Hi, I am preparing for my CPL performance exam and I’m working through the performance study guide (a slightly older version Dec 2021 but checking against errata).

Part 135 chapter 7 states contingency fuel should be 10% of trip fuel, but a lot of the examples on the Performance book apply the 10% contingency to ALL of the remaining fuel after reserves and taxi have been considered. Unless I am mistaken this applies 10% contingency to the trip fuel AND any extra fuel one may be carrying rather than just to the trip fuel.

Tried to find a clear answer on the forum to this one but could not. Would appreciate any guidance as using the wrong method in the exam will have a knock on effect on the correctness of many answers across the exam. Thanks

Hi Stratus. This calculation depends on what you are trying to calculate. If calculating the minimum fuel required, then the contingency fuel is calculated on your known trip fuel. If working in reverse, how much trip fuel would be available or safe endurance with a given fuel in tanks figure? In this case, the fuel remaining after removing final reserve fuel, startup and taxi, and any holding or alternate fuel is trip fuel plus contingency.
Cheers W

Thanks for the quick reply Wayne. I was thinking of a scenario where you were carrying additional fuel (not required by the trip or reserves) in that case if you worked back from total fuel amount removing final reserve fuel, startup and taxi, and any holding or alternate fuel and then divided that number by 1.1 you would be applying the contingency factor to both the trip fuel and any additional fuel being carried