All the seats in the liberator contribute to its success, but they are disproportionally rewarded. The pilot is the one investing all the certs into the lib, lining up shots and avoiding flak, and only gets half XP. The bomber doesn't have to invest a thing, and gets full XP, often with things like kill streak bonuses as well that the pilot doesn't benefit from. The tail gunner practically gets nothing. Not only do they not get a share of the bomber's kill XP, but often they don't even get ESF kills. They are helping by hassling and scaring the ESF's until they have to veer off, but they get no reward unless they managed to kill it, a very hard task when even the anti-air A30 Walker doesn't do much damage. I fly with a group of friends, each of us specializing in a role. At the end of a long run, the bomber had two hundred certs, the pilot (me) had one hundred certs, and the tail gunner had... I don't know, maybe three? We really, really felt bad for our tail gunner. Switching seats would even out the distribution, yes, but it shouldn't have to be that way. Manning the tail gun shouldn't be like drawing the short stick. So, simple suggestion. Split kill XP evenly among the crew, each getting one third.