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68-724: If the weather is less than VMC, pilots are required to use instrument flight rules , and operation of the aircraft will be primarily through referencing the instruments rather than visual reference. In a control zone , a VFR flight may obtain a clearance from air traffic control to operate as Special VFR . VFR requires a pilot to be able to see outside the cockpit to control the aircraft's altitude, navigate, and avoid obstacles and other aircraft. Governing agencies establish specific requirements for VFR flight, including minimum visibility, and distance from clouds, to ensure that aircraft operating under VFR are visible from enough distance to ensure safety. Under visual meteorological conditions ,

136-503: A standard terminal arrival route (STAR), describing common routes to fly to arrive at an initial approach fix (IAF) from which an instrument approach commences. An instrument approach terminates either by the pilot acquiring sufficient visual reference to proceed to the runway, or with a missed approach because the required visual reference is not seen in time. To fly under IFR, a pilot must have an instrument rating and must be current (meet recency of experience requirements). In

204-486: A transponder to help Air Traffic Control identify the aircraft on radar in order that ATC can provide separation to IFR aircraft. Meteorological conditions that meet the minimum requirements for VFR flight are termed visual meteorological conditions (VMC). If they are not met, the conditions are considered instrument meteorological conditions (IMC), and a flight may only operate under IFR. IFR operations have specific training requirements and certification required of

272-627: A congested area (town, settlement, etc.) it must fly high enough so that in the case of an engine failure, it is able to land clear safely AND it must not fly less than 300 m (1000 ft) above the highest fixed object within 600 m of the aircraft. Member states are allowed to modify the low flying rule to suit their jurisdiction, for instance in the UK, the "500 ft Rule" allows pilots to fly below 500 ft as long as they are no closer than 500 ft to any person, vessel, vehicle, building or structure. The rules for flying near congested areas are

340-566: A distance from clouds of 500 feet below, 1,000 feet above, and 2,000 feet horizontally. Flight conditions reported as equal to or greater than these VFR minimums are referred to as visual meteorological conditions (VMC). Any aircraft operating under VFR must have the required equipment on board, as described in FAR Part 91.205 (which includes some instruments necessary for IFR flight). VFR pilots may use cockpit instruments as secondary aids to navigation and orientation, but are not required to;

408-569: A factor in deciding which type of flight plan to file, weather conditions themselves do not affect one's filed flight plan. For example, an IFR flight that encounters visual meteorological conditions (VMC) en route does not automatically change to a VFR flight, and the flight must still follow all IFR procedures regardless of weather conditions. In the US, weather conditions are forecast broadly as VFR, MVFR ( marginal visual flight rules ), IFR, or LIFR (low instrument flight rules). The main purpose of IFR

476-718: A higher altitude. Class B is used a lot as well. Anywhere in the Netherlands, Class A airspace ends at FL195 (19,500 ft; 5,950 m) and changes into Class C. Most of the CTRs are class D, some of them are class C. Class F is the only class that cannot be found in the Dutch airspace. In New Zealand , Classes B, E and F are not used at all. Class A is used in Oceanic airspace above FL245 (24,500 ft; 7,450 m) whereas Classes C and D are used in domestic airspace as part of

544-546: A last layer of defense if a sequence of errors or omissions causes a dangerous situation. Because IFR flights often take place without visual reference to the ground, a means of navigation other than looking outside the window is required. A number of navigational aids are available to pilots, including ground-based systems such as DME / VORs and NDBs as well as the satellite-based GPS/GNSS system. Air traffic control may assist in navigation by assigning pilots specific headings ("radar vectors"). The majority of IFR navigation

612-425: A low coastal overcast forces instrument approaches , while the rest of the state is still under visual flight rules. For pilots without an instrument rating who cannot legally fly by instrument flight rules, the restrictions of VMC minima can be troublesome in locations where weather conditions can change suddenly and unexpectedly or when weather events are highly localized. For instance, a small cloud forming over

680-448: A much wider latitude in determining how they get there. When operation of an aircraft under VFR is not safe, because the visual cues outside the aircraft are obscured by weather, instrument flight rules must be used instead. IFR permits an aircraft to operate in instrument meteorological conditions (IMC), which is essentially any weather condition less than VMC but in which aircraft can still operate safely. Use of instrument flight rules

