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## quick performance question

• rossy
• Topic Author

### rossy created the topic: quick performance question

Hi guys, just a quick question, possibly silly but here goes...

I excercise 5.2 page 5.8 question 6. (with full tanks at start up) under the heading for fueal at take off.

How come we use 180 gallons(usable), minus the 3 used for start/taxi as the fuel at t/o figure and not the 190 gallons(total) minus 3? Is that because the 'empty aircraft' weight given in the question is the basic empty weight which includes the unusable fuel already?

Just want confirmation or if wrong then explanation please.

BTW this will be my 4th exam. Sat and passed AGK MET and ADY in that order so far.

• Posts: 2285

### bobtait replied the topic: Re: quick performance question

The Echo holds 190 gallons of fuel in the tanks when they are totally full. However 10 gallons of that is unuseable fuel. That means that the tanks are constructed so that those 10 gallons can never be sent to the engines. This is done to allow any water or other contamination to remain trapped in the tank and so protect the engines. So as far as fuel planning is concerned, the maximum amount of fuel that can ever be considered as useable fuel is 180 gallons.

The examiner does not try to trick you on this point as he will always talk about useable fuel. Full tanks will always be 180 gallons of useable fuel.

• rossy
• Topic Author

• rossy
• Topic Author

### rossy replied the topic: Re: quick performance question

Hey Bob, think ive found a couple of typo's in the latest edition (issue 5) performance book.

On page 5.73 the answer to question No 15 says 'add up all the.......1118 - 1022 = 93.

it should read 1115 as the max t/o weight.

Further down in the same question, the ZFW moment index is given as 28263 when it should in fact be 28236.

Just thought id give you a heads up incase you had not yet realised.

How many more do i have to find to get a free copy of the next CPL subject text im going to complete?? Which is Nav incase you were curious