VFR Flight Part 1a: Basics

Aviation Topic of the Week
By Michael Oxner, August 10, 2003

Introduction

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This week's topic:
VFR Flight Part 1: Basics

For some reason, many pilots in Flight Simulation begin by flying the "big iron" on instruments. This is the equivalent of having someone turn 16 and start learning to drive by running a tandem trailer on a semi. In the real world, you start your flight training under VFR, or Visual Flight Rules, on light, single-engined aircraft in fine weather. This gives the pilot-to-be the basics of flight, rather than trying to teach advanced rules and concepts of instrument and multi-engine flight when the pilot doesn't even know how an airplane flies. Many people have requested information on VFR flight, and the transition from IFR flight to visual manoeuvring. Before we return to the IFR series, I think we should have a look at some basics into VFR flight. Remember that all the information in this page applies specifically to Canadian rules and airspace.

Basics
Weather Minima
    178 Seconds to Live
    Special VFR
Cruising Altitudes
    Minimum Altitudes for VFR
Clearance Readbacks
    "Hold Short" Instructions
    Acknowledging Take-Off and Landing Clearances
    Information
Radar Flight Following

Basics

While IFR has had its acronym unofficially changed to a new meaning of "I follow Rules", VFR has been similarly changed to mean, "Very Few Rules". It doesn't seem like that at first, but once you compare how many rules and procedures exists for IFR flight to VFR flight, you'll agree. Simply look at the number of pages encountered so far for the IFR flight series, and see how few develop from VFR.

The easiest way to sum up VFR flight is, "See and be seen". Rather than concentrating on instruments to determine where you are, you are primarily concerned (or should be, anyway) with what's visible out those clear panels around you called "windows". Your primary source of traffic avoidance is by seeing other aircraft and manoeuvring as required to avoid conflicts with them, and your primary means of navigation is what you see outside the aircraft as well. Rather than navigating by GPS or airways, you use land features, including highways, railways, power lines, rivers and lakes to ensure you're on course.

Weather Minima

To promote the concept of visual navigation and collision avoidance, there are minimum weather requirements for VFR flight. As demonstrated in a previous topic, many classes of airspace permit both VFR and IFR aircraft. This makes an IFR pilot's job more difficult. He must fly by instruments to follow ATC clearances, but he must also keep alert while in Visual Meteorological Conditions (VMC) to ensure he doesn't run into a VFR aircraft. Somewhat easier for a VFR aircraft in that he is, at least in theory, already keeping his head up and looking out the window. This is the primary reason for different weather limits in controlled airspace vs uncontrolled airspace. See the table below.

AIP RAC Figure 2.8 - VFR Weather Minima & CAR 602 Division VI - Visual Flight Rules

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Airspace		Flight Visibility	Distance From Cloud	Distance AGL
Control Zones		not less than 3 miles *	horizontally: 1 mile vertically: 500 feet	vertically: 500 feet
Other Controlled Airspace		not less than 3 miles	horizontally: 1 mile vertically: 500 feet	-
Uncontrolled Airspace	1000 feet AGL or above	not less than 1 mile (day) 3 miles (night)	horizontally: 2000 feet vertically: 500 feet	-
	below 1000 feet AGL - fixed-wing	not less than 2 miles (day) 3 miles (night)	clear of cloud	-
	below 1000 feet AGL - helicopter	not less than 1 mile (day) 3 miles (night)	clear of cloud	-