748-428: A pilot at night may not be able to see and avoid obstacles. The VFR pilot is required to "see and avoid" obstacles and other aircraft. Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control (ATC). Depending on the category of airspace in which the flight is being conducted, VFR aircraft may be required to have

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816-506: A sweep-second pointer or digital equivalent, attitude indicator , radios and suitable avionics for the route to be flown, alternator or generator , gyroscopic rate-of-turn indicator that is either a turn coordinator or the turn and bank indicator . From 1999 single-engine helicopters could not be FAA-certified for IFR. Recently, however, Bell and Leonardo have certified the single engine helicopters for instrument flight rules. Airspace class The world's navigable airspace

884-573: Is also required when flying in "Class A" airspace regardless of weather conditions. Class A airspace extends from 18,000 feet above mean sea level to flight level 600 (60,000 feet pressure altitude ) above the contiguous 48 United States and overlying the waters within 12 miles thereof. Flight in Class A airspace requires pilots and aircraft to be instrument equipped and rated and to be operating under instrument flight rules (IFR). In many countries commercial airliners and their pilots must operate under IFR as

952-478: Is conducted in visual meteorological conditions (VMC). Anytime a flight is operating in VMC and in a volume of airspace in which VFR traffic can operate, the crew is responsible for seeing and avoiding VFR traffic; however, because the flight is conducted under instrument flight rules, ATC still provides separation services from other IFR traffic, and can in many cases also advise the crew of the location of VFR traffic near

1020-835: Is divided into lower airspace below FL245 (24,500 ft; 7,450 m) and upper airspace above FL245 (24,500 ft; 7,450 m) . In Iraq , the Flight Information Regions (FIR) is known as Baghdad FIR. It is classified into Class A, D, E and G airspace. Class B, C and F airspace are not used in the Baghdad FIR. Air traffic services are provided in all controlled airspace, by the controlling ATC Unit, based on an ATS Surveillance System (supplemented by procedural non-ATS Surveillance System procedures) or MRU where authorized based on Procedural (non- ATC Surveillance System) procedures and supplemented by ATC Surveillance System where possible. In Ireland , airspace

1088-520: Is divided into classes A, C and G only. Classes A, C, D, G are used in Kenyan airspace, alongside unclassified military operation areas which are defined in Restricted Areas and Prohibited Areas , and are controlled by military air traffic control units. In Lithuania , Classes A and B are generally not used at all. Classes C and D are used in the following areas of controlled airspace of

1156-615: Is divided into three-dimensional segments, each of which is assigned to a specific class. Most nations adhere to the classification specified by the International Civil Aviation Organization (ICAO) and described below, though they might use only some of the classes defined below, and significantly alter the exact rules and requirements. Similarly, individual nations may also designate special use airspace (SUA) with further rules for reasons of national security or safety. On March 12, 1990, ICAO adopted

1224-456: Is given by ground- and satellite-based systems, while radar vectors are usually reserved by ATC for sequencing aircraft for a busy approach or transitioning aircraft from takeoff to cruise, among other things. Specific procedures allow IFR aircraft to transition safely through every stage of flight. These procedures specify how an IFR pilot should respond, even in the event of a complete radio failure, and loss of communications with ATC, including

1292-655: Is highly advantageous. An example of airspace where CVFR is common would be Canadian Class B airspace. The CVFR concept is used in Canada and certain European countries, but not in the U.S., where the Private Pilot certificate itself authorizes the pilot to accept clearances under VFR. In Israel, for example, VFR does not exist. All visual flights must be performed under CVFR rules. Instrument flight rules In aviation , instrument flight rules ( IFR )

1360-422: Is known as operating the aircraft under visual flight rules (VFR), and is the most common mode of operation for small aircraft. However, it is safe to fly VFR only when these outside references can be clearly seen from a sufficient distance. When flying through or above clouds, or in fog, rain, dust or similar low-level weather conditions, these references can be obscured. Thus, cloud ceiling and flight visibility are

1428-480: Is not a separate classification from the ATC-based classes; each piece of SUA is contained in one or more zones of letter-classed airspace. SUAs range in restrictiveness, from areas where flight is always prohibited except to authorized aircraft, to areas that are not charted but are used by military for potentially hazardous operations (in this case, the onus is on the military personnel to avoid conflict). Refer to

