[{"data":1,"prerenderedAt":431},["ShallowReactive",2],{"learn-\u002Flearn\u002Fduty-time-flight-time-and-fdp":3,"learn-nav-\u002Flearn\u002Fduty-time-flight-time-and-fdp":395},{"id":4,"title":5,"body":6,"date":331,"description":332,"draft":333,"extension":334,"faqs":335,"howTo":345,"keyTakeaways":345,"meta":346,"navigation":347,"path":348,"quiz":349,"seo":376,"series":377,"seriesOrder":357,"sources":378,"stem":392,"topic":393,"__hash__":394},"learn\u002Flearn\u002Fduty-time-flight-time-and-fdp.md","Duty time, flight time and the flight duty period",{"type":7,"value":8,"toc":319},"minimark",[9,19,25,30,46,82,85,89,92,113,124,149,153,156,186,189,193,196,200,206,213,235,242,245,249,252,266,273,276,280,312,316],[10,11,12,13,18],"p",{},"Almost every fatigue rule is built from four ideas: flight time, the flight duty period, duty, and rest. Getting them straight, and understanding how the flight duty period is worked out, is the foundation for reading any flight time limitation scheme. This goes a level deeper than our overview of ",[14,15,17],"a",{"href":16},"\u002Flearn\u002Fflight-time-limitations-explained","flight time limitations",".",[20,21,22],"blockquote",{},[10,23,24],{},"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.",[26,27,29],"h2",{"id":28},"the-four-terms","The four terms",[10,31,32,33,39,40,45],{},"The ",[14,34,38],{"href":35,"rel":36},"https:\u002F\u002Fwww.easa.europa.eu\u002Fen\u002Fdocument-library\u002Feasy-access-rules\u002Feasy-access-rules-air-operations",[37],"nofollow","EASA definitions in ORO.FTL.105"," and the ",[14,41,44],{"href":42,"rel":43},"https:\u002F\u002Fwww.ecfr.gov\u002Fcurrent\u002Ftitle-14\u002Fchapter-I\u002Fsubchapter-G\u002Fpart-117",[37],"FAA Part 117 definitions in 14 CFR 117.3"," describe the same four ideas in close, but not identical, terms:",[47,48,49,57,70,76],"ul",{},[50,51,52,56],"li",{},[53,54,55],"strong",{},"Flight time"," is block time, measured from when the aircraft first moves under its own power for the purpose of taking off until it comes to rest at the end of the flight. It is the narrowest of the four.",[50,58,59,69],{},[53,60,61,62,68],{},"Flight duty period (",[14,63,67],{"href":64,"className":65},"\u002Flearn\u002Fglossary#gt-fdp",[66],"glossary-link","FDP",")"," runs from the moment you are required to report for a flight or a series of flights until the aircraft comes to rest at the end of the last sector. It is flight time plus the ground time between and around the sectors.",[50,71,72,75],{},[53,73,74],{},"Duty"," is broader again: any task the operator requires you to carry out, including the FDP, positioning, training, and administrative duties.",[50,77,78,81],{},[53,79,80],{},"Rest"," is a continuous, protected period during which you are free of all duties and can sleep.",[10,83,84],{},"Picture them nested: flight time sits inside the flight duty period, which sits inside duty, with rest as the counterweight that has to come before the next duty begins.",[26,86,88],{"id":87},"how-the-maximum-fdp-is-built","How the maximum FDP is built",[10,90,91],{},"The flight duty period is the one that drives the working day, and its maximum is not a single number. It is built from two main inputs.",[10,93,94,97,98,106,107,112],{},[53,95,96],{},"Report time."," Both systems recognise that a duty starting in the small hours, when the body expects to be asleep, is more fatiguing. EASA reduces the maximum FDP for reports that fall in or touch the ",[53,99,100,101,68],{},"window of circadian low (",[14,102,105],{"href":103,"className":104},"\u002Flearn\u002Fglossary#gt-wocl",[66],"WOCL",", roughly 0200 to 0559 in the time zone you are acclimatised to. The FAA's ",[14,108,111],{"href":109,"rel":110},"https:\u002F\u002Fwww.ecfr.gov\u002Fcurrent\u002Ftitle-14\u002Fchapter-I\u002Fsubchapter-G\u002Fpart-117\u002Fsection-117.13",[37],"Table B in 14 CFR 117.13"," sets the maximum FDP directly against the local report time.",[10,114,115,118,119,123],{},[53,116,117],{},"Number of sectors."," More take-offs and landings mean more workload, so EASA's ",[14,120,122],{"href":35,"rel":121},[37],"ORO.FTL.205"," reduces the maximum FDP as the number of sectors rises. The FAA table is structured by the number of flight segments alongside the report time.",[10,125,126,127,130,131,134,135,139,140,143,144,148],{},"As an illustration with the source attached: under EASA, the ",[53,128,129],{},"basic maximum daily FDP for an acclimatised crew"," starting at the most favourable time is ",[53,132,133],{},"13 hours",", reduced from there for unfavourable report times and for additional sectors (",[14,136,138],{"href":35,"rel":137},[37],"EASA ORO.FTL.205","). Under the FAA, the unaugmented maximum FDP runs up to around ",[53,141,142],{},"14 hours"," at the most