Ask The Pilot

[dfcatch]

Noticed yesterday at SYD T1 the A330s seem to have faded red paint on the tail yet the rudder was not faded, it would suggest the tail is in fact need of a wash but it did get me thinking as to the real reason why it appeared so, any ideas??

In the last year I have noticed many faded red tails, quite frankly it looks terrible, perhaps QF got some cheap red paint, it certainly seems worse than ever when it comes to fleet appearance?

Hmmm - you must have been somewhere with a large panoramic view of the T1 apron to see that.........

Perhaps the faded tail was due to looking out through champagne flutes

 

[markis10]

The view from the MEL J lounge yielded the same result, and that included a very faded TJJ tail!

 

[dfcatch]

The view from the MEL J lounge yielded the same result, and that included a very faded TJJ tail!

Hmmm. I should make a point of checking it out.....

In all seriousness - is this a new observation? Ie. more faded than normal?

 

[jb747]

Noticed yesterday at SYD T1 the A330s seem to have faded red paint on the tail yet the rudder was not faded, it would suggest the tail is in fact need of a wash but it did get me thinking as to the real reason why it appeared so, any ideas??

In the last year I have noticed many faded red tails, quite frankly it looks terrible, perhaps QF got some cheap red paint, it certainly seems worse than ever when it comes to fleet appearance?

The red has always shown that tendency to fade to a pinkish colour. The older 330s must be getting near 10 years old now, so certainly time for it to have faded. I doubt that too many cars would look all that good if left outside for that timeframe. Sadly, cosmetics aren't high on their list...although I do know of a couple of airlines that always do the cosmetic stuff...but aren't so good on the stuff you can't see.

Actually, in this age of high tech decals, I wonder if that wouldn't be better than paint for the tail.

Airbus paintwork in general has not been particularly good, and brings to mind some comments by Jeremy Clarkson about French cars.....

 

[Sprucegoose]

Noticed yesterday at SYD T1 the A330s seem to have faded red paint on the tail yet the rudder was not faded, it would suggest the tail is in fact need of a wash but it did get me thinking as to the real reason why it appeared so, any ideas??

In the last year I have noticed many faded red tails, quite frankly it looks terrible, perhaps QF got some cheap red paint, it certainly seems worse than ever when it comes to fleet appearance?

I have heard that colour RED fades five times faster than other colours. Its a real bugger of a colour as it makes the planes look 'unkept'.................

 

[Flying Fox]

My understanding is that a clean aircraft is more fuel efficient than a dirty one. If so, do aircraft ever get washed (bring on the jokes about AF aircraft never being washed)?

I also read somewhere that a company (AUS from memory) offers a clear surface coating that makes aircraft more slippery and hence more fuel efficient. Do QF aircraft have any special clear coat to save fuel?

 

[jb747]

My understanding is that a clean aircraft is more fuel efficient than a dirty one. If so, do aircraft ever get washed (bring on the jokes about AF aircraft never being washed)?

Whilst I'm sure that's the case (my cars are at least 50 kph faster when clean), I doubt that any saving would offset the additional costs incurred in keeping them clean all of the time. The only places where they tend to sit around for long enough, also tend to be either the places with lots of environment reasons not to be cleaning them, or where it would just be difficult.

I also read somewhere that a company (AUS from memory) offers a clear surface coating that makes aircraft more slippery and hence more fuel efficient. Do QF aircraft have any special clear coat to save fuel?

I doubt it. In fact I'd have to wonder just how efficient such a coating could be, unless you were able to strip the aircraft back, to ensure the original paintwork was clean and smooth enough. If the paintwork on the aircraft were delivered to you on your new car...you'd tear up the cheque.

 

[serfty]

AFAIK, Qantas wash the planes every few weeks.

Any who've done the 'free' Bus trip at SYD between T1 and T3 Gt1 would have seen the washing hangars that face north - on the other side of the hangars that face those in the T3 QP/JL.

