9.1.2 Basic Radar Service for VFR traffic
9.1.3 Visual Meteorological Conditions
9.1.6. ASRC and VRC Sector Files
9.1.7 ATC VFR Instructions and Phraseology
9.1.8 Special Visual Flight Rulest
9.1.10 Non Charts on Board (VATSIM)
9.1 VFR – Visual Flight Rules
As both navigation and phraseology is different than when dealing with IFR pilots we hope you will find this guide interesting.
The last few years have seen an ever increasing number of VFR scenery add-on packages and VFR flights are becoming more popular. As a controller you will sooner or later have one or more VFR aircraft in your area.
VFR contrary to popular belief does not mean a pilot can take of from where ever he wants and crisscross a FIR to a destination aerodrome.
Pilots flying under VFR assume responsibility for their separation from all other aircraft and are not assigned routes or altitudes by ATC. They fly on their own using a "see and be seen" separation criteria. In busier controlled airspace, VFR aircraft are required to have a transponder this amplifies the radar signal (as well broadcasting altitude level and a transponder code), and is used to allow controllers to warn IFR aircraft of any potential conflict. Governing agencies establish strict VFR "weather minima" for visibility, distance from clouds, and altitude to ensure that VFR pilots can be seen from a far enough distance.
In airspace ‘C’ ATC separates all aircrafts from each other (including VFR from VFR). ATC can assign VFR routings or altitudes (minimum or maximum or both) to aircrafts in airspace C and D
Whilst the VFR pilot does not “need” to rely on radar for navigation or separation the fact is that the VFR aircraft in VATSIM is tagged on radar at all times. A pilot following a Visual Flight still has to adhere to a number of rules, follow specific VFR routes and report at specific VFR reporting points.
9.1.2 Basic Radar Service to VFR Aircraft
VFR pilots can request, and ATC can elect to provide "VFR Advisory Services," if the controllers' workload permits. This is also referred to as "Flight following." Under this environment, the controllers will radar identify the VFR aircraft and provide traffic information and weather advisory services for the VFR pilot.
Controllers do not provide any instructions concerning direction of flight, altitude, or speed to the VFR pilot receiving advisory services, and they do not provide separation services. This is an optional service and may be discontinued by ATC or the pilot at any time. Other optional service provided can be:
- Safety alerts
- Traffic advisories
- Limited radar vectoring, when requested by the pilot and ATC workload is low.
- Sequencing at locations where procedures have been established for this purpose and/or when covered by a letter of agreement
9.1.3. Visual Meteorological Conditions
Needless to mention that the weather needs to meet minimum VMC at all times to allow a VFR flight from taking place.
No person may operate an aircraft under basic VFR when the flight visibility is less, or at a distance from clouds that is less, than that prescribed for the corresponding altitude and class of airspace. if they are not met then the flight must be flown under IFR
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|
Class B |
Class C, D, E |
|
Visibility |
At or above FL100: 8 km |
At or above FL100: 8 km |
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Clouds |
Clear of clouds |
Horizontal distance minimum 1500m |
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|
Class F & G |
|
|
|
Above 3000ft MSL or 1000ft AGL whichever is higher |
At or below 3000ft MSL or 1000ft AGL whichever is higher |
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Visibility |
5 km |
3 km |
|
Clouds |
Horizontal distance minimum: 1500m |
Clear of clouds and ground in sight |
9.1.4. VFR Waypoints
In real life operations VFR Waypoints exist, these ease navigation for VFR pilots, using GPS systems for additional information to that contained in their VFR charts. The primary reason they were introduced was to enhance navigation when aircraft operate around congested airspace requiring route restrictions or mandatory reporting points.
VFR Waypoints are assigned a discrete five-letter designator, which will be added to navigation databases. The waypoints will all begin with the letters "VP" and then have an additional three letters. The "VP" letters will provide immediate recognition that the waypoint is for VFR purposes only.
VFR Waypoints will also be used in conjunction with Visual Reporting Points. These points are used by air traffic control (ATC) for position reporting purposes. These VFR Waypoints will also be assigned a five-letter identifier. However, in communications with ATC, the reporting point will still be referred to by the full name and VFR Waypoints should be used as a tool to supplement current navigation procedures. Pilots are strongly encouraged to rely on aeronautical charts published specifically for visual navigation. If operating in a terminal area, pilots should take advantage of the charts available for that area.
Pilots must use the waypoints only when operating under VFR conditions. Anytime cloud clearance or flight visibility diminishes below minimums, VFR flight should be terminated immediately.
