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A380 In "severe" Windshear At JFK  
User currently offlinecanyonblue17 From United States of America, joined Oct 2008, 441 posts, RR: 0
Posted (3 years 5 months 3 weeks 3 days 13 hours ago) and read 31061 times:

An Air France A380 pilot reported experiencing "moderate to severe" wind shear shortly after takeoff from runway 31 left this evening at JFK Airport in New York City. Pilot did not specifiy if it was negative/positive or both. Several other pilots had previously reported windshear plus and minus 10 knots during approach. Winds had been gusting between 20-31 mph.

Any idea how this bird handles wind shear compared to other aircraft? Does it's size or power make it more or less vulnerable to windshear?

25 replies: All unread, showing first 25:
 
User currently offlineWingedMigrator From United States of America, joined Oct 2005, 2212 posts, RR: 56
Reply 1, posted (3 years 5 months 3 weeks 3 days 13 hours ago) and read 31047 times:

Quoting canyonblue17 (Thread starter):
Any idea how this bird handles wind shear compared to other aircraft?

Not reaaly any differently. The wing loading, which determines response to windshear, is not particularly high on the A380--whose wings are sized for much heavier growth variants. On JFK - CDG, the aircraft would have been far below its maximum takeoff weight, making it somewhat more susceptible.


User currently offlineMir From United States of America, joined Jan 2004, 21527 posts, RR: 55
Reply 2, posted (3 years 5 months 3 weeks 3 days 12 hours ago) and read 30703 times:

Quoting WingedMigrator (Reply 1):
On JFK - CDG, the aircraft would have been far below its maximum takeoff weight, making it somewhat more susceptible.

At the same time, having a higher power-to-weight ratio as a result of the relatively low weight would help.

-Mir



7 billion, one nation, imagination...it's a beautiful day
User currently offlineebbuk From , joined Dec 1969, posts, RR:
Reply 3, posted (3 years 5 months 3 weeks 3 days 6 hours ago) and read 27985 times:

Quoting canyonblue17 (Thread starter):
An Air France A380 pilot reported experiencing "moderate to severe" wind shear shortly after takeoff from runway 31 left this evening at JFK Airport in New York City. Pilot did not specifiy if it was negative/positive or both. Several other pilots had previously reported windshear plus and minus 10 knots during approach. Winds had been gusting between 20-31 mph.

Did they send you texts? Please share with us your source of this information


User currently offlinebueb0g From United Kingdom, joined Jul 2010, 642 posts, RR: 0
Reply 4, posted (3 years 5 months 3 weeks 3 days 6 hours ago) and read 27014 times:

Quoting ebbuk (Reply 3):
Did they send you texts? Please share with us your source of this information

Obviously over the radio... what else?



Roger roger, what's our vector, victor?
User currently offlinealberchico From United States of America, joined Sep 2004, 2911 posts, RR: 0
Reply 5, posted (3 years 5 months 3 weeks 3 days 5 hours ago) and read 26666 times:

Quoting ebbuk (Reply 3):
Did they send you texts? Please share with us your source of this information

Last night in NYC the winds were indeed incredible. the gustiest I've seen in a while.......



short summary of every jewish holiday: they tried to kill us ,we won , lets eat !
User currently offlineArcher From United States of America, joined Mar 2005, 129 posts, RR: 0
Reply 6, posted (3 years 5 months 3 weeks 3 days 5 hours ago) and read 25630 times:
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In the Albany NY area they went from 5 kts. from southwest to gusting near 30 from the west around 1:30 AM.
House was creaking and crackling from them (sort of).


User currently offlinebahadir From United States of America, joined Oct 2001, 1772 posts, RR: 10
Reply 7, posted (3 years 5 months 3 weeks 3 days 4 hours ago) and read 25025 times:

I did PIT-PHL-PIT-PHL within 4 hours yesterday.. When we first took off from PIT the winds were from south about 5 mph.
Landing in PIT for the second time it was from west at 20ish gusting 30ish mph.. Not to mention the fact that we were getting +/-15 knots of variations around PHL at 7000 feet ..Pretty wild and we were ready for a potential go around..