favourable report times and reduces from there (",[14,145,147],{"href":109,"rel":146},[37],"FAA 14 CFR 117.13, Table B","). These are not the same number for the same situation, which is the whole point: read the table for your authority and your day.",[26,150,152],{"id":151},"extensions-and-commanders-discretion","Extensions and commander's discretion",[10,154,155],{},"The maximum FDP can be stretched, but only within defined bounds:",[47,157,158,174],{},[50,159,160,163,164,167,168,173],{},[53,161,162],{},"Planned extension."," EASA allows the maximum daily FDP to be extended by up to ",[53,165,166],{},"one hour"," a limited number of times within a period, under conditions set in ORO.",[14,169,172],{"href":170,"className":171},"\u002Flearn\u002Fglossary#gt-ftl",[66],"FTL",".205.",[50,175,176,179,180,185],{},[53,177,178],{},"Commander's discretion."," Once the FDP has begun and unforeseen circumstances arise, the commander may extend it further within limits, and the FAA gives the pilot in command an equivalent power to extend in unforeseen operational circumstances under ",[14,181,184],{"href":182,"rel":183},"https:\u002F\u002Fwww.ecfr.gov\u002Fcurrent\u002Ftitle-14\u002Fchapter-I\u002Fsubchapter-G\u002Fpart-117\u002Fsection-117.19",[37],"14 CFR 117.19",", within a capped amount.",[10,187,188],{},"Both kinds of extension are bounded and must be reported, so they are a safety valve for the unexpected, not a routine way to beat the limit.",[26,190,192],{"id":191},"why-the-distinctions-matter","Why the distinctions matter",[10,194,195],{},"Because flight time, FDP, and duty are different, a long day can hit a limit on one while leaving room on another. You can be inside your flight time limit but out of FDP because of a long ground delay between sectors, or inside your FDP but bumping a cumulative duty limit across the week. Knowing which clock is closest to its limit is what lets you plan a roster realistically rather than discovering the problem on the day.",[26,197,199],{"id":198},"augmented-crews-and-in-flight-rest","Augmented crews and in-flight rest",[10,201,202,203,18],{},"The maximum flight duty period for a normal, unaugmented crew is a hard constraint, but long-haul flying gets around it in a controlled way: by carrying extra pilots and giving them a chance to sleep in flight. This is the ",[53,204,205],{},"augmented crew",[10,207,208,209,212],{},"The idea is that if a pilot can take genuine rest during the cruise, handing the aircraft to another qualified pilot, then the crew as a whole can be on duty longer without the same fatigue. Both systems allow it, and both tie the allowance to the ",[53,210,211],{},"quality of the rest facility",":",[47,214,215,228],{},[50,216,217,218,223,224,227],{},"Under the FAA, ",[14,219,222],{"href":220,"rel":221},"https:\u002F\u002Fwww.ecfr.gov\u002Fcurrent\u002Ftitle-14\u002Fchapter-I\u002Fsubchapter-G\u002Fpart-117\u002Fsection-117.17",[37],"14 CFR 117.17"," sets the maximum FDP for an augmented crew in a table that depends on the report time, the number of pilots (three or four), and the ",[53,225,226],{},"class of onboard rest facility",". A Class 1 facility is a proper bunk that lets a pilot lie flat, a Class 2 is a lie-flat or near-flat seat separated from the passengers, and a Class 3 is a reclining seat. A better facility buys a longer maximum FDP, because it allows better sleep.",[50,229,230,231,234],{},"Under EASA, ",[14,232,122],{"href":35,"rel":233},[37]," and the associated certification specifications (CS-FTL.1) extend the basic maximum FDP when the crew is augmented and in-flight rest is provided, again graded by the class of rest facility.",[10,236,237,238,241],{},"The same logic explains ",[53,239,240],{},"split duty",", where a long break on the ground in suitable accommodation during the duty can extend the flight duty period, because part of the duty is spent resting rather than working.",[10,243,244],{},"The practical point for anyone reading a roster is that a flight duty period well beyond the unaugmented maximum is not necessarily a mistake: it may be a planned augmented operation with a third or fourth pilot and a rest facility. The allowance is still bounded by a table, still tied to the facility class, and still set by the regulation, so it is read from the rule, not assumed.",[26,246,248],{"id":247},"a-worked-maximum-fdp","A worked maximum FDP",[10,250,251],{},"An illustrative example shows how report time and sectors combine, with the firm caution that the binding figures come from the regulation and the operator's scheme, not from this example.",[10,253,254,255,257,258,261,262,265],{},"Under EASA, an acclimatised crew reporting at the most favourable time of day for a single sector has a basic maximum flight duty period of ",[53,256,133],{}," (",[14,259,122],{"href":35,"rel":260},[37],"). Now change the day. The crew reports at 0500, which falls within the window of circadian low (the WOCL, 02:00 to 05:59), and flies ",[53,263,264],{},"four sectors",". Both factors cut the maximum: the unfavourable early report reduces it, and each sector beyond the first reduces it further. The result, read from the regulation's table, is a maximum FDP materially shorter than 13 hours, perhaps in the region of 11 hours, with the exact figure set by the table rather than estimated.",[10,267,268,269,272],{},"Under the FAA, the same kind of reasoning uses ",[14,270,111],{"href":109,"rel":271},[37],": you read the maximum FDP straight off against the local report time and the number of flight segments, and an early report with several segments lands well below the most favourable figure.",[10,274,275],{},"The lesson is not the precise number, which differs by authority and is always read from the table, but the shape of it: the same crew and aircraft can have a very different maximum FDP depending on when they start and how many sectors they fly, which is why you check the table for the specific day rather than carrying one figure around.",[26,277,279],{"id":278},"common-pitfalls","Common pitfalls",[47,281,282,288,294,300,306],{},[50,283,284,287],{},[53,285,286],{},"Confusing flight time with duty."," Flight time is just block time; the working day is the FDP, and duty is broader still.",[50,289,290,293],{},[53,291,292],{},"Treating the maximum FDP as fixed."," It depends on report time and sectors, read from a table.",[50,295,296,299],{},[53,297,298],{},"Forgetting the WOCL."," An early-hours report cuts the maximum FDP because of the body clock.",[50,301,302,305],{},[53,303,304],{},"Relying on extensions."," Planned extensions and commander's discretion are bounded and reportable, not routine.",[50,307,308,311],{},[53,309,310],{},"Carrying one authority's number across."," The EASA 13-hour basic maximum and the FAA Table B values are different schemes.",[26,313,315],{"id":314},"in-pilot-efb","In Pilot EFB",[10,317,318],{},"Pilot EFB can import your roster from a CSV file and work out your flight time and duty across a day and across the rolling periods, so you can see how a planned series of sectors sits against the limits, and run a quick what-if for an added sector. 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, and Pilot EFB is not a certified Electronic Flight Bag. Saved roster data stays available offline; pulling a fresh roster needs a connection.",{"title":320,"searchDepth":321,"depth":321,"links":322},"",2,[323,324,325,326,327,328,329,330],{"id":28,"depth":321,"text":29},{"id":87,"depth":321,"text":88},{"id":151,"depth":321,"text":152},{"id":191,"depth":321,"text":192},{"id":198,"depth":321,"text":199},{"id":247,"depth":321,"text":248},{"id":278,"depth":321,"text":279},{"id":314,"depth":321,"text":315},"2026-04-30","The four terms at the heart of every fatigue rule, how the maximum flight duty period is built from report time and sectors, and how EASA and the FAA each handle extensions.",false,"md",[336,339,342],{"q":337,"a":338},"What is the difference between flight time, duty and the flight duty period?","Flight time is block time, from when the aircraft first moves for take-off until it comes to rest. The flight duty period, or FDP, runs from reporting for a flight or series of flights until the aircraft comes to rest at the end of the last sector, so it includes flight time plus the ground time between sectors. Duty is broader, covering any task the operator requires, and rest is the protected period free of all duties.",{"q":340,"a":341},"What sets the maximum flight duty period?","Mainly the time you report and the number of sectors you fly. Both EASA and the FAA reduce the maximum FDP for reports in or near the body's natural low period overnight, and EASA also reduces it as the number of sectors rises. The exact figures are tabled in the regulation, so the maximum for a given day is read from the table, not a single fixed number.",{"q":343,"a":344},"Can a flight duty period be extended?","Within limits. EASA allows a planned FDP extension up to one hour a limited number of times, and gives the commander discretion to extend further in unforeseen circumstances once the FDP has started. The FAA likewise lets the pilot in command extend the FDP in unforeseen operational circumstances within a defined cap. Both are bounded, and both must be reported, so they are not a way around the limit.",null,{},true,"\u002Flearn\u002Fduty-time-flight-time-and-fdp",[350,359,368],{"q":351,"options":352,"answer":357,"explanation":358},"How does this article define flight time?",[353,354,355,356],"Any task the operator requires