VFR Waypoints should not be used as a sole or primary means of visual navigation. Use of these waypoints, as one of many supplemental sources to navigation will increase proper situational awareness.
The five-letter identifier shall not be used in communications with ATC facilities. ATC will not be required to be familiar with VFR Waypoint's positions or identifiers. However, in communications with ATC, those waypoints used in conjunction with VFR reporting points shall be referred to by the Visual Reporting Point name.
To explain the concept we use as an example the VFR charts for EHBK (Maastricht Airport) in The Netherlands.
9.1.5. Reporting Points
To avoid VFR traffic from flying crisscross within a Control Zone which is also used for IFR traffic and to enable ATC to mix and match these various flights into and out from an aerodrome a VFR pilot has to follow standard VFR Arriving and Departing Routes which begin, end or are intersected by Reporting Points.
Usually these Reporting Points are distinctive natural or man-made landmarks, or buildings. The VFR Arrival and Departure Routes usually follow a road or a river. All aircraft flying under VFR conditions have to follow these routes with the exception of Police and Search and Rescue Helicopters.
The reporting points can be either compulsory reporting points or on request reporting points. A pilot has to report over the compulsory reporting point at all times except if ATC has issued an instruction invalidating this requirement. A pilot does not need to report over the on request reporting point, except if ATC has instructed to the contrary.
As you can see on the charts below the Compulsory Reporting Points are shown as a Solid Triangle whilst the on request reporting points are shown as an Non- filled-in Triangle, for example ROMEO is a Compulsory Reporting Point whilst HOTEL is an on request reporting point.
As you can see on the chart for Maastricht there are 3 Compulsory Reporting Points, BRAVO, MIKE and UNIFORM. Each of these points also designates the beginning or the end of the VFR departure or arrival routes.
The VFR routes are useable for VFR traffic regardless if arriving or departing and regardless of which runway is in use. If you look at the BRAVO route you will see that a pilot would have to report over BRAVO and proceed to the next compulsory reporting point which is GOLF via a non compulsory reporting point called SIERRA, or vice versa. This route clearly follows a river, in this case the Juliana Canal.
GOLF and ROMEO are the two exit or entry points into the Traffic Circuit which can only be accessed at the discretion of ATC. In practice if ATC is unable to provide a direct entry into the pattern then the VFR traffic would have been asked to circle at one of the four visual holding points, which as you can see are next to HOTEL, INDIA PAPA and SIERRA
9.1.6. Sector Files
The VFR routes and reporting points can either be added to the regular sector file as part of the SID/STAR section and Fixes section or a stand alone dedicated VFR sector file can be created.
9.1.7. ATC VFR instructions and phraseology
A VFR pilot usually calls Ground or Tower directly, in real life they should call APRON or DELIVERY for their start up approval, assuming the pilot has done his pre-flight check and has started his engine(s), let us follow a flight from Start up to Engine shut. Bear in mind that VFR traffic does not have to listen in on ATIS, therefore the initial taxi clearance shall include the QNH.
As we are using the chart for Maastricht as the example, let us assume that our VFR pilot is PH-2GY a PA31 and that all ATC positions belong to Maastricht,
Pilot: Maastricht Ground, PH-2GY, good afternoon
GND: PH-2GY Maastricht Ground, good afternoon
Pilot: PH-2GY, PA31, General Aviation Apron VFR to Rotterdam via MIKE, request taxi
GND: PH-2GY, taxi to holding position runway 21 via, W and W1, QNH 1017
Pilot: PH-2GY, taxiing to runway 03 via W and W1, QNH 1017
The Pilot in the above example clearly stated his intention to fly VFR to Rotterdam via MIKE. The pilot could also have stated VFR to Rotterdam, or VFR via MIKE all three are possible, but stating the destination as well as the VFR departure route is the most complete manner.
Pilot: PH-2GY, ready for departure
GND: PH-2GY, contact Tower on 135.450
Pilot: PH-2GY, contacting Tower on 135.450
Pilot: Maastricht Tower, PH-2GY, at W1, ready for departure
TWR: PH-2GY, Maastricht Tower, line-up runway 21
Pilot: PH-2GY, lining up runway 21
TWR: PH-2GY, leave control zone via GOLF right turn approved, wind 175 degrees 11 knots, cleared for takeoff runway 21
Pilot: PH-2GY, leaving control zone via GOLF, right turn approved, cleared for takeoff runway 21
The clearance tells the pilot that he can take off, enter the right hand traffic pattern and leave the control zone over GOLF a Compulsory Reporting Point from where he would continue following the MIKE departure route.