* Ground visibility when reported

178 Seconds to Live

Additionally, I read a statistic some time ago that reportedly came from the University of Illinois that was interesting. It said the VFR pilot encountering IFR weather conditions had an average life expectancy of 178 seconds. The longest time frame in their study was 480 seconds (think, just eight minutes) and the shortest was merely 20 seconds! Even with IFR instrumentation (yes, the Cessna 172 in Microsoft Flight Simulator is *very* well equipped), a pilot without IFR training entering cloud, or even ending up between layers of cloud, can become disoriented quickly. Since the force of gravity is normally used by our body to determine up from down, we get used to that feeling. Properly coordinated flight means that there is no side force experienced by your butt in the seat. If you're in a descending turn with a 60 degree bank, you may only feel approximately 1 G, the force of gravity as far as your body is concerned. If you're turn is well coordinated, you actually feel like you're in straight and level flight. Your clues would come from the instruments, but far too many pilots in the past have ignored instruments that showed something bad happening. Even qualified IFR pilots have made grave errors while on instruments, or after one or more instruments have failed. There are many incidents of VFR and IFR aircraft in good VMC having difficulty at night, since the horizon isn't always easy to pick out (think of a sparsely settled area with few towns and lighted roads to judge by). VFR aircraft should make every reasonable effort to avoid IFR conditions, even if the aircraft is equipped for it and the pilot thinks he can handle it. If you're IFR rated and the aircraft is equipped, you can always call ATC and "airfile" an IFR flight plan for an IFR clearance to continue on. For the VFR pilot, though, visibility is life.

Special VFR

CAR 602.117 gives a pilot authorization, under certain circumstances, to fly in control zones under lower weather than the minima listed above. This is called Special VFR. A pilot must have authorization from ATC to fly SVFR in a control zone when flight visibility, and ground visibility when reported, are not less than 1 statute mile for fixed wing aircraft, and ½ SM for helicopters. Flights must be operated clear of cloud at all times, and within sight of the ground at all times. Authorization to fly SVFR is granted on the basis of current or anticipated IFR traffic and is not based on the experience level of the pilot in any way. The request for SVFR (it must be requested by the pilot, not initiated by ATC) serves as proof of ability to accomplish the manoeuvers required in the lower weather conditions.

Conditions must be met to allow SVFR flight. First off, the aircraft must have a two-way radio and maintain communication with the appropriate ATC unit. Helicopters must operate at reduced speed to allow more time to react to other traffic or obstructions. And, if SVFR at night, ATC will only authorize SVFR for the purpose of allowing the aircraft to land at the destination aerodrome.

Cruising Altitudes

Like IFR flight, VFR has some rules regarding cruising altitudes. These are designed to keep aircraft traveling in similar directions at similar altitudes, attempting to provide more time to see and avoid others, and aircraft on opposite tracks at different altitudes since they have less time to see and react. VFR aircraft are not under control of ATC in most airspaces where en route flight would occur, so it's up to the pilot to choose altitudes appropriately. Many a VFR aircraft has been spotted using an altitude inappropriate for direction of flight, and often, in my experience, this is simply an oversight. Other factors may come into play, such as a combination of terrain and cloud base, and so on, so ragging out a VFR pilot on this basis alone is not always a good thing. The rules for choosing VFR cruising altitudes are detailed below.

Altitudes	Aircraft Track
Fly at 2,000 foot intervals (flight levels in standard pressure region)	000°-179°	180°-359°
	CVFR (Class B Airspace)
	Odd Thousand Feet ASL (3,000, 5,000, 7,000, 9,000, 11,000, 13,000, 15,000, 17,000)	Even Thousand Feet ASL (2,000, 4,000, 6,000, 8,000, 10,000, 12,000, 14,000, 16,000)
	VFR (Other Classes of Airspace)
	Odd Thousand Feet Plus 500 ASL (3,500, 5,500, 7,500, 9,500, 11,500)	Even Thousand Feet Plus 500 ASL (4,500, 6,500, 8,500, 10,500, 12,500)

The cruising altitudes indicated for VFR in other than CVFR flight, meaning the "thousand plus 500", are only required if the aircraft is operating above 3,000 AGL. Below this altitude, whatever the pilot desires, with certain minimum altitudes in mind, are fair game. For CVFR flight, which is only considered in Class B airspace, altitude selection would be the same as IFR flight, covered in another topic earlier. Altitudes at and above 18,000 feet (considered in Canada to be FL180 and above) are in Class A airspace where VFR flight is not allowed. Well, I suppose if your aircraft can get above FL600, you could operate VFR since it's Class E way up there. Not many Cessnas and Pipers can get there, though.

One other note: Changing altitudes while en route, provided you're not in airspace where you need a clearance (like Class B, for example), can be done at pilot's discretion. Have a good look ahead and to