41 CFR § 301-11.605
When should I file my “Statement of Income and Tax Filing Status” for my taxable extended TDY assignment?
June 9, 2020
You should file your “Statement of Income and Tax Filing Status” for your taxable extended TDY assignment at the beginning of your extended TDY assignment, or as soon as you or your agency realizes that your TDY assignment will incur taxes. You should provide the same information as the sample “Statements of Income and Tax Filing Status” shown in part 302-17, subpart F (one-year process) or subpart G (two-year process) of this subtitle.
[FTR Amdt. 2014-01, 79 FR 49643, Aug. 21, 2014]