Airbus Pilots - ground speed mini question
05-23-2016, 02:03 PM
#1
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Airbus Pilots - ground speed mini question
I've been flying the A320/321 for about 16 months and have observed groundspeed mini in action but my question is this - doesn't this impact the separation standards enacted by ATC - or more likely how can it not? If everyone else is flying indicated and my aircraft is changing indicated speed to target a groundspeed it seems this would affect time based separation standards - including those recently established as part of the new wake turbulence recat. Thoughts on this? Issues?
05-23-2016, 02:34 PM
#3
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Originally Posted by Douglas9
It works when you're in managed speed. How far out are you pushing managed speed?
Most people use selected speed to the marker or 5 miles or as instructed. Inside of that, speeds will vary anyway due to aircraft type & weight.
05-23-2016, 04:32 PM
#4
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Originally Posted by PRS Guitars
Exactly,
Most people use selected speed to the marker or 5 miles or as instructed. Inside of that, speeds will vary anyway due to aircraft type & weight.
Most people use selected speed to the marker or 5 miles or as instructed. Inside of that, speeds will vary anyway due to aircraft type & weight.
05-23-2016, 04:39 PM
#5
Stuck Mic
Joined APC: Dec 2013
Posts: 1,059
Separation....737-900ER with wind correction additive and you are at 160 knots consistently! So if you have a guppy on your tail it's definitely not a bad thing for GS mini to be working its magic for you.
Man I miss the bus....
Man I miss the bus....
05-23-2016, 05:18 PM
#6
Da Hudge
Joined APC: Oct 2006
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Originally Posted by Firsttimeflyer
Separation....737-900ER with wind correction additive and you are at 160 knots consistently! So if you have a guppy on your tail it's definitely not a bad thing for GS mini to be working its magic for you.
Man I miss the bus....
Man I miss the bus....
And man, I sure don't miss the 737!
05-23-2016, 09:10 PM
#7
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Originally Posted by Std Deviation
I've been flying the A320/321 for about 16 months and have observed groundspeed mini in action but my question is this - doesn't this impact the separation standards enacted by ATC - or more likely how can it not? If everyone else is flying indicated and my aircraft is changing indicated speed to target a groundspeed it seems this would affect time based separation standards - including those recently established as part of the new wake turbulence recat. Thoughts on this? Issues?
To answer your question though, yes it would close separation assuming you and the guy you're following are at Vref/Vapp. Reasonable man theory would suggest if the wind is bad enough, they've added whatever correction already, so mini G corrections probably aren't going to close that gap. As everyone else has said, I never see anyone go managed speed until FAF or inside it.
05-24-2016, 04:37 AM
#8
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That's what I've been doing as well - managed at the FAF. Good thoughts guys, thank you. I've just been trying to wrap my head around the implications of it on the system as a whole - which in an Airbus probably falls into the realm of "you don't need to know that."
05-24-2016, 05:33 AM
#9
Line Holder
Joined APC: Sep 2005
Position: CA: A321/A320/A319
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GS mini = Vapp - Tower Wind(Wind Entered on the Perf Page) + Real Wind (Wind Read Out From Your ND from your ADRS)
Example: Vapp is 130 and Tower Wind is 15 Knots and Real Wind is 25.
GS mini at your Altitude is 130 - 15 + 25 = Equals 140 Knots Ground Speed Mini. As you come down the Glide Slope it will change as the wind changes, unless wind is constant but rare. All designed to keep your Ground Speed Constant to avoid being behind the "curve" in case of wind gusts or wind shear.
Example: Vapp is 130 and Tower Wind is 15 Knots and Real Wind is 25.
GS mini at your Altitude is 130 - 15 + 25 = Equals 140 Knots Ground Speed Mini. As you come down the Glide Slope it will change as the wind changes, unless wind is constant but rare. All designed to keep your Ground Speed Constant to avoid being behind the "curve" in case of wind gusts or wind shear.
05-24-2016, 05:53 AM
#10
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Flaps setting from perf entered incorrectly
Next question - performance churns out flaps 3 takeoff. CA incorrectly enters flaps 1 on FMS perf and I incorrectly set the flaps at 1. Company procedure requires comparing what's been entered to what's been set. But what if what's been entered is incorrect. I'm comparing two errors that happen to coincidentally correlate. So I guess two wrongs do make a perceived right? Will the aircraft catch the fact we have flaps 1 but require 3? Let's make it interesting and say this is Burbank with a flex takeoff.
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