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1496-510: Is not available. Aircraft position reports are sent as voice radio transmissions. In the United States, a flight operating under IFR is required to provide position reports unless ATC advises a pilot that the plane is in radar contact. The pilot must resume position reports after ATC advises that radar contact has been lost, or that radar services are terminated. IFR flights in controlled airspace require an ATC clearance for each part of

1564-484: Is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR). The U.S. Federal Aviation Administration 's (FAA) Instrument Flying Handbook defines IFR as: "Rules and regulations established by the FAA to govern flight under conditions in which flight by outside visual reference is not safe. IFR flight depends upon flying by reference to instruments in

1632-483: Is practical (often known under ICAO as an advisory service in class G airspace), but separation is not mandated nor widely provided. Despite the protection offered by flight in controlled airspace under IFR, the ultimate responsibility for the safety of the aircraft rests with the pilot in command , who can refuse clearances. It is essential to differentiate between flight plan type (VFR or IFR) and weather conditions (VMC or IMC). While current and forecast weather may be

1700-509: Is provided by ATC to all aircraft. In these situations the VFR pilot only needs to see where his/her own aircraft is going, so visibility requirements are less stringent, and there is no designated minimum distance from clouds. Similar considerations determine whether a VFR aircraft must use a two-way radio and/or a transponder . Each national authority designates areas of special use airspace (SUA), primarily for reasons of national security. This

1768-501: Is the safe operation of aircraft in instrument meteorological conditions (IMC). The weather is considered to be MVFR or IMC when it does not meet the minimum requirements for visual meteorological conditions (VMC). To operate safely in IMC ("actual instrument conditions"), a pilot controls the aircraft relying on flight instruments and ATC provides separation. It is important not to confuse IFR with IMC. A significant amount of IFR flying

1836-532: The flight deck , and navigation is accomplished by reference to electronic signals." It is also a term used by pilots and controllers to indicate the type of flight plan an aircraft is flying, such as an IFR or VFR flight plan. It is possible and fairly straightforward, in relatively clear weather conditions, to fly an aircraft solely by reference to outside visual cues, such as the horizon to maintain orientation, nearby buildings and terrain features for navigation, and other aircraft to maintain separation. This

1904-582: The FAR 91 minimums, so long as their operation is conducted without hazard to persons or property on the surface. In all EU member states, the Standardised European Rules of the Air apply: these set out a minimum altitude of 150 m (500 ft) above any obstacle within a radius of 150 m (500 ft), except with permission, or when taking off or landing. If an aircraft is flying over

1972-460: The ICAO definitions to derive additional rules for Visual Flight Rules (VFR) cloud clearance, visibility, and equipment requirements. For example, consider Class E airspace. It is possible that an aircraft operating under VFR is not in communication with ATC, so it is imperative that its pilot be able to see and avoid other aircraft (and vice versa). That includes IFR flights emerging from a cloud, so

2040-576: The ICAO standardisation. Australia has adopted a civil airspace system based on the United States National Airspace System (NAS): Australia used to have a non-standard class of airspace for use at the capital city general aviation airports, called a General Aviation Airport Procedures Zone (GAAP Zone). A control tower provided procedural clearances for all aircraft inside the zone. Additionally, any aircraft operating within 5 nmi (9.3 km; 5.8 mi) of

2108-566: The New Zealand FIR . In Norway , airspace is divided into classes A, C, D and G. Russia adopted a modified version of ICAO airspace classification on November 1, 2010. The division into classes for the airspace of the Russian Federation was introduced for the first time in the history of Russia. The airspace above the territory of the Russian Federation is divided as follows: Airspace controlled by Russia outside

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2176-605: The Republic of Lithuania: Classes A, C and G are used in Mauritius . In the Netherlands , a relatively large part of the country is Class A airspace. Near Amsterdam , the capital of the Netherlands, the airspace is almost completely built up with class A. It starts at 1,500 ft (460 m) MSL, and ends at FL195 (19,500 ft; 5,950 m) . Further away from Amsterdam and its airport Schiphol , Class A starts at

2244-418: The UK has a couple of special classes of airspace that do not fall within the ICAO classes: The U.S. adopted a slightly modified version of the ICAO system on September 16, 1993, when regions of airspace designated according to older classifications were converted entirely. The exceptions are some terminal radar service areas (TRSA), which have special rules and still exist in a few places. Authorities use