Earthbound misfit I
User currently offlinercair1 From United States of America, joined Oct 2009, 1308 posts, RR: 52
Reply 8, posted (3 years 5 months 3 weeks 3 days 4 hours ago) and read 24964 times:
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Quoting WingedMigrator (Reply 1):
been far below its maximum takeoff weight, making it somewhat more susceptible.

It seems to me this would help, not hurt. Wind shear is a rapid change in relative airspeed (speed of the wind over wings) as you climb/descent past the shear. This means that either the aircraft is developing lots more lift (where the relative speed increases) or lots less lift (where speed decreases). In the first case, you over climb, not a big problem (though it can screw up your approach). In the second, you can approach stall or CFIT.
The corrective action is to speed or slow the aircraft quickly to compensate for the change in relative airspeed. The defining factors in how well you can do that are power (only on decrease case) and inertial (both). Lighter aircraft, less inertial, faster response.

In fact, the original question is interesting. Do VLA and LA require more differential in airspeed than, say my 182, during wind shear events because the increased inertial requires more energy to change forward velocity. Do they need more cushion. Or does the fact that the speed range of the aircraft is so much larger (stall to Vne) mean that there is inherently more cushion - or less?



rcair1
User currently offline777fan From United States of America, joined Jan 2006, 2492 posts, RR: 2
Reply 9, posted (3 years 5 months 3 weeks 3 days 3 hours ago) and read 23532 times:

Quoting bueb0g (Reply 4):
Quoting ebbuk (Reply 3):
Did they send you texts? Please share with us your source of this information

Obviously over the radio... what else?

One would think it'd register as a PIREP; I didn't note one on ADDS last night although there were a decent number of turbulence-related reports in the area, as well as a couple of wind shear idents in the northeast.

777fan



DC-8 61/63/71 DC-9-30/50 MD-80/82/83 DC-10-10/30 MD-11 717 721/2 732/3/4/5/G/8/9 741/2/4 752 762/3 777 A306/319/20/33 AT
User currently onlineNavigator From Sweden, joined Jul 2001, 1181 posts, RR: 14
Reply 10, posted (3 years 5 months 3 weeks 3 days 2 hours ago) and read 21655 times:

Quoting canyonblue17 (Thread starter):
Any idea how this bird handles wind shear compared to other aircraft? Does it's size or power make it more or less vulnerable to windshear?

It takes time for those engines to spool up so a windshear is difficult to adjust against fast in a large airliner like the A380. The weight also make speed changes difficult. So an A380 has to put in margins beforehand if they forecast windshear.



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User currently offlineMir From United States of America, joined Jan 2004, 21527 posts, RR: 55
Reply 11, posted (3 years 5 months 3 weeks 3 days 2 hours ago) and read 21604 times:

Quoting rcair1 (Reply 8):
Do VLA and LA require more differential in airspeed than, say my 182, during wind shear events

Not really. There's a gust factor that's added to the approach speed, which varies from operator to operator and aircraft to aircraft, but it's half the gust up to a maximum of 10 is a common policy. The same thing works in light aircraft, though the difference between landing at 65 knots and 75 knots is greater than the difference between landing at 130 knots and 140 knots - the light aircraft will end up with a longer float (as compared to its total landing roll) due to the higher speed.

-Mir



7 billion, one nation, imagination...it's a beautiful day
User currently offline777fan From United States of America, joined Jan 2006, 2492 posts, RR: 2
Reply 12, posted (3 years 5 months 3 weeks 3 days 2 hours ago) and read 20633 times:

Quoting Navigator (Reply 10):
It takes time for those engines to spool up so a windshear is difficult to adjust against fast in a large airliner like the A380. The weight also make speed changes difficult. So an A380 has to put in margins beforehand if they forecast windshear.

This particular bird had just taken off, so presumably its engines were running at or very close to takeoff/climb out power, so in this instance, that shouldn't be much of a factor.

