performance review
a few more relevant points:
1. it should be just that - a 'review,, not a 'revelation'. too often the manager uses it to bring up issues that should have been aired at the time the problem cropped up. otherwise the appraisee has no opportunity to modify his behaviour.
2. the appraisee should be entitled to a) request further training if there are identified areas of weakness. you can't ding an appraisee yet deny him/her the opportunity to improve performance and b)raise any issues where his/her job has been made more difficult by lack of personnel, equipment or managerial support.
personally, i found a refusal to 'sign-off' on an appraisal was sufficient to get a critical manager to revise it to a more acceptable form.
I do not see that it is impossible to appraise cabin crew because they work away from base or because they work in no settled team. these factors can be turned to advantage. cabin crew will be appraised over time by (properly trained-not always a given factor) senior staff and the fact that they are working with numerous seniors should help to eliminate the sort of personal bias that has been mentioned.