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TakeOff
Topic Author
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Timing Of Flap/Slat Deployment

Mon Jun 06, 2011 3:06 pm

I flew yesterday ATH-FRA-LHR on LH. Both flights on A320 family aircraft. In the first leg, the flaps and slats were deployed right after we pushed back from the gate. From FRA, though, they had already been extended when we were boarding. Is that normal? I'm a seasoned flyer (I've flown roughly 200,000 miles last year alone) and this is the first time I saw this happening. The only thing I can think of is that, since we were delayed by a thunderstorm around FRA, the folks at the flight deck had performed all their checks while waiting for the passengers to board. Would this make sense? Any thoughts/ideas would be much appreciated.

TakeOff

[Edited 2011-06-06 08:10:07]
 
IAHFLYR
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RE: Timing Of Flap/Slat Deployment

Mon Jun 06, 2011 6:03 pm

Did you notice any maintenance folks around the airplane at all, if so that could be your answer? IIRC, a B727 had some peculiar reason to fully extend the wing on the ground, but I can't even make an educated guess as to the reason or if I'm dreaming!  
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wilco737
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RE: Timing Of Flap/Slat Deployment

Mon Jun 06, 2011 6:06 pm

At LH the procedure is to set the flaps after pushback prior taxi. Maybe there was indeed some maintenance going on.

Or I have seen it several times on airport with high temperatures that the airbus left the flaps extended while taxiing in and left them extended while at the gate.

wilco737
  
 
TakeOff
Topic Author
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RE: Timing Of Flap/Slat Deployment

Mon Jun 06, 2011 7:26 pm

Thanks both for your answers.

There wasn't any maintenance activity going on – at least none that I noticed of going down the jetway and while on board (I was in seat 4A).

To wilco737's point, the temperature in FRA was 27C: would that warrant the leaving the flaps and the slats extended?

Again, thanks.

TakeOff
 
wilco737
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RE: Timing Of Flap/Slat Deployment

Mon Jun 06, 2011 7:35 pm

Quoting TakeOff (Reply 3):
To wilco737's point, the temperature in FRA was 27C: would that warrant the leaving the flaps and the slats extended?

I think the temperature should be above 30°C, but maybe they were just careful or expected the temperature to rise even further, so they left the flaps extended.

wilco737
  
 
stratosphere
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RE: Timing Of Flap/Slat Deployment

Mon Jun 06, 2011 7:52 pm

Quoting IAHFLYR (Reply 1):
Did you notice any maintenance folks around the airplane at all, if so that could be your answer? IIRC, a B727 had some peculiar reason to fully extend the wing on the ground, but I can't even make an educated guess as to the reason or if I'm dreaming!  

On the 727 the inboard kruger flaps would droop with no hydraulic pressure applied. From what I remember the old A300's slats would droop as well. On the DC-9's sometimes the trailing edge flaps would droop. I have worked around the A320 quite a bit and I do not recall that a/c doing that. It is possible the inbound crew did not raise them for whatever reason or maintenance reasons.
 
vikkyvik
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RE: Timing Of Flap/Slat Deployment

Mon Jun 06, 2011 8:31 pm

Quoting wilco737 (Reply 2):
Or I have seen it several times on airport with high temperatures that the airbus left the flaps extended while taxiing in and left them extended while at the gate.

What's the reasoning behind that, out of curiosity?

Thanks!
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B747forever
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RE: Timing Of Flap/Slat Deployment

Mon Jun 06, 2011 8:32 pm

Quoting wilco737 (Reply 2):
Or I have seen it several times on airport with high temperatures that the airbus left the flaps extended while taxiing in and left them extended while at the gate.