777fan



DC-8 61/63/71 DC-9-30/50 MD-80/82/83 DC-10-10/30 MD-11 717 721/2 732/3/4/5/G/8/9 741/2/4 752 762/3 777 A306/319/20/33 AT
User currently offlinespencer From United Kingdom, joined Apr 2004, 1635 posts, RR: 17
Reply 13, posted (3 years 5 months 3 weeks 3 days 1 hour ago) and read 19650 times:

Slightly O/T but I was on an AFR A380 approaching JFK last year and we had to go around! It was such a powerful climb yet very little noise, and it happened very quickly. Not something I would have directly imagined such a huge a/c could do. Very impressive indeed. Cause of the G/A was rwy incursion.
Spence.



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User currently offlinerolfen From Germany, joined Jan 2006, 1803 posts, RR: 2
Reply 14, posted (3 years 5 months 3 weeks 3 days 1 hour ago) and read 19443 times:

Quoting rcair1 (Reply 8):
In the first case, you over climb, not a big problem

This can become deadly if pilots reduce thrust to compensate for that. As windshear is a temporary condition, the aircraft can enter a stall when the wind goes back to normal.

[Edited 2011-02-06 08:39:56]


rolf
User currently onlineNavigator From Sweden, joined Jul 2001, 1181 posts, RR: 14
Reply 15, posted (3 years 5 months 3 weeks 3 days 1 hour ago) and read 19443 times:

Quoting 777fan (Reply 12):
This particular bird had just taken off, so presumably its engines were running at or very close to takeoff/climb out power, so in this instance, that shouldn't be much of a factor.

You are right. I´m talking about approach and landing. That is where wind shear is dangerous.



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User currently offlineJohnJ From United States of America, joined Jun 2000, 1656 posts, RR: 2
Reply 16, posted (3 years 5 months 3 weeks 3 days 1 hour ago) and read 18775 times:

Wind shear on takeoff was pretty dangerous for Pan Am 759.

User currently offlinewingnutmn From United States of America, joined Jan 2004, 640 posts, RR: 0
Reply 17, posted (3 years 5 months 3 weeks 3 days ago) and read 18154 times:

The worst I have experienced was a +15/-25 on final to CLE a couple years ago. In a CRJ200. You could feel the tail sink on the minus, put when we went around it climbed right out of it. That was associated with a thunderstorm that had moved across the airport 10-15 minutes prior to our approach.

Wingnut



Any landing you can walk away from is a good landing! It's a bonus if you can fly the plane again!!
User currently offlineKC135TopBoom From United States of America, joined Jan 2005, 12128 posts, RR: 51
Reply 18, posted (3 years 5 months 3 weeks 2 days 20 hours ago) and read 11045 times:

For windshear on the initial climb out the procedure would be to lower the nose for either a + or - in airspeed, as more power from the engines may not be available because the engines are already at a high power setting. But when lowering the nose you decrease the rate of climb and still maintane a positive climb. If you are still below about 1,000' AGL, you should not lower the nose below the horizon, above 1,000' AGL you can, if you need to (this is assuming there is no obstacal).

User currently offlinecanyonblue17 From United States of America, joined Oct 2008, 441 posts, RR: 0
Reply 19, posted (3 years 5 months 3 weeks 2 days 18 hours ago) and read 8908 times:

Quoting ebbuk (Reply 3):
Did they send you texts? Please share with us your source of this information



Sorry for not posting this in the original thread. I heard the report on LiveATC.net as it happened.


User currently onlinePihero From France, joined Jan 2005, 4392 posts, RR: 76
Reply 20, posted (3 years 5 months 3 weeks 2 days 18 hours ago) and read 8419 times:
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Quoting KC135TopBoom (Reply 18):
For windshear on the initial climb out the procedure would be to lower the nose for either a + or - in airspeed, as more power from the engines may not be available because the engines are already at a high power setting.

Certainly not. Your procedure is a recipe for disaster. Why would you lower the nos efor an increasing IAS ? The end result would be a Vfe bust, a pribable blown in LE or TE device and frankly you're in a windshear and you wouldn't compound that situation with more problems.

Quoting KC135TopBoom (Reply 18):
But when lowering the nose you decrease the rate of climb and still maintane a positive climb.

Why do you want to lower that nose is beyond me...

