-12 P 1/2)
‐ Maximum demonstrated crosswind................................................... .................40 kt (gust included)
Note: The maximum demonstrated crosswind value is not an Airplane Flight Manual (AFM)
limitation : It is the maximum crosswind condition experienced during the aircraft
certification campaign. Airbus recommends that operators should not intentionally
operate in crosswinds that exceed this value.
Note: The maximum demonstrated crosswind value is not an Airplane Flight Manual (AFM)
limitation : It is the maximum crosswind condition experienced during the aircraft
certification campaign. Airbus recommends that operators should not intentionally
operate in crosswinds that exceed this value.
Joined: Jun 2001
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From: Chicago, IL, USA
Due to risk of compressor stall.
In order for the fan (and thus the downstream compressors) to work properly, the airflow needs to be smooth and straight.
For the most part, the nacelle, the diffuser (cone) and stators all serve to smooth and direct airflow to the compressor, but in the case of crosswind, low airspeed and high power setting the airflow may be disrupted to the point of causing a compressor stall.
In order for the fan (and thus the downstream compressors) to work properly, the airflow needs to be smooth and straight.
For the most part, the nacelle, the diffuser (cone) and stators all serve to smooth and direct airflow to the compressor, but in the case of crosswind, low airspeed and high power setting the airflow may be disrupted to the point of causing a compressor stall.
Joined: Dec 1999
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From: Oop North, UK
Think you somewhat missed the point.
Joined: Nov 2004
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From: Asia
Is the Xwind TO limitation applicable to all A330 variants or specific to one engine type?
Some years back the RR Trent 700 powered A330 experienced FAN stall in a strong Xwind takeoff with some damage to fan case mounted parts from the resulting pressure pulse. The fix was to revise the EEC software to slow the engine acceleration on take off to allow the aircraft to achieve some forward speed before the engine got into the high power range.
Some years back the RR Trent 700 powered A330 experienced FAN stall in a strong Xwind takeoff with some damage to fan case mounted parts from the resulting pressure pulse. The fix was to revise the EEC software to slow the engine acceleration on take off to allow the aircraft to achieve some forward speed before the engine got into the high power range.
Joined: Apr 2008
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From: A tropical island.
The fix was to revise the EEC software to slow the engine acceleration on take off to allow the aircraft to achieve some forward speed before the engine got into the high power range.
Joined: Feb 2008
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From: Wingham NSW Australia
Done it before - I'll do it again
aviatorhi, somewhat of a conflict in your comments. You speak of flying in X-winds which exceed the limitation stated and yet question airmanship standards in another.
Joined: Mar 2002
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From: Florida
Wasn't there an incident at Gatwick when a 747 had both upwind engines stall when it rotated in a strong crosswind?
I believe the problem was mostly tired engines (not on the same side) and over pitch after one stalled at rotation due to deterioration of its compressor.
Typically rotation speed (both aircaft and fan) are enough to overcome crosswinds. The takeoff roll however is the pinch point.
Joined: Apr 2008
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From: A tropical island.
Crosswind Limitations on all the aircraft I've ever flown are advisory only, hence I don't consider them, only what I know the pilot/crew is capable of doing. The fact that somebody doesn't want to fly when it's windy is something I find comical. Going past this A330 limitation would be hard/impossible to justify since it seems like a hard limit from what I've read in this thread, but if the fix is/was changing the rate at which the engine is spooling up then the fix is contained in the pilot's hand, don't think changing software should be necessary.
Joined: Nov 2011
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From: Wales
xwind limits
There are a couple of posts here that horrify me, I hope that you 2 are not airline Captains.
Why would you want to even attempt a take off in a crosswind of 40 knots +. Have you no thought of petrfying your passengers? Are you so subjected to commercial pressure that you dont care? Have you considered that if something went wrong, blown tyre or impact with airborne debris, they would hang you out to dry?
The only reasons to operate in those conditions would be a dire emergency (civil war ect.)
If you want to fly like that, go join the military or do it by yourselves.
Why would you want to even attempt a take off in a crosswind of 40 knots +. Have you no thought of petrfying your passengers? Are you so subjected to commercial pressure that you dont care? Have you considered that if something went wrong, blown tyre or impact with airborne debris, they would hang you out to dry?
The only reasons to operate in those conditions would be a dire emergency (civil war ect.)
If you want to fly like that, go join the military or do it by yourselves.
Joined: Oct 2009
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From: UK
Hi lomapaseo,
I remember the event very well.
http://www.aaib.gov.uk/cms_resources...9%20N605PE.pdf
It took over 1 minute from VR before V2 was achieved at a height of 105 ft agl!
22 degs of pitch (with the stick shaker warning on/off) didn't help it climb or accelerate.
I remember the event very well.
http://www.aaib.gov.uk/cms_resources...9%20N605PE.pdf
It took over 1 minute from VR before V2 was achieved at a height of 105 ft agl!
22 degs of pitch (with the stick shaker warning on/off) didn't help it climb or accelerate.
Joined: Jul 2006
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From: USA
I remember...
I remember the wonderful 727. Great airplane. Loved it.
Anyway, if starting the takeoff roll in strong, gusty crosswinds,
the center engine used to cough a bit.... (sometimes)
A lot of guys would line up on the runway....facing into the wind
(crooked on the runway)...to first spool up the center engine.
Once spooled, they would straighten out the plane with the
runway, spool up the pods, and off you go.
Fly safe,
PantLoad
Anyway, if starting the takeoff roll in strong, gusty crosswinds,
the center engine used to cough a bit.... (sometimes)
A lot of guys would line up on the runway....facing into the wind
(crooked on the runway)...to first spool up the center engine.
Once spooled, they would straighten out the plane with the
runway, spool up the pods, and off you go.
Fly safe,
PantLoad
Joined: Apr 2008
Posts: 461
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From: A tropical island.
@Pantload
In the 727 my method is to spool up the pods then release the brakes and advance #2 to takeoff power "carefully". Power's always set by the time the speed comes alive.
Funny you mention the "coughing" though; quite entertaining to see the uninitiated go wide eyed when the bird starts shaking.
In the 727 my method is to spool up the pods then release the brakes and advance #2 to takeoff power "carefully". Power's always set by the time the speed comes alive.
Funny you mention the "coughing" though; quite entertaining to see the uninitiated go wide eyed when the bird starts shaking.
