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channel4
1st Jul 2011, 10:05
Hi Guys,

1. As I understand when a flaps/slats are deployed the red barber pole = VFE (for that flap selection)....... I don't understand what is the difference between VFE and Max Speed (for flaps/slats jammed). Which one does the red barber pole indicate?

2. VFE is shown on PFD according to lever position? Overspeed is according to actual flap/slat position? Where is Overspeed indication / shown on PFD? What is difference between VFE and Overspeed in this case?

Bit of confusion with that red barber pole and the differences between VFE, Max Speed and Overspeed

Many thanks for your help guys!

C4

Dream Land
1st Jul 2011, 10:43
Imagine that you are now flying clean, VFE next will be located at 230KTS (VMAX or barber pole 350KTS), now you slow to 220KTS and request config 1, when you do this, barber pole comes down to 230KTS and VFE next = will be at 215KTS. And so on and so forth.

Cheers, D.L.

TyroPicard
1st Jul 2011, 11:06
VMAX (barber's pole) and VFE next are displayed according to Flap Lever postition.
Overspeed is not displayed - it's an AURAL warning - and relates to the actual slat/flap position, not the lever.

channel4
1st Jul 2011, 11:10
Dream Land,

I already understand the principle and movement of VFE next.

My 2 questions above are asking what is the difference between VFE, Max Speed (flaps/slats jammed) and Overspeed.

If the red barber pole = VFE for a flap/slat config. (of course this VFE/barber pole naturally moves to the previous VFE next as we increase flap setting).

But what is the difference between VFE and Max Speed (flaps and slats jammed) and Overspeed? and how are the latter indicated? This is what I would like to find out, what is the difference between these 3 conditions?

Cheers

C4

channel4
1st Jul 2011, 11:16
TP,

thanks for your reply.

I understand now your point about Overspeed.

Can you please help me:

If I am in Config one, the barber pole will be at 230Kts. You state that the barber pole = Max Speed (for this config). Is this not the same / a representation of VFE for config 1 also?

thanks,

C4

TyroPicard
1st Jul 2011, 12:09
C4
Yes it does represent that. And VFE NEXT will have moved to the value for CONF 2. To summarise for the jammed flap/slat condition...

1. Flap lever position determines the limits displayed on the PFD IAS scale. The limits may or may not be correct for your actual config.
2. Aural Overspeed warning is always valid for the ACTUAL Flap/Slat config.
3. VLS is also valid for the ACTUAL config.
4. The QRH table in LANDING WITH SLATS OR FLAPS JAMMED allows you to determine the VMAX for the current and landing configs, for any combination of slat/flap positions.
Hope that helps. TP

mcdhu
1st Jul 2011, 17:24
Think about it this way - YLO+BLU failure only the flaps will run. Select VFE-5 and at VFE (230kts) select Flaps1. Barbers pole will come down to 200Kts (for Flap2) because you have moved the Flap Lever to 1 - but nothing has happened - you are still clean!! You can therefore fly into the barber's pole and not get an overspeed warning because that is computed according to the actual flap position.

Any clearer? If not, apologies.

I-2021
1st Jul 2011, 20:31
YLO+BLU failure only the flaps will run.

You have the Green system for both slats and flaps.

channel4
1st Jul 2011, 20:45
Thanks TP and Mcdhu,

You've cleared that up for me!

Much appreciated

C4

PS. I2021 I agree with you there.

mcdhu
1st Jul 2011, 21:53
Sorry, GRN+BLU!!

TyroPicard
3rd Jul 2011, 11:51
mcdhu
Barbers pole will come down to 200Kts (for Flap2) because you have moved the Flap Lever to 1
er...pardon?