[{"data":1,"prerenderedAt":321},["ShallowReactive",2],{"learn-\u002Flearn\u002Fwake-turbulence-categories-and-separation":3,"learn-nav-\u002Flearn\u002Fwake-turbulence-categories-and-separation":292},{"id":4,"title":5,"body":6,"date":219,"description":220,"draft":221,"extension":222,"faqs":223,"howTo":233,"keyTakeaways":241,"meta":246,"navigation":247,"path":248,"quiz":249,"seo":275,"series":276,"seriesOrder":276,"sources":277,"stem":289,"topic":290,"__hash__":291},"learn\u002Flearn\u002Fwake-turbulence-categories-and-separation.md","Wake turbulence categories and separation",{"type":7,"value":8,"toc":210},"minimark",[9,21,27,32,40,51,62,66,80,105,122,126,141,169,173,199,203],[10,11,12,13,20],"p",{},"Every wing that makes lift also makes a pair of trailing vortices, and ",[14,15,19],"a",{"href":16,"className":17},"\u002Flearn\u002Fglossary#gt-wake-turbulence",[18],"glossary-link","wake turbulence"," separation is the system that stops a following aircraft flying into the invisible, rolling air a heavier one leaves behind.",[22,23,24],"blockquote",{},[10,25,26],{},"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.",[28,29,31],"h2",{"id":30},"where-the-wake-comes-from","Where the wake comes from",[10,33,34,35,39],{},"Wake turbulence is not engine exhaust. It is the ",[36,37,38],"strong",{},"trailing vortex"," that forms whenever a wing produces lift: higher pressure under the wing spills around the tip to the lower pressure above, rolling into two counter-rotating cores that stream behind the aircraft.",[10,41,42,43,46,47,50],{},"Their strength depends on the wing loading and how it is flying. Vortex intensity ",[36,44,45],{},"rises with weight and angle of attack and falls with speed",", so the strongest wake comes from an aircraft that is ",[36,48,49],{},"heavy, slow and clean",", with little flap or gear to spread the load. That is exactly the configuration on take-off and on short final, which is why most wake encounters happen near the ground.",[10,52,53,54,57,58,61],{},"Once shed, the vortices ",[36,55,56],{},"sink"," a few hundred feet below the flight path and ",[36,59,60],{},"drift with the wind",". A light crosswind can hold one stationary over the runway, or carry it onto a parallel runway, which is why a calm or light-crosswind day can be the trickiest.",[28,63,65],{"id":64},"the-icao-categories","The ICAO categories",[10,67,68,69,75,76,79],{},"To turn this into a workable rule, ",[14,70,74],{"href":71,"rel":72},"https:\u002F\u002Fstore.icao.int\u002Fen\u002Fprocedures-for-air-navigation-services-air-traffic-management-doc-4444",[73],"nofollow","ICAO Doc 4444 (PANS-ATM)"," groups aircraft by ",[36,77,78],{},"maximum certificated take-off mass",":",[81,82,83,89,94,99],"ul",{},[84,85,86],"li",{},[36,87,88],{},"Light (L): 7000 kg or less.",[84,90,91],{},[36,92,93],{},"Medium (M): more than 7000 kg but less than 136 000 kg.",[84,95,96],{},[36,97,98],{},"Heavy (H): 136 000 kg or more.",[84,100,101,104],{},[36,102,103],{},"Super (J): the largest types",", specified as such in ICAO Doc 8643. Today that is the Airbus A380. (Some authorities, including the FAA, additionally treat the Antonov An-225 as super under their own national schemes, but under ICAO the An-225 is Heavy.)",[10,106,107,108,113,114,117,118,121],{},"Each aircraft type's category is published alongside its designator in ",[14,109,112],{"href":110,"rel":111},"https:\u002F\u002Fwww.icao.int\u002Fpublications\u002Fdoc8643\u002FPages\u002FSearch.aspx",[73],"ICAO Doc 8643",", and it is the category of the aircraft ",[36,115,116],{},"ahead"," (the one generating the wake) and the one ",[36,119,120],{},"behind"," (the one at risk) that together set the spacing.",[28,123,125],{"id":124},"how-separation-is-applied","How separation is applied",[10,127,128,129,132,133,136,137,140],{},"The principle is simple: a ",[36,130,131],{},"lighter aircraft following a heavier one needs more room",", because it is the one most easily upset. Controllers apply this as a ",[36,134,135],{},"distance"," behind an aircraft in the air, or as a ",[36,138,139],{},"time"," interval between departures from the same runway, with the largest gaps behind Super and Heavy types and progressively less behind Medium and Light.",[10,142,143,144,148,149,154,155,158,159,164,165,168],{},"The exact minima are where it gets local. The baseline values are in ",[14,145,147],{"href":71,"rel":146},[73],"Doc 4444"," and the ",[14,150,153],{"href":151,"rel":152},"https:\u002F\u002Fwww.faa.gov\u002Fair_traffic\u002Fpublications\u002Fatpubs\u002Faim_html\u002Fchap7_section_4.html",[73],"FAA AIM",", but many regions now use ",[36,156,157],{},"recategorisation"," schemes, such as ",[14,160,163],{"href":161,"rel":162},"https:\u002F\u002Fwww.eurocontrol.int\u002Fpublication\u002Feuropean-wake-turbulence-categorisation-and-separation-minima-approach-and-departure",[73],"RECAT-EU"," and the FAA's RECAT, that divide the fleet into more groups to use airspace more efficiently. Because of that, the figures differ by region and keep evolving, so treat the ",[36,166,167],{},"separation the controller applies, and your operator's procedures, as the authority"," rather than a memorised table.",[28,170,172],{"id":171},"common-pitfalls","Common pitfalls",[81,174,175,181,187,193],{},[84,176,177,180],{},[36,178,179],{},"A wake can outlast the aircraft."," The vortices linger after the generating aircraft has gone, so a clear-looking runway is not always clear air.",[84,182,183,186],{},[36,184,185],{},"It sinks and drifts."," Stay at or above the heavier aircraft's path, and watch the crosswind that can move a vortex where you do not expect it.",[84,188,189,192],{},[36,190,191],{},"\"Caution wake turbulence\" shifts the responsibility."," When ATC passes that and clears you to follow, accepting visual separation can make the spacing yours to judge.",[84,194,195,198],{},[36,196,197],{},"Categories are standard; minima are not."," Do not assume the numbers from one country apply in another.",[28,200,202],{"id":201},"in-pilot-efb","In Pilot EFB",[10,204,205,206,209],{},"Pilot EFB keeps a quick ",[36,207,208],{},"wake-turbulence separation reference"," so the categories and the principle are easy to recall on the ground during planning. It is a personal reference on your device; Pilot EFB is offline-first and is not a certified Electronic Flight Bag, so the separation issued by air traffic control and your operator's procedures are always the authority on the day.",{"title":211,"searchDepth":212,"depth":212,"links":213},"",2,[214,215,216,217,218],{"id":30,"depth":212,"text":31},{"id":64,"depth":212,"text":65},{"id":124,"depth":212,"text":125},{"id":171,"depth":212,"text":172},{"id":201,"depth":212,"text":202},"2026-06-20","Why aircraft trail wingtip vortices, the ICAO Light, Medium, Heavy and Super categories by maximum take-off mass, and how wake separation keeps a following aircraft clear.",false,"md",[224,227,230],{"q":225,"a":226},"What are the ICAO wake turbulence categories?","ICAO groups aircraft by maximum certificated take-off mass: Light is 7000 kg or less, Medium is more than 7000 kg but less than 136 000 kg, and Heavy is 136 000 kg or more. A separate Super category covers the largest types, notably the Airbus A380. The categories set the wake separation a controller applies.",{"q":228,"a":229},"Why is wake turbulence worst behind a heavy, slow, clean aircraft?","Wingtip vortices are a by-product of the lift a wing makes. The strength rises with weight and with angle of attack and falls with speed, so the strongest vortices come from an aircraft that is heavy, slow and in a clean configuration, which is exactly the picture on take-off and on final approach.",{"q":231,"a":232},"Does wake separation change between countries?","The ICAO Light, Medium, Heavy and Super categories are standard, but the exact separation minima vary. Many regions have moved to recategorisation schemes such as RECAT-EU or the FAA's RECAT that split the fleet into more groups. Always treat the separation the controller applies, and your local procedures, as the authority.",{"name":234,"steps":235},"Reduce your exposure to another aircraft's wake",[236,237,238,239,240],"Know the category of the aircraft ahead: vortices are strongest behind Heavy and Super types.","Remember vortices sink below and drift with the wind, so a light crosswind can hold one over the runway or push it onto a parallel.","On approach behind a heavier aircraft, stay at or above its flight path and aim to land beyond its touchdown point.","On departure behind a heavier aircraft, plan to lift off before its rotation point and climb at or above its path.","If in doubt, ask for or accept the wake separation, and never shave it to save time.",[242,243,244,245],"Wake turbulence is the wingtip-vortex by-product of lift, strongest behind a heavy, slow, clean aircraft.","ICAO categories by maximum take-off mass: Light up to 7000 kg, Medium above that to below 136 000 kg, Heavy 136 000 kg or more, plus