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## Practice Exam Question - ECHO

• lostinspace2011
• Topic Author

### lostinspace2011 created the topic: Practice Exam Question - ECHO

Given:
```ZFW	2278	2781	633.6
Main	272	1780	48.4
Aux		2800	0.0
Gross	2550	2675	682.0```

To move the Gross weight from 2675 to the limit of 2680 it worked out
5.5mm x 2550 / (2800-2680) = 116.87

Which was the suggested solution

I am concerned however that the ZFW limit of 2781 is well outside of the CoG range. As the AUX tank is outside the CoG range, no amount of fuel will bring the CoG forward into the range.

I am hoping that I made another silly mistake here.

• Posts: 2468

### bobtait replied the topic: Practice Exam Question - ECHO

Yes, you are quite correct. If the CofG condition with the main tanks full was 2550kg and 682 the actual ZFW would have to be way outside the aft limit that means the aircraft would burn itself out of the aft limit as you burnt the main tanks. The question needs rewording. Congratulations! I'll make some changes to the wording of the question. Well done....