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-   -   A330 questions (https://www.pprune.org/tech-log/514150-a330-questions.html)

michaela74 6th May 2013 11:13

A330 questions
 
I'm brand new on the A330 and have found information rather lacking in certain areas. To start with:
(1) I've been advised never to use the auto thrust for landing. But when I've tried it out the system seemed to do a fantastic job. Well, certainly better than I could do.
(2) During a cross wind landing don't use cross controls in the flare due to the threat of a pod strike. But when I've tried to hit a pod (in the sim. obviously). I found it very hard. Has there ever been an occurrence of a pod strike on an A330?
They're the first of many questions, hope I get some good answers.
Mik74.

rudderrudderrat 6th May 2013 11:50

Hi Mik74,

One disadvantage with using autothrust is that you will enter the flare either with the TLs closed (engines spooling down) or in the climb gate (engines spooling up to maintain VAPP) or something in between.

This Airbus document on cross wind landings is worth reading.
http://www.airbus.com/fileadmin/medi...LAND-SEQ05.pdf

Good luck.

rick.shaw 7th May 2013 03:29

A330 Auto Thrust
 
Aah - this old chestnut. Personally, and in accordance with my company's recommendations, I use auto thrust 80-90% of the time. It works pretty well but there are occasions where manual thrust is appropriate to give you the speedy thrust control that you,as a pilot, may require from time to time. It's also a nice idea to practice it once in a while. There are those out there who puff up their chests and declare, in a manly sort of way, that they always use manual thrust. Their choice. It really doesn't bother me.

An extra few knots on VApp on those 'in between' days can work wonders on the 330. I normally don't do it on the 340. The 340 seems to be more speed stable than the 330 in my opinion.

As for the comment above, for a manual landing, the thrust will stay in speed mode until you physically retard the thrust lever(so you still effectively have control over the thrust, but I may have misinterpreted the intent of the comment). Idle thrust will only be commanded during an autoland without you retarding the thrust lever.

Uplinker 7th May 2013 11:56

Wow, interesting. We are advised to USE autothrust for landing, except in very thermal conditions, and I believe that's what Airbus recommend too?

The Airbus autothrust is often accused of being lazy, but Airbus fly a constant groundspeed on approach, (incorporating 'ground speed mini'[mum]), not a constant airspeed, so it may dip below bug or reduce the engines to idle, but the groundspeed is still fine. (I realise this is technically not a "stable" approach in the usual definition of the word).

Crossed control approaches as you know are easy for us the pilots, but uncomfortable for the pax, (not the primary consideration, I know). Without checking my manuals, I can't remember about engine pod vulnerability - I think you would have to have a hell of a bank angle on to strike a pod. Crabbing approaches are do-able, and are what the aircraft itself does on an autoland. The only thing is with strong cross wind, you can feel that you in the cockpit are almost over the grass at the edge as you go over the threshold before de-crabbing, which is an odd picture to get used to and stay on the centreline.


Enjoy the A330 - it is a majestic aircraft !


(For descent planning; use 4x your height rather than 3x. With that huge wing, it don't want to go down !:))


U

SloppyJoe 7th May 2013 16:08


The Airbus autothrust is often accused of being lazy, but Airbus fly a constant groundspeed on approach, (incorporating 'ground speed mini'[mum]), not a constant airspeed, so it may dip below bug or reduce the engines to idle, but the groundspeed is still fine. (I realise this is technically not a "stable" approach in the usual definition of the word).
The bug moves with GS mini calculations in managed speed so if the speed is not on the bug the thrust will be adjusting to maintain the magenta bug. GS mini is not hidden from the pilot with the autothrust adjusting to maintain some unknown value, GS mini is displayed via the magenta bug and that is the autothrust target.

Personally I thing the A/THR does a good job, with Vapp just above Vls sometimes it lets the speed decay a bit but I have never seen it go below Vls and there are very quick and large changes to prevent this. Vls is its bottom limit and it does a very good job at not busting that limit.

michaela74 7th May 2013 21:37

Thanks guys. This backs up my thinking on the idea. And yes, I've learned the hard way that its 1 in 4 on the descent planning. What a wing.

misd-agin 7th May 2013 23:50

mik74 -

Read the document posted by rudderrudderrat. The guy who told you point #2(don't cross control) is wrong. Period. Cross control is what Airbus, and Boeing, recommend.



This Airbus document on cross wind landings is worth reading.
http://www.airbus.com/fileadmin/medi...LAND-SEQ05.pdf


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