Hey everyone,

First question is in relation to the first example on page 5.5. How did you get 41kg for the fixed reserve? Not too sure where you got it from. Also, with the 3 possible cases just below the diagram, wouldnt the second two considerations be out of the question anyway since they are both above the take off weight limit of 2800kg? (Landing Limit+burn off=2836kg. 2630+all fuel at take off=2827kg)

Am a little bit confused with exam question 12 on page 4.52

To find the safe endurance that should be used, I first determined how long it will take to travel 500nm at 170kts, which gives an answer of about 178mins. With 65% power we are burning 28gph. So 28gph in 178mins will cause 82.5gallons of fuel to be burnt. 82.5 gallons at 28gph gives around 178mins as the safe endurance?. I'm just not sure why this way doesn't give the correct answer. Because the question is asking the safe endurance that should be used which is also the flight fuel.

I know I'm not doing it correctly, just want to know why so I prevent myself from doing it on future questions (PNRs are not my forte) :/

Thanks in advanced

Concerning Question No 12 on page 4.52. The 500 nm flight has nothing to do with the calculation. To calculate a PNR all you need to know is the amount of flight fuel available out of the fuel you have on board. For the Echo, if you have 145 gallons on board, you simply find how much of that is available as flight fuel.

145 - 15 - 3 -20 (holding) ÷ 1.15 = 93 gals. Note the only holding you need to allow for is the holding at the departure aerodrome because when you calculate a PNR, the departure aerodrome is your destination.
@ 28 gals per hour that give you safe endurance of 199 minutes.

You have based you calculation on departing with minimum fuel required, but in this case, you are carrying more fuel than you need.

Concerning Page 5.5. There is no problem if any of the checks is above 2950 kg, that just means that that cannot be the limit for this flight.

The 41 kg is simply the fixed reserve in kilograms. 15 gallons x 2.72 = 41 kg.

Thanks for clearing the first question up Bob.

With the 41kg/15gallons however is that a made up figure with the fuel flow of 20 gallons per hour? Or did you actually get that from somewhere in the Echo? Can't seem to find it. Apologies for sounding confusing but I'm not sure how you actually figured out the fixed reserve since no specific fuel flow is mentioned. Am I expected to use that same fuel flow for every question in excercise 5.1?

Also, I'm really struggling with trying to understand the whole concept when you say "If you always check these three possibilities, the smallest one will control the take off weight for a particular flight". Is there anychance you can explain that?

Cheers

The fixed reserve for the Echo is given in the supplement under fuel policy. It is 15 gallons fixed reserve and 3 gallons taxi allowance. 15 gallons at 2.72 kg per gallons is 41 kg.