× Welcome to the CPL Performance question and answer forum. Please feel free to post your questions but more importantly also suggest answers for your forum colleagues. Bob himself or one of the other tutors will get to your question as soon as we can.

## Finding Max Range

• simsim
• Topic Author

### simsim created the topic: Finding Max Range

Hi All,

I will be sitting my first attempt at performance exam next Tuesday 26th July 2011 in Sydney, I have came across question asking for MAX Range achieved out of the following:

TAS - 153 Knots
Fuel Flow - 20.4 gal p/h
Usable fuel - 150 US gal
Wind component - 25kt Tailwind
Fixed reserve 15 gallons

All above are based on Echo.

Given Answers are: 1000nm , 1024nm , 1050nm and 1075nm

What I have done:
I have subtracted fixed reserve from usable fuel as fixed reserve needs to be intact at arrival.

Therefore: 150-15=135 gal usable

Then, I used the following formula:

Fuel Capacity / Fuel Flow x TAS (135/20.4x153 = 1012nm)

Any ideas would be much helpful.

Given Answers are : 1000nm , 1024nm , 1050nm and 1075nm

What I have done:
I have subtracted fixed reserve from usuable fuel as fixed reserver needs to be intact at arrival.

therefore: 150-15=135 gal usable

then, I used the following formula:

Fuel Capacitiy / Fuel Flow x TAS (135/20.4x153 = 1012nm)

Any ideas would be much helpful.

• Collie

### Collie replied the topic: Re: Finding Max Range

hey mate did you allow for the 15% variable cos i think ive seen this questions i got performance tommorow so ill give you a few heads up on what to look out for cheers

• Posts: 1914

### bobtait replied the topic: Re: Finding Max Range

Two things you may have missed. If it is a charter flight and I suspect it is, you would also have to account for the variable reserve. So flight fuel available would be 150-15 /1.15 = 117.39 gal. Also, you have not allowed for the wind. So the ground speed would be 153+25 = 178kt.

The working then becomes: 117.39/20.4 x 178 = 1024nm.