Pilot: PH-2GY position GOLF at 1500 feet for 2500 feet
TWR: PH-2GY roger, continue
Pilot: PH-2GY, position MIKE, at 2500 feet
TWR: PH-2GY approved to leave the frequency, bye bye
Pilot: PH-2GY, Good bye
At this point the pilot would leave the frequency but could ask for VFR advisory service in which case the pilot would normally be asked to switch frequency to a radar controller. Or the pilot would continue on his own route to Rotterdam.
Half way to Rotterdam however the pilot decides to turn around and return to Maastricht. The aircraft is approaching the aerodrome from the South and the pilot will need to report his intentions before arriving over the compulsory reporting point UNIFORM.
Pilot: Maastricht Tower, PH-2GY
TWR: PH-2GY, Maastricht Tower go ahead
Pilot: PH-2GY, PA13, VFR, 10 miles South of UNIFORM, 2500 ft, for landing
TWR: PH-2GY, enter control zone via UNIFORM, runway 03, QNH 1009
Pilot: PH-2GY, entering control zone via UNIFORM, runway 03, QNH 1009
The pilot now knows he can enter the Control Zone and approach the aerodrome via the UNIFORM arrival route, and will need to report over ROMEO next. However further ATC clearance is required before the pilot can enter the actual traffic circuit after ROMEO.
Pilot: PH-2GY, position UNIFORM, 2500 feet
TWR: PH-2GY, roger
Pilot: PH-2GY, position ROMEO, 2500 feet
TWR: PH-2GY, join traffic circuit runway 3
Pilot: PH-2GY, joining traffic circuit runway 3
TWR: PH-2GY, wind 050 degrees 8 knots, cleared to land runway 3
Pilot: PH-2GY, cleared to land runway 3
As you see the Pilot needs the clearance by ATC before entering the traffic pattern after ROMEO. In the event no such clearance is received then the pilot should enter the circling pattern as indicated on the charts or as instructed to by ATC.
TWR: PH-2GY, hold over HOTEL
TWR: PH-2GY, hold south of the field
for the rest the approach and landing clearances are similar to those used when dealing with IFR.
As TWR controller in VATSIM you most likely will have a mix of VFR and IFR traffic at the same time, most VFR traffic will be slow and most IFR traffic will be heavy or fast, below find a number of traffic situations and the required action needed to make the flow and sequencing of VFR and IFR be as smooth as possible.
The IFR traffic is being vectored and sequenced by Approach and as Tower your influence in this process is non existent. If you have VFR traffic under your control you will need to slot them into the landing pattern the one and only influence you as TOWER has over Approach is to request that the IFR inbound traffic be separated more than usual to allow the VFR plane to be slotted in between.
Here are a few examples; again we will use PH-2GY the PA13 for approach to rwy 03 in Maastricht together with KL123 a B737 on its way in on the ILS for rwy 03.
Orbit
The most common and easiest way to increase separation is to issue an Orbit or 360 degree instruction. This automatically increases the separation between the traffic.
TWR: PH-2GY make a right three sixty
Note the differences bellow:
TWR PH-2GY Orbit over POINT
This results in a continuous circling until ATC instructs to the contrary.
TWR PH-2GY Fly 360° over POINT
This results in one complete 360 degree circle after which the pilot will resume his original course.
TWR PH-2GY Fly one orbit over POINT
This results in one complete 360 degree circle after which the pilot will resume his original course.
TWR PH-2GY Fly 360s over POINT until further instructions
This results in a continuous circling until ATC instructs to the contrary.
Once the VFR pilot has made a full circle he would normally continue his downwind leg, and by this time the IFR traffic will either be on short final or will already have landed. Hence the VFR traffic can be cleared for the approach.
The thing to bear in mind is the Wake Turbulence factor between aircraft categories as explained earlier. The wake turbulence warning should be given when the VFR traffic is still on his downwind leg as the pilot of the VFR aircraft can then use best judgment in deciding to increase or decrease this leg before turning in to final.
TWR: PH-2GY, caution wake turbulence from just landed Boeing 737
TWR: PH-2GY, caution wake turbulence from Boeing 737 on short final
In the event one full circle should not suffice to ensure sufficient separation between the various aircraft in the pattern or on final ATC can instruct the VFR traffic to continue orbiting until cleared for the approach.
TWR: PH-2GY, orbit left
TWR: PH-2GY, continue approach
Short Approach
If the IFR traffic is further than 8 miles distant from the field then ATC can ask a VFR pilot if he can follow a short approach. This in essence means that the VFR aircraft will shorten his final approach to less than 1nm and land before the IFR traffic.
