How do split flight duty periods work, and how much extra FDP does a break buy?

Section 700.50 lets a flight duty period be scheduled longer than the 700.28 maximum if you’re given a break in suitable accommodation of at least 60 consecutive minutes during the FDP.

The calculation

1. Take the length of the break.
2. Subtract 45 minutes (fixed — it covers getting to bed, falling asleep, and waking up; CARs 700.50(2), AC 700-047 § 4.50).
3. Multiply by the rate for when the break falls, at your acclimatized local time:

   • 100% if the break is between 00:00 and 05:59 (CARs 700.50(1)(a));

   • 50% if it’s between 06:00 and 23:59 (CARs 700.50(1)(b));

   • 50% if the FDP is re-planned in flight because of an unforeseen operational circumstance (CARs 700.50(1)(c)).

     700.50(2) says the 45-minute deduction applies “for the purposes of subsection (1)” — so to (a), (b) and (c). AC 700-047 § 4.49 describes the UOC case as “50% of the duration of the break provided” without repeating the deduction; this site follows the regulation text and deducts 45 minutes in all three cases.

The result is added to the 700.28 maximum. There is no cap on the total length of an FDP extended this way (AC 700-047 § 4.49).

Conditions

• The break must be in suitable accommodation; travel time to and from it doesn’t count toward the 60 minutes.
• On night duty, split duty may extend the FDP for at most three consecutive nights (CARs 700.50(3)).
• No extra rest is required afterwards beyond the normal 700.40(1) rest (AC 700-047 § 4.50(5)).
• On reserve: the reserve duty period may be extended by two hours, and no more than two flights may follow the break (CARs 700.50(5)).

See also: Split flight duty (700.50) · FDP calculator