2312-593: The US in September, 1993. Some key concepts are: Note: These are the ICAO definitions. Country-specific adaptations (such as "two-way communications" instead of "clearance" for Class C in the US) are discussed in the sections below. Special Airspace: these may limit pilot operation in certain areas. These consist of Prohibited areas, Restricted areas, Warning Areas, MOAs (military operation areas), Alert areas and Controlled firing areas (CFAs), all of which can be found on

2380-534: The United Kingdom, this is known as a "Traffic Service". In other countries, it is known as "Flight Information Service". In the United States and Canada, any certified pilot who meets specific recency of experience criteria may operate an airworthy aircraft under VFR. In the US, there are specific VFR cruising altitudes, based on the aircraft's course, to assist pilots in separating their aircraft while operating under visual flight above 3,000 ft above

2448-421: The United States, Canada, and Australia, a pilot operating under VFR outside Class B, C, D airspace can request "flight following" from ATC, to receive continuous verbal updates on air traffic. This service is provided by ATC if workload permits, but it is an advisory service only. The responsibility for maintaining separation with other aircraft and proper navigation still remains with the pilot in command (PIC). In

2516-468: The United States, class A airspace is measured using flight levels , and begins at FL180 up to FL600, which is about 18,000 to 60,000 feet as measured using an altimeter at standard pressure (29.92 inHg, 1013 mbar). An exception to IFR-only flying in this airspace is the occasional allowance of sailplanes within designated wave windows which may be opened by air traffic control when high altitude flights are to be conducted into mountain lee waves . In

2584-407: The United States, to file and fly under IFR, a pilot must be instrument-rated and, within the preceding six months, have flown six instrument approaches , as well as holding procedures and course interception and tracking with navaids . Flight under IFR beyond six months after meeting these requirements is not permitted; however, currency may be reestablished within the next six months by completing

2652-442: The VFR flight must keep a designated distance from the edges of clouds above, below, and laterally, and must maintain at least a designated visibility, to give the two aircraft time to observe and avoid each other. The low-level speed limit of 250 knots (460 km/h; 290 mph) does not apply above 10,000 feet (3,000 m), so the visibility requirements are higher. On the other hand, in Class B and Class C airspaces, separation

2720-407: The aircraft operates in VMC using a hybrid of VFR and IFR rules, and "VFR over the top", a VFR procedure in which the aircraft takes off and lands in VMC but flies above an intervening area of IMC. Also possible in many countries is "Special VFR" flight, where an aircraft is explicitly granted permission to operate VFR within the controlled airspace of an airport in conditions technically less than VMC;

2788-424: The aircraft to take off or to land; these vary according to the kind of operation, the type of navigation aids available, the location and height of terrain and obstructions in the vicinity of the airport, equipment on the aircraft, and the qualifications of the crew. For example, Reno-Tahoe International Airport (KRNO) in a mountainous region has significantly different instrument approaches for aircraft landing on

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2856-403: The airport at less than 1000 feet technically requires the airport to allow only IFR flights using instrument approaches/departures. A VFR flight intending to land there would normally be denied clearance, and would either have to divert to another field with VMC, or declare an emergency and override the denial of clearance, which can prompt an inquiry and possibly result in adverse consequences for

2924-416: The current airspace classification scheme. The classes are fundamentally defined in terms of flight rules and interactions between aircraft and air traffic control (ATC). Generally speaking, the ICAO airspaces allocate the responsibility for avoiding other aircraft, namely either to ATC (if separation is provided) or to the aircraft commander (if not). These airspace classifications were put into use in

2992-409: The expected aircraft course and altitude. Departures are described in an IFR clearance issued by ATC prior to takeoff. The departure clearance may contain an assigned heading, one or more waypoints, and an initial altitude to fly. The clearance can also specify a departure procedure (DP) or standard instrument departure (SID) that should be followed unless "NO DP" is specified in the notes section of

3060-571: The filed flight plan. En route flight is described by IFR charts showing navigation aids, fixes, and standard routes called airways . Aircraft with appropriate navigational equipment such as GPS, are also often cleared for a direct-to routing, where only the destination, or a few navigational waypoints are used to describe the route that the flight will follow. ATC will assign altitudes in its initial clearance or amendments thereto, and navigational charts indicate minimum safe altitudes for airways. The approach portion of an IFR flight may begin with

3128-442: The flight charts. Classes A–E are referred to as controlled airspace . Classes F and G are uncontrolled airspace . The table below provides an overview of the above classes, and the specifications for each. Each national aviation authority determines how it uses the ICAO classifications in its airspace design. In some countries, the rules are modified slightly to fit the airspace rules and air traffic services that existed before

