ASP question from last ATPL sitting
 

Hi all,
Can anyone who took the May ASP ATPL exam remember the question regarding the straining of the fuel to check for contamination. It was something to do with when should you strain in order to be sure there are no impurities. The options were something like

Before each flight

After refuelling

Each morning


I can't remember the question for the life of me. Can anyone shed some light on it?

Thanks

L-P

Each morning or before the first fly.

:ok:

In the morning you'd normally check for mainly for overnight condensation and to some degree for impurities (which you should already know about from last refuel), but as the question asks for impurities only it's a tricky one, I'd have gone for after refuelling. If I can find the actual definite question/answer I'll post it,
MTV

You drain the fuel is to check if the fuel has impurities and water.

Why should you do it first thing in the morning, before fly or before refuelling?
That is becuase during the night all the impurities sinks to the bottom and the water too ( water has heigher density than fuel). So if you move the plane or you refuel th plane all the impurities and water will be suspended again. If you refuel or move the aircraft you donnt have to drain because the result may be worng. As you know the drain is at the lowest part of the fuel tank.


:ok:

You would also normally drain again after refuelling or at least you do in small planes. Any commercial guys care to comment? Is it drained and checked again after each refuelling or done just once?

Thanks,

L-P

From a practical airmanship point of view, I would do the fuel drain check before each flight AND after each refuelling.

If your friendly refuellers had kindly uploaded you with a dose of water or other contaminant, in addition to the right stuff, it would be better to find out before you then go flying - and perhaps to advise the refuellers of your findings ? Also, I recommend that you do not assume that the previous pilot already did the 'first flight of the day' fuel drain check. Perhaps he did; he may even say he did, but ... Flight itself, with fuel sloshing around, may dislodge contaminants from a deteriorating tank system, so the next flight is always vulnerable.

As to the answer to the specific ATPL exam question, who can say ? They are notorious for weaselly wording ... :hmm:

Refuelling using Avgas, definitely check after each refuelling and first flight of the day.
Refuelling with Avtur. First flight of the day, however, usually the engineers have done that (if you're lucky). Water takes so long to come out of solution in Avtur that it is impractical to check after refuelling. Water in Avtur isn't nearly as much of a problem with Avgas. It's a lot harder to accidently leave the caps open on an Avtur powered aircraft (and let water in that way).
That's the beauty of turbine engines, they aren't as fussy as piston engines with respect to impurities in the fuel.