Legal? Electronic weight and balance calculators (excel, etc)

[aphexau]

Hi all,

After doing a bit of light reading (CAR 235/CAO 20.7/100.7) I am still unsure whether creating a weight and balance calculator in an Excel spreadsheet is legal.

I have been using one such calculator which I created a few months back for my private flying in light, single engine aircraft. It uses the weights and moments published in each aircraft AFM and passenger/cargo weights using a set of scales. However, I have recently been told that if CASA 'caught' me using it I would get in trouble since it is not approved software.

My understanding of the law is that you simply need to prove you have calculated an accurate weight and balance, it doesn't specify that it has to be done by hand, or that electronic calculators need to be approved. I know operators of RPT aircraft require load/trim software which needs to be approved - but I cant find references to that either...If I am missing something, I would greatly appreciate some enlightenment.

Thanks

[falconx]

Are you flying privately or comm?

[aphexau]

Some PVT and some pre-CPL training flights.

[john_tullamarine]

Have a read of (I know you've done that but the references might be useful for other readers) -

(a) CAO 20.16.1 (http://www.comlaw.gov.au/Details/F2008C00037)

(b) CAO 20.16.2 (http://www.comlaw.gov.au/Details/F2005B00989/Html/Text#para0.92)

(c) CAO 20.16.3 (http://www.comlaw.gov.au/Details/F2009C00628)

(d) CAO 100.7 (http://www.comlaw.gov.au/Details/F2008C00038)

Basically means that you should have some paperwork in your flight manual signed by a weight control officer which either says that your aeroplane can't be loaded outside the envelope or gives you details of the current approved loading system .. which, probably, isn't the desired electronic animal.

If you want to use an electronic gizmo, then you should engage a WCO to check that it complies with the Orders and call it up in the Flight Manual.

Alternatively, if your aeroplane has a simple set of load rules, you should be able to check that the electronic gadget keeps you inside the parameters of the load rules and, in effect, you are complying with the load rules.

Beyond the above it's a bit difficult to provide advice without having a looksee at the specific aircraft's paperwork.

The main problem with Excel is that you would need to have a lot of protections in the sheet for the WCO to sign off on it.

[-_HowUdoiN_-]

If you are doing pre-cpl training flights at a flying school, do they have a operations manual that specifies how weight and balance calculations shall be performed? If they do, I would very much recommend complying with their procedure as the next ramp check could involve headaches for yourself and the flying school.

As far as private ops in your own aircraft, from a quick reading of the CAO sections posted by JT, my interpretation is CASA or a Weight Control Officer need to approve your system.

Loading data prepared in accordance with the provisions of this subsection may be approved by a weight control officer whose appointment covers the activity. Where a flight manual page is used as the load data sheet or to specify any required loading system, 2 copies of the same shall be submitted to CASA.
Note Such flight manual pages will be issued by CASA as a flight manual amendment.

The owner or operator shall keep in a safe place on the ground duplicate copies of all current approved loading data applicable to his aircraft.

As JT said, I think a WCO would find it difficult to sign off your excel spreadsheet ticks all the boxes, especially data corruption, however if you wanted to use it as a backup, or gross error checking tool in addition to the requirements I see no harm in that.

[Oktas8]

In some circumstances you should maintain a printed load sheet to satisfy the law. It would seem to me to be irrelevant (for private & training flights) how you generate the paper copy, as long as all the required data appeared in a clear format.

So format your spreadsheet to print out in a way that shows all required numbers, and carry the signed printout.

You could of course print several copies of your "standard" load in advance, ready for each flight - if you fly the same aircraft loaded in the same way each time. Or print blank sheets and plug in the numbers in ink based on your on-the-spot spreadsheet data.

[aphexau]

Thanks for the feedback guys. I should clarify that i don't actually print out anything...but i use the calculated numbers in the Excel table and directly transpose them onto the company-approved weight/balance form. I've tested it with manually-calculated forms and found that the numbers are identical, but I will err on the side of caution from now on.

[john_tullamarine]

In some circumstances you should maintain a printed load sheet to satisfy the law

Loadsheet is required for heavy and RPT. Refer CAO 20.16.1. Otherwise you just need to check that you are OK. Mind you, a paper record is easier to defend at the Inquiry ..


One other concern when transferring data from the AFM to your own system relates to the datum used.

For instance, if the AFM calls up a trimsheet for the balance calculations of the loading system, it is quite common for the trimsheet datum to be different from the standard AFM datum. It is also quite common that the trim datum used is not specified explicity. As an aside, we do this to maximise the physical accuracy of the trimsheet calculation. One common trim datum used for lighties is the aft most limit of the CG envelope. This was pioneered in Oz by a Melbourne-based WCO in the 70s and 80s and a lot of the trimsheets floating around are plagiarised versions of that fellow's originals.

