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Selected Speeds on A320

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Selected Speeds on A320

Old 14th Oct 2017, 16:03
  #21 (permalink)  
 
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LHRPony
Genuine question, what manoeuvre margin exists at the f and S? it's defined for VLS,but I haven't come across any definition for manoeuvre margin for f and s.
17th Performance and Operations Conference in Dubai explains this topic in detail. Extract below:
Maneuvering capability
At V2, one engine out:
Stabilized turn at 30 bank before alpha max
At V2 + 10, all engines operative:
Stabilized turn at 40 before alpha floor
At Green Dot:
Stabilized turn at 45 bank before alpha prot
At Vls (final takeoff up to landing) :
Stabilized turn at 40 bank before alpha floor
With AP on you won't use these bank angles nor for that matter in manual flight.

Last edited by vilas; 15th Oct 2017 at 04:42.
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Old 15th Oct 2017, 12:10
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That's great, many thanks Vilas.
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Old 17th Oct 2017, 07:26
  #23 (permalink)  
 
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Originally Posted by LHRPony View Post
Cheers Chrome,
So we have fcom defining they are retraction speeds, fctm saying they are man speeds.
Affirm LHRPony, on takeoff they are retraction speeds. The same part of the FCOM also defines F and S speeds are target speeds for the approach.

And thanks too vilas for sharing.
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Old 27th Jul 2021, 13:10
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Vilas,
This is regarding S and F speed mentioned in your post. As far as my understanding goes, the VFE next and VFE that are displayed on the PFD is based on the the FLAPS lever position. I couldn't locate the information that S and F are also displayed according to the flap lever position. I have referred to the old blue bulletin "Characteristic and protection speeds" as well. Could you please clarify. Thanks in advance
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Old 27th Jul 2021, 17:13
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Hi,

check FCTM - PRO - ABN - F/CTL - Abnormal flaps/slats configuration - Failure during approach.
It’s the main reason we must pull speed selected to avoid further deceleration.
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Old 29th Jul 2021, 16:38
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Hi sonic,
have a look at the above attachments. The QRH clearly states that the vfe and vfe next are displayed according to the lever position. Also, have a look at the blue bulletin( airbus has stopped publishing these). The F,S,O speeds are computed according to the aircraft configuration and not according to the lever position
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Old 29th Jul 2021, 19:14
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I am not sure I got Your point…
Once You select flaps 1 in approach you will get S speed displayed, computed by the FAC based on aerodynamic or FMGC data. This depends on MSNs as “newer” ones (and NEOs) will display FMGC speeds based on weight data for consistency purposes, so you don’t have different characteristic speeds between the PFD and the MCDU values.
If you get slats locked the S speed will not change, hence pull the speed in order to avoid decelerating to a speed not suitable for that configuration.
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Old 30th Jul 2021, 04:33
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please refer to my post #24. My question was with reference to a statement by VILAS that Fand S speeds are calculated in accordance to the lever position. I am of the opinion that only VFE and VFE next are calculated according to the lever position. The screen shots were attached as an exhibit for my source of information.
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Old 30th Jul 2021, 04:55
  #29 (permalink)  
 
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CM pilot 1
It's sure confusing. One way to make out if it's real time speed is it will move gradually as the surface extends. VFE changes instantly and even if the surface doesn't extend but VLS changes gradually. If S or F speeds don't change with a jam then they are predetermined. VLS remains correct with proper flap/slat configuration or even with one or both surfaces jammed. Also if S and F speeds are correct then there's no need to select speed but procedure demands it.
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Old 30th Jul 2021, 05:24
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This is in the Airbus training document and we always taught this.
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Old 30th Jul 2021, 06:19
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Vilas,
Thanks for sharing the slide. However, would you be having any other document to corroborate the information provided on this slide. The QRH and blue bulletin doesn't substantiate the information provided in the slide. Thanks
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Old 30th Jul 2021, 06:27
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I had the training DVD for FFS but a few years ago there was a problem between Adobe and some other agency involved after that it stopped working. But I remember it was always taught that way at least for more than a decade.
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Old 30th Jul 2021, 09:12
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Just thinking loud. Could this info be as outdated as the term "PNF" denoted on top of the slide
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Old 30th Jul 2021, 11:52
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The last training DVD made by Airbus was in 2016/17. That also gives the same info. After that it's available to only their trainees on line.
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Old 30th Jul 2021, 13:14
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Thanks Vilas.
How can I access these videos?
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Old 30th Jul 2021, 14:12
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As I said before there was some issue with the app and it doesn't work anymore.
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Old 31st Jul 2021, 08:59
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Hi all,
There is no harm in reverting to managed spd after setting the flaps lever to landing confg and ensuring that Vapp is correctly programmed in Fmgc....
Even if the spd is left selected for landing, it will change to managed if GA is initiated... And again, you have to go from managed to selected spd during GA....
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Old 31st Jul 2021, 09:55
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You can find all in this channel , but be careful is not updated...


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Old 31st Jul 2021, 10:23
  #39 (permalink)  
 
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Rocket3837

As discussed before in managed speed you will activate GSmini. If you happen to be in direct law the shifting speed target will make flying difficult. Direct law unlike conventional speed stable aircraft doesn't have any feel and is sensitive. Also depending on the position of the jam speed addition could be high you wouldn't want any addition to that for any reason.
In case of GA the SRS will engage in managed speed. You need select speed only during acceleration phase and by then you are back in alternate law. It's not a good idea to fly the approach in managed speed.
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Old 31st Jul 2021, 15:58
  #40 (permalink)  
 
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Rocket3837

Hi,

As per FCTM, use of selected speed is a must during abnormals involving slats/flaps. Although something may seem like a smart move, don’t go against manufacturer’s/operators documentation as you might end up with big arguments during sim sessions or worst in real life occurrences.
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