Hi Mark,
Sorry to hear the exam didn't work out for you and maybe we can help you if you want to post any problems you are having here to the forums. However, using minimum fuel as ballast is actually covered fully in the textbook and in the full time class.
Flight fuel is exactly that: fuel needed for the actual flight. It is the fuel that will run through the engines getting from your departure point to the destination. On top of that you will naturally always need reserves and allowances.
If they stated "flight fuel" then you need to factor in fixed reserve in any case and a variable reserve on top of that (assuming it is a commercial flight which it most likely is).
If they say the "minimum fuel required", then that value will include the reserves already.
To help you find the pages covering this material take a look at:
- Flight fuel, reserves and margin fuel: page 4.20-4.21
- Using fuel as ballast: pages 5.40 - 5.46 (which also includes an 11 question set of drill exercises on using minimum ballast fuel).
These topics are discussed in the course and are consolidated with homework exercises. Plus, there are more exercises on this in the exam prep you received as part of your course enrolment.
As a rule of thumb to help you: questions on using fuel as ballast can usually be solved using fuel alone but this is the wrong approach. The aim is to use "minimum fuel as ballast", so you need to add hard ballast first. This is done either until you reach the compartment limit or the ZFW limit for the Echo.
That usually improves the situation somewhat but usually not completely. The last C of G correction needs to be achieved with ballast fuel but since you have already used some hard ballast, the amount of ballast fuel required is minimised.
Check out those pages I mentioned, and if you are still stuck, just holler.
Cheers,
Rich
