Legal Interpretations
Anderson 2014
Summary
The Question
How does the two-hour extension of 14 CFR 117.19 apply to the combined flight duty period and reserve availability period limit in 14 CFR 117.21(c)(3)?
Background
An airline transport pilot posed a scenario: short-call reserve begins at 0400, two three-hour segments are assigned starting at 0900, and a mechanical delay would push the flight duty period end from 1600 to 2100.
The FAA’s Interpretation
The extension is added directly to the applicable combined limit. Here, Table B allows 14 hours for a two-segment flight duty period beginning at 0900; plus 4 hours is 18, so the 16-hour cap governs, requiring the duty period to end by 2000. With the 14 CFR 117.19(a) extension, assuming its conditions are met, the limit becomes 18 hours, ending at 2200, so a 2100 finish would not violate 14 CFR 117.21(c)(3).
- Requester
- Anderson
- Issued
- August 18, 2014
- Subjects
- Flight & Duty Time · Definitions
Regulations Cited
Page 1
U.S. Deportment
of Transportation
Fed eral Aviation
Administration
AW 18 1014
Douglas Anderson
Airline Transport Pilot
Dear Mr. Anderson,
Office of the Chief Counsel 800 Independence Ave., S.W .
Washington, D.C. 20591
This is in response to your letter asking for information about how to calculate and appfy a two-hour extension taken under 14 C.F.R. § 117.19 to the sh01t-call reserve limit of § 117.21(c)(3).
Your letter posits the following scenario. A flightcrew member on short-call reserve begins a reserve availability period (RAP) at 0400. That flightcrew member is then assigned two three-hour flight segments that begin at 0900. The flight segments are spaced apart such that the flightcrew member's flight duty period (PDP) is scheduled to end at 1600. However, prior to the beginning of the second flight segment, the aircraft experiences a mechanical issue that delays the departure until 1800. This would change the FDP termination time to 2100 if the flight segment is taken. You ask how the 2-hour extension specified in§ 117.19 would apply to this scenario.1
Patt 117 contains a set of flight, duty, and rest regulations that apply to all part 1'21 passenger operations and certain patt 91 operations.2 Those regulations govern, among other things, the length of aflightcrew member's short-call reserve and FDP. Subsection 117.2 l(c)(3) limits the total amount of time that a flightcrew member can spend on a combined reserve availability period (RAP) and an unaugmented FOP. However,§ 117.19(a) allows the combined FDP+RAP limit specified in§ 117.21 (c)(3) to be extended by up to 2 hours if the conditions specified in§ 117.19(a) are satisfied. For the purposes of answering your question, we will assume that the conditions specified in § 117.19(a) have been satisfied.3
1 In answering this question, we will assume that the t1ightcrew member is acclimated. We will also assume that taking the extension wi ll not cause the flightcrew member to exceed any cumulative limits or his daily flight time limit. We will also assume that the PDP to which the flightcrew member is assigned is unaugmeuted.
2 14 C.F.R. §I l7. I.
3 We also note that § 117.21 (c) cannot be used to exceed the FDP limits specified in § 117.13 and 117.17. See Letter to Joshua Foltz from Mark W. Bury, Assistant Chief Counsel, AGC 200 (May 13, 2014). The FDP extension in § 117.19 can be used to extend those FDP limits, but that is unconnected to the provisions of§ l J7 .21(c).
Page 2
In order to apply the 2-hour extension to§ 117.21(c)(3), a flightcrew member must first determine the FDP+RAP limit that is applicable to him or her. After determining the applicable FDP+RAP limit, the 2-hour extension is then applied directly to that limit. Applying the above discussion to your scenario, we will first determine the FDP+RAP limit applicable to the flightcrew member in your scenario. Section 117.21(c)(3) states that:
For an unaugmented operation, the total number of hours a flightcrew member may spend in a flight duty period and a reserve availability period may not exceed the lesser of the maximum applicable flight duty period in Table B of this part plus 4 hours, or 16 hours, as measured from the beginning of the reserve availability period.
The pilot in your scenario begins a two-segment FDP at 0900. The applicable maximum PDP limit in Table B for a two-segment FDP that begins at 0900 is 14 hours. Adding 4 hours to this number results in 18 hours. Since 18 hours is greater than 16 hours, the combined FDP and RAP time of the flightcrew member in your scenario cannot exceed 16 hours without an extension. Because that flightcrew member began his RAP at 0400, § 117.21(c)(3) requires that an FDP that is assigned during this RAP has to terminate by 2000 without an extension.
However, as mentioned previously, the FDP+RAP limit of§ 117.21(c)(3) can be extended by up to 2 hours under the provisions of§ 117.19(a). Applying this extension to your scenario would increase the applicable lQ-hour FDP+RAP limit to 18 hours. This means that an FDP assigned during the short-call reserve taken in your scenario would not have to end until 2200. Because the flightcrew member in your scenario would have an PDP that terminates at 2100, that FDP would not violate§ 117.21(c)(3) if an extension is taken pursuant to § 117.19(a).
We appreciate your patience and trnst that the above responds to your concerns. If you need further assistance, please contact my staff at (202) 267-3073. This response was prepared by Alex Zektser, Attorney, International Law, Legislation, and Regulations Division of the Office of the Chief Counsel, and coordinated with the Air Transportation Division of Flight Standards Service.
International Law, Legislati , ·and Regulations, AGC-200
Regulations Referenced
Snapshot retrieved August 6, 2026.