TWR: PH-2GY, can you accept a short approach?
Pilot: PH-2GY, affirm
TWR: PH-2GY, make a short approach, wind 090 at 5 knots, cleared to land rwy 03
ATC would then provide the pilot of the IFR flight with the required traffic information.
Extended Approach
In the event that a pilot cannot execute a short final approach or if there is other traffic on short final, ATC can instruct the VFR traffic to extend the downwind leg thereby ensuring that the traffic is sequenced and sufficient separation exist between the different approaching aircraft. Remember as ATC, if you are sequencing a light propeller type aircraft in after a medium or heavy jet that wake turbulence will most probably be a factor.
TWR: PH-2GY; fly extended right downwind, standby for base.
TWR: PH-2GY; continue approach, caution wake turbulence from preceding 737.
Pilot in Command
Another manner to deal with the situation is to pass the entire process to the pilots. In essence ATC advises the VFR pilot to follow and maintain visual separation with the IFR traffic
TWR: PH-2GY, Number two, follow Boeing 737 on 5 miles final, caution wake turbulence
The pilot in turn has the responsibility to inform ATC of having preceding traffic in sight and indeed also report it he does not have traffic in sight, in which case the responsibility for separation returns to ATC.
Bear in mind that it is good practice to advise the IFR flight crew of the existence of the VFR traffic in the area.
TWR: KL123, PA13 on downwind runway 03 at your 3 o’clock, report traffic in sight
9.1.8. Special Visual Flight Rules
We have mentioned these before and whilst these are no relevant to VATSIM on line flying we thought it would be interesting to briefly explain what this is.
Special visual flight rules (SVFR) are a set of aviation regulations under which a pilot may operate an aircraft. A pilot can request an SVFR clearance from air traffic control to operate within a area of controlled airspace when the local weather is less than the minimums required for flight under visual flight rules. Like flight under instrument flight rules, air traffic control will provide separation from other aircraft; unlike IFR flight, the pilot does not require an instrument rating (for daytime SVFR flight) and the aircraft must remain clear of clouds and must maintain at least one mile of flight visibility. The pilot continues to be responsible for obstacle and terrain clearance.
SVFR clearances only apply within CTR’s once the aircraft leaves the CTR the flight reverts to visual flight rules and weather requirements.
An example of a use for special visual flight rules would be ground fog or mist obscuring the ground visibility at a controlled airport while visual meteorological conditions exist above, or at to fly visually at night in control zones in countries that do not allow VFR night flights.
9.1.9. Composite Flight Plans
The type of flight plan which a pilot intends to file and fly forms part of the flight plan in VATSIM you can identify these by looking at the Target or by looking at the flight plan. VATSIM only allows for I, V and S. in real life there are two other types the so called composites being Y and Z as outlined bellow.
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I |
IFR Instrument Flight Rules |
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V |
VFR Visual Flight Rules |
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Y |
Composite IFR/VFR aircraft will commence flight under IFR and change to VFR during the flight |
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Z |
Composite VFR/IFR aircraft will commence flight under VFR and change to IFR during the flight. |
|
S |
Special VFR, an aircraft that will fly VFR when weather is under the normal VFR minima. |
9.1.10. VATSIM non Charts on board
It does happen on VATSIM that the pilot having filed the VFR flight has no charts what so ever on board and as such has no knowledge or ability to follow VFR routings, or report over VFR reporting points etc.
In these cases, ATC should monitor the progress and guide the traffic if required during the flight.
The main interaction will be on departure or approach where the pilot will not be able to follow the prescribed VFR routes. As such a departure clearance would normally be
TWR: PH-2GY; winds 240 at 11, runway 22R, depart runway heading cleared for take off
or
TWR: PH-2GY; winds 240 at 11, runway 22R, straight out departure runway heading cleared for take off
or
TWR: PH-2GY; winds 240 at 11, runway 22R, 45 degree left/right Departure cleared for take off
Similarly during Approach, instead of having the pilot report at the normal VFR reporting points, the pilot will most probably be flying direct to the airport; therefore ATC would limit the instructions to the basic.
TWR: PH-2GY; report filed in sight
9.1.11. Further Reading
http://en.wikipedia.org/wiki/Visual_flight_rules
VFR operations (Australian CAA) a very comprehensive manual with some extremely interesting and above all very good graphics and explanations can be found here: http://www.casa.gov.au/pilots/flitgde.htm