For interest, the general equation for the trimsheet entry argument IU is

IU = C1 + (W * (CG - TD))/C2

C1 gets rid of negative IU values in the entry start IU line. Negative numbers are so untidy.
W is the empty (or whatever) weight relating to CG
CG is the empty (or whatever) CG referenced to the OEM FS diagram
TD is the chosen trim datum referenced to the OEM FS diagram
CG-TD is the revised arm to the new trim datum
C2 is the chosen moment to IU constant, typically a power of ten

All very straight forward so long as you know what you are doing and take care with the housekeeping.


If the WCO has been sensible, he will have made sure that his non-standard datum is obviously not the standard animal. However, some folks don't worry too much about this and I certainly have seen some trimsheets set up to make the user fail should they try and lift the entry data without doing the appropriate due diligence checks and balances ... traps are there for the unwary.

Years ago, a mate who ran a maintenance shop and had a WCO, did some work on one of his cabin class twins, thought he should revise the weight data and, for good measure, reissued the call up for the trimsheet. You guessed it, he should have known better, got caught out and called up the wrong entry IU. The following day his Chief Pilot caught up to me with a plaintive "This doesn't work ..." My TDs were always set up for that to happen so that everyone had a bit of protection ...

[djpil]

Further to JT's posts:

Let's assume that you have a bit of paper with W&B stuff that you have written in it which conforms to the approved loading system. If that approved loading system requires that you use arithmetic then it is your responsibility to do that arithmetic and ensure that it is correct.

You may do the sums in your head or by long multiplication counting on your figures or use an electronic calculator. You may use Excel iff you check the cell contents are correct wrt data and calculations every time i.e. treating Excel as a simple calculator.

Grabbing an Excel worksheet and just typing in the specific loading configuration or using the W&B functions in the popular iPad Apps - then carefully read the appropriate section in the CASA CAAP on Electronic Flight Bags.

[601]

but i use the calculated numbers in the Excel table and directly transpose them onto the company-approved weight/balance form.

So you are only using it as an expensive calculator that you could by from Change Alley for a $1.00 or as an electronic lead pencil:cool:

[aphexau]

Im not sure if what im saying is being understood correctly, so here is a screenshot of my newest excel file - for a Seminole. The table is laid out as per the AFM/POH so I can directly copy the figures onto a paper weight/balance sheet. I've read the CAAP 233, and all thru CAO 20.16 but it doesn't seem to answer my question. The EFB rules comes close, but the definitions of an EFB doesn't lend itself to a computer not intended to be used during flight.

http://s7.postimg.org/75rhni6gb/Capture.jpg

[SOPS]

I can't tell you if it's legal, but I'm impressed:ok:

[john_tullamarine]

Probable outcome -

(a) if your sums are set up correctly

(b) you designed and are the only user of the sheet

(c) the OEM calcs are called up in the approved loading system

then you are likely fine. I wouldn't bother printing it to hardcopy .. rather to file.

Not a significant concern but try plotting the fuel line for several points between ZFW and TO .. might be a little surprise there for you ..

[PPRuNeUser0161]

All is good if you use a spreadsheet that works and calculates in accordance with the approved flight manual. There's no difference really you can work it out with a paper and pencil if you like!

SN

[Arm out the window]

I bought the rotary-wing iBal phone app which seems to work a treat accuracy-wise, but haven't looked into the legalities of it as a replacement for using the flight manual graphs handraulically.

Anyone been down the path of having it or something similar approved in their operation?

[Flying Ted]

I had been using Excel for flight planning until I switched to Ozrunways. (My spread never look as impressive as AX.) They say this approved by CASA, I assume this applies to the W&B as well as everything else.

[601]

They say this approved by CASA, I assume this applies to the W&B as well as everything else.

I believe that the operator has to have a piece of paper signed by an approved WCO that the W&B system you have designed is an approved system for the particular aircraft

Can be done $$$$.

[kalavo]

I had been using Excel for flight planning until I switched to Ozrunways. (My spread never look as impressive as AX.) They say this approved by CASA, I assume this applies to the W&B as well as everything else.

Assumption is the mother of all ****ups.

CASA Approval | OzRunways | The CASA Approved Australian Electronic Flight Bag, Flight Planner, GPS Navigator for iPad (http://www.ozrunways.com/approved/)
MAPS, DAPS, ERSA and AIP

anything else and you're on your own. It may be possible to get a WCO to approve Ozrunways as a loading system, but each loading system for the aircraft has to be approved. Ozrunways generically does not have this approval, as they can't guarantee the data you enter about your own aircraft is correct (or that it is locked and you're prevented from modifying it).