5 C.F.R. § 847.441 Election requirements.
Title 5 - Administrative Personnel
(a) An employee who completed a qualifying move under §847.402(b) may elect to be covered by a NAFI retirement system for all Federal service following the qualifying move. (b) A survivor eligible for benefits under FERS may make an election under this section if the employee was otherwise eligible to make an election, but died before expiration of the time limit under §847.304.
Title 5: Administrative Personnel
PART 847—ELECTIONS OF RETIREMENT COVERAGE BY CURRENT AND FORMER EMPLOYEES OF NONAPPROPRIATED FUND INSTRUMENTALITIES
Subpart C—Procedures for Elections Under the Retroactive Provisions
Elections of NAFI Coverage Based on a Move From NAFI to FERS
§ 847.441 Election requirements.

