Advisory Circular 90-66A Traffic Patterns

8/7/2019 Advisory Circular 90-66A Traffic Patterns

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Advisorv.S. Departmentof TransportationFederal AviationAdministration CircularSubject: RECOMMENDED STANDARD TRAFFICPAiTERNS AND PRACTICES FORAERONAUTICAL OPERATIONS ATAIRPORTS WITHOUT OPERATINGCONTROL TOWERS1. PURPOSE.This adv isory circular (AC) calls attention to regu -latory requirements and rec6mmended proceduresfor aeronauticaloperationsat airports without opera t-ing control towers. It recommends traffic patternsand operational procedures or aircraft, lighter thanair, glider, parachute, otorcraft, and ultralight vehicleoperations where such use is not in conflict withexisting proceduresn effect at thoseairports.2, CANCELLATION.AC 90-66, RecommendedStandardTraffic Patternsfor Airplane Operations at Uncontrolled Airports,datedFebruary27,1975, is cancelled,3. PRINCIPAL CHANGES.This AC has been updated to reflect current proce-dures at airports without operating control towers.Principal changes nclude: adding on Other TrafficPattern section, amendingappendixcharts to remainconsistent with the Airmans Information Manual(AIM), expanding the Related Reading Materialsection from airplane to aeronautical oper-ations, adding definition and references o, CommonTraffic Advisory Frequency (CTAF), acknowledgingstraight-in approachesare not prohibited but maybe operationally advantageous,and adding a para-graphon wake turbulence.4. DEFINITIONS.

a. Airports Without Operating Control Towers.Airports without control towers or an airport witha control tower which is not operating . Theseairports are commonly referred to as non-towered,uncontrolled,or part-time toweredairports.b. Common raffic Advisory Frequency (CTAF).A frequency designed for the purpose of carryingout airport advisory practices while operating toor from an airport without an operating controltower. The CTAF may be a UNICOM, MULTICOM,

Date: 8126193 ACNo.90-66AInitiated by: ATP-230

flight service station, or tower frequency and isidentified in appropriate aeronautica l publications.5. REMTED READING MATERIAL.a. Airport/Facility Directory (AFD).b. Airmans Information Manual (AIM).

c. Fly Neighborly Guide, Helicopter AssociationInternational.d. Aviation USA, Aircraft Owners and PilotsAssociation (AOPA). .e. Stateaviation publications.f. Various pilot guides.Q. Pilot Operationsat Nontowered Airports, AOPAAir Safety Foundationpamphlet.h. Guidelines for the Operation of UltralightVehicles at Existing Airports, United StatesUltralightAssociation.i. Factsor Pilots, United StatesParachuteAssocia-tion.j. The latest addition of the following ACsalso contain information applicable to operationsat airportswithout operatingcontrol towers:

(1) AC 90-23 , Aircraft Wake Turbulence.(2) AC 90-42 , Traffic Advisory Practices atAirports Without OperatingControl Towers.(3) AC 90-48, Pilots Role in Collision Avoid-ance.(4) AC 91-32, Safety In and Around Helicopters.(5) AC 103-6, Ultralight VehicleOperations-A irports, Air Traffic Control, andWeather.(6) AC 105-2, Sport Parachute umping.6.BACKGROUNDANDSCOPE.

a. Regulatory provisions relating to traffic patternsare found in Parts 91, 93, and 97 of the FederalAviation Regulations (FAR). The airport traffic


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AC !W66A 8/26/93

patterns contained in Part 93 relate primarily tothose airports where there is a need for uniquetraffic pattern procedures not provided for in Part91. Part 97 addressesnstrument approach rocedures.At airports without operating control towers, Part91 requires only that pilots of airplanesapproachingto land make all turns to the left unless lightsignals or visual markings indicate that turns shouldbe made o the right.

b. The Federal Aviation Administration (FAA)believes that observanceof a standard raffic patternand the use of CTAF procedures as detailed inAC 90-42 will improve the safety and efficiencyof aeronautical perationsat airportswithout operatingcontrol towers.7. GENERAL OPERATING PRACTICES.a. Use of standard raffic patterns for all aircraftand CTAF procedures by radio-equipped aircraftare recommended at all airports without operatingcontrol towers. However, it is recognized that othertraffic patterns may already be in common useat some airports or that special circumstances orconditions exist that may prevent use of the standardtraffic pattern.