3196-448: The flight path. Although dangerous and illegal, a certain amount of VFR flying is conducted in IMC. A scenario is a VFR pilot taking off in VMC conditions, but encountering deteriorating visibility while en route. Continued VFR flight into IMC can lead to spatial disorientation of the pilot which is the cause of a significant number of general aviation crashes. VFR flight into IMC is distinct from "VFR-on-top", an IFR procedure in which

3264-511: The flight. The distance by which an aircraft avoids obstacles or other aircraft is termed separation . The most important concept of IFR flying is that separation is maintained regardless of weather conditions. In controlled airspace , air traffic control (ATC) separates IFR aircraft from obstacles and other aircraft using a flight clearance based on route, time, distance, speed, and altitude. ATC monitors IFR flights on radar , or through aircraft position reports in areas where radar coverage

3332-451: The flight. A clearance always specifies a clearance limit , which is the farthest the aircraft can fly without a new clearance. In addition, a clearance typically provides a heading or route to follow, altitude, and communication parameters, such as frequencies and transponder codes. In uncontrolled airspace, ATC clearances are unavailable. In some states a form of separation is provided to certain aircraft in uncontrolled airspace as far as

3400-405: The instrument panel. A safety pilot's primary duty is to observe and avoid other traffic. In the UK, an IR (UK restricted) - formerly the "IMC rating" - which permits flight under IFR in airspace classes B to G in instrument meteorological conditions, a non-instrument-rated pilot can also elect to fly under IFR in visual meteorological conditions outside controlled airspace. Compared to the rest of

3468-428: The majority of flights enter Class A airspace. Procedures and training are significantly more complex compared to VFR instruction, as a pilot must demonstrate competency in conducting an entire cross-country flight solely by reference to instruments. Instrument pilots must carefully evaluate weather, create a detailed flight plan based around specific instrument departure, en route, and arrival procedures, and dispatch

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3536-448: The minimum visual range, distance from clouds, or cloud clearance requirements to be maintained above ground vary by jurisdiction, and may also vary according to the airspace in which the aircraft is operating. In some countries, VFR flight is permitted at night, and is known as night VFR . This is generally permitted only under more restrictive conditions, such as maintaining minimum safe altitudes , and may require additional training as

3604-435: The most important variables for safe operations during all phases of flight. The minimum weather conditions for ceiling and visibility for VFR flights are defined in FAR Part 91.155, and vary depending on the type of airspace in which the aircraft is operating, and on whether the flight is conducted during daytime or nighttime. However, typical daytime VFR minimums for most airspace is 3 statute miles of flight visibility and

3672-450: The pilot asserts they have the necessary visibility to fly despite the weather, must stay in contact with ATC, and cannot leave controlled airspace while still below VMC minimums. During flight under IFR, there are no visibility requirements, so flying through clouds (or other conditions where there is zero visibility outside the aircraft) is legal and safe. However, there are still minimum weather conditions that must be present in order for

3740-425: The pilot must be flying in VMC by the time they leave the surface footprint of the controlled airspace (otherwise they would be flying VFR in IMC which is illegal). VFR flight is not allowed in airspace known as class A , regardless of the meteorological conditions except after failure of two way radio communications or during declared emergencies such as VFR traffic attempting to avoid severe weather formations. In

3808-496: The pilot, and increased equipment requirements for the aircraft. Additionally, an IFR flight plan must usually be filed in advance. For efficiency of operations, some ATC operations will routinely provide "pop-up" IFR clearances for aircraft operating VFR, but that are arriving at an airport that does not meet VMC requirements. For example, in the United States, California's Oakland ( KOAK ), Monterey ( KMRY ) and Santa Ana ( KSNA ) airports routinely grant temporary IFR clearance when

3876-412: The pilot. To avoid these scenarios, VFR flights intending to land at or take off from an airport experiencing localized conditions marginally below VMC minima may request Special VFR clearance from the tower. SVFR flight is only allowed while within the portion of an airport's controlled airspace (class B, C, or D) that extends to the surface, and it must be explicitly requested by the pilot and granted by