you to carry out","Block time, from when the aircraft first moves under its own power for take-off until it comes to rest at the end of the flight","The period from reporting until the aircraft comes to rest at the end of the last sector","A continuous, protected period free of all duties",1,"Flight time is block time, measured from when the aircraft first moves under its own power for the purpose of taking off until it comes to rest at the end of the flight. It is the narrowest of the four terms.",{"q":360,"options":361,"answer":366,"explanation":367},"According to the article, what mainly sets the maximum flight duty period?",[362,363,364,365],"The report time and the number of sectors","A single fixed number that applies to every day","The class of onboard rest facility alone","The total flight time accumulated over the week",0,"The maximum FDP is built from two main inputs: the report time and the number of sectors. Both EASA and the FAA reduce it for unfavourable reports, and EASA also reduces it as the number of sectors rises, so it is read from a table rather than being a single number.",{"q":369,"options":370,"answer":321,"explanation":375},"What is the window of circadian low (WOCL) as described in this article?",[371,372,373,374],"Roughly 1200 to 1559 local time","The hour either side of sunset","Roughly 0200 to 0559 in the time zone you are acclimatised to","Any duty starting after a long ground delay","EASA reduces the maximum FDP for reports that fall in or touch the window of circadian low, roughly 0200 to 0559 in the time zone you are acclimatised to, because an early-hours report is more fatiguing.",{"title":5,"description":332},"duty-rest-and-flight-time-limits",[379,381,383,385,387,389],{"label":380,"url":35},"EASA Easy Access Rules for Air Operations (ORO.FTL.105 and .205)",{"label":382,"url":42},"FAA 14 CFR Part 117 (Flight and Duty Limitations and Rest Requirements)",{"label":384,"url":109},"FAA 14 CFR 117.13 (Flight duty period: unaugmented operations)",{"label":386,"url":220},"FAA 14 CFR 117.17 (Flight duty period: augmented flightcrew)",{"label":388,"url":182},"FAA 14 CFR 117.19 (Flight duty period extensions)",{"label":390,"url":391},"ICAO Annex 6: Operation of Aircraft, Part I","https:\u002F\u002Fstore.icao.int\u002Fen\u002Fannex-6-operation-of-aircraft-part-i-international-commercial-air-transport-aeroplanes","learn\u002Fduty-time-flight-time-and-fdp","Regulations","Z8qiaAUi9k3MfSL32GksNJffj439WuqqfeadRUOWkUU",{"related":396,"newer":414,"older":421,"series":428},[397,402,408],{"path":16,"title":398,"description":399,"date":400,"topic":393,"draft":333,"minutes":401,"series":377,"seriesOrder":321},"Flight time limitations explained","Flight time, duty, flight duty period and rest, explained plainly, with the EASA\u002FUK CAA and FAA limits attributed to each authority. Numbers differ by authority and change, so always check the current rule.","2026-06-14",4,{"path":403,"title":404,"description":405,"date":406,"topic":393,"draft":333,"minutes":401,"series":407,"seriesOrder":321},"\u002Flearn\u002Fvfr-weather-minima-and-cruising-levels","VFR weather minima and cruising levels","The visibility and distance-from-cloud minima for visual flight, and the semicircular cruising-level rule, with the ICAO baseline and the EASA and FAA figures attributed because the units and numbers differ.","2026-05-30","plan-a-vfr-cross-country",{"path":409,"title":410,"description":411,"date":412,"topic":393,"draft":333,"minutes":401,"series":407,"seriesOrder":413},"\u002Flearn\u002Ffuel-planning-and-reserves","Fuel planning and reserves","Why a flight carries more fuel than the trip needs, the ICAO baseline, the FAA VFR and IFR reserve rules, and the EASA fuel-scheme components, each attributed because the numbers differ.","2026-05-29",3,{"path":415,"title":416,"description":417,"date":418,"topic":419,"draft":333,"minutes":420,"series":345,"seriesOrder":345},"\u002Flearn\u002Fthunderstorms-and-convective-weather","Thunderstorms and convective weather","What makes a thunderstorm, the three stages of its life, the hazards from turbulence to hail and microbursts, and how the convective SIGMET warns you, with avoidance distances from the FAA.","2026-05-01","Weather",8,{"path":422,"title":423,"description":424,"date":425,"topic":426,"draft":333,"minutes":427,"series":345,"seriesOrder":345},"\u002Flearn\u002Fthe-preflight-information-bulletin","What is in a Pre-flight Information Bulletin","What a PIB is, how it packages the NOTAMs for your route, the difference between aerodrome, area and route bulletins, and why it is a snapshot you have to refresh.","2026-04-28","Briefing",7,{"slug":377,"title":429,"part":357,"total":430,"prev":345,"next":397},"Duty, rest and flight time limits",5,1781989191357]