A330 App Spd Corrections
Thread Starter
Joined: Dec 2004
Posts: 12
Likes: 0
From: sussex
A330 App Spd Corrections
Hi,just reading about the 330 and it says that for single eng app. you add an increment of 5 kts to vref conf full and then press conf 3 and fly a conf 3 app. Isnt this the same as flying at Vls conf 3?
Joined: Aug 2003
Posts: 232
Likes: 4
From: Earth, where else?
Dustypfd interesting you bring this up...
Your way of thinking is correct, but the figures are a bit of.
Lets work on an example using the QRH for the A332-RR at 160T with calm winds:
The "correct Airbus way" is;
1/ From the QRH 2,40, Abnormal/Emerg config. Vref=Vls Full=128 or you can just see what the MCDU gives you as Vls Conf Full...should be the same.
2/ Add 5kts for the engine failure (2,42), 128+5= 133
3/ Select Conf 3 (MCDU/PERF) and enter 133 on the Vapp (MCDU/PERF)
If you check VLS Conf3 in the books (or in the MCDU, after having selected Conf3) @160T, you'll find 130. So in this case you'll fly Vls+3 and not Vls or Vls+5.
The way idg describes it, is a quicker way, but will give you a Vapp Conf3 of 135. 2 kts faster, and with the usual 5kts add on for using autothrust. The 5kts min above Vls when using ATHR is only for normal ops...
What is strange about the "correct airbus" procedure is that you'll fly 2kts or so slower (closer to Vls) with one engine out than coming in with both engines and doing a Conf3 landing, 133 iso 135. I know, only 2kts....
brgds:
Your way of thinking is correct, but the figures are a bit of.
Lets work on an example using the QRH for the A332-RR at 160T with calm winds:
The "correct Airbus way" is;
1/ From the QRH 2,40, Abnormal/Emerg config. Vref=Vls Full=128 or you can just see what the MCDU gives you as Vls Conf Full...should be the same.
2/ Add 5kts for the engine failure (2,42), 128+5= 133
3/ Select Conf 3 (MCDU/PERF) and enter 133 on the Vapp (MCDU/PERF)
If you check VLS Conf3 in the books (or in the MCDU, after having selected Conf3) @160T, you'll find 130. So in this case you'll fly Vls+3 and not Vls or Vls+5.
The way idg describes it, is a quicker way, but will give you a Vapp Conf3 of 135. 2 kts faster, and with the usual 5kts add on for using autothrust. The 5kts min above Vls when using ATHR is only for normal ops...
What is strange about the "correct airbus" procedure is that you'll fly 2kts or so slower (closer to Vls) with one engine out than coming in with both engines and doing a Conf3 landing, 133 iso 135. I know, only 2kts....
brgds:
Joined: Jan 1999
Posts: 187
Likes: 1
From: hongkong
Gents,
Agreed with the calculations but most of our a/c need the Vapp bumping up by 2 kts or so to give us the 5kts differential. We suspect the a/c are heavier (when using assumed pax weights) than the FMGS thinks it is, so after all the above, F3 works well! And flying the a/c at Vls is a sure way to ensure a heavy touchdown!
Agreed with the calculations but most of our a/c need the Vapp bumping up by 2 kts or so to give us the 5kts differential. We suspect the a/c are heavier (when using assumed pax weights) than the FMGS thinks it is, so after all the above, F3 works well! And flying the a/c at Vls is a sure way to ensure a heavy touchdown!
Joined: Oct 2006
Posts: 27
Likes: 0
From: A town called malice
The way to do it is to work out your Vref from the QRH at the given weight, add 5 kts and any corrections for wind. Then insert the resulting Vapp figure into the appr page. Then select Conf 3 and check that your Vapp is at least 5kts above the Vls, if not, adjust Vapp so it is at least that amount. Happy Flying!
Joined: Aug 2003
Posts: 232
Likes: 4
From: Earth, where else?
Hi Capt Galactic,
I don't think there's requirement to look for Vref in the QRH. If the MCDU is giving you the VLS Conf full, just take it from there.
Also, not too sure about the requirement to add min 5kts for the A/THR if in Abnormal/Emerg. The QRH 2,40 only has this requirement for the top table (Normal ops). Yes, I do know the Vol3 Supp proc, states the +5kts for the A/THR as well...
Thanks for your further thoughts
I don't think there's requirement to look for Vref in the QRH. If the MCDU is giving you the VLS Conf full, just take it from there.
Also, not too sure about the requirement to add min 5kts for the A/THR if in Abnormal/Emerg. The QRH 2,40 only has this requirement for the top table (Normal ops). Yes, I do know the Vol3 Supp proc, states the +5kts for the A/THR as well...
Thanks for your further thoughts
