The date fully insured status was first attained (at full retirement age or later).

First checks for fully insured status as of full retirement age. If uninsured at that time, checks every future quarter through the quarter of the benefit date. For this purpose, being insured for totalization benefits is considered to be fully insured. 

Requires adjusted date of birth, quarters of coverage filled in from 1937 to date, total quarters of coverage from 1937 to 1950, dates of disability onset and cessation. 

This is called from monthsDriCal.

PiaCal Methods