Do special paint schemes affect BEW?
 

I remember some years ago reading that Wunula Dreaming used something like 200kg of paint to complete. Does CASA have to approve this and specific changes be made the the aircrafts individual weight and balance or?

Also refer to DJs shick, Black eyed peas and other promo paint schemes...

In theory - yes.

I doubt 200KG of weight on a 737 or 747 is going to affect performance in any sort of meaningful or even measurable way.

Yes and Yes.

You need approval for certain paint schemes. There is a rule somewhere too about how only a certain percentage of the aircraft can be coloured beyond that of the factory specification, eg 10%.

There have been many occasions when aircraft / operators have been penalised for too much colour on their aircraft but you usually only hear this offence tacked on behind a string of others.

Ummm 200kg's would definitely need to be added into W&B calculations, that is a substantial amount of weight no matter how many tonnes you are talking!

Yes 200kg is substantial.... if you are talking about a human!

From the Qantas webiste.

Maximum Take-off Weight 412,769kg/910,000lb
so 200Kg
= 0.05%

I doubt QF would get the thing re-weighed for that!?

200kgs is 2 pax or a decent number of bags to offload if you're right at MTOW - it's certainly substantial!

Nobody is saying it would need to be "re-weighed" however it would need to be factored into w&b and pax loading considerations.

That much extra weight would cost a lot of money over a year in service let alone the aircraft service life.

Last I heard you were meant to reweigh after any paint job?

And LAME's that aren't also a WCA are only able to approve very very minor changes in weight.

Unless you can provide a reference, I'm calling Bovine Scatology on that one.

Arrrggh I knew someone would ask!

I only know about it as we sold an aircraft a couple of years back which had extra stickers/decals applied and the company agent removed them as they were in breach of the regs because there was more than ~10% colour added. (or whatever the figure was)

I do specifically recall when CASA took an operator up north to task that their aircraft were fitted with decals that weren't approved by CASA. In my defence, perhaps this was the materials that they were made from that didn't comply?

There are (or were) certainly regulations pertaining to advertising on aircraft and I recall a friend having "issues" with CASA/DOT/DOTA/CAA/ or whoever it was on that particular day over a sign on his aircraft promoting his real estate business. But I remain unconvinced on the color scheme thing.

Decals may also be different because you'd have to consider what effect they may have if they peel back.

I cant recall but awhile back a new startup airline had to change their colour scheme as the paint required to make up the clours they wanted would have put a load of weight on the aircraft. AA satrted to fly with a all metal to save on fuel

Some interesting observations above. Considerations -

(a) CAO 100.7 requires that an LDS change be made if the accumulated weight and balance data has varied outside prescribed limits. Whether this requires a reweigh or can be done by calcs is up to the WCO and this would be expected to be based on historical evidence of how much paint goes onto a particular sort of paint scheme.

Generally, a major paint job is done in association with other maintenance so it would be reasonable to do a good clean up on the aircraft. Whether the weight will go up or down depends on the delta between what comes out (dirt, rubbish etc.), what comes off (I've seen more than a few paint jobs over paint jobs over paint jobs), and what goes on (the current paint job).

My preference always is to reweigh .. not a major cost in the overall scheme of things and can result in an advantage to the operator. For instance, I can recall a DC3, years ago, which went down several hundred pounds after a good cleanout .. and repaint.

(b) CASA ought not to be involved at all in the normal course of things .. unless the repaint is associated with a significant mod program involving CASA airworthiness oversight.

(c) There is a rule somewhere too about how only a certain percentage of the aircraft can be coloured beyond that of the factory specification, eg 10%.

Never came across that one .. might be in the realm of OWT ?

(d) There have been many occasions when aircraft / operators have been penalised for too much colour on their aircraft but you usually only hear this offence tacked on behind a string of others.

I think that we'd all love to have you cite some specific examples of this one ?

(e) Last I heard you were meant to reweigh after any paint job?

Generally a good gameplan but not "required", per se. However, the WCO would need to justify the calculations in lieu of a reweigh.

(f) LAME's that aren't also a WCA are only able to approve very very minor changes in weight.

The non-WCO LAME can update the RWA data sheet within the LDS reissue limits. When the limit is reached and the LDS requires revision, that approval requires a WCO.

(g) I only know about it as we sold an aircraft a couple of years back which had extra stickers/decals applied and the company agent removed them as they were in breach of the regs because there was more than ~10% colour added. (or whatever the figure was)

Again, a pity you didn't ask him to cite the particular regs ?

(h) CASA took an operator up north to task that their aircraft were fitted with decals that weren't approved by CASA

advertising or confusion with the registration marks, most likely.

(i) Decals may also be different because you'd have to consider what effect they may have if they peel back.

Most of us would view decals in the nature of a mod requiring a CAR 35 tick in the box. Decal loss happens occasionally but, generally, isn't a problem (down the gullet may be a problem, however).

(j) as the paint required to make up the clours they wanted would have put a load of weight on the aircraft.

Then one either accommodates the weight penalty or changes the colour scheme.

(k) AA satrted to fly with a all metal to save on fuel

I recall reading a long time ago that the AA alloy paint scheme was driven principally by weight savings.

Wunala was heavier than other aircraft with respect to the paint job and it may have been my more than 200kg. A number of numbers I've heard range from 200-500kg.

As others have pointed out, that makes a significant difference with many departures of the 744 at MTOW. The aircraft would most certainly be weighed after painting as every aircraft will have a document listing the BEW of the particular aircraft down to the last kg. EG an empty 767 may be listed as 88039. Another one may be 87458 due to a different galley/ seating config. To suggest that these sorts of things don't matter is completely ignorant.

The 10% colour rule may be aircraft specific to some composite aircraft and is an manufacturers requirement.

And then 250-350 pax walk on all weighing 5-10kg more than 'standard'.:ok:

If you believe the experts, then this is already happening as we get more obese my the minute and supposedly moreso than Americans, but news for the experts, I've been there and we aren't anywhere near as fat as they are.

I thought they retired "Wunala" or whatever it was but I swear I saw the red one in Melbourne at the Tulla terminal last week. It was very early so maybe it was something else similar.


Good call 43inches and I suspect you are exactly right - this was indeed an American manufactured composite GA aircraft I was referring to. Probably the same reason why Jabiru's can only be predominantly white in colour, so they don't melt in the Aussie sun.

aircraft down to the last kg

The LDS usually will quote mass to the kilo and CG to the millimetre. However, the reality is that the numbers are comparatively approximate due to the limitations of weighing equipment and errors in replicating the calibration conditions at the weigh.

The 10% colour rule may be aircraft specific to some composite aircraft and is an manufacturers requirement.

Indeed, that may be the case and would apply in principle to any composite structure. One would be a bit adventurous painting a composite totally black without some data on potential structural consequences.

However, that is quite different to weight and balance considerations.

And then 250-350 pax walk on all weighing 5-10kg more than 'standard'

True but a matter for operator protocol and procedural discipline ..

as we get more obese my the minute

A basic premise underlying the use of standard weights (but generally ignored for obvious reasons) is that the operator uses an appropriate population statistic where appropriate means that the standard weight relates to the real population in question.

FokkerInYour12

I'm sure the airlines would love to take another 200kg of freight!!?

i may be wrong but i read somewhere it may be in the region of 2000 kg??

Way back when flying was dangerous and sex was safe, MMAs DC-3s were all metal, POLISHED finish(good old dura-glint, done by hand) to so called save weight, some 100kg was I think the figure and they went well when polished.
A photo in "I flew for MMA" shows a group in reflection under the wing very clearly.
If you have a repair, paint can hide all sorts of things.

:ok::ok: