By Roger Curtiss
To explain operations and procedures for an aircraft operating to and from an airport while in the Visual Flight Regulations (VFR) environment.
Explanation of aircraft operation under Visual Flight Rules in the departure and arrival phases of flight.
Basic Traffic Pattern procedures
VFR operations are the basic procedures used by all pilots. It is expected that pilots will operate utilizing VFR procedures until they have sufficient knowledge and expertise in the use of instruments only techniques. VFR refers to a minimum weather condition that must be present in order to operate under visual conditions. In the United States, those weather minima vary depending on the type of airspace involved and pertain to visibility requirements and distance to be kept away from clouds:
Class........Flight Visibility.....Distance from Clouds
Class B.....3 statute miles.....clear of clouds
Class C.....3 statute miles.....500' below/1000' above/2000' laterally
Class D.....3 statute miles.....500' below/1000' above/2000' laterally
Class E.....less than 10,000' MSL
..............3 statute miles.....500' below/1000' above/2000' laterally
Class E.....at or above 10,000' MSL
..............5 statute miles.....1000' below/1000' above/1 statute mile laterally
Class G.....1200' or less above the surface (regardless of MSL altitude)
.....Day....1 statute mile.......clear of clouds
.....Night...3 statute miles.....500' below/1000' above/2000' laterally
Class G.....more than 1200' above the surface but less than 10,000' MSL
.....Day....1 statute mile.......500' below/1000' above/2000' laterally
.....Night...3 statute miles.....500' below/1000' above/2000' laterally
Class G.....more than 1200' above the surface and at or above 10,000' MSL
...............5 statute miles.....1000' below/1000' above/1 statute mile laterally
The only exceptions to these requirements are for operations conducted in Class G airspace below 1200' above the surface:
Helicopters may be operated clear of clouds at a speed that allows the pilot adequate opportunity to see any air traffic or obstruction in time to avoid a collision.
Airplanes when the visibility is less than 3 statute miles but at least 1 statute mile during night hours, an airplane may be operated clear of clouds if operated in an airport traffic pattern within one-half mile of the runway.
In addition, with a limited exception, VFR aircraft operation within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for an airport is prohibited when the ceiling is less than 1000' and takeoff or landing or entering a traffic pattern of an airport in those airspace boundaries is prohibited unless ground visibility at that airport is at least 3 statute miles or if no ground visibility report is available, flight visibility is at least 3 statute miles.
Class C - 1500M laterally, 1000ft vertically, 5000M Vis (below 10k, above 10k the vis requirement increases to 8000M)
Class D - 1500M laterally, 1000ft vertically, 5000M Vis
Class E - 1500M laterally, 1000ft vertically, 5000M Vis (below 10k, above 10k the vis requirement increases to 8000M)
GAAP Control Zone (General Aviation Aerodrome Procedures) - Clear of Cloud, 5000M Vis
Class G - 1500M laterally, 1000ft vertically, 5000M Vis (below 10k, above 10k the vis requirement increases to 8000M) - Excepting that below 3000ft AMSL or 1000ft AGL (whichever is the higher) you may operate clear of cloud with a vis of 5000M.
For Helos in Class G you can operate below 700ft with a vis minima of 800M and clear of cloud provided the operation is: - By Day, - At a speed that enables the PIC to avoid any obstructions or traffic.
The limited exception is for operation to or from an airport in controlled airspace and is referred to as Special VFR. These require a pilot to remain clear of clouds in flight and takeoff or landing visibility minimum of 1 statute mile.
United Kingdom Procedures
CLASS B - ABOVE FL100=Clear of Cloud & 8km Vis, BELOW FL100=Clear of Cloud and 5km Vis
CLASS C, D or E - ABOVE FL100=1500m Horizontally and 1000ft Vertically from cloud & 8km Vis, BELOW FL100=1500m Horizontally and 1000ft Vertically from cloud & 5km Vis
CLASS F or G - ABOVE FL100=1500m Horizontally and 1000ft Vertically from cloud & 8km Vis, BELOW FL100=1500m Horizontally and 1000ft Vertically from cloud & 5km Vis. (If an aircraft is flying below 3000ft and either: a) flying at more than 140 kt: must be clear of cloud and in sight of the surface with a visibility of 5km. b) flying at 140 kt or less: clear of cloud and in sight of the surface with a visibility of 1500m. c) helicopters flying at a reasonable speed for the actual visibility: Clear of Cloud and in Sight of the Surface.
VFR flights are not be authorized within the London and Scottish UIRs above FL 290
In order for ATC to issue Special VFR clearance to any fixed-wing aircraft intending to depart from an aerodrome within a Control Zone the visibility must be greater than 1800 m and the cloud ceiling must be more than 600 ft.
The interpretation of "cloud ceiling" refers to a broken or overcast layer of clouds. It is the responsibility of the pilot to determine if the weather conditions will permit legal operations. The pilot should also bear in mind that the legal minimum does not take into consideration a pilot's skill level or degree of experience. Therefore, each pilot's comfort level may be different and some may choose not to fly even though the weather is "legal".
Weather minimums exist because a basic tenet of VFR flying is the see and avoid method of maintaining separation from other aircraft. It is expected that pilots will maintain a constant vigil for other aircraft that may be operating in proximity to their aircraft and take the necessary actions to avoid a potential collision. There are some procedures built into the system to assist pilots in maintaining situational awareness and to predict the likely actions of other aircraft. However, no system is foolproof and the final responsibility for maintaining separation falls to the pilot-in-command of each aircraft.
Departure from and arrival to airports while rather straightforward will have some differences depending on whether the airport is controlled or uncontrolled.
Simply put; this means an air traffic controller is online and providing ATC service to an airport. When a controller is present ATC will provide assistance to pilots and manage the sequencing of aircraft using the runway and taxiway areas. Pilots are expected to comply with ATC instructions unless doing so would pose an undue risk of harm to the aircraft or safety of flight.
In the online flying world this condition can occur at any airport at any time regardless of the size of the airport and/or the volume of traffic. Such is the nature of our virtual world that the presence of controllers cannot be guaranteed due to staffing issues and even technical failures that may prevent controllers from logging in. At an uncontrolled airport, the pilots are fully responsible for maintaining separation and safe operation. Therefore, pilots should be proficient in the procedures and etiquette for operating in a non-ATC situation. To promote safety and organization the two main components of uncontrolled airport operations are:
- Maintaining a watch for other aircraft
Maintaining a watch simply means that pilots should not confine their view to the narrow, straight ahead view window. There may be aircraft to the sides or above and below that are a factor. Also, the dynamic nature of the movement of aircraft and even wind effect means that an area that was clear of airplanes one minute ago may now be occupied. Pilots should utilize the different view windows offered by the simulation and check each one as if they are turning their heads and looking out each window. It is implied in the "see and avoid" concept that each pilot will be maintaining a constant vigil while operating an aircraft.
The communication component can be met by tuning the COM radio to 122.8 which is the UNICOM frequency (in the United States). This channel is used for pilots to announce traffic movements "in the blind", meaning that pilots are not expected to reply to UNICOM broadcasts, the broadcasts are intended to be informative and because of its use over a wide geographical area there are certain conventions that should be followed:
UNICOM transmissions should be in text. SB3 does not offer a voice option for this channel and it can be difficult regardless to determine if another pilot is voice enabled while everyone has text capability.
UNICOM messages should be as short as possible "arriving runway 12", "entering downwind 9L", "clear of 9L", etc
UNICOM transmissions should follow a specific format:
/location/message/location example: KMIA traffic departing 9R KMIA
This leaves no doubt as to what airport is involved
The limitation of a UNICOM transmission is that there is no assurance that other pilots in the vicinity are tuned to UNICOM or paying attention to it. There is no easy remedy for this other than for pilots to maintain their vigilance and be pessimistic; assuming that the transmissions have not been received. Broadcasting one's intentions on UNICOM is not the same as having clearance or authorization to conduct a maneuver or activity and does not relieve a pilot of the responsibility to see and avoid other aircraft.
- Weather minimums
- See and Avoid concept
Set up a flight with the weather at VFR minimums and incrementally increase the visibility in order to recognize the limitations and determine your own comfort zone
Practice creating a UNICOM text message while in-flight to ensure your ability to simultaneously do both