Duty Time Limit Calculator

Work out duty time limit instantly with clear inputs, formula shown and shareable results.

About Duty Time Limit Calculator

Flight duty period limits shorten as sectors increase and as the reporting time moves into the early morning or night. This models the common structure: a base limit reduced by about half an hour for each sector beyond two, with a further reduction for duties starting in the night window.

Formula

Flight duty period

FDP = base limit - 0.5 h per sector above two - night/early start reduction, floored at 9 h

Worked example

With the default values below, Duty Time Limit Calculator returns Maximum flight duty period of 12.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Duty start hour (24h clock): 6 h
Sectors planned: 4 sectors
Base maximum flight duty period: 13 h

Results

Maximum flight duty period: 12.00 h
Reduction for sectors: 1.00 h
Start-time band: Daytime band
Latest finish hour (24h clock): 18.00 h

Step by step

1Values used
2Flight duty period
3Maximum flight duty period= 12.00 h
4Reduction for sectors= 1.00 h
5Start-time band= Daytime band
6Latest finish hour (24h clock)= 18.00 h

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or fees or charges into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.

Frequently Asked Questions

Are these the actual legal limits?

No. The real tables (for example EASA ORO.FTL or your national equivalent) are specific to reporting time, sectors and acclimatisation state, and must be applied directly.

Can the limit be extended?

Most schemes allow a limited commander's discretion extension for unforeseen circumstances, with reporting requirements attached.