Are the centerline lights considered as part of the runway enviroment (runway lights?) to which descent can be made to the runway if they are in sight? I always figured they were part of the runway lights, but I saw an interview gouge that implied they were not. I can't find any specifics in the AIM or FAR. Also, is there a good rule of thumb for calculating when and at what rate to climb in order to clear a minimum crossing altitude. Thanks for any information.