Quoting KC135TopBoom (Reply 18):
If you are still below about 1,000' AGL, you should not lower the nose below the horizon, above 1,000' AGL you can, if you need to (this is assuming there is no obstacal).

As far as I know, the recommended windshear escape techniques are fairly universal : TOGA thrust and fly the pitch limit indicator. That PLI should take you out of trouble although it could be hard to follow, due to turbulence and your aircraft instability in wildly fluctuating position of your *lift center*.
Of course, if you're lucky enough to be in a 'Bus, TOGA thrust and sidestick full back (and hold it there !) is a lot simpler method.



Contrail designer
User currently offlineMir From United States of America, joined Jan 2004, 21527 posts, RR: 55
Reply 21, posted (3 years 5 months 3 weeks 2 days 15 hours ago) and read 6591 times:

Quoting KC135TopBoom (Reply 18):
For windshear on the initial climb out the procedure would be to lower the nose for either a + or - in airspeed

Not what I've been taught. Throttles as far forward as they'll go, and pitch up. If you're lucky enough to have a limit indicator, go to that. If not, go as far as you need to get a climb going, but not above the onset of stick shaker.

Lowering the nose in a severe windshear is a precursor to unwanted contact with the ground.

-Mir



7 billion, one nation, imagination...it's a beautiful day
User currently offlinewjcandee From United States of America, joined Jun 2000, 5116 posts, RR: 22
Reply 22, posted (3 years 5 months 3 weeks 2 days 9 hours ago) and read 4570 times:

Winds were gusty at LGA, too, Friday night. Arriving around midnight in a 757, a lot of work was necessary to maintain a consistent descent profile and keep it lined up in the last two minutes of approach.

[Edited 2011-02-07 00:13:42]

User currently onlineSEPilot From United States of America, joined Dec 2006, 6834 posts, RR: 46
Reply 23, posted (3 years 5 months 3 weeks 2 days 3 hours ago) and read 3982 times:

It depends on what you mean by "how this bird handles" windshear. The fact that a change in relative wind velocity translates to a change in airspeed is independent of size and weight. How the plane reacts will depend entirely on how close to stall speed it comes. If it drops below stall speed, it will stall. If it doesn't it won't. These are dependent primarily on pilot response, not plane size, and how much speed the pilot had to begin with. If he had ample speed margin over stall speed then it will not stall; if he didn't then he must react quickly to prevent a stall. As to what the passengers feel, that is primarily a factor of wing loading, as WingedMigrator pointed out. What it comes down to is that aerodynamics are pretty much independent of size and weight; the relevant factors are airspeed, stall speed, wing loading and power loading. Response characteristics will depend on those, not on size or weight. The same plane at different weights will respond differently, because that changes the wing loading, power loading, and stall speed.


The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offline71Zulu From United States of America, joined Aug 2006, 3061 posts, RR: 0
Reply 24, posted (3 years 5 months 3 weeks 2 days 2 hours ago) and read 3828 times:

Quoting Mir (Reply 21):
Lowering the nose in a severe windshear is a precursor to unwanted contact with the ground.

Was holding the nose up a change that happened after the 1985 DL L-1011 crash at DFW? I thought I remembered reading something about that. Also I thought the Pan Am 759 pilots at MSY did lower the nose trying to gain back the airpseed they were losing. Also in the 1982 Air Florida crash, the Capt kept saying 'forward, forward, we only need 500' which I take to mean he wanted the nose lowered to gain airspeed.

[Edited 2011-02-07 07:28:56]


The good old days: Delta L-1011s at MSY
User currently offlinescouseflyer From United Kingdom, joined Apr 2006, 3380 posts, RR: 9
Reply 25, posted (3 years 5 months 3 weeks 2 days 2 hours ago) and read 3771 times:

Quoting spencer (Reply 13):
Slightly O/T but I was on an AFR A380 approaching JFK last year and we had to go around! It was such a powerful climb yet very little noise, and it happened very quickly. Not something I would have directly imagined such a huge a/c could do. Very impressive indeed. Cause of the G/A was rwy incursion.
Spence.

I remember seeing an empty A380 do a missed approach at the Airbus family day a coupe of years back and it was like a RAF Phanton the way it shot into the sky 


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