Why would they keep them extended if the temperature is high?
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Luftfahrer
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RE: Timing Of Flap/Slat Deployment

Mon Jun 06, 2011 10:07 pm

A while ago, aircraft of Delta Connection carrier(s) (ASA/EV at least) used to leave the flaps extended after landing, with the anticipated setting for the next take off. I once read this was done because the flaps of the CRJ failed commonly, which could prevent the aircraft from leaving an inhospitable outstation. It made me wonder whether this was true in earnest. Wouldn't a flap fail in the air be actually dangerous (granted that it was likely to happen not only on the ground, but also in the air)?

[Edited 2011-06-06 15:14:59]
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contrails15
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RE: Timing Of Flap/Slat Deployment

Mon Jun 06, 2011 10:28 pm

Could be MX doing a bird strike check. Our policy is everything gets looked at when a strike occurs. You'd be surprised how many times it happens. Of course there can be other reasons such as MX checking out the flaps ect ect but flaps are deployed after pushback with our policy. A320's and E190's

I mention bird strike because 9 times out of 10 its either that or the one time its mechanically problem. Flaps are also never put down when fueling is going on. If they need to be put down the fueler either has to wait or MX waits for the the fueler. Whatever the case, something was up with your flight because I've never pushed a flight out with flaps down and i've done 100's of pushes. Thats just me, can't speak for others.
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tdscanuck
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RE: Timing Of Flap/Slat Deployment

Tue Jun 07, 2011 4:25 am

Quoting vikkyvik (Reply 6):
What's the reasoning behind that, out of curiosity?
Quoting B747forever (Reply 7):
Why would they keep them extended if the temperature is high?

According to several posts in this thread: Leaving Flaps Down On Stand (by Bdak Jul 15 2009 in Tech Ops)

It's to prevent the bleed air ducts in the leading edge from overheating.

Tom.
 
wilco737
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RE: Timing Of Flap/Slat Deployment

Tue Jun 07, 2011 5:31 am

Quoting vikkyvik (Reply 6):
What's the reasoning behind that, out of curiosity?
Quoting B747forever (Reply 7):
Why would they keep them extended if the temperature is high?
Quoting tdscanuck (Reply 10):
It's to prevent the bleed air ducts in the leading edge from overheating.

Yes   That's what I read as well.

wilco737
  
 
PGNCS
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RE: Timing Of Flap/Slat Deployment

Thu Jun 09, 2011 10:00 pm

Quoting tdscanuck (Reply 10):
Quoting vikkyvik (Reply 6):
What's the reasoning behind that, out of curiosity?
Quoting B747forever (Reply 7):
Why would they keep them extended if the temperature is high?

According to several posts in this thread: Leaving Flaps Down On Stand (by Bdak Jul 15 2009 in Tech Ops)

It's to prevent the bleed air ducts in the leading edge from overheating.

Yes, and to avoid the ECAM messages that come with it (some Airbuses assess this as a bleed air duct leak in the wing.)

Nothing to be concerned with.
 
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Faro
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RE: Timing Of Flap/Slat Deployment

Fri Jun 10, 2011 10:21 am

Off-topic but have also seen flaps retracted on departure until shortly before take-off on contaminated apron/runway areas.

Faro
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wilco737
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RE: Timing Of Flap/Slat Deployment

Fri Jun 10, 2011 10:51 am

Quoting faro (Reply 13):
ff-topic but have also seen flaps retracted on departure until shortly before take-off on contaminated apron/runway areas.

You do that so no slush, snow etc is thrown up to the flaps and freeze there. If you retract the flaps then, they could be damaged. So you leve them up shortly before you take off.

wilco737
  
 
lowrider
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RE: Timing Of Flap/Slat Deployment

Fri Jun 10, 2011 1:26 pm

Quoting Luftfahrer (Reply 8):
It made me wonder whether this was true in earnest. Wouldn't a flap fail in the air be actually dangerous

The explanation was partially correct. The early CRJs did have a high incidence of flap failures caused by the flap panel twisting and jamming. Lowering the max flap extension speed helped, but while a more permanent fix was being engineered, the crew had to examine the flaps for twist before each departure. This could only be accomplished with the flaps extended. If the flaps did not retract in departure, it is unlikely the aircraft had enough fuel to make it to the destination, unless is was a very short flight to begin with.
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JETPILOT
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RE: Timing Of Flap/Slat Deployment

Sat Jun 11, 2011 12:39 am

Pilots do not extend the flaps at the gate because of the possibility of causing injury to ramp workers or damage to the plane by dropping the flaps and hitting ground equipment. Flaps are called for on the "taxi checklist" after the "after start" checklist is complete.

