As for health benefits, the criteria have to be determined by health care professionals. There are physicians who specialize in geriatric medicine and they would have a view. There are physicians who can deal specifically with airline pilots, and there are physicians who can make recommendations with respect to truck drivers or locomotive engineers.
You have to rely on appropriate data from experts, but you have to have the flexibility once those decisions are made. You have to be able to manage those decisions without being accused of discriminatory practices.