b. The use of any traffic pattern procedure doesnot alter the responsibility of each pilot to seeand avoid other aircraft. Pilots are encouragedto participate in Operation Lights On, whichis a voluntary pilot safety program described inthe AIM designed o enhance he see-and-avoidrequirement.C . As part of the preflight familiarization withall available information concerning a flight, eachpilot should eview all appropriatepublications AFD,AIM, Notices to Airmen (NOTAM), etc.), for perti-nent information on current traffic patterns at thedeparture ndarrival airports.d. It is recommended that pilots utilize visualindicators, such as the segmented ircle, wind direc-tion indicator, landing direction indicator, and trafficpattern indicators which provide traffic patterninformation.e. The FAA encourages ilots to use the standard

traffic pattern. However, for those pilots who chooseto execute a straight-in approach, maneuvering forand execution of the approachshould be completedso as not to disrupt the flow of arriving anddeparting traffic. Therefore, ilots operating in thetraffic pattern should be alert at all times toaircraft executingstraight-in approaches .f. Pilots who wish to conduct instrumentapproaches should be particularly alert for other

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aircraft in the pattern SO as to avoid interruptingthe flow of traffic. Position reports on the CTAFshould include distance and direction from theairport, as well as the pilots intentions upon comple-tion of the approach.g. Pilots of inbound nonradio-equipped aircraftshould determine he runway in use prior to enteringthe traffic pattern by observing the landing directionindicator or by other means. Pilots should beaware that procedures at airports without operatingcontrol towers generally do not require the useof two-way radios; therefore, pilots should beespecially vigilant for other aircraft while operatingin the traffic pattern.h. Wake turbu lence is generated by all aircraft.Therefore, pilots should expect to encounter turbu-lence while operating in a traffic pattern and inproximity to other aircraft. Aircraft componentsand equipment can be damagedby wake turbulence.In flight, avoid the area below and behind theaircraft generating turbulence especially at low alti-tude where even a momentary wake encountercan be hazardous. All operators should be awareof the potential adverse effects that their wake,rotor or propeller turbulence has on light aircraftandultralight vehicles.8. RECOMMENDED STANDARD TRAFFICPATTERN.Airport owners and operators, n coordination withthe FAA, are responsible for establishing trafficpatterns. However, the FAA encourages airportowners and operators to establish traffic patternsas recommended in this AC. Further, left trafficpatternsshouldbe establishedexceptwhere obstacles,terrain, -and noise-sensitive areas dictate otherwise.Appendix 1 contains diagrams for recommendedstandard raffic patterns.a. Prior to entering the traffic pattern at anairport without an opera ting control tower, aircraftshould avoid the flow of traffic until establishedon the entry leg. For example, wind and landingdirection indicators can be checked while at analtitude above the traffic pattern. When the p ropertraffic pattern direction has been determined, thepilot should then proceed to a point well clearof the pattern before descending to the patternaltitude.

b, Arriving aircraft shouldbe at the appropriatetraffic pattern altitude before entering the trafficpattern. Entry to the downwind leg should beat a 45-clegree angle abeam the midpoint of therunway.PAR 6


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8/26/93 AC 90-66Ac. It is recommended that airplanes observe alOOO-footabove ground level (AGL) traffic patternaltitude. Large and turbine-powered airplanesshouldenter the traffic pattern at an altitude of 1,500feet AGL or 500 feet above the establishedpatternaltitude. A pilot may vary the size of the traffic

pattern depending on the aircrafts performancecharacteristics.d. The traffic pattern altitude shouldbe maintaineduntil the aircraft is at least abeam the approachend of the landing runway on the downwind leg.e. The base leg *turn should commence whenthe aircraft. is at a point approximately 45 degreesrelativebearing rom the runway threshold.f. Landing and takeoff should be accomplishedon the operating runway most nearly aligned intothe wind. However, -if a cf econdary runway isused, pilots using the secondary runway should

