différence entre ravitaillement et remplissage

07:04 Jun 17, 2013 

is the term used for the actually quite large refuelling 'pod' that is fitted below the supply plane, and contains all the gubbins for the refuelling process — including the carefully reeled hose and the 'drogue' (like a badminton shuttlecock) that the 'probe' docks into. So it could be referring to how this is 'filled' — though note that it is not usually filled with fuel! It does, however, contain the hose, which is possibly what it has to be filled with? Or maybe it is talking about filling the hose with fuel before paying it out — only I didn't think it worked that way...
The first examples of Flight Refuelling apparatus were built in my home town, and when I worked in a test house, we were always having these 'pods' in for testing.

06:45 Jun 17, 2013 

Also the French impersonal "vérifier le remplissage..." without more context is difficult to understand accurately. It could mean :
- make sure that the filling is taking place
- make sure that the filling is complete/has finished
- makes sure that someone is going to take care of it...
In terms of time and thus tense, it runs the gamut of past, conditional and future!
Also, although "ravitaillement" can be translated in a number of ways, as described and explained by Chris, it is quite likely that it is referring to the light for refueling, although we lack context to confirm that. If that is the case, there may be a very specific term for that light. It would be a good idea to post "phare de ravitaillement" as a seperate post and with more context. Perhaps an URL cross-ref to this question.

06:38 Jun 17, 2013 

VERY little context here, but I assume your text refers to in-flight aircraft refuelling. The "phare" almost certainly refers to the bright light used as an aid to "connecting" the two aircraft. "The receiver moves to a position behind the tanker, within safe limits of travel for the boom, aided by director lights or directions radioed by the boom operator."
Ravitaillement refers specifically to in-flight refuelling, whereas "remplissage" is just "filling". Again, lack of context makes it difficult to say anything intelligent about the "nacelle" or why it should be filled.
See http://en.wikipedia.org/wiki/Aerial_refueling

06:18 Jun 17, 2013 

Where is the "phare de ravitaillement" located? Is it used when restocking food and other supplies or when taking on fuel?

06:17 Jun 17, 2013 

Effectively, both describe what amounts to the action of filling. However, in some contexts these terms are used interchangeably, in others specifically. It can depend not only of what volume is being "filled", but also what that volume is being filled with.