3944-496: The previous Class D procedures were changed. The new Class D procedures are similar to the FAA Class D procedures. VFR aircraft are no longer required to enter the airspace via set inbound/outbound points, however can be directed there by ATC. VFR and IFR aircraft now require taxi clearance in the "manoeuvring area" of the aerodrome, but can still taxi within set apron areas without a clearance. IFR aircraft now receive slot times and

4012-437: The requirements above. Beyond the twelfth month, examination ("instrument proficiency check") by an instructor is required. Practicing instrument approaches can be done either in the instrument meteorological conditions or in visual meteorological conditions – in the latter case, a safety pilot is required so that the pilot practicing instrument approaches can wear a view-limiting device which restricts his field of view to

4080-596: The same in the UK as the rest of the EU CVFR flight is used in locations where aviation authorities have determined that VFR flight should be allowed, but that ATC separation and minimal guidance are necessary. In this respect, CVFR is similar to instrument flight rules (IFR) in that ATC will give pilots headings and altitudes at which to fly, and will provide separation and conflict resolution. However, pilots and aircraft do not need to be IFR rated to fly in CVFR areas, which

4148-615: The same runway surface, but from opposite directions. Aircraft approaching from the north must make visual contact with the airport at a higher altitude than when approaching from the south because of rapidly rising terrain south of the airport. This higher altitude allows a flight crew to clear the obstacle if a landing is aborted. In general, each specific instrument approach specifies the minimum weather conditions to permit landing. Although large airliners, and increasingly, smaller aircraft, carry their own terrain awareness and warning system (TAWS), these are primarily backup systems providing

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4216-641: The surface (AGL) but below 18,000 ft Mean Sea Level (MSL). Unofficially, most pilots use these rules at all levels of cruise flight. FAR 91.159 states that any aircraft: In the US, FAR Part 91 (specifically 91.119) of the Federal Aviation Regulations controls the minimum safe altitudes by which aircraft can be operated in the National Airspace System . Other aircraft, such as helicopters, powered parachutes, and weight-shift-control aircraft, are not required to meet

4284-657: The territory of Russia has different division into classes and includes redefined Class A and Class G, but no class C airspace. Specific boundaries of airspaces are determined by the Order of the Ministry of Transport of the Russian Federation #199 of September 15, 2010. In Sweden , airspace is divided into airspace class C and G only with a small E class area stretching over the Danish border into Swedish airspace. Some airways and CTAs may have sections of Class C. In addition

4352-428: The tower (some airports, primarily large Class B facilities, do not allow SVFR operation in their airspace at all). Visibility on the ground must still be greater than one statute mile, but most other VMC minima such as ceiling are waived. The pilot is required to maintain VFR separation distances from other aircraft and, by requesting SVFR, asserts that they can do so despite the marginal conditions. For departing flights,

4420-453: The view outside of the aircraft is the primary source for keeping the aircraft straight and level (orientation), flying to the intended destination (navigation) , and avoiding obstacles and hazards (separation). Visual flight rules are generally simpler than instrument flight rules, and require significantly less training and practice. VFR provides a great degree of freedom, allowing pilots to go where they want, when they want, and allows them

4488-563: The visibility requirements of Special VFR are reduced from 3000m visibility to 1600m. There are seven airspace classes in use in Canada (letters A through G), but the letters do not always correspond with ICAO definitions. In Estonia , airspace is divided into only classes C, D and G. In France , Classes B and F are not used at all. Airspace is divided into lower airspace below FL195 (19,500 ft; 5,950 m) and upper airspace above FL195 (19,500 ft; 5,950 m) . In Germany , Classes A, B, and F are not used at all. Airspace

4556-582: The world, the UK's flight crew licensing regime is somewhat unusual in its licensing for meteorological conditions and airspace, rather than flight rules. The aircraft must be equipped and type-certified for instrument flight, and the related navigational equipment must have been inspected or tested within a specific period of time prior to the instrument flight. In the United States, instruments required for IFR flight in addition to those that are required for VFR flight are: heading indicator , sensitive altimeter adjustable for barometric pressure , clock with

4624-530: The zone must obtain a clearance. VFR aircraft arrive and depart using standard arrival and departure routes, while instrument arrival and departure procedures are published for IFR operations. During visual meteorological conditions (VMC), IFR aircraft are not provided with full IFR services. During instrument meteorological conditions (IMC), or marginal VMC, VFR operations are restricted in order to facilitate full IFR service for IFR aircraft. In June 2010, all GAAP aerodromes were changed to Class D aerodromes, and

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