Ask The Pilot

  • Thread starter Thread starter NM
  • Start date Start date
  • Featured
this talk about de-icing reminds me of the story someone told for a (winter) departure ex Melbourne. apparently the captain said the plane needed de-icing, so a tug came, pushed the plane back from the terminal into the sunshine and it it stayed there for 15 minutes until it was ready to leave :) (dunno how much of that is true or not but it makes a nice story)

It wouldn't surprise me. There is no deicing capability of any note in Oz. Not needed often, but it does curtail operations when it is needed.
 
Read our AFF credit card guides and start earning more points now.

AFF Supporters can remove this and all advertisements

The autothrust always has a target speed, generally provided by the FMC. As it becomes lighter, the target speed is reduced, so the aircraft slows. About the time the speed reduction reaches .02 mach, it then becomes viable to climb to the next step, and the speed goes back to the faster cruise. In the 380 that range is normally .85 reducing to .83. A330 is about .04 (or so) slower.

Why is there a "deadband" in target speed? Is it to prevent surging or over-reaction to required speed changes?

I would have thought that as the aircraft load reduces it would want to speed up, FMC detects this and reduces power output accordingly.
 
With a strong crosswind, do you anticipate the aircraft movement after rotation and be prepared to provide correction or is it automatic in FBW acft ?


During takeoff, the aircraft will want to yaw into the wind. It will also have different relative wing sweep on each side, so it will want to roll away from the wind. Upshot is that you will need quite a bit of rudder throughout the takeoff roll, and an increasing amount of aileron in the opposite direction. You hold those crossed controls throughout the rotation, and sort them out once airborne.

FBW isn't that helpful. It may see the aircraft as having some sideslip after liftoff, and it will put in some rudder to counter that, but it doesn't take away the need for crosswind technique. In theory it also takes care of the aileron on the runway, but in practice doesn't do a good job, so you're better off doing it yourself.

Landing, you'll carry the drift right down to the flare, and then if you get it right, complete the flare, and then smoothly use the rudder to align the aircraft with the runway. A common error here is to align too early, in which case the aircraft immediately starts drifting downwind. Another error is to put in the rudder too quickly, which will give a strong roll response. The Boeing were much easier to handle in a crosswind than the Airbus, basically because they could be landed with ALL of the drift intact, and you simply sort out the alignment after touchdown. That was the preferred method on a wet runway. Airbus have a 5 degree drift limit at touchdown, so you at least need to get the drift below that level.

Is landing worse than take off in strong crosswinds or are they both a PITA ?

Landing is much harder than the takeoff, especially as the wind is never constant so you're almost always fighting a constantly varying enemy.
 
Thanks! Scares the willies out of me when there is ice about. I watch them in their cherry-pickers squirting the de-icing fluid over the plane and just hope the guys controlling it aren't new on the job.!

I have a friend who lives in Indiana, and he just got a job fuelling aircraft. They pay a mere 10 bucks an hour. The de-icers get 12. I'm not sure which part of that worries me more.

This coming Christmas, my SWMBO wanted a "white" Christmas in NY, but I would rather avaiod the Northern parts of the LOTFAP (and especially Canada) in winter (especially on aircraft).

I talked her into New Orleans > Florida and cruising the Carribean instead.
 
jb, I was on QF2 out of LHR yesterday. It was an A380. After we pushed back we sat just near the gate for about 15 minutes. The pilot then came over the PA and said that there was a couple of errors showing in the computer which he could not clear. He said they were going to do what we would refer to as a CTL+ALT+DEL on the on board computer to see if that would clear it. I know it is not that straight forward, but would doing such a reset (if indeed that exists) on an A380 computer clear the problem? Would that not just hide the problem and the root cause still be there?

Clearly it didn't work this time as we taxied back to the gate eventually for an engineer to board the aircraft and sort the problem and were delayed about an hour.
 
Why is there a "deadband" in target speed? Is it to prevent surging or over-reaction to required speed changes?

I would have thought that as the aircraft load reduces it would want to speed up, FMC detects this and reduces power output accordingly.

Sorry, I noticed this the other day, but forgot to answer.

There is no deadband as such, but there is a range of speeds that will be used. The closest thing to a deadband is the autothrust 'soft' mode, which it goes into in the cruise. In that mode it gently corrects for any small speed excursions faster than the target, though it remains aggressive about speed below the target.

Basically, an aircraft has a most efficient angle of attack. In any given set of conditions, that angle will correspond to an airspeed. As the weight reduces, the speed for that angle of attack will also reduce. So, at a given altitude, as the weight comes down, so does the target airspeed.

If the engines were left at a fixed power setting, then the aircraft would accelerate...but of course we don't operate that way.

The FMC constantly calculates a target airspeed. That target is sent to the autothrust (which is actually a subset of any one of the primary flight control computers or PRIMS), which in turn sends the power commands to the engines. Even if operating in manual thrust, the FMC targets are still available, both on the FMC itself and also the primary flight display.
 
jb, I was on QF2 out of LHR yesterday. It was an A380. After we pushed back we sat just near the gate for about 15 minutes. The pilot then came over the PA and said that there was a couple of errors showing in the computer which he could not clear. He said they were going to do what we would refer to as a CTL+ALT+DEL on the on board computer to see if that would clear it. I know it is not that straight forward, but would doing such a reset (if indeed that exists) on an A380 computer clear the problem? Would that not just hide the problem and the root cause still be there?

