A single day's flight time and duty are capped to stop one day being too long. The cumulative limits do a different job: they stop a run of long-but-legal days from quietly piling up into a fatigue problem over weeks and months. This extends our overview of flight time limitations.
This is general educational information, not operational, legal, or regulatory advice. Rules differ by authority and change over time. Always verify against current official sources and follow your operator's approved procedures.
Two kinds of limit
It helps to separate the daily limits from the cumulative ones:
- Daily limits cap a single flight duty period and the flight time within it, and require rest before the next duty. They are about one working day.
- Cumulative limits cap the total flight time and total duty across rolling periods, from a week up to a year. They are about the running total.
You can be comfortably inside every daily limit and still hit a cumulative one, because the cumulative limit is counting all those legal days together.
The EASA cumulative limits
Under EASA ORO.FTL.210, the headline cumulative caps for commercial air transport are:
- Flight time: 100 hours in any 28 consecutive days; 900 hours in any calendar year; and 1000 hours in any 12 consecutive calendar months.
- Duty: 60 hours in any 7 consecutive days; 110 hours in any 14 consecutive days; and 190 hours in any 28 consecutive days.
Note that the flight-time caps mix two kinds of window. The 28-day and 12-month limits are rolling (any consecutive period), while the 900-hour limit is tied to the calendar year. The UK CAA operates the retained version of the same scheme.
The FAA cumulative limits
Under FAA 14 CFR 117.23, the equivalent caps for the operations Part 117 covers are:
- Flight time: 100 hours in any 672 consecutive hours (that is, 28 days); and 1000 hours in any 365 consecutive calendar days.
- Flight duty period: cumulative FDP is limited to 60 hours in any 168 consecutive hours (7 days), and 190 hours in any 672 consecutive hours (28 days).
The FAA expresses its windows in hours (672 hours, 168 hours), but 672 hours is 28 days and 168 hours is a week, so the structure mirrors the EASA one. The figures themselves are not identical, which is the familiar warning: do not carry one authority's number across to the other.
Why a rolling window is the tricky part
The single most misunderstood thing here is the rolling window. A calendar limit resets on a fixed date: a calendar month starts fresh on the first. A rolling window does not reset. "Any 28 consecutive days" means you look back 28 days from today, total the flight time in that span, and check it against 100 hours, and you redo that calculation every single day.
The consequence is that a heavy block of flying keeps counting against you until it rolls out of the back of the window. Fly 40 hours in one busy week, and those 40 hours sit inside your rolling 28-day total for the next four weeks, shrinking how much you can fly in each of those weeks, before they finally drop off. Plan against a calendar month and you will misjudge it, because the rolling total is almost always higher than the current calendar month suggests.
A worked example
Imagine your flight times over four weeks were 30, 30, 20, and 25 hours. Today is the last day of week 4.
- Your rolling 28-day total is 30 + 30 + 20 + 25 = 105 hours, which is already over the EASA 100-hour rolling limit, even though no single week was heavy.
- Tomorrow, the first day of week 1 begins to roll off the back, so the total falls as those early hours drop out of the 28-day window.
A pilot thinking in calendar months might see "only 25 hours this week" and assume there is plenty of room. The rolling total tells the real story. This is exactly the kind of bookkeeping that is easy to get wrong by hand and easy to track if something totals it for you.
Why operators roster below the limit
It is tempting to read the cumulative limits as targets, the amount of flying you are entitled to. They are the opposite: they are ceilings, the legal maximum, and a well-run operation deliberately rosters below them. There are good reasons for the buffer.
First, the limits interact across windows. A heavy month spends down your room in the 28-day window for the four weeks that follow, so a roster that runs you to the edge in one period leaves no margin to absorb the next. Disruption, a crew sickness, a weather day that displaces flying into the following week, all need slack to handle, and slack only exists if the planned totals sit comfortably under the caps.
Second, the cap is a legal floor for safety, not a fatigue plan. The cumulative limits are blunt: they count hours, not the timing or the disruptiveness of those hours. A pilot can be well inside every cumulative limit and still be fatigued from a run of early starts and night duties. Operators that take fatigue seriously, and the regulators that oversee them, treat the numbers as one control among several, alongside the rest rules, the disruptive-schedule provisions, and, where approved, a Fatigue Risk Management System that manages fatigue with data rather than hours alone. The framework comes from ICAO Annex 6, which allows an FRMS as an alternative to fixed limits where equivalent safety is shown.
Third, the operator's approved scheme can be more restrictive than the regulation's headline numbers, and often is. So the real limit that binds you on a given day may be tighter than the 100-hour or 60-hour figures, which is another reason not to plan to the regulatory ceiling.
For the individual pilot, the message is to monitor your own running totals rather than assume the roster has left you room, and to treat a cumulative total creeping towards a limit as a planning signal well before it becomes a hard stop. The totals are awkward to keep by hand precisely because they are rolling, which is the case for having something total them for you.
Watching two windows at once
The cumulative limits are easiest to underestimate when two different windows are filling up at the same time. A worked example shows how.
In a busy fortnight a pilot flies heavily. By the end of it, their rolling 28-day flight time stands at 92 hours, comfortably under the EASA 100-hour ORO.FTL.210 limit, so flight time looks fine. But duty is broader than flight time, and their rolling 7-day duty has reached 58 hours against the 60-hour limit. The duty window, not the flight-time window, is the one about to bite, and a single extra long duty day this week would breach it even though there is apparently room on flight hours.
The general lesson is that flight time and duty are counted over different rolling windows, 28 days and a year for flight time, 7, 14, and 28 days for duty, and any of them can be the binding one on a given day. A pilot watching only the headline 100-hour flight-time figure can be caught out by a 7-day duty limit, or by the 110-hour 14-day or 190-hour 28-day duty caps.
The practical defence is to track all the windows together, not just the most famous one, and to treat whichever is nearest its limit as the constraint for planning. Keeping several rolling totals in step by hand is genuinely awkward, which is precisely why having them totalled for you is useful, as long as the binding figures remain the operator's scheme and the regulation.
Common pitfalls
- Confusing rolling with calendar. "Any 28 consecutive days" is not "this month".
- Watching only flight time. Duty is broader and its cumulative cap can be reached first.
- Forgetting the long windows. The annual and 12-month flight-time limits creep up over a busy year.
- Mixing authorities. The EASA and FAA cumulative figures are different schemes.
- Assuming the operator scheme equals the baseline. An approved scheme can be more restrictive than the regulation's headline numbers.
In Pilot EFB
Pilot EFB can import your roster from a CSV file and total your flight time and duty across the rolling periods, so the running totals that are awkward to keep by hand are worked out for you and you can see when you are approaching a limit. It is a planning and awareness aid, not a compliance system: the binding limits are those in your operator's approved scheme and the current regulation, which can be more restrictive than the headline figures. Pilot EFB is not a certified Electronic Flight Bag. Saved roster data stays available offline; pulling a fresh roster needs a connection.