Not your heli(copter,) not your game, and not your place to say who gets to ride in 'your' chopper.
Those 'n00bs' payed for the game too, they have just as much right to it as you do. They can't use the gunner position properly? Big deal! Maybe they might benefit from your vast experiance and become a valuable team member, you never know.
If it was real world, where it was a matter between life and death, than yes, certain positions are assigned to specific people who will be able to execute their tasks properly, but this is a game where people have fun, and people who are less experianced than your clan mate have a right to have fun as much as anyone else does.
Who gives a shit if your mate has to take an alternative form of transport to rack up kills? He could take a jeep, APC, Linebacker type AA, Tank, Jet, or simply hoof it. That's the great thing about BF2, so many options. If he is indeed the talented player you believe he is, than he should still be a valuable asset in your team even without being behind the gun of a Helicopter.
It's people like who who are ruining Battlefield 2. You're doing it by taking the whole thing far too seriously. You guys are serious candidates for unranked servers, where the pressure of maintaining good stats or earning awards is taken away.
not saying it is, but havn't you ever stopped to think that it may be your error that results in people not being effective at their game? I've been in plenty a chopper where the pilot asks me 'what the fuck are you doing? Use the TV missile.' the fact of the matter is, I couldn't with them zipping all over the place, hoping to take out the tank with their missiles. They're hoping that I somehow manage a lucky shot. Fuck those people.
If people crash planes, choppers, jeeps, anything, or proove to be worthless gunners, what have you lost? Nothing! Okay, maybe it'll chalk up one loss for your stats, but that's not all bad. Plus, and especially in a chopper, it dosn't even matter, if you are a talented pilot, if you have a gunner at all. I've seen plenty of pilot be effective on their own. I may be nice to have a gunner, or a good gunner, but it's not essential.
A message I pass on to you from my Dad who saw me throw a hissy fit because we lost a soccer game:
"Cool it. It's only a game."