Wednesday, July 18, 2018

Part 117 Support

FAR 117  covers requirements for crew rest.  MyFlightbook supports it and will display your status with respect to 117 in currency if you like.  To use this, you must first turn on the option for Part 117 currency on the website by going to "Preferences" under the "Profile" tab, expanding the "Currency/Totals" section, and checking the option to track Part 117 status.

There's a lot in this reg, but 117.23(b)/(c), which concern flight time and flight duty periods, and 117.25(b), which concerns rest periods, are what MyFlightbook currently tracks.  (MyFlightbook does not currently track 117.25(c)/(d)/(e)).

There are three concepts (defined in 117.3) that are most relevant here:
  • Duty means any task that a flightcrew member performs as required by the certificate holder, including but not limited to flight duty period, flight duty, pre- and post-flight duties, administrative work, training, deadhead transportation, aircraft positioning on the ground, aircraft loading, and aircraft servicing.  
  • Flight duty period (FDP) means a period that begins when a flightcrew member is required to report for duty with the intention of conducting a flight, a series of flights, or positioning or ferrying flights, and ends when the aircraft is parked after the last flight and there is no intention for further aircraft movement by the same flightcrew member. A flight duty period includes the duties performed by the flightcrew member on behalf of the certificate holder that occur before a flight segment or between flight segments without a required intervening rest period. Examples of tasks that are part of the flight duty period include deadhead transportation, training conducted in an aircraft or flight simulator, and airport/standby reserve, if the above tasks occur before a flight segment or between flight segments without an intervening required rest period. 
  • Rest period means a continuous period determined prospectively during which the flightcrew member is free from all restraint by the certificate holder, including freedom from present responsibility for work should the occasion arise.
Or, more succinctly: Rest is considered to be any time that is neither in an FDP or otherwise designated as duty time.

There are 4 properties that you must use for Part 117 status to be computed and displayed:
  • Flight Duty Period Start (UTC)
  • Flight Duty Period End (UTC)
  • Duty Time Start (UTC)
  • Duty Time End (UTC)
The first two properties indicate the start and end of an FDP.  The second pair of properties are used to denote additional duty period, other than flight duty period, that may needs to be blocked off from rest periods.  As noted by the "(UTC)" suffix, these are all assumed to be in UTC.  Note that any time within an FDP is already duty time, so use of duty time start/stop within an FDP is redundant.

In MyFlightbook, an FDP can be declared in a single flight, or it can be declared to start in one flight and end in another flight.  Duty times (other than FDP) will typically start before an FDP starts and end after an FDP ends, but it's possible to have a duty period without any FDP (e.g., for required training), so for that it would make sense to enter a single empty flight that declares a duty period with no corresponding flight period (and, since no flying was performed, zero for all flight times as well).

The following three scenarios illustrate the typical ways you record these times:

Scenario 1: multiple flights in an FDP

  • Flight 1: Duty start 14:20 FDP Start 15:10
  • Flight 2: ...
  • Flight 3: ...
  • Flight 4: FDP end 21:18, Duty end 21:45
In this scenario, your FDP is 6:08 (from 15:10 to 21:18), and 7:25 (from 14:20 to 21:45) is excluded from rest.

Scenario 1a: multiple flights in an FDP, duty time at only one end

  • Flight 1: FDP Start 15:10
  • Flight 2: ...
  • Flight 3: ...
  • Flight 4: FDP end 21:18, Duty end 21:45
This is the same as above, but only 6:35 is excluded from rest (from 15:10 to 21:45).

Scenario 2: single flight in an FDP
  • Flight 1:  Duty start 14:20, FDP start 15:10, FDP End 21:45, Duty End 21:45
As above, the Duty Start/End at either end is optional; the FDP time will denote the end of a rest exclusion in this scenario.

Scenario 3: no FDP, just duty time (e.g., for training)
  • Flight 1: Duty start 14:20, Duty End 21:45
Note: you can record FDP without additional duty time; if you do so, your 117.25(b) computation may overstate how much rest you've had.

117.23(c) requires determining flight duty time.  If a flight does not specify any duty time, specifies an invalid duty time (e.g., end before start), or is not otherwise not bracketed by an FDP start/end, then MyFlightbook conservatively blocks off the entire 24 hour period containing that flight as FDP.  So it is a good idea to record FDP's if you want this to be accurate.  However, some personal/recreational flying may be excluded from FDP limits; there is an option (in Preferences) to exclude flights that are outside of declared FDP's from part 117 computations.

If you use these properties to record your duty time and FDP, MyFlightbook should report the following in your currency:
  • 117.23(b)(1) - How many flight hours you have in the preceding 672 (limit of 100).
  • 117.23(b)(2) - How many flight hours you have in 365 calendar days (limit of 1,000)
  • 117.23(c)(1) - How much FDP you've had in 168 hours (limit of 60)
  • 117.23(c)(2) - How much FDP you've had in 672 hours (limit 190)
  • 117.25(b) - have you had a 30-consecutive-hour period in the past 168 hours?
  • 117 (general) - if you are currently in a rest period, how much time has elapsed since it began?


  1. I believe there's a typo:
    "In this scenario, your FDP is 6:06 (from 15:10 to 21:18)"

    I believe it should read:
    "In this scenario, your FDP is 6:08 (from 15:10 to 21:18)"