When doing one of the old tarmac tours (OzFest 2) we were told that often up to 2 tonne of accumulated grit is washed of a 747. Moreover the drag caused by dirt makes a noticeable difference in fuel consumption, .

 

[jb747]

AFAIK, Qantas wash the planes every few weeks.

I'll follow that up. I'll be prepared to eat hat if they get a wash anywhere near that often.

Any who've done the 'free' Bus trip at SYD between T1 and T3 Gt1 would have seen the washing hangars that face north - on the other side of the hangars that face those in the T3 QP/JL.

You mean the semi open hangars? They aren't for washing...it was just a cheapish way of building a 747/380 hangar.

When doing one of the old tarmac tours (OzFest 2) we were told that often up to 2 tonne of accumulated grit is washed of a 747. Moreover the drag caused by dirt makes a noticeable difference in fuel consumption, .

Two tonnes would show up in the fuel usage and performance figures (i.e. it would be commercially viable to know the actual numbers and use them). They make no allowance for it at all. Whilst it sounds like a nice number, I'd take it with a grain or two of salt.

 

[ColinP]

Using a very rough guestimate of around 500 sq metres for top wing surface and 1000 sq metres for entire fuselage of a 747 it would only take around 1mm of dirt to create 1.5 cubic metres. If it was around the same specific gravity of garden soil that would be well over 2 tonnes.
A millimetre all over would be rather excessive but 500 kg of dirt doesn't sound like a totally unreasonable amount to get off a filthy 747.

Somebody check my maths please

 

[Flashback]

AFAIK, Qantas wash the planes every few weeks.

Any who've done the 'free' Bus trip at SYD between T1 and T3 Gt1 would have seen the washing hangars that face north - on the other side of the hangars that face those in the T3 QP/JL.

When doing one of the old tarmac tours (OzFest 2) we were told that often up to 2 tonne of accumulated grit is washed of a 747. Moreover the drag caused by dirt makes a noticeable difference in fuel consumption, .

As opposed to most .eu carriers who don't seem to at all........

 

[meloz]

I'll follow that up. I'll be prepared to eat hat if they get a wash anywhere near that often.


You mean the semi open hangars? They aren't for washing...it was just a cheapish way of building a 747/380 hangar.


Two tonnes would show up in the fuel usage and performance figures (i.e. it would be commercially viable to know the actual numbers and use them). They make no allowance for it at all. Whilst it sounds like a nice number, I'd take it with a grain or two of salt.

I used to have the contract with Ansett washing their aircraft (you may have lost points, I lost $'s), their turn around for a wash was something like every 8-10 weeks. Every second wash they may get a polish.

The open hangars at QF have drainage gutters designed to capture the wash water from aircraft hence that was the only place the 74's were washed back in the early 2000's. I imagine the same still stands.

I think we are talking microns when it comes to dirt on aircraft. The speeds alone would get rid of most. My guys dealt with grime and staining when cleaning the aircraft. It is completely different to a dirty 4WD.

The coating refered to is probably a product we used to elimate the grimes clingability on the aircraft and also makes it easier and quicker to clean.

Meloz

 

[NM]

Whilst it sounds like a nice number, I'd take it with a grain or two of salt.

Or perhaps a ton or two?

There are plenty of references to airlines like AA choosing to polish the aluminum skin rather than paint it, saving a considerable amount of paint weight. Obviously this is not an option for modern aircraft made with composite or other weight-saving materials. Was AA's decision to polish rather than paint really due to weight reduction? Or was it just a marketing ploy?

Similarly, there are reports that the artistic paintwork on aircraft like VH-OJB (in its original scheme) added several tons to the aircraft. Was this significant enough to make a difference to operational performance calculations?

 

[jb747]

There are plenty of references to airlines like AA choosing to polish the aluminum skin rather than paint it, saving a considerable amount of paint weight. Obviously this is not an option for modern aircraft made with composite or other weight-saving materials. Was AA's decision to polish rather than paint really due to weight reduction? Or was it just a marketing ploy?

