1 Airspace: AIM Chapter 3: What is airspace? On any given day, mre than 87,000 flights are in the skies in the United States. [naa.gv] T handle all f this traffic, the FAA has develped what is called the Natinal Airspace System. The atmsphere is divided up int unique sectrs, with each sectr s prperties based upn that area s level f traffic and any particular needs f that area. This lessn will cver 1. Terms and definitins f airspace 2. The categries and classes f airspace, alng with the requirements t perate in each kind f airspace 3. Special use airspace 4. and ther areas f the natinal airspace system Hw airspace gets it classificatin. The Natinal Airspace System divides up the classificatins f airspace based n: 1. The level f air traffic 2. The nature f the peratins cnducted 3. The level f safety required 4. Natinal and public interest Busy airprts like Chicag s O Hare will be classified differently frm a single-runway airprt in the middle f n-where. Areas like the Kennedy Space Center and Washingtn DC have unique rules, which restrict r prhibit aircraft frm flying in that area due t safety and/r security reasns. Categries and types f airspace There are tw categries f airspace r airspace areas: Regulatry and Nn-Regulatry. Regulatry airspace has a set f specific regulatins that gvern that area; whereas Nn-Regulatry airspace is just used t advise r warn pilts f the peratins that are cnducted within the airspace 1. Regulatry airspace cnsists f: a. Classes A, B, C, D, E, G b. Restricted areas c. Prhibited areas 2. Nn-Regulatry airspace cnsists f: a. Military peratins areas (MOAs)
2 b. Warning areas c. Alert areas d. Cntrlled firing areas Within these tw categries, there are fur types: 1. Cntrlled 2. Uncntrlled 3. Special use 4. Other airspace Each unique sectr f airspace is defined by its lateral and vertical bundaries. The lateral bundaries can be thught f as the airspace s ftprint n the grund. It can range frm as simple as a circle surrunding an airprt, t a cmplicated, multi-sided plygn. The vertical bundaries describe the upper and lwer altitude limits. These altitudes are labeled in ne f three ways. AGL, r Abve Grund Level, which describes the altitude in terms f height abve the grund. MSL, r Mean Sea Level, which describes the altitude in terms f height abve the average sea level. This is the altitude that is read ff an aircraft s altimeter. Finally, Flight Levels, which als describe the altitude in terms f height abve the average sea level, but is als based upn using a standard pressure f 29.92 inches f mercury. Flight levels are typically used t measure an aircraft s altitude when at 18,000 feet MSL and abve. This wuld then be labeled as FL180. T figure ut which classificatin f airspace yu are navigating thrugh, there are varius aernautical maps, called charts, which can be used. The mst prminent chart starting-ff pilts will use is the sectinal chart. Sectinal charts prvide detailed infrmatin t aviatrs, such as terrain elevatin, grund features, airprts, and ther infrmatin including airspace classes, navigatin aids, radi frequencies, and navigatin rutes. One ther factr t remember when dealing with airspace is the difference between IFR and VFR flight plans. IFR stands fr instrument flight rules meaning that the flight ccurs using the aircraft instruments as the primary reference instead f VFR r visual flight rules where the pilt uses utside references like the hrizn and landmarks n the grund t navigate. Different types f airspace: Each f the different types f airspace has specific requirements that must be met in rder t perate in it. These include, but are nt limited t: pilt qualificatin requirements aircraft equipment requirements clud clearance and visibility requirements speed requirements
3 et cetera. Class A Airspace: An easy way t remember class A r Alpha airspace is that it is abve the airspace that small aircraft perate in. Mst f the traffic perating in class A airspace will be cmmercial airlines r crprate and military jets Class A airspace is lcated frm 18,000 feet MSL up t and including Flight Level 6-0-0, and cvers bth the 48 cntiguus states and Alaska and extends ffshre 12 nautical miles. Aircraft that perate in class A airspace must be n an instrument flight plan, be in an instrument rated airplane, and be flwn by a pilt with an instrument rating. While perating in class A airspace, tw-way radi cmmunicatin with ATC must be maintained, the aircraft must pssess at least a Mde-C transpnder, and if perating abve 24,000 feet MSL, must als pssess sme frm f distance measuring equipment like GPS. A transpnder is a piece f equipment that helps relay the lcatin, and speed f an aircraft