Split Duty — the Break That Shrinks Your FDP Without Ending It
Truckers get split sleeper berth; Part 117 crews get §117.15. Same idea, different math: time in a suitable accommodation is excluded from the FDP — if every condition holds.
All six conditions (§117.15)
- The rest opportunity falls between 22:00 and 05:00 local time.
- Time in the accommodation is at least 3 hours, measured from when you reach it (not from release).
- It was scheduled before the FDP began.
- What you actually got is not less than what was scheduled.
- It comes only after the first segment is complete.
- FDP + rest combined ≤ 14 hours.
What it does to your numbers
Example: report 1900, one leg ending 2300, 4 hours in a hotel (23:30–03:30), then two more legs and park at 0730. FDP on the clock = 12.5 h, plus 4 h rest = 16.5... over 14, non-compliant. Trim the rest to 3 h and it fits: 12.5 + 3 = 15.5 — still over. The 14-hour combined cap is what usually kills these constructions, not the 3-hour minimum.
"Suitable accommodation" is a ground facility — temperature controlled, light-controllable, sound mitigated, with a bed/bunk or a flat-or-near-flat chair. A crew lounge recliner does not qualify; an aircraft rest facility does not either (that's Table C territory).
How this differs from a real rest period
- Split duty is unaugmented operations only.
- It is not a rest period under §117.25 — no 10-hour/8-hour protection applies inside it, and it does not satisfy the weekly 30.
- It still counts inside the 3-consecutive-nights limit of §117.27 — unless each night FDP gets its own 2-hour accommodation rest, which unlocks 5 consecutive nights.
- Your Table B column is chosen by report time as usual; the break just makes the day fit inside it.
Check whether a break actually buys you time in the free Part 117 calculator.