[{"data":1,"prerenderedAt":378},["ShallowReactive",2],{"learn-\u002Flearn\u002Ftransition-altitude-and-transition-level":3,"learn-nav-\u002Flearn\u002Ftransition-altitude-and-transition-level":349},{"id":4,"title":5,"body":6,"date":289,"description":290,"draft":291,"extension":292,"faqs":293,"howTo":294,"keyTakeaways":302,"meta":307,"navigation":308,"path":309,"quiz":310,"seo":336,"series":293,"seriesOrder":293,"sources":337,"stem":346,"topic":347,"__hash__":348},"learn\u002Flearn\u002Ftransition-altitude-and-transition-level.md","Transition altitude and transition level",{"type":7,"value":8,"toc":279},"minimark",[9,21,27,32,79,83,99,128,145,149,158,189,205,209,227,243,247,267,271],[10,11,12,13,20],"p",{},"Low down, you fly altitudes: feet above the sea, set on the local pressure. High up, you fly flight levels: a shared yardstick that ignores the local pressure entirely. The boundary where one gives way to the other is the ",[14,15,19],"a",{"href":16,"className":17},"\u002Flearn\u002Fglossary#gt-transition-altitude",[18],"glossary-link","transition altitude"," and transition level, and the small altimeter change you make there is one of the tidiest, most testable bits of procedure in flying.",[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},"two-ways-to-measure-height","Two ways to measure height",[10,33,34,35,39,40,48,49,52,53,56,57,60,61,64,65,68,69,72,73,78],{},"Near the ground, what matters is your height above the terrain and obstacles, so you set the ",[14,36,38],{"href":37},"\u002Flearn\u002Faltimetry-qnh-qfe-qne","altimeter"," to the local ",[41,42,43],"strong",{},[14,44,47],{"href":45,"className":46},"\u002Flearn\u002Fglossary#gt-qnh",[18],"QNH"," and read ",[41,50,51],{},"altitudes"," in feet above mean sea level. Aloft, what matters is staying separated from other aircraft, and for that everyone needs to be measuring from the ",[41,54,55],{},"same datum",", regardless of whose local pressure is whose. So above a certain point all aircraft set the ",[41,58,59],{},"standard pressure"," of ",[41,62,63],{},"1013 hectopascals",", equivalently ",[41,66,67],{},"29.92 inches of mercury",", and read ",[41,70,71],{},"flight levels",". With everyone on the same setting, a ",[14,74,77],{"href":75,"className":76},"\u002Flearn\u002Fglossary#gt-flight-level",[18],"flight level"," is directly comparable between aircraft, which is exactly what vertical separation needs.",[28,80,82],{"id":81},"the-altitude-the-level-and-the-layer","The altitude, the level and the layer",[10,84,85,86,92,93,98],{},"Three terms, defined in ",[14,87,91],{"href":88,"rel":89},"https:\u002F\u002Fstore.icao.int\u002Fen\u002Fprocedures-for-air-navigation-services-pans-aircraft-operations-volume-i-flight-procedures-doc-8168",[90],"nofollow","ICAO Doc 8168"," and the ",[14,94,97],{"href":95,"rel":96},"https:\u002F\u002Fwww.faa.gov\u002Fair_traffic\u002Fpublications\u002Fatpubs\u002Faim_html\u002Fchap7_section_2.html",[90],"FAA AIM",":",[100,101,102,113,122],"ul",{},[103,104,105,106,109,110,112],"li",{},"the ",[41,107,108],{},"transition altitude (TA)"," is the altitude at or below which you control your vertical position by reference to ",[41,111,51],{}," on QNH;",[103,114,105,115,118,119,121],{},[41,116,117],{},"transition level (TL)"," is the lowest ",[41,120,77],{}," available for use above the transition altitude, flown on the standard setting;",[103,123,105,124,127],{},[41,125,126],{},"transition layer"," is the airspace between the two, which you pass through rather than cruise in.",[10,129,130,131,134,135,138,139,144],{},"Where the TA sits varies. In the United States it is fixed at ",[41,132,133],{},"18,000 feet",", so the lowest usable level above it is FL180. Across Europe and elsewhere the TA is ",[41,136,137],{},"lower and varies"," by aerodrome or region, published on the chart and often passed by ATC, which is why you confirm it rather than assume it. The European rules sit in the ",[14,140,143],{"href":141,"rel":142},"https:\u002F\u002Fwww.easa.europa.eu\u002Fen\u002Fdocument-library\u002Feasy-access-rules\u002Feasy-access-rules-standardised-european-rules-air-sera",[90],"Standardised European Rules of the Air",".",[28,146,148],{"id":147},"the-rule-for-changing","The rule for changing",[10,150,151,152,157],{},"The change-over is one line each way, and ",[14,153,156],{"href":154,"rel":155},"https:\u002F\u002Fskybrary.aero\u002Farticles\u002Ftransition-altitudelevel",[90],"SKYbrary"," states it