t an ATC radar statin. Transpnders equipped with Mde-C als relay the aircraft s altitude t ATC. Because all peratins are cnducted in accrdance with instrument flight rules, there are n specific weather requirements. There is n speed limit ther than t remain slwer than the speed f sund. Finally, when perating in class A, r anytime abve 18,000 ft MSL, make sure t reset the altimeter setting t 29.92. Class B Airspace: Class B, r Brav, airspace surrunds the natin s busiest and largest airprts. The main airprt that a Class B area has been designated fr is cnsidered the primary airprt. There can als be ther smaller airprts within Class B, which are designated as secndary airprts. T find class brav airspace n a VFR Sectinal Chart, lk fr the slid blue lines. The lateral distances f the airspace will vary with the lcal area, but will typically maintain the shape f an upside dwn wedding cake with several layers. Vertically, this airspace is generally lcated between the surface and 10,000 feet MSL, but exceptins d exist. Inside each unique sectr f airspace there are numbers published n sectinal charts t indicate the vertical dimensins f class B airspace in that sectr. In this example at Orland, Flrida, the tp f class B airspace is lcated at 10,000 ft MSL and the bttm is lcated at 6,000 ft MSL. In rder t perate in class B airspace there are several requirements that must be met: The pilt must be at least a private pilt, r a student pilt with the necessary endrsements. Tw-way cmmunicatin with ATC must be maintained
4 In additin, a clearance t enter the airspace must be given t the pilt. Skyhawk 4-5-4 Ech Rme cleared t enter Orland Brav airspace And, the aircraft must pssess a Mde-C transpnder There are twelve airprts arund the cuntry that student pilts are never authrized t enter, even with an endrsement. These are the busiest f the busy airprts, and therefre cannt handle student pilts. A listing f these airprts can be fund in the Aernautical Infrmatin Manual, r AIM, in sectin 3-2-3. A 30-mile ring, knwn as a Mde-C Veil, surrunds the primary airprt f Class B airspace. An aircraft must perate with a Mde-C transpnder within this ring, even if they are nt necessarily inside f Class B airspace. This is shwn n a sectinal chart with a slid magenta line, and the label 30 NM Mde C The minimum weather requirements fr Class B are as fllws: The visibility must nt be any less than 3 statute miles, and the pilt must remain clear f any cluds. Speed limitatins in class B airspace are twfld: Whenever perating belw 10,000 feet MSL, the speed limit is 250 knts. Whenever perating belw Class B airspace, the speed limit is 200 knts. Class C Airspace: Class C, r Charlie, airspace is designated fr airprts, like Daytna Beach Internatinal Airprt, that are nt as busy as Class B, but are still busy enugh t require radar apprach assistance t rganize and separate aircraft traveling int and ut f the lcal area. This airspace is labeled n a VFR Sectinal Chart using slid magenta lines. The typical shape f Class C airspace cntains tw cylinders, the inner cre, and the uter shelf, but can be tailred t meet the needs f certain airprts. The cre cnsists f a 5 NM area extending frm the surface up t 4,000 feet AGL. The shelf cnsists f a 10 NM area, and extends frm 1,200 feet AGL t 4,000 feet AGL. Radar cverage is available up t 20 NM frm the airprt. Aernautical charts depict the MSL altitudes f each segment f airspace. Sme Class C airprts, like Orland Sanfrd, lie underneath Class B. Airspace like this may have custm dimensins that extend up t the flr f Class B. The requirements t perate in class C are as fllws: Pilts must be rated at least a student pilt. Aircraft must pssess a Mde-C transpnder. N clearance is necessary t enter, but tw-way cmmunicatin with ATC must be established and maintained. If the cntrller respnds t yur initial call with yur call sign, yu are cleared
5 t enter the airspace. The ne exceptin wuld be if they replied t yur call with the phrase Remain clear f Class Charlie. Skyhawk 4-5-4 Ech Rme, Remain clear Class Charlie As previusly stated in Class Brav, anytime the aircraft is perating belw 10,000 feet MSL, the speed limit is 250 knts. The limit is reduced dwn t 200 knts when perating belw 2,500 feet AGL and within 4 NM f the primary Class C airprt. T perate inside Class C VFR, the visibility must nt be less than 3 statute miles, and the pilt cannt be any clser t the cluds than 500 feet belw, 1,000 feet abve, and 2,000 feet hrizntally. Class D Airspace: Class D, r Delta, airspace is cntrlled airspace surrunding smaller lcal airprts that are quiet enugh nt t require any radar separatin, but still busy enugh t require a