Computer resets are pretty common. They generally have no downside, and only take a couple of minutes. Obviously there are many systems than cannot be reset (in flight), and for those systems there will be more redundancy (for instance there are 6 flight control computers, any one of which can take care of the FBW). After a reset, if a problem is real, then the failure checking will almost certainly catch it again within a very short span.

Ok, I found out what it was. Not a big deal, but it's a reset that has to be done by the engineers.

Turns out you were lucky anyway...the 2 was an hour late from this, but the 10 diverted to Dubai with a sick passenger.
 
Last edited:
Flying for the next couple of weeks:

QF2 ex Singapore 8/1

QF9 ex Melbourne 24/1
QF9 ex Singapore 25/1
QF2 ex London 28/1
QF10 ex Singapore 31/1 (looks like this will be my last departure from Singapore)

QF93 ex Melbourne 7/2
QF94 ex LA 8/2

And then I'm on a mix of annual and long service leave for a couple of months.
 
Ask The Pilot

What do you need to do to get "current" after LSL? I assume sim time?

Do the "currency" requirement restrict your ability to take a/l or LSL? Certainly in our industry "leave cover" is often very difficult and whilst lip service is often paid to "we are happy for you to take leave", the reality is that often you miss your preferred leave slot due to non-availability of leave. I know (from your previous answers) there's a "surplus" of QF a380 pilots, so "cover" presumably isn't that big an issue vs "currency" and sim time.

Sorry if this has been partly covered previously.
 
What do you need to do to get "current" after LSL? I assume sim time?

Do the "currency" requirement restrict your ability to take a/l or LSL? Certainly in our industry "leave cover" is often very difficult and whilst lip service is often paid to "we are happy for you to take leave", the reality is that often you miss your preferred leave slot due to non-availability of leave. I know (from your previous answers) there's a "surplus" of QF a380 pilots, so "cover" presumably isn't that big an issue vs "currency" and sim time.

Whilst there may be a surplus, it really doesn't take much leave or sickness to whittle that down to thin coverage. They balance the leave over the year, so basically the same number are available at any given time. Taking leave at a point when you want it is generally just a pipe dream.

There are a couple of ways to handle the recency issue. Some people are happy to come back from leave for a day, to do something in the sim, or even a quick flight (not really applicable to the 380/747 though). As far as I'm concerned, coming back ruins my leave, so I'd prefer to sort it out afterwards. There's a formula in the manuals for what has to be done after an absence. In the case of a 4 week leave slot, you'll often be able to get straight back into it. The 6 week slots that I take (we have the choice...one obviously happens more than the other) will always require a sim, which could be an extra, but will most likely be your normal licence renewal (so straight away that ruins the last week of leave). Longer than that, and the requirements ramp up. The slot I'm going to take will require two sims (one of which will the the renewal) and then another route check. Back in 2007 I was off for 4 months, and that additionally required two sectors with a training captain in the right hand seat. You need more leave by the time you get back on line.
 
Flying for the next couple of weeks:

QF2 ex Singapore 8/1

QF9 ex Melbourne 24/1
QF9 ex Singapore 25/1
QF2 ex London 28/1
QF10 ex Singapore 31/1 (looks like this will be my last departure from Singapore)

QF93 ex Melbourne 7/2
QF94 ex LA 8/2

And then I'm on a mix of annual and long service leave for a couple of months.

Hi JB I am on QF9 on the 24th Hope to meet you I am in Emerald City for that flight. Where you by any chance on QF9 on the 22nd of December or QF10 on the 28th December?
 
jb, I was on QF2 out of LHR yesterday. It was an A380. After we pushed back we sat just near the gate for about 15 minutes. The pilot then came over the PA and said that there was a couple of errors showing in the computer which he could not clear. He said they were going to do what we would refer to as a CTL+ALT+DEL on the on board computer to see if that would clear it. I know it is not that straight forward, but would doing such a reset (if indeed that exists) on an A380 computer clear the problem? Would that not just hide the problem and the root cause still be there?

Clearly it didn't work this time as we taxied back to the gate eventually for an engineer to board the aircraft and sort the problem and were delayed about an hour.

Hey jb,
just wondering, does QF have many of their own ground engineers at overseas ports or do they rely on contractors/host airlines?

Thanks once again for your wisdom and insight.
 
just wondering, does QF have many of their own ground engineers at overseas ports or do they rely on contractors/host airlines?

Bit of a mix...which I suspect depends upon the quality of the locals. The QF line engineers are some of the best qualified people that you'll meet anywhere, with multiple trade licences and lots of experience.
 
It wouldn't surprise me. There is no deicing capability of any note in Oz. Not needed often, but it does curtail operations when it is needed.

In CBR there is de-icing equipment, as we frequently get very cold mornings. I've been on quite a few early morning flights from CBR where they have had to de-ice the plane (surprised me the first time as well)
 
In CBR there is de-icing equipment, as we frequently get very cold mornings. I've been on quite a few early morning flights from CBR where they have had to de-ice the plane (surprised me the first time as well)

Corporate offer it as part of their FBO services.
 

Become an AFF member!

Join Australian Frequent Flyer (AFF) for free and unlock insider tips, exclusive deals, and global meetups with 65,000+ frequent flyers.

AFF members can also access our Frequent Flyer Training courses, and upgrade to Fast-track your way to expert traveller status and unlock even more exclusive discounts!

AFF forum abbreviations

Wondering about Y, J or any of the other abbreviations used on our forum?

Check out our guide to common AFF acronyms & abbreviations.
Back
Top