Weight and balance of amateur-built aircraft

[djpacro]

http://www.casa.gov.au/scripts/nc.dll?WCMS:PWA::pc=PC_102020

 

"Amateur aircraft builders have traditionally weighed their aircraft and calculated the empty weight centre of gravity (CG) as part of the build process in the belief that it was their prerogative as the aircraft manufacturer to do so.

 

The SAAA recently became aware that CAO 100.7 applied to their members and has advised all builders that prior to applying for a special certificate of airworthiness, they must obtain weight and balance data produced under the control of a weight control officer (WCO). This has created difficulties for those builders whose projects are nearing completion because of a shortage of WCOs who are available for the purpose.

 

The SAAA advises that approximately 60 amateur-built experimental certificates are issued annually. The SAAA also advises that WCO authority holders are not plentiful, and most are unavailable for this type of work. The net effect of this shortage is that travel and accommodation costs must be factored for many builders which can push the cost of weighing as high as $4000 for an aircraft.

 

The SAAA has requested that CASA provide a legislative solution to deal with their concerns.

 

...

 

The Objective of this project is to permit CASR 21.191(g) experimental amateur built aircraft under CAO 100.7 to use alternative weighing processes and procedures controlled by the SAAA."

 

I can understand that a country builder (and pilot) would find a number of required services to be expensive because of distance from the providers. CASA has rarely considered such factors in regulatory matters.

 

I don't know about other states but around Melbourne I don't see a shortage of WCOs available for amateur-built aircraft.

 

Surprised to hear that these people thought that they were exempt from the rules. Also surprised that a CofA was issued without W&B by a WCO.

 

 

[Guest Nobody]

I wonder if this applies to RAAus aircraft too? Does every RAAus Aircraft have to be weighted by a CASA approved WCO?

 

 

[Dafydd Llewellyn]

I wonder if this applies to RAAus aircraft too? Does every RAAus Aircraft have to be weighted by a CASA approved WCO?

Yes; see CAO 100.7. This CAO comes under CAR 235, which is NOT included in the exemptions in CAO 95.55

 

 

[ave8rr]

http://www.casa.gov.au/scripts/nc.dll?WCMS:PWA::pc=PC_102020"Amateur aircraft builders have traditionally weighed their aircraft and calculated the empty weight centre of gravity (CG) as part of the build process in the belief that it was their prerogative as the aircraft manufacturer to do so.

The SAAA recently became aware that CAO 100.7 applied to their members and has advised all builders that prior to applying for a special certificate of airworthiness, they must obtain weight and balance data produced under the control of a weight control officer (WCO). This has created difficulties for those builders whose projects are nearing completion because of a shortage of WCOs who are available for the purpose.

 

The SAAA advises that approximately 60 amateur-built experimental certificates are issued annually. The SAAA also advises that WCO authority holders are not plentiful, and most are unavailable for this type of work. The net effect of this shortage is that travel and accommodation costs must be factored for many builders which can push the cost of weighing as high as $4000 for an aircraft.

 

The SAAA has requested that CASA provide a legislative solution to deal with their concerns.

 

...

 

The Objective of this project is to permit CASR 21.191(g) experimental amateur built aircraft under CAO 100.7 to use alternative weighing processes and procedures controlled by the SAAA."

 

I can understand that a country builder (and pilot) would find a number of required services to be expensive because of distance from the providers. CASA has rarely considered such factors in regulatory matters.

 

I don't know about other states but around Melbourne I don't see a shortage of WCOs available for amateur-built aircraft.

 

Surprised to hear that these people thought that they were exempt from the rules. Also surprised that a CofA was issued without W&B by a WCO.

In my situation, the aircraft was weighed on scales used for aircraft weighing and the figs were sent to a WCO and a Cert issued prior to issue of a Special CofA.

 

 

[M61A1]

Yes; see CAO 100.7. This CAO comes under CAR 235, which is NOT included in the exemptions in CAO 95.55

I thought the key words might have been "airworthiness certificate". CAO 100.7 says that an aircraft must be weighed prior to issue of an airworthiness certificate, so, my understanding would be that if your aircraft does not need the airworthiness cert, it does not need to be weighed under a weight control officer, but would still need to comply with other regs like the RAA tech manual referred to in CAO 95.55. Feel free to correct if this is wrong.

 

 

[rankamateur]

I thought the key words might have been "airworthiness certificate". CAO 100.7 says that an aircraft must be weighed prior to issue of an airworthiness certificate, so, my understanding would be that if your aircraft does not need the airworthiness cert, it does not need to be weighed under a weight control officer, but would still need to comply with other regs like the RAA tech manual referred to in CAO 95.55. Feel free to correct if this is wrong.

I hope you are right! This crap is heaping up faster than I can shovel it away lately.

 

 

[Dafydd Llewellyn]

I thought the key words might have been "airworthiness certificate". CAO 100.7 says that an aircraft must be weighed prior to issue of an airworthiness certificate, so, my understanding would be that if your aircraft does not need the airworthiness cert, it does not need to be weighed under a weight control officer, but would still need to comply with other regs like the RAA tech manual referred to in CAO 95.55. Feel free to correct if this is wrong.