cntrl twer. This airspace is labeled n a VFR Sectinal Chart using dashed blue lines. The dimensins f Class D are relatively simple, cnsisting f a single cylindrical area, generally extending frm the surface t 2,500 feet AGL. Just as stated fr Class C, the altitudes shwn n VFR Sectinal Charts are labeled in MSL. Similar t Class C, ccasinally a Class D airprt may be lcated underneath either Class B r C airspace. In these cases, Class D will extend up t the flr f the underlying airspace. Ormnd Beach and New Smyrna Beach airprts are lcated underneath Daytna Beach s uter shelf. Since Daytna s shelf begins at 1,200 feet MSL, Ormnd and New Smyrna extend up t, but nt including, 1,200 feet MSL. The typical radius f the airspace is abut 5 NM, but can vary between 3 and 7 miles. T perate in Class D, the pilt must be at least a student pilt, and tw-way radi cmmunicatins must be established with the twer. Flying VFR in Class D requires the visibility t be at least 3 statute miles, and t get n clser t the cluds than 500 feet belw, 1,000 feet abve, and 2,000 feet hrizntally. As previusly stated, the maximum speed ne can perate belw 10,000 feet MSL is 250 knts. Hwever, when at r belw 2,500 feet AGL and within 4 NM f the Class D airprt, the maximum allwable speed is 200 knts. Class E Airspace: Class E, r Ech, airspace is defined as cntrlled airspace that is nt Class A, B, C, r D, and is ne f the largest parts f the natinal airspace system. Since this may seem like a vague definitin, we can split the airspace up int seven unique types, r lcatins. T remember them all, we ll use the acrnym set fd. Surface Area Designated Fr an Airprt: This area is depicted surrunding an airprt, starting at the surface, much like a Class D airprt, and is designed t be cnfigured t cntain any instrument prcedures fr that particular airprt. It is depicted n a VFR Sectinal Chart with a dashed magenta line.
6 Extensin t a surface area: These areas serve as extensins t Classes B, C, r D t allw fr instrument apprach prcedures int an airprt. This area is als depicted with a dashed magenta line, but des nt surrund an airprt. Airspace used fr transitin. These areas are used t transitin aircraft t r frm the terminal area and en-rute envirnments. A vignette is used t depict these n sectinal charts. A magenta vignette indicates the flr f Class E at 700 feet AGL, and a blue vignette indicates the flr at 1,200 feet AGL. Federal Airways: These airways can be thught f the highways f the sky, and serve as a ppular methd t get aircraft t their destinatin. Each airway is 8 nautical miles wide, and starts at 1,200 feet AGL, extending up t, but nt including 18,000 feet MSL. Offshre Airspace Areas. This airspace is used t allw ATC t prvide services t IFR traffic that perate beynd 12 NM frm the cast. The brders f these areas depicted n a sectinal chart resemble that f a zipper. The flr f each sectr is indicated inside each respective area. Other. In certain parts f the cuntry, Class Ech des nt start until 14,500 ft MSL, excluding any areas that are within 1,500 feet f the grund. The airspace cntinues upward until reaching 18,000 feet, which is where Class Alpha starts. At FL600, where Class Alpha ends, Class Ech cntinues upward t an indefinite altitude. En Rute Dmestic Areas: These areas are lcated utside f any federal airway t allw fr ATC t separate traffic. In the lcal Flrida area, these areas start at 1,200 feet AGL. As previusly described, these varius types f Class Ech airspace can be fund n sectinal and ther lwaltitude charts as lng as that airspace begins belw 14,500 feet MSL. There are n defined vertical limits t Class Ech. This airspace will either start at the surface r a defined altitude, and cntinue upward until cming in cntact with a different class f cntrlled airspace. There are n specific pilt qualificatins, equipment requirements, r peratinal prcedures necessary in rder t fly within this airspace. Similar t ther airspace, the maximum airspeed an aircraft can fly is 250 knts, when belw 10,000 feet MSL. There is n speed limit when at r abve 10,000 feet, except t remain slwer than the speed f sund. Because Class Ech can be lcated in many different areas, the weather minimums t perate VFR within Class Ech depend n yur altitude. When belw 10,000 feet MSL, the visibility must be at least 3 statute miles, and pilts cannt be any clser t cluds than 500 feet belw, 1,000 feet abve, and 2,000 feet hrizntally. Hwever, when perating at r abve 10,000 feet MSL, the requirements increase. There, the visibility must be at least 5 statute miles and cluds must remain at least 1,000 feet abve, 1,000 feet belw, and 1 statute mile hrizntally frm an aircraft.
