How many go-arounds and alternates are usually accounted for? Assuming EU, high-airport density etc, typical 2h flight.
Does the estimation change depending on weather forecast, season of the year etc?
How many go-arounds and alternates are usually accounted for? Assuming EU, high-airport density etc, typical 2h flight.
Does the estimation change depending on weather forecast, season of the year etc?
3 go arounds + 2 hours in a holding pattern should result in at least 45 to 60 minutes left in the tanks after landing. Depending on the kind of aircraft that can be a pretty impressive amount of fuel.
> Does the estimation change depending on weather forecast, season of the year etc?
Yes. There are many factors that go into this including trade winds (which vary quite a bit seasonally and which can make a huge difference), time of day, altitude of the various legs, route flown, weather, distance to alternates, altitude of the place of departure and altitude of the place where you are landing, weight of the aircraft, engine type, engine hours since last overhaul, weight of passengers, luggage and cargo, angle-of-attack and so on. The software I wrote was a couple of thousand lines just to output a single number and 10x as much code for tests, and it was just one module in a much larger pre-flight application.
I can only imagine how the test suite looks like. Wild.
This made me think about the fuel itself: is aviation fuel globally standardised and the same quality in every single airport in the world?
The test suite was much larger than the code. It took ages to get it certified, the calculations had to be correct to the last significant digit on reference problems to prove that the algorithms had been implemented correctly. This caused a bit of a headache because the floating point library that I used turned out to be slightly different than the one from the benchmark.
There are three different kinds of jet fuel and all are produced to strict standards, and then there are allowances for ppm water contamination (very low, to ensure the fuel system will never freeze at altitude or in freezing weather on the ground or at lower altitude).