Me again....

Well I have done question 6 three times now and I can still only get 20kg of cargo in the rear compartment. The boss is missing out on an extra 20kg of paid cargo I guess. The answer is 40kg
Anyway, I started at -20 and drew a perfectly vertical line down to the C of G chart and then marked "A" at 1500kg.

Then added 60kg on the 'Rear Baggage' line and went 'right' and drew a line vertically and marked the extra 60kg point at 1560kg as "B"

Took the join of the two and it crossed the C of G box at 1520kg (extra 20kg of baggage)each time.

Would this be a major cause for concern in the exam if their charts are not aligned properly; or if my ruler is crooked? Thanks.

G'day Brenton,

How good is this, I opened up the Supplement to Loading System Alpha and this very question is what is still drawn up!

Your method seems to be correct.. actually it's definitely correct. Not sure why you'd get a different answer to me?

First things first. Are you getting your weight envelope division mixed up? They are in 20kg.

Here's what I did:

1. Enter from the top at -20 (2 divisions left of 0)
2. Draw a line straight down. You should be able to follow it more or less perfectly because each row has a vertical line directly below the -20 line.
3. Where 1500kg and your vertical line meet is the current situation.
4. Add a hypothetical 50kg to the rear compartment.
5. Draw a horizontal line 5 divisions to the right.
6. From there, draw a vertical line down.
7. On the weight envelope, draw a horizontal line from 1550kg (new hypothetical weight) all the way across it.
8. Diagonally join where 1500kg meets 1550kg and find where the line crosses the aft limit of the envelope.
9. This equals 40kg

Hope this is follow-able.. But here's a pic to put it into perspective.



Cheers!

Brenton

I have had a look at that question and worked it. I get just a tad under 40kg. Ben has worked it an he also gets 40kg. By the way, the CASA exam almost always uses the phrase "is closest to". So they don't expect that everyone will get an exact answer. If your method is correct and you are reasonably accurate, you should have no problem selecting the correct answer.

Bob

Thanks all - I appreciate the follow up. Here is a shot directly from my load sheet. I still cannot see where I went wrong here but as you say Bob, they ask for 'nearest' so 40kg is nearest.

Brenton,

Looking at your picture, I would take a look at where you entered the chart from the top. Are you sure you started from -20 and not +20?? That would make your first vertical line much closer to Bob's dashed line and the line I've drawn in my photo.

Be careful about choosing answers that are (in this case) 20kg's out as the 'closest to' answer. From memory with this sort of question they'll have choices as 38 or 42kg which qualify better as 'closest to' than 20kg.

Sorry to be pedantic about this but I just remember the pain this exam gave me!

Cheers

Cheers Captain.... And yes the charts do require 'exact' lines in 'exact' places but even then a minor variance can throw you off. Good thing that this sort of 'detail' is only needed in an exam. yes we need to be aware of loading and CoG but to fly that close to the 'envelope' is not something I want to do anyway so I will always (and do always) have plenty of buffer in my calcs in the real world. Just an aside; do you think that these CHARLIE charts were written by frustrated physicists who loved mathematics or was it engineers who loved both - they are certainly not designed by pilots. I like the ALPHA charts much better - and I really like the Command Flight Planner software that does it all for me.