7 Class G Airspace: Class G, r Glf, airspace is cnsidered uncntrlled, and makes up the rest f the area that has nt been designated already as Class A, B, C, D, r E. This means that, mre ften than nt, Class G will start at the surface and cntinue upward until reaching 1,200 feet AGL, which is where Class Ech s en-rute dmestic areas typically start. Just like Class Ech, there are n specific pilt qualificatins, equipment requirements, r peratinal prcedures necessary in rder t fly within this airspace. As previusly stated, the maximum airspeed an aircraft can fly is 250 knts, when belw 10,000 feet MSL. There is n speed limit when at r abve 10,000 feet, except t remain slwer than the speed f sund. The weather minimums t perate VFR in Class Glf are relatively cmplicated, and depend n bth the aircraft s altitude and time f day. T rganize all the varius pssibilities, let s create a chart. Anytime the aircraft is within 1,200 feet f the surface, regardless f the MSL altitude, during the day, the nly requirement is t remain clear f cluds. At night, the visibility must be at least 3 statute miles and clud clearances are 500 feet belw, 1,000 feet abve, and 2,000 feet hrizntal. When flying abve 1,200 feet AGL, but less than 10,000 feet MSL, during the day, the minimum visibility is 1 statute mile and, again, 500 feet belw, 1,000 feet abve, and 2,000 feet hrizntally frm cluds. At night, the visibility is nce again 3 statute miles, and the same 5-1-2 fr clud clearances. When flying bth abve 1,200 feet AGL and 10,000 feet MSL, regardless f the time f day, the visibility must be at least 5 statute miles and the clud clearances are at least 1,000 feet belw, 1,000 feet abve, and 1 statute mile hrizntally. This is the same requirement fr Class Ech, abve 10,000 feet MSL. Class F Airspace Yu might have nticed there was n listing f Class F, r Fxtrt, airspace. This is because, in the United States, the FAA Natinal Airspace System has nt declared any airspace that falls under this classificatin. Hwever, in ther cunties arund the wrld, Class F airspace des exist. Special Use Airspace: In additin t the six classes f airspace already mentined, ther types f airspace exist, which fall int a separate categry. This airspace is called Special Use Airspace. Special Use Airspace cnsists f areas wherein certain activities are being cnducted that must be cnfined t that area, r wherein limitatins are impsed upn ther aircraft that are nt a part f thse activities, r bth. Except fr cntrlled firing areas, special use airspace areas are depicted n aernautical charts. Fr Regulatry special use airspace, there are Prhibited Areas, and Restricted Areas. Nn-regulatry special use airspace cnsists f Warning Areas, Military Operating Areas, Alert Areas, and Cntrlled Firing Areas.
