Legal Interpretations
Wykoff and Mullen-ALPA 2013
Summary
The Question
Do the cumulative-limit look-back provisions of 14 CFR 117.23 count flight time and duty periods flown before part 117 took effect on January 4, 2014?
Background
The Air Line Pilots Association and Airlines for America jointly asked several part 117 implementation questions; the FAA answered this look-back question first to ensure clarity about cumulative limits during implementation.
The FAA’s Interpretation
No. Part 117 is not retroactive, so the 14 CFR 117.23 look-back does not reach flight time or flight duty periods before January 4, 2014; each cumulative limit takes effect as its flight time and duty periods accrue after that date. For flightcrew members who switched to part 117 earlier under an FAA exemption, the look-back reaches back to the date they began operating under part 117.
- Requester
- Wykoff and Mullen
- Organization
- ALPA
- Issued
- November 26, 2013
- Subject
- Flight & Duty Time
Regulations Cited
Page 1
U.S. Department
of Transportation
Federal Aviation
Administration
NOV 2 6 2013
Captain Don Wykoff
Office of the Chief Counsel
Air Line Pilots Association, International
1625 Massachusetts Ave., NW
Washington, DC 20036
Douglas K. Mullen
Airlines for America
1301 Pennsylvania Ave., NW
Suite 1100
Washington, DC 20004
Dear Messrs. Wykoff and Mullen,
800 Independence Ave., S.W.
Washington, D.C. 20591
This letter is an initial response to your joint letter requesting clarification of a number of questions relating to the implementation of part 117. It specifically responds to the question relating to the cumulative limit " look back" provisions found in§ 117.23. The FAA believes that our response to this question needs to be issued sooner in order to ensure clarity about how the cumulative limits will be handled during the implementation of part 117. The remaining questions will be the subject of a separate letter. In your letter you specifically ask whether "the cumulative limits require a monthly and yearly look back for flight time limits and a weekly and monthly look back for flight duty period limits on January 4, 2014 (or effective Part 117 implementation date if different than January 4, 2014)." Part 117 is not retroactive. Thus, the look back provisions of 14 C.F .R. § 117.23 would not apply to flight time or duty periods that took place prior to January 4, 2014. Accordingly, the cumulative limits in§ 117.23 will become effective as the flight times and flight duty periods for each cumulative limit are reached after the effective date of part 117.
We note, however, that some flightcrew members will switch to part 117 prior to January 4 pursuant to an FAA-issued exemption. For those flightcrew members, the look back provisions of§ 117.23 will reach back to the date that the flightcrew member began operating under part 117.
Page 2
If you need further assistance, please contact my staff at (202) 267-3073. This letter has been prepared by Robert H. Frenzel, Manager, Operations Law Branch, Office of the Chief Counsel and coordinated with the Air Transportation of Flight Standards Service.
Assistant Chief Couns for International
Law, Legislation and Regulations, AGC-200
Regulations Referenced
Snapshot retrieved August 6, 2026.