I once flew with an FO who was working on a uni degree, and that was a subject that she was investigating. Apparently there were both positives and negatives. Lighter weight, but less corrosion resistance and more maintenance were the points that I remember.

Similarly, there are reports that the artistic paintwork on aircraft like VH-OJB (in its original scheme) added several tons to the aircraft. Was this significant enough to make a difference to operational performance calculations?

It would have been allowed for in the basic weight of the aircraft. They are all weighed (various times, but delivery and after major checks are two). That weight is then used as the basic weight for all of our calculations. In the case of the 380s there's around a 5 tonne spread of weights....some are fatter than others.

 

[jb747]

A bit of follow up....there is no washing schedule. It is all on an ad hoc basis. So, I guess if there is a noticeable performance degradation, or someone takes one 4 wheel driving, they'll get a wash. Otherwise, never (which fits in with what I thought).

They are never polished.

 

[simongr]

It would have been allowed for in the basic weight of the aircraft. They are all weighed (various times, but delivery and after major checks are two). That weight is then used as the basic weight for all of our calculations. In the case of the 380s there's around a 5 tonne spread of weights....some are fatter than others.

WTF? How can the same aircraft built to the same spec for the same airline be fatter or thinner? Not doubting you but it just seems absurd. It also brings into question whether one is safer than the other (implying one was built to spec and the other was a Friday afternoon job).

 

[nlagalle]

WTF? How can the same aircraft built to the same spec for the same airline be fatter or thinner? Not doubting you but it just seems absurd. It also brings into question whether one is safer than the other (implying one was built to spec and the other was a Friday afternoon job).

Simongr,

Although built to the same spec, there are always weight differences. It's even the same for light aircraft. There are differences in what are put inside the plane that affect the basic empty weight.

 

[anat0l]

WTF? How can the same aircraft built to the same spec for the same airline be fatter or thinner? Not doubting you but it just seems absurd. It also brings into question whether one is safer than the other (implying one was built to spec and the other was a Friday afternoon job).

Standard error from design mean?

Not sure I read jb747 correctly, but from his last sentence ("5 tonne spread of weights") I read this to mean that every 380 is equal to its design +/- 5 tonne. Whether this is the correct interpretation or not I am not sure.

What would be interesting is to note whether the resulting shape of the aircraft markedly changes how one operates each A380. Also brings to light that there must be some error (i.e. in measurements, uncertainty) that carries over into loading and fuel calculations, and what is the expected error/contingency that is budgeted for to allow for safety, correct loading etc.

 

[ajw373]

Remember with the A380's that the program is new and Qantas has some very early ones so some difference is to be expected. You will find over time as the design and build has bedded down the difference off the production line will be much smaller.

 

[jb747]

All aircraft have weight variations. In fact I recall a comment from the bloke who was responsible for the 747-400 initial deliveries, to the effect that "all of them were the same, until we got OJB".

There are tolerances in everything. Whilst they might be pretty narrow in the more important engineering areas, they will be dramatically less so in items like cabin fittings. So, whilst there will be swings and roundabouts in what items weigh, the end result will never give you the same total weight...even variation in paint thickness will give a measurable result at the end.

The aircraft themselves have different equipment in them. Not just from orders with slightly different options, but the boxes themselves tend to vary as the makers find better or cheaper ways to make things.

And, in the case of the 380 in particular, the aircraft was always quite a bit heavier than what Airbus had wanted/promised, so there is an ongoing weight reduction process happening on the manufacturing line. Having said that, in service aircraft tend to get heavier with time.

Car manufacturers have this sort of thing down to a fine art, but I'll bet that if you take two ostensibly identical cars and weigh them, there will be some level of variation...and they get to make millions of the things, not a paltry few hundred like the aircraft makers.