FAA Order 8130.2M — Operating Limitation 50
Appendix D · Table D-1 · p. p189
Phase I: Newly-built aircraft or aircraft that have not demonstrated initial compliance with § 91.319(b)(1) and (2) must complete Phase I flight testing using either of the following:(a)Completion of a task-based flight test program described in FAA Advisory Circular (AC) 90- 89 (latest version); or(b)The aircraft is flown for at least ____ hours with at least ____ takeoffs and landings.(50)_____
Verify it yourself: the eyeball above opens the exact page of Order 8130.2M with this limitation highlighted.