8 Prhibited Areas Prhibited Areas exist fr security r ther reasns assciated with natinal welfare, where aircraft are nt permitted t fly. This airspace starts at the surface and extends up t a specified altitude. On Sectinal Charts, this airspace is depicted with a blue hashed shape. Inside the shape will be the letter P, fllwed by a series f numbers, acting as the identifier f that area. Restricted Areas Restricted Areas cntain the existence f unusual, ften invisible, hazards t aircraft, such as artillery firing, aerial gunnery, r guided missiles. Because f this aircraft are nt allwed t fly within the area, unless that area is nt in use, r permissin has been received frm the designated cntrlling agency. Unless therwise depicted, this airspace starts frm the surface and extends up t a designated altitude. Sectinal Charts depict this airspace in the same manner as prhibited areas, using a blue hashed shape Hwever, the identifier starts with the letter R instead f P. Warning Areas Warning Areas cntain activity that may be hazardus t nnparticipating aircraft. They exist t warn nnparticipating pilts f ptential danger, but d nt prevent r limit ther aircraft frm perating within that area. These areas exist ver dmestic and internatinal waters, as clse as three nautical miles frm the cast. Unless therwise depicted, this airspace starts frm the surface and extends up t a designated altitude. They are again depicted n Sectinal Charts with blue hashed lines; this time starting with the letter W. Military Operating Areas Military Operating Areas, r MOAs, cntain activities such as air cmbat tactics, air intercepts, aerbatics, frmatin flying, and lw-altitude tactics. They exist t separate certain military training frm IFR traffic. Whether r nt an MOA is in use, VFR traffic may still fly thrugh the area. Hwever, extreme cautin shuld be used when flying thrugh an active MOA. Unless therwise depicted, MOAs typically start at a designated altitude and extend up t, but nt including FL180. Sectinal Charts depict these areas using magenta hashed lines. Instead f a numbered identifier like ther previusly-mentined areas, MOAs are given names. Alert Areas Alert Areas are used t infrm pilts f areas that may cntain a high vlume f pilt training, r an unusual type f aerial activity. Nnparticipating aircraft shuld use extra cautin when perating within these areas. These areas are depicted n Sectinal Charts using magenta hashed lines, but use the previusly-mentined numeric identifier, this time starting with the letter A. Cntrlled Firing Areas Cntrlled Firing Areas, r CFAs, cntain activities which, if were nt cnducted in a cntrlled envirnment, culd be hazardus t aircraft. CFAs are different frm ther hazardus areas due t the fact that their activities are immediately suspended when a nnparticipating aircraft appears t be appraching the area. Because f this, they d nt get charted, as they d nt require pilts t alter their curse.
9 Other Airspace Areas This last categry f airspace cntains varius auxiliary types are airspace that are each unique and dn t fall int any ther classificatin f airspace. We will be discussing Airprt Advisry Areas, Temprary Flight Restrictins, Air Defense Identificatin Znes, Military Training Rutes, VFR Flyways, VFR Crridrs, VFR Transitin Rutes, Terminal Radar Service Areas, Natinal Security Areas, and finally, U.S. Wildlife Refuges, Parks, and Frest Service Areas. Airprt Advisry Areas Airprt advisry areas are areas surrunding a nn-twered airprt n which a flight service statin is lcated. The Flight service statin can prvide advisries ver the CTAF frequency pertaining t wind and weather infrmatin and even basic traffic advisries. Remember that the FSS is nly advising abut traffic and it is up t the PIC t maintain safe and adequate traffic separatin frm ther aircraft. Temprary Flight Restrictins Temprary Flight Restrictins are shrt-term blcks f airspace used t temprarily prevent r limit nnparticipating aircraft frm entering that area. These culd be used fr such things as T prtect peple r prperty in the air, r n the surface frm specific hazards r situatins; Or t prvide a safe envirnment fr such things as disaster relief, r shuttle launches; Or t prtect the President, Vice President, r any ther public figure. Depending n the impact f the TFR, a Ntice t Airman, r NOTAM, may be issued t alert pilts that a TFR is in effect. Pilts are respnsible fr being aware f and cmplying with any TFRs that are r will be in effect during their flights. Cntact the lcal Flight Service Statin fr the mst up-t date infrmatin by calling 800- WX-BRIEF. Air Defense Identificatin Znes Air Defense Identificatin Znes, r ADIZs, serve as the bundary between dmestic US airspace and internatinal airspace. They are lcated ver the brders f neighbring cuntries, and alng the cast lines. Sectinal Charts depict these with a magenta line and dts. All aircraft entering the US airspace frm utside the cuntry must prvide identificatin prir t entry. Generally, aircraft must file an IFR r Defense VFR flight plan fr any peratins that enter r exit an ADIZ. As part f filing yur flight plan with Flight Service, yu will need t prvide the estimated time yu plan n passing thrugh the ADIZ. In additin, the aircraft must have an perating Mde-C transpnder; and the pilt must establish and maintain tw-way radi cmmunicatins with ATC in rder t make peridic psitin reprts. Failure t fllw these rules may result in yur aircraft being intercepted by US security.