Taxiing into the ramp with flaps extended is communicating that a hi-jacking is taking place.
 
tdscanuck
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RE: Timing Of Flap/Slat Deployment

Sat Jun 11, 2011 5:27 am

Quoting jetpilot (Reply 16):
Taxiing into the ramp with flaps extended is communicating that a hi-jacking is taking place.

*If* you don't tell them you're doing it. If you tell tower you're taxing in with flaps down they don't pay you any attention, you can see this happen fairly often at Boeing Field.

Tom.
 
wilco737
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RE: Timing Of Flap/Slat Deployment

Sat Jun 11, 2011 8:31 am

Quoting jetpilot (Reply 16):
Taxiing into the ramp with flaps extended is communicating that a hi-jacking is taking place.

This happens very often that you taxi in with the flaps extended. As mentioned above at many airports with high temperature the AIrbus pilots leave the flaps extended. Saw it in BAH where all Airbus had their flaps extended.

wilco737
  
 
Speedbird741
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RE: Timing Of Flap/Slat Deployment

Sat Jun 11, 2011 9:16 am

Quoting wilco737 (Reply 18):
AIrbus pilots leave the flaps extended

Wilco737, what about on Boeings? More specifically, I quite often notice BA's 744s with flaps at 30 while parked at the gate (LHR). Is there any operational need that calls for this on a 744, or is it simply maintenance related?

Speedbird741
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wilco737
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RE: Timing Of Flap/Slat Deployment

Sat Jun 11, 2011 9:32 am

Quoting Speedbird741 (Reply 19):
Is there any operational need that calls for this on a 744, or is it simply maintenance related?

We at LH don't have any procedures to leave the flaps extended after landing. Except during contamination on the runway, then you retract them to 20 and leave them there until the maintenance guys say that it is free of ice and slush and can be safely retracted.

wilco737
  
 
FlyASAGuy2005
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RE: Timing Of Flap/Slat Deployment

Mon Jun 13, 2011 5:46 pm

Quoting Luftfahrer (Reply 8):
A while ago, aircraft of Delta Connection carrier(s) (ASA/EV at least) used to leave the flaps extended after landing, with the anticipated setting for the next take off. I once read this was done because the flaps of the CRJ failed commonly, which could prevent the aircraft from leaving an inhospitable outstation. It made me wonder whether this was true in earnest. Wouldn't a flap fail in the air be actually dangerous (granted that it was likely to happen not only on the ground, but also in the air)?



This problem has since been fixed. As Lowrider explaiend correctly they were procedurally left extended for inspection on the ground. You won't see this anymore, however.

[Edited 2011-06-13 10:46:50]
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Luftfahrer
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RE: Timing Of Flap/Slat Deployment

Mon Jun 13, 2011 7:59 pm

Quoting Lowrider (Reply 15):
Quoting FlyASAGuy2005 (Reply 21):

Thanks for the information. I figured so, as I flew on an ASA CRJ last year and the flaps were retracted after landing in earnest.

[Edited 2011-06-13 13:00:46]
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330guy
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RE: Timing Of Flap/Slat Deployment

Tue Jun 14, 2011 4:06 pm

Quoting jetpilot (Reply 16):
Taxiing into the ramp with flaps extended is communicating that a hi-jacking is taking place.

Iv never heard of that before,

I have heard however that taxiing in with the spoilers up is communicating that you want the Police to meet the aircraft on stand.
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