avoid the flow of traffic to the runway mostnearly aligned nto the wind.g. Airplanes on takeoff should continue straightaheaduntil beyond the departureend of the runway.&craft executing a go-around maneuver shouldcontinue straight ahead, beyond the departure endof the runway, with the pilot maintaining awarenessof other traffic so as not to conflict with thoseestablished n the pattern. n caseswhere a go-aroundwas causedby an aircraft on the runway, maneuveringparallel to the runway may be required to maintainvisualcontactwith the conflicting aircraft.h. Airplanes remaining in the traffic patternshouldnot commence a turn to the crosswind leg untilbeyond the departure end.of. the runway and within300 feet below traffic pattern altitude, with thepilot ensuring that the turn to downwind leg willbe made at the traffic patternaltitude.i. When departing the traffic pattern, airplanesshould continue straight out or exit with a 45-degreeleft turn (right turn for right traffic pattern ) beyondthe departu re end of the runway after reachingpattern altitude. Pilots need to be aware of anytraffic entering he traffic pa tternprior to commencinga turn.j. Airplanes should not be operated n the trafficpattern at an indicated airspeed of more than 200knots (230 mph).k, Throughout the traffic pattern, right-of-wayrules apply as stated in FAR Part 91.113;Anyaircraft in distress has the right-of-way over allother aircraft. In addition, when converging aircraftare of different categories, a balloon has theright-of-way over any other category of aircraft;

a glider has the right-of-way over an airship,airplane, or rotorcraft; and an airship has theright-of-way over an airplaneor rotorcraft.9. OTHER TRAFFIC PATTERNS.Airport operators outinely establish ocal proceduresfor the operation of gliders, parachutists, lighterthan air aircraft, helicopters, and ultralight vehicles.Appendices 2 and 3 illustrate these operationsas they relate to recommended standard trafficpatterns.a. Rotorcraft.(1) In the case of a helicopter approaching-to land, the pilot must avoid the flow of fixed-wingaircraft and land on a marked helipad or suitableclear area . Pilots should be aw are that at someairports, the only suitable landing a rea s the runway.(2). All pilots should be aware that rotorcraft,may fly slower and approach at steeper anglesthan airplanes. Air taxi is the preferred methodfor helicopter ground movements which enablesthe pilot to proceedat an optimum airspeed,minimizedownwash effect, and conserve uel. However, flightover aircraft, vehicles, and personnel should beavoided.(3) In the case of a gyrocopte r approachingto land, the pilot should avoid the flow of fixed-wingaircraft until turning final for the active runway.(4) A helicopter operating in the traffic patternmay .fly a pattern similar to the airplane patternat a lower altitude (500 AGL) and closer tothe airport. This pattern may be on .the oppositeside of the runway with turns in - -the oppositedirection if local policy permits.(5) Both classes of rotorcraft can be expec tedto practice. power-off landing (autorotation) whichwill involve -a very steep angle of approach andhigh rate of descent 1,500-2,000 eet/minute).b. Gliders.. (1) A glider, including the tow aircraft duringtowing operations,has he right-f-way over poweredaircraft.(2) If the same runway is usedby both airplanesand gliders, the glider traffic pattern will be insidethe pattern of engine driven aircraft. If a GliderOperating Area is established to one side ofa powered-aircraft runway, the glider pattern willnormally be on the side of the airport closestto the Glider Operating Area. This will allowgliders to fly the same direction traffic pa tternas powered aircraft in one wind condition andnecessitate a separate opposing direction traffic

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AC 90-66A 8/26/93

pattern n the oppositewind condition. (See examplesin Appendix 2, Glider Operations).(3) Typically, glider traffic patterns have entrypoints (initial points) from 600 to 1,000 feet AGL.C. Ultralight Vehicles.(1) In accordancewith FAR Part 103, ultralightvehicles are required to yield the right-of-wayto all aircraft.(2) Ultralight vehicles should fly the rectangularpattern as described n Appendix 2. Pattern altitudeshould be 500 feet below and inside the standardpattern altitude established for the airport. Anultralight pa ttern with its own dedicated landingarea will typically have a lower traffic patternparallel to the standard pattern with turns in theoppositedirection.(3) All pilots should be aware that ultralightswill fly s ignificantly slower thanairplabes. n addition,ultralights may also exhibit very steep takeoff andapproach angles. Turns may be executed near theend of the runway in order to clear the areaexpediently.d. Lighter Than Air Aircraft.(1) A balloon has the right-of-way over anyother category of aircraft and does not followa standard raffic pattern.(2) Due to limited maneuverability, airshipsdo not normally fly a standard traffic pattern.However, if a standard traffic pattern is flown,it will be at an airspeedbelow most other aircraft.

e. ParachuteOperations.(1) All activities are normally conducted undera NOTAM noting the location, altitudes, and timeor dura tion of jump operations.The Airport/FacilityDirectory lists airports where permanentdrop zonesare ocated.