plainly:",[100,159,160,175],{},[103,161,162,165,166,169,170,172,173,144],{},[41,163,164],{},"Climbing:"," set the ",[41,167,168],{},"standard"," pressure (1013 \u002F 29.92) as you pass the ",[41,171,19],{},", and from then on report ",[41,174,71],{},[103,176,177,165,180,183,184,172,187,144],{},[41,178,179],{},"Descending:",[41,181,182],{},"local QNH"," as you pass the ",[41,185,186],{},"transition level",[41,188,51],{},[10,190,191,192,195,196,198,199,195,202,204],{},"A memory aid that holds in both hemispheres: going up, you reach the transition ",[41,193,194],{},"altitude"," first, so the ",[41,197,194],{}," is where you swap to standard; coming down, you reach the transition ",[41,200,201],{},"level",[41,203,201],{}," is where you swap to QNH.",[28,206,208],{"id":207},"a-worked-example","A worked example",[10,210,211,212,215,216,219,220,222,223,226],{},"Departing an aerodrome with a published transition altitude of ",[41,213,214],{},"6000 feet"," on a QNH of ",[41,217,218],{},"1004",". You climb on QNH reading altitudes, and as you pass ",[41,221,214],{}," you wind the subscale to ",[41,224,225],{},"1013"," and call the next stop as a flight level, say \"climbing FL080.\" You cruise at FL120 on the standard setting, directly comparable with the traffic around you.",[10,228,229,230,233,234,236,237,239,240,242],{},"Returning later, ATC passes a transition level of ",[41,231,232],{},"FL065"," and a QNH of ",[41,235,218],{},". You descend on standard reading flight levels, and as you pass ",[41,238,232],{}," you set ",[41,241,218],{}," and revert to altitudes, \"descending to 3000 feet on 1004.\" You did not level off inside the transition layer; you passed straight through it.",[28,244,246],{"id":245},"common-pitfalls","Common pitfalls",[100,248,249,255,261],{},[103,250,251,254],{},[41,252,253],{},"Confirm the transition altitude; do not assume it."," Outside the US it varies by place and is published or passed by ATC, so check it for the aerodrome you are at.",[103,256,257,260],{},[41,258,259],{},"Change at the right boundary."," Standard at the transition altitude going up, QNH at the transition level coming down; mixing the two is a classic slip.",[103,262,263,266],{},[41,264,265],{},"Do not cruise in the layer."," The transition layer is for passing through; level off above the TL or below the TA, not between them.",[28,268,270],{"id":269},"in-pilot-efb","In Pilot EFB",[10,272,273,274,278],{},"Pilot EFB is a study and planning companion for altimetry and the altitude-to-level change-over, alongside the decoded pressure in your ",[14,275,277],{"href":276},"\u002Flearn\u002Fhow-to-read-a-metar","METAR"," and the rest of your briefing in one offline-first place. It does not set your altimeter or replace ATC and the published procedures, so fly the transition altitude and level from your official source of record. Pilot EFB is not a certified Electronic Flight Bag, so treat it as a study and planning aid and brief from your official source of record.",{"title":280,"searchDepth":281,"depth":281,"links":282},"",2,[283,284,285,286,287,288],{"id":30,"depth":281,"text":31},{"id":81,"depth":281,"text":82},{"id":147,"depth":281,"text":148},{"id":207,"depth":281,"text":208},{"id":245,"depth":281,"text":246},{"id":269,"depth":281,"text":270},"2026-06-22","Where altitudes give way to flight levels, why pilots swap between the local QNH and the standard 1013 pressure setting, and the simple rule for when to change the altimeter climbing and descending.",false,"md",null,{"name":295,"steps":296},"How to change altimeter setting through the transition layer",[297,298,299,300,301],"Below the transition altitude, fly altitudes set on the local QNH.","Climbing through the transition altitude, set the standard pressure of 1013 hectopascals (29.92 inches of mercury) and from then on report flight levels.","Cruise above on flight levels, with everyone on the same standard setting so levels are directly comparable.","Descending, change from the standard setting back to the local QNH as you pass the transition level.","Avoid levelling in the transition layer between the two; it is a layer to pass through, not to cruise in.",[303,304,305,306],"Below the transition altitude you fly altitudes on the local QNH; above the transition level you fly flight levels on the standard 1013 hectopascals (29.92 inches of mercury).","Climbing, set standard pressure passing the transition altitude; descending, set QNH passing the transition level.","The transition