Section 843.408 - Commencing and terminating dates of child annuities(a) An annuity under this subpart-(1) Commences on the day after the retiree or employee dies;(2) Commences or resumes on the first day of the month in which the child later becomes or again becomes a student as described by § 843.313 , if any lump sum paid is returned to the Civil Service Retirement Fund; or(3) Commences or resumes on the first day of the month in which the child later becomes or again becomes incapable of self-support because of a mental or physical disability incurred before age 18 (or a later recurrence of such disability), if any lump sum is returned to the Fund.(b) An annuity under this subpart terminates on the last day of the month before the child-(1) Becomes 18 years of age unless he or she is a student as described in § 843.410 or is incapable of self-support;(2) Becomes capable of self-support after becoming 18 years of age unless he or she is a student as described in § 843.410 ;(3) Becomes 22 years of age if he or she is a student as described in § 843.410 and-(i) Capable of self-support; or(ii) Incapable of self-support because of a mental or physical disability incurred after age 18;(4) Ceases to be such a student as described in § 843.410 after becoming 18 years of age unless he or she is incapable of self-support; or(c) A survivor annuity accrues on a daily basis, one-thirtieth of the monthly rate constituting the daily rate. An annuity does not accrue for the 31st day of any month, except in the initial month if the survivor's (of a deceased employee) annuity commences on the 31st day. For accrual purposes, the last day of a 28-day month constitutes 3 days and the last day of a 29-day month constitutes 2 days.