CHQIAH
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Airbus Aileron Setting When Parked?

Mon Jun 30, 2008 8:56 pm

My usual lunchbreak consists of throwing in some chew and driving to RWY 15L/R for my daily takeoff spotting of KLM and Lufthansa 744's. But the other day while driving past Term A to get to my spot I noticed a NWA 319 with both left and right ailerons simultaneously in the up position. Since I am not up to par on my Airbus A&P I was wondering why the setting, or if not a setting is this the same reaction of flight controls as the MD-80 (i.e. the elevator sys) with hyd sys off and wind variations on ground? Very strange sight, we don't have many Airbus a/c here and I have never seen a Boeing or RJ do this.
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EMBQA
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RE: Airbus Aileron Setting When Parked?

Mon Jun 30, 2008 9:33 pm

Hydraulics were most likely off. Since they are FBW, there is no physical connection between the L and R side

[Edited 2008-06-30 14:41:57]
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CHQIAH
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RE: Airbus Aileron Setting When Parked?

Mon Jun 30, 2008 9:55 pm

Yeah the FBW is what I figured, it was just a very intersting sight.
If you fly fast enough, the sun never sets
 
GST
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RE: Airbus Aileron Setting When Parked?

Mon Jun 30, 2008 10:02 pm

If anything I would have thought they would both be in the down position with hydraulics off, due to their weight. Are A319 ailerons counterbalanced anyone?
 
CHQIAH
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RE: Airbus Aileron Setting When Parked?

Mon Jun 30, 2008 10:09 pm

Well, this is a complete left field guess, but throwing in the weight factor, could it have been an mx check with the ailerons not coinciding from commands in the cockpit since it is FBW?
If you fly fast enough, the sun never sets
 
Mir
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RE: Airbus Aileron Setting When Parked?

Tue Jul 01, 2008 6:05 am



Quoting GST (Reply 3):
If anything I would have thought they would both be in the down position with hydraulics off, due to their weight.

Down is the standard position for both ailerons when the hydraulics are off, due to the weight of the surfaces as you said. Though I've never seen it happn, if both were up it's likely that they were testing the hydraulic system to ensure sufficient pressure to both ailerons.

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Tristarsteve
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RE: Airbus Aileron Setting When Parked?

Tue Jul 01, 2008 8:39 am



Quoting CHQIAH (Reply 4):
could it have been an mx check with the ailerons not coinciding from commands in the cockpit since it is FBW?

I cannot think of any way I could make the ailerons move both up. I could try by pressurising only one hyd system and moving the left aileron up. Then turning it off and pressurising another system and moving the right aileron up, and hoping the left was still up. But there is no routine check for it. It would be playing. All aileron movements are controlled by the sidestick.
 
buckfifty
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RE: Airbus Aileron Setting When Parked?

Tue Jul 01, 2008 9:07 am

I think it's almost impossible to have both ailerons in the up position. Like TristarSteve was saying, I can't think of any scenarios where both ailerons will end up in the up position, hyd's on or off. Even during a maintenance check, I don't think it is possible...

Are you sure it's in the up position? Or where they both facing downwards?
 
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HAWK21M
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RE: Airbus Aileron Setting When Parked?

Tue Jul 01, 2008 9:09 am

Was there a strong wind blowing at the time?
regds
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boeing767mech
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RE: Airbus Aileron Setting When Parked?

Tue Jul 01, 2008 2:57 pm



Quoting BuckFifty (Reply 7):
I think it's almost impossible to have both ailerons in the up position. Like TristarSteve was saying, I can't think of any scenarios where both ailerons will end up in the up position, hyd's on or off. Even during a maintenance check, I don't think it is possible...

It's not a airbus, but I have seen both outboard ailerons trailing edge up at the same time. Granted they where screaming for help, considering the next sounds was the sound of the wing getting hacked off. So the hyd. pressure has been 0psi for months. But the PCU's and all the cables are still in the airframe.

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CHQIAH
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RE: Airbus Aileron Setting When Parked?

Tue Jul 01, 2008 3:12 pm



Quoting HAWK21M (Reply 8):
Was there a strong wind blowing at the time?
regds
MEL.

Winds were just as calm as they could be. I'm bringing my camera for the next few days in hopes MAYBE I will see it again. Then of course I will snap it and post it. But they were at about a 60-70deg angle up.
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474218
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RE: Airbus Aileron Setting When Parked?

Wed Jul 02, 2008 2:27 am



Quoting TristarSteve (Reply 6):
I cannot think of any way I could make the ailerons move both up. I could try by pressurising only one hyd system and moving the left aileron up.



Quoting BuckFifty (Reply 7):
I think it's almost impossible to have both ailerons in the up position. Like TristarSteve was saying, I can't think of any scenarios where both ailerons will end up in the up position, hyd's on or off. Even during a maintenance check, I don't think it is possible...

I don't know about the A-300, but I can make all four ailerons go up or down on an L-1011 by using the "roll disconnect" handle. If the "roll disconnect" handle is pulled with power on all four aileron servos turn the captains control wheel to left and turn the first officers to the right and all four ailerons will go up. Reverse the direction of the control wheels and all four ailerons will go down. This is possible because there are bungees built into the system that prevent jams and in this scenario they would extend or compress just like there was a jam.

If there is an actual jam sensors on the bungees would tell the crew which servos to shut down. If the jam is in the right wing the captain would shut down the right hand inboard and outboard aileron servos and control the aircraft using the two left hand ailerons. If the jam was in the left wing the first officer would have control using the right wing ailerons after the left hand servos were shut down.

Quoting Boeing767mech (Reply 9):
It's not a airbus, but I have seen both outboard ailerons trailing edge up at the same time. Granted they where screaming for help, considering the next sounds was the sound of the wing getting hacked off. So the hyd. pressure has been 0psi for months. But the PCU's and all the cables are still in the airframe.

In the pictures there appears to be counter weights forward of the aileron hinge line. So with no hydraulic power the weights would make the nose of the aileron go down and the trailing edge go up, just like in the picture.
 
wirelock
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RE: Airbus Aileron Setting When Parked?

Wed Jul 02, 2008 8:49 pm



Quoting CHQIAH (Reply 10):
Winds were just as calm as they could be. I'm bringing my camera for the next few days in hopes MAYBE I will see it again. Then of course I will snap it and post it. But they were at about a 60-70deg angle up.

It is indeed strange that both ailerons were in that position. On new A320 when the mounts and mount bolts are new the aileron will stay in the neutral position even with gravity acting on it.
i need to investigate more but it could be possible that both ailerons could be in the up position during the freeplay checks. these are done through the MCDU and the ELAC are moving the aileron(no input from sidestick). however it is only checking 1 side at a time. next time im due to do this check i'll stand outside and watch.
because the ailerons have 2 servo actuators attached to each aileron the force needed to put it in the up position would need to be from HYD or from MX and then sticking a rag in there to hold the ailerons up. The wind alone i dont think would be able to do it

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