layer sits between the two and is passed through, not cruised in.","Standard pressure keeps every aircraft on the same datum aloft, so flight levels are directly comparable for separation.",{},true,"\u002Flearn\u002Ftransition-altitude-and-transition-level",[311,320,328],{"q":312,"options":313,"answer":318,"explanation":319},"What altimeter setting do you use above the transition level?",[314,315,316,317],"The local QNH","The standard pressure of 1013 hectopascals (29.92 inches of mercury)","QFE, the aerodrome pressure","Whatever was last set on the ground",1,"Above the transition level everyone flies on the standard pressure setting of 1013 hectopascals, or 29.92 inches of mercury, so flight levels are directly comparable between aircraft.",{"q":321,"options":322,"answer":318,"explanation":327},"Climbing, when do you change to the standard pressure setting?",[323,324,325,326],"Passing the transition level","Passing the transition altitude","At the top of climb","On the runway before takeoff","Climbing, you set standard pressure as you pass the transition altitude; descending, you set the local QNH as you pass the transition level.",{"q":329,"options":330,"answer":318,"explanation":335},"Why is the standard setting used for flight levels instead of the local QNH?",[331,332,333,334],"Because it is more accurate near the ground","So that every aircraft uses the same datum and flight levels are directly comparable for separation","Because QNH is secret","To save fuel","Above the transition level all aircraft use the same standard datum, so their flight levels are directly comparable and vertical separation is assured regardless of the local pressure.",{"title":5,"description":290},[338,340,342,344],{"label":339,"url":88},"ICAO Doc 8168: PANS-OPS, Volume I (Flight Procedures)",{"label":341,"url":95},"FAA Aeronautical Information Manual, Chapter 7 Section 2 (Altimeter Setting Procedures)",{"label":343,"url":141},"EASA Easy Access Rules for Standardised European Rules of the Air (SERA)",{"label":345,"url":154},"SKYbrary: Transition Altitude\u002FLevel","learn\u002Ftransition-altitude-and-transition-level","Operations","xTLPcbJfKVabF5wnRx_u8MCXwJwe3whK1OqvHzQS-Ws",{"related":350,"newer":368,"older":373,"series":293},[351,358,364],{"path":352,"title":353,"description":354,"date":289,"topic":347,"draft":291,"minutes":355,"series":356,"seriesOrder":357},"\u002Flearn\u002Fairspace-speed-limits","The 250-knot speed limit and other airspace speed rules","Why there is a 250-knot speed limit below 10,000 feet, the slower 200-knot limits near and under busy airspace, and how the FAA and EASA wordings line up and differ, with a worked descent that puts the rules in order.",4,"plan-a-vfr-cross-country",7,{"path":359,"title":360,"description":361,"date":289,"topic":347,"draft":291,"minutes":362,"series":356,"seriesOrder":363},"\u002Flearn\u002Fminimum-safe-altitudes-msa-mora-mea-moca","Minimum safe altitudes: MSA, MORA, MEA, MOCA and MEF","The family of minimum altitudes that keep you clear of terrain and obstacles, what each one guarantees, and the difference between an altitude that also promises navigation signal and a chart figure that only tells you the highest obstacle.",3,6,{"path":365,"title":366,"description":367,"date":289,"topic":347,"draft":291,"minutes":355,"series":293,"seriesOrder":293},"\u002Flearn\u002Freading-an-instrument-approach-chart","Reading an instrument approach chart","How an instrument approach chart is laid out, what the plan view, profile view, minimums box and missed approach each tell you, and how to read one in order so you brief the approach the way you will fly it.",{"path":369,"title":370,"description":371,"date":289,"topic":372,"draft":291,"minutes":355,"series":293,"seriesOrder":293},"\u002Flearn\u002Fthe-tropopause","The tropopause and where weather lives","What the tropopause is, why it sits higher over the equator than the poles, and why nearly all the weather a pilot deals with happens in the troposphere below it.","Weather",{"path":374,"title":375,"description":376,"date":289,"topic":372,"draft":291,"minutes":362,"series":377,"seriesOrder":357},"\u002Flearn\u002Fturbulence-reporting-and-intensity","Turbulence reporting and intensity scales","What light, moderate, severe and extreme turbulence actually mean, how the intensity is judged by the aircraft's reaction rather than a guess, and how pilots report it so the aircraft behind benefits.","decode-the-weather",1782089963942]