Well, that's an interesting point; indeed CAO 100.7 does refer to weighing as a pre-requisite to the issue of an airworthiness certificate.

3.1 Initial Weighing

 

(1) Except as specified in subparagraph (2) of this paragraph, all aeroplanes, gliders and rotorcraft shall be weighed prior to the initial issue of a certificate of airworthiness.

 

(2) The weighing of an aircraft, other than a prototype aircraft, prior to the initial issue of a certificate of airworthiness is not required if the empty weight and empty weight centre of gravity position have been established to the satisfaction of a weight control officer.

 

(3) CASA may require an aircraft to be weighed or reweighed, as applicable, if reasonable doubt exists as to the accuracy of the weight and balance data submitted in respect of that aircraft.

 

I suspect this is because CAO 100.7 was extant long before CAO 95.55 was drafted, and nobody twigged that the wording did not make the situation clear for CAO 95.55 aircraft.

 

I cannot answer for the legal definition; however I suspect that if it came to a point, CASA would invoke 3.1(3) and require the aircraft to be weighed, before it goes into service; even if an airworthiness certificate is not needed. What does the RAA Technical Manual have to say on the subject?

 

Weight & balance is so fundamental to aircraft safety that neglect of proper establishment of the empty weight & CG position, and suitable loading rules, would be gross negligence, I should think. Having said that, scratch designed homebuilts obviously do not have previously-defined CG limits; and neither do prototypes - the CG limits are a result of the flight testing process. American-origin experimental kit aircraft may not have properly-determined CG limits either.

 

So far as I am aware, weighing & setting loading rules are requirements of the Production Certificate for Australian-manufactured recreational aircraft; and it's a requirement of the ASTM QA procedures:

 

8.1.2.1 Ground Check—Prior to flight testing, the manufacturer shall conduct a thorough ground inspection of each LSA

 

produced to verify at least the following:

 

(1) Weight and Balance—Empty weight and proper center of gravity location has been calculated and verified to be within

 

limits, and that a weight and balance report has been completed for the airplane;

 

 

so this is covered so far as factory-built aircraft are concerned.

 

 

[M61A1]

Well, that's an interesting point; indeed CAO 100.7 does refer to weighing as a pre-requisite to the issue of an airworthiness certificate.3.1 Initial Weighing

 

(1) Except as specified in subparagraph (2) of this paragraph, all aeroplanes, gliders and rotorcraft shall be weighed prior to the initial issue of a certificate of airworthiness.

 

(2) The weighing of an aircraft, other than a prototype aircraft, prior to the initial issue of a certificate of airworthiness is not required if the empty weight and empty weight centre of gravity position have been established to the satisfaction of a weight control officer.

 

(3) CASA may require an aircraft to be weighed or reweighed, as applicable, if reasonable doubt exists as to the accuracy of the weight and balance data submitted in respect of that aircraft.

 

I suspect this is because CAO 100.7 was extant long before CAO 95.55 was drafted, and nobody twigged that the wording did not make the situation clear for CAO 95.55 aircraft.

 

I cannot answer for the legal definition; however I suspect that if it came to a point, CASA would invoke 3.1(3) and require the aircraft to be weighed, before it goes into service; even if an airworthiness certificate is not needed. What does the RAA Technical Manual have to say on the subject?

 

Weight & balance is so fundamental to aircraft safety that neglect of proper establishment of the empty weight & CG position, and suitable loading rules, would be gross negligence, I should think. Having said that, scratch designed homebuilts obviously do not have previously-defined CG limits; and neither do prototypes - the CG limits are a result of the flight testing process. American-origin experimental kit aircraft may not have properly-determined CG limits either.

 

So far as I am aware, weighing & setting loading rules are requirements of the Production Certificate for Australian-manufactured recreational aircraft; and it's a requirement of the ASTM QA procedures:

 

8.1.2.1 Ground Check—Prior to flight testing, the manufacturer shall conduct a thorough ground inspection of each LSA

 

produced to verify at least the following:

 

(1) Weight and Balance—Empty weight and proper center of gravity location has been calculated and verified to be within

 

limits, and that a weight and balance report has been completed for the airplane;

 

 

so this is covered so far as factory-built aircraft are concerned.

Yes, weight and balance is important, and is required in the tech manual, and must be carried out under the supervision of , or by a L2/3/4. Also specified that the person doing the weighing is not to have an interest in the aircraft ( from memory ).

[planesmaker]

If we read that CAO 100.7 correctly it does not specify the weighing must be done by a WCO. Otherwise 3.1(3) would make no sense if a WCO was doing all the weighing. I can just see it now CASA telling someone authorised by them that their figures are dubious go and do it again. Reminds me of primary school. Tom

 

 

[planesmaker]

Seems funny to me that the only mention of a weight control officer is where the aircraft is not required to be weighed! Tom

 

 

[M61A1]

If we read that CAO 100.7 correctly it does not specify the weighing must be done by a WCO. Otherwise 3.1(3) would make no sense if a WCO was doing all the weighing. I can just see it now CASA telling someone authorised by them that their figures are dubious go and do it again. Reminds me of primary school. Tom

People make mistakes, if the data doesn't add up, it would be quite reasonable to reweigh. This is not just a procedural issue, Weight and balance is critical, and errors are often fatal.

