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FM_A320
29th Dec 2017, 11:32
Hello all,

As a spectator I like trying to inform as much as possible about A320. I’m curious about energy management. I see the standard profile is:
* Flap 1 S speed at Loc intercept
* s speed at GS intercept
* F2 at the latest 2000aal
In order to monitor the approach I read those are the max speeds:
180 to 6, 170 to 5 and 160 to 4.

My question is: 2000 is approx at 6nm, many times Sspeed is around 185kts. With Sspeed higher than 180, is it impossible to delay F2 at 2000? Or Did I miss something?

Cheers

eckhard
30th Dec 2017, 17:54
Some operators allow flight below ‘S’ Speed without F2. As long as you are above Vls you should be OK. It’s been 18 months since I last flew the Airbus, so sorry if this info is now out of date....

FlightDetent
30th Dec 2017, 19:56
2 o.p.: The suggested OEM Airbus configuration sequence (quoted correctly) is not compatible with the speed values you provided. There are no such IAS gates in the manufacturer's FCOM..

S speed A320 64t = 192 kt
S speed A321 74t = 200 kt

FM_A320
30th Dec 2017, 22:50
If there are no such IAS gates in the FCOM, I suspect those are some airlines specific limitations.
However reading on an Airbus FOBN: "Aircraft Energy Management on Approach"
(unfortunately I'm not allowed yet to post urls on the forum)
They report that intercepting GS in slats only will take 3NM/1000ft to decelerate to VAPP but they also mention the deceleration characteristic of the A320 - 10 to 20kts each 1NM - suggesting no more than 160kts at 6NM (based on a conservative approach 10kts/1NM), in my "ignorance" and willingness to learn from every contribution, 180 to 6 appears sensible as a max speed at that distance.
Do you manage to do regularly the decelerated approach by the book? Obviously where you are not under speed control.
Cheers

Capt Scribble
31st Dec 2017, 07:27
Our company allows flying below flap speeds down to a value of VLS +10kts. But at 6 miles most Airbus are at 170-160 kts as specified by ATC and is the latest point I would consider for configuring for landing to achieve stability at 1000 ft.

FM_A320
31st Dec 2017, 14:46
Thank you all for your contribution. So if there’s no trace of those max IAS in the FCOM, I suspect this could be company specific.
However, reading an Airbus FOBN “Energy management on approach”, even if they confirm that if intercepting the GS in slats only, the plane needs 3NM/1000ft to decel to vapp, they also suggest monitoring the path and accepting ATC speeds based on a conservative 10kts/1NM deceleration rate. This means 160kts at 6NM. The maximum deceleration expressed on this document is 20kts/10nm, so also 180 to 6 as max speed appears sensible.
Looking from outside it seems a bit contradictory with their standard decelerated profile as quoted on the first post