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Question 33 in Final Test
skewes created the topic: Question 33 in Final Test
I've just completed the final test in the back of the performance book (ISSUE 4 ) and just going through the Q's that i got incorrect. Q33 states that there is a 180kg weight gain for the added fuel however i seem to get 100kg. Is this a misprint or Do I need to get some more study done.
Richard replied the topic: Re: Question 33 in Final Test
I'm looking at Issue 5 and if the diagram in the answer is the same as yours, the upper arrow is perhaps pointing to the wrong line and might be causing some confusion.
Basically, you start with the current situation (marked as A on the answer) and then add (for example) 100 kg of fuel to the auxilliaries in order to generate a new weight and moment index for plotting in the envelope. You could add 200kg if you wanted, it doesn't matter. It's the next step that is important.
After you have added your fuel, plot the weight and moment index as point B. After adding only 100kg, you are still in the enveope so that means we could add even more than 100kg. Let's extend the line A-B all the way up until it exits the C of G envelope. Now, look at the point where it crosses the forward limit and if you measure the weight difference between that point and the weight at A, you'll see it comes to a weight of about 180kg.
The upper arrow and the label "180kg" could be mistakenly assumed to refer to the area between the dotted lines (at 2650kg and 2750kg). However, the 180kg is really referring to the weight difference between point A and the solid line (at about 2830kg). The upper arrow should perhaps point to that solid line, not the dotted line.