 

 

[planesmaker]

People make mistakes, if the data doesn't add up, it would be quite reasonable to reweigh. This is not just a procedural issue, Weight and balance is critical, and errors are often fatal.

Yes I agree it is critical. The point I'm making is that a WCO is not necessarily required to do the weighing, well that's how I read it. I am open for correction. Tom

 

 

[Dafydd Llewellyn]

You may notice that CAO 100.7 is quite explicit concerning gliders. So, when that CAO was written, (it was an ANO, back then), it was thought necessary to make it quite clear that although gliders came under ANO 95.4, they were NOT exempt. Of course, gliders do have airworthiness certificates and M16's argument could be applied to them, but I think it would be incorrect to do so; they are weighed because it it essential for safety; the reference to doing it as a prerequisite for an airworthiness certificate I read merely as a convenient way to specify when it must be done - because when ANO 100.7 was written, NOTHING flew unless it had a C of A.

 

For decades, the GFA Chief technical Officer was also a WCO, and whilst the people doing the weighing were not, they sent the weighing results to him. Gliders, being almost exclusively factory-built certificated aircraft, were (and still are) always weighed as part of their manufacture process - and the experimental category had not even been thought about.

 

I started weighing aircraft (up to DC-4 size) in about 1965 whilst I was working for de Havilland at Bankstown; and as well as GA aeroplanes, I've weighed dozens of amateur-built aircraft and gliders since; in those days DCA kept several sets of calibrated scales and made them available for this purpose. That stopped when DCA became the CAA, in the '80s. The cost to an amateur builder was nothing like what has been mentioned in this thread; it was often done for no charge, frequently by DCA when they performed the final inspection required by ANO 95.28. As the GFA RTO/A for NSW in the mid-'70s, I often re-weighed gliders when they came up for their 20-year inspection - and got some surprises in doing so. People DO make mistakes, and W & B is an area where one simply MUST get it correct.

 

I've mostly used my CAO 100.7 authority as an adjunct to my CAR 35 work, or when involved in flight testing, not as a primary means of earning a living; so getting an aircraft weighed has not been a problem for me. I've occasionally obliged somebody who needed a weighing - and hired scales for the purpose; I've never charged more that $ 600 to do that, even when a day's driving and hire of scales were involved. I don't do this any more. So I'm not the person to answer the question in this thread.

 

It's a serious question and needs to be sorted out between RAA and CASA.

 

There are a small number of individuals who specialise in aircraft W & B, especially since possession of a set of approved aircraft scales became necessary to do this work; scales are not cheap, and keeping them calibrated is also costly. These people are very reliable and professional in how they go about the process; however, they have to eat, too.

 

The GFA nowadays has the ability to issue its own W & B authorities, and it does not do so willy-nilly. Gliders are nowadays subject to very tight W & B control, because it has proven to be necessary. It's also very complex for gliders that have disposable water-ballast and complicated weight-CG diagrams.

 

So, whilst M16 may have put his finger on a loophole in CAO 100.7 - which may or may not have been intentional on the part of CASA - it sounds as though the RAA Tech Manual is, as usual, inexplicit about the qualification of persons performing this function, and the procedures to be followed. This is a question for Darren Barnfield, I believe.

 

 

[M61A1]

Yes I agree it is critical. The point I'm making is that a WCO is not necessarily required to do the weighing, well that's how I read it. I am open for correction. Tom

I would agree that it says the WCO is not necessarily required to do the weigh, but that it is under his control. If you were the WCO, it would depend how well you trusted those actually carrying out the weigh. I am not a WCO, but I have done many weighs, and would usually gather all the data on the correct forms and hand it over to the weighing officer. He then does all the calculations and signs off on the weight and balance.

 

 

[M61A1]

So, whilst M16 may have put his finger on a loophole in CAO 100.7 - which may or may not have been intentional on the part of CASA - it sounds as though the RAA Tech Manual is, as usual, inexplicit about the qualification of persons performing this function, and the procedures to be followed. This is a question for Darren Barnfield, I believe.

The RAA is quite explicit inasmuch as it must be witnessed by a L2 who does not have any personal interest in the aircraft is a minimum for carrying put a weight and balance (same for condition reports), and has a special form for just that. That data is then sent off to RAA.

http://www.raa.asn.au/wp-content/uploads/2012/02/Aircraft-weight-and-balance-form-up-to-600kg.pdf

 

I don't know that I would call it a loophole, the trade off for operating non certificated aircraft is less bureaucracy, I would like to believe that it was by design. CAO 95.55 puts the ball in the RAA court for maintenance regulation, and I believe that it's adequately covered for those who build and maintain.

 

 

[Dafydd Llewellyn]

OK, Darren is ahead of the game - good on him.