a Super category for the largest types.","Vortices sink and drift with the wind, so they can linger over a runway or move onto a parallel.","The categories are standard worldwide, but separation minima and recategorisation schemes vary, so the controller's applied separation governs.",{},true,"\u002Flearn\u002Fwake-turbulence-categories-and-separation",[250,259,267],{"q":251,"options":252,"answer":257,"explanation":258},"Which ICAO category covers an aircraft with a maximum take-off mass of 136 000 kg or more?",[253,254,255,256],"Medium","Heavy","Light","Standard",1,"Heavy is 136 000 kg or more. Medium is above 7000 kg but below 136 000 kg, and Light is 7000 kg or less.",{"q":260,"options":261,"answer":257,"explanation":266},"When is an aircraft's trailing vortex strongest?",[262,263,264,265],"Light, fast and clean","Heavy, slow and clean","Light, slow and with full flap","Heavy, fast and clean","Vortex strength rises with weight and angle of attack and falls with speed, so heavy, slow and clean produces the strongest wake, the picture on take-off and final approach.",{"q":268,"options":269,"answer":257,"explanation":274},"Which is true of wake separation minima around the world?",[270,271,272,273],"They are identical everywhere","The categories are standard but the minima and schemes vary","They no longer exist","They apply only to departures","The Light, Medium, Heavy and Super categories are standard, but minima differ and many regions use recategorisation schemes such as RECAT-EU or FAA RECAT.",{"title":5,"description":220},null,[278,280,282,284,286],{"label":279,"url":71},"ICAO Doc 4444: PANS-ATM (wake turbulence categories and separation)",{"label":281,"url":110},"ICAO Doc 8643: Aircraft Type Designators (wake turbulence category)",{"label":283,"url":151},"FAA Aeronautical Information Manual, Chapter 7 Section 4 (Wake Turbulence)",{"label":285,"url":161},"EUROCONTROL: RECAT-EU wake turbulence recategorisation",{"label":287,"url":288},"UK CAA: UK wake turbulence categories","https:\u002F\u002Fwww.caa.co.uk\u002Fcommercial-industry\u002Fairspace\u002Fair-traffic-management-and-air-navigational-services\u002Fair-navigation-services\u002Fuk-wake-turbulence-categories\u002F","learn\u002Fwake-turbulence-categories-and-separation","Operations","1RBRzLq1AsfmH1Wg6C6ozcdKw2fQtBghsfsbgRUIPzk",{"related":293,"newer":309,"older":315,"series":276},[294,300,304],{"path":295,"title":296,"description":297,"date":298,"topic":290,"draft":221,"minutes":299,"series":276,"seriesOrder":276},"\u002Flearn\u002Fcold-temperature-altimeter-corrections","Cold-temperature altimeter corrections","Why a pressure altimeter over-reads in cold air, leaving you lower than indicated, and how to correct minimum altitudes for temperature on an approach in mountainous or freezing conditions.","2026-06-21",4,{"path":301,"title":302,"description":303,"date":298,"topic":290,"draft":221,"minutes":299,"series":276,"seriesOrder":276},"\u002Flearn\u002Fmode-s-and-ads-b-explained","Mode S and ADS-B explained","How Mode S adds a 24-bit address, selective interrogation and a data link to the transponder, the difference between elementary and enhanced surveillance, and how ADS-B broadcasts your GPS position.",{"path":305,"title":306,"description":307,"date":298,"topic":290,"draft":221,"minutes":308,"series":276,"seriesOrder":276},"\u002Flearn\u002Fthe-global-reporting-format-for-runway-conditions","The Global Reporting Format for runway conditions","How the Global Reporting Format (GRF) describes a contaminated runway, including the runway condition code (RWYCC) from 6 to 0, the assessment matrix (RCAM), and how the report is split into thirds.",5,{"path":310,"title":311,"description":312,"date":219,"topic":313,"draft":221,"minutes":314,"series":276,"seriesOrder":276},"\u002Flearn\u002Fthe-international-standard-atmosphere","The International Standard Atmosphere (ISA)","What the ICAO International Standard Atmosphere is, its sea-level values and lapse rate, and how ISA deviation underpins altimetry, performance and density altitude.","Weather",3,{"path":316,"title":317,"description":318,"date":319,"topic":313,"draft":221,"minutes":308,"series":320,"seriesOrder":299},"\u002Flearn\u002Fhow-to-read-a-sigmet-and-airmet","How to read a SIGMET and an AIRMET","What SIGMETs and AIRMETs warn of, the phenomena codes, how long each stays valid, and a worked SIGMET decoded field by field, with the ICAO baseline and the US differences.","2026-06-18","decode-the-weather",1781989193273]