Selected Speeds on A320
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LHRPony
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.
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.
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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And thanks too vilas for sharing.
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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
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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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.
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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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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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.
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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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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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.
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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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
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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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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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....
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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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.
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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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.
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.