10 Military Training Rutes Military Training Rutes, r MTRs, are rutes arund the cuntry where military aircraft practice maneuvers and high speed peratins smetimes at very lw levels. Generally MTRs are established belw 10,000 ft MSL with aircraft perating at speeds in excess f 250 knts. On Sectinal Charts, MTRs are depicted by gray shaded lines. The names f an MTR start with either VR r IR which cnveys whether the rute is flwn VFR r IFR. The rute number tells pilts what altitudes the rute is flwn at. MTRs with n segment abve 1,500 feet AGL shall be identified by fur number characters; fr example IR1206 r VR1207. MTRs that include ne r mre segments abve 1,500 feet AGL will be identified by tw r three digit characters; fr example IR24 r VR318. VFR Flyways A VFR Flyway is defined as a general flight path, fr use by pilts in planning flights int, ut f, thrugh r near cmplex terminal airspace. These rutes d nt require an ATC clearance and are nt a specific curse that is flwn, but merely a rute that will keep the aircraft clear f the Class Brav airspace. These flyways can be fund n the back f the Terminal Area Chart. VFR crridr A VFR Crridr is defined as airspace thrugh Class B airspace, with defined vertical and lateral bundaries, in which aircraft may perate withut an ATC clearance r cmmunicatin with air traffic cntrl. Essentially a crridr is like a hle thrugh the class B airspace. With the increase f air traffic thrughut the cuntry, VFR crridrs have nt been used recently in the Natinal Airspace System. VFR transitin rute A VFR Transitin Rute is a published rute thrugh Class B airspace t accmmdate VFR traffic flying thrugh the area. Befre flying a VFR transitin rute and entering class B airspace, a pilt must receive clearance frm ATC t d s. These rutes, fund n the Terminal Area Chart, list specific frequencies, altitudes, and curses t fly. VFR transitin rutes are indicated n the chart by duble magenta lines with an arrw indicating the directin f the rutes. Terminal radar service area A Terminal radar service area, r TRSA, is a relic f the ld natinal airspace system. It is essentially a class D airprt surrund by ptinal r vluntary class C-type radar service. The key difference is that this radar service is recmmended t be used but nt required in rder t land at the primary class D airprt. TRSAs are depicted by black lines n a sectinal chart, similar t the lk f a class C airprt, but the dimensins widely vary between each individual airprt. Natinal security area Natinal Security Areas are established at lcatins where there is a requirement fr increased security and safety f grund facilities. These areas are depicted n the sectinal chart by dashed magenta lines. While the
11 airspace abve these areas is nt restricted, Pilts are requested t vluntarily avid flying thrugh the depicted NSA. U.S. Wildlife Refuges, Parks, and Frest Service Areas The areas abve U.S. Wildlife Refuges, Parks, and Frest Service Areas are depicted by a blue line and dtted brder and are usually labeled with name f the area. Pilts are requested t maintain a minimum altitude f 2,000 feet abve the surface f these areas. Cnclusin The natinal airspace system is a cmplex and evlving system. Whether yu re flying ut f yur lcal cunty airprt, r arriving int the wrld s mst cmplicated terminal areas, airspace is always arund yu. By understanding the cmpnents f this system, including airspace dimensins, pilt and aircraft requirements, and minimum weather cnditins, yu will be able t perate in and arund the United States safely and legally.