(2) Jumpers normally exit the aircraft eitherabove, or well upwind of, the airport and ataltitudeswell above raffic patternaltitude. Parachutesare normally deployed between 2,000 feet and5,000 feet AGL and can be expected to be below3,000 feet AGL within 2 miles of the airport.(3) Pilots of jump aircraft are required byPart 105 to establish wo-way- radio communicationswith the air traffic control facility or Flight ServiceStation which has jurisdiction over the affectedairspace prior to jump operations for the purposeof receiving information in the aircraft about knownair traffic in the vicinity. In addition, when jumpaircraft are operating at or in the vicinity ofan airport, pilots are also encouraged to provideadvisory information on the CTAF, i.e., Chambers-burg traffic, jumpers away over Chambersburg.

(4) When a drop zone has been establishedon an airport, parachutists are expected to landwithin the drop zone. At airports that have notestablished drop zones, parachutists should avoidlanding0on runways, taxiways, aprons, and theirassociated afety areas.Pilots and parachutists houldboth be aware of the limited flight performanceof parachutesandconflicts between(5) Appendixby parachutists.

take steps to avoid any potentialaircraft and parachute operations.3 diagrams operations conducted

Harold W. BeckerActing Director, Air TrafficRules and Procedures Service

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8/2@/SZS AC SO-MAAPPENDIX I

SINGLE RUNWAY AIRPORT OPERATIONS8 84PPLICATION OF TRAFFIC3 . :: e

PATTERN INDICATORS

ST

IAS E4RAIGHT-IN APPROACH

PARALLEL RUNWAYS

# - :), ,), .a r LANDING RUNWAY + TRAFFIC PATTERP(OR LANDING STRIP) IN

A IA .WAAAId ma .a

1 INDICATORS - d - WINDCONE

LEGEND:STANDARD LEFT-HAND- - - - - - - - ~TRAFFIC PAlTERN (DEPICTED)

LANDINGDIRECTIONINDICATOR

-ah&4 RUNWAY k-1ASTRAIGHT-IN APPROACHIT

IECEND:STANDARD RIGHTMANDTRAFFIC PATfERN (DEPICTED)

KEY01 Enter pattern in level flight, abeam the midpoint ofthe runway, at pattern altitude. (1000 AGL isrecommended pattern altitude unless establishedotherwise).0 Maintain pattern altitude until abeam approachend of ihe landing runway, or downwind leg.0 complete turn to final at least l/4 mile from therunway.0 Continue straight ahead until beyond departureend of runway.

0 If *remaining in the traffic pattern, commence turnto ctosswind leg beyond the departure end of therunway, within 300 feet of pattern altitude.0 If departing the traffic pattern, continue straightout, or exit with a 45* left turn beyond the depar-ture end of the runway, after reaching patternaltitude.0 Do .not overshoot final o r continue on a trackwhich wi ll penetrate the final approach of theparallel runway.0 Do not continue on a track wh ich wi ll penetratethe departure path of the parallel runway.


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8/M/93 AC 9046AAPPENDIX 2

ULTRALIGHT OPERATIONS

DOWNWIND -ULTRALIGHTOPERATINGAREA

FlNAt -ULTRALIGHTSEPARATEOPERATING AREA

GLIDER OPERATIONSGLIDER PATTERN AND POWER PATTERNSAME SIDE OF RUNWA YGLIDER PATTERN INSIDE TRAFF IC CUDERPAlTERN FOR ENGINE-DRIVEN PATTERNE NTRYA IRCRA FT (600 1,ow ACl)

I--.

+600-1,OO~~G~ -5, \, EXITTOWS TO 2,ow - 3,ooo~GLIDER AGL UPWIND

PATTERNENTRY

P O W E RE D RUNW A Y

GLIDER PATTERN AND POWER PA7TERNOPPOSKE SIDE OF RUNWA YGLIDER PATTERN IS SEPARATEFRO M P O W E RE D RUNW A Y E NTRY600 - 1,000

I

AG L

TOWS TO2,000 - 3,000 FT. AGLUP W IND

PAGE I (AND 2)


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8/26/93 AC SO-66AAPPmDix 3

SIDE VIEW ~~-~PARACHUTE OPERATIONS

I< 2 MILESI I 1 MILE - I I

WINDOW RUNWAY 750

TOP VIEW

NOTE: THIS DEPICTS AN AWHERE NO DROP ZONE HAESTABLISHED.JRPORTS BEEN

b U.S. GOVERNMENT PRINTING OFFICE : 1997 - 516 - 623 / 83535

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