Comment by dotancohen 4 days ago
> fuel burned stays burned, you don't 'get it back'
Nah. You want to land, but you are really not shedding most of your velocity until after touchdown. What you gain by burning fuel is energy, and you can either bank it into altitude, or velocity. You must shed both to land, but not so for go-around. There you shed almost all of your altitude, but you keep most of your velocity -> you still have a lot of energy left. That's why on go-around you spool your engines and start climbing basically right away, unlike typical takeoff, where after spooling up the engines you are still earth-bound until you build enough velocity.
So you only ever really lost your "altitude" component of energy, not "velocity" one. You run your engines at TOGA (Take Off / Go Around = maximum thrust), thrust to gain mainly altitude, only increasing speed a little bit. Then on another approach attempt you use both the altitude and excess velocity bank again.
In flight, ~all your energy losses go to drag. Doesn't matter if you bank it into speed or altitude, both is exchanged to be at minimums (0 altitude above ground, lowest safe landing speed) at touchdown. If you produce extra energy in your engines, it has to go to either speed or altitude, which you then pull out again, usually by maintaining speed while lowering altitude while having engines at idle.
So it seems. But because you want to land you then want to shed all that velocity. So you 'get it back' only to have to waste the bigger fraction of it. A go around is much like a mini take-off, you just miss the runway portion of it.