(a) A member who has 5 years of credited service, develops a disability and is no longer employed shall become eligible to receive a disability pension beginning with the month following the inception of his or her disability. Such member shall cease to be eligible at the end of the month in which he or she recovers from disability, if such recovery occurs before his or her attainment of age 60.
(b) A member shall be deemed to have a disability who is unable to engage in any substantial gainful activity for which the employee is reasonably suited by training or experience by reason of any medically determinable physical or mental disability which can be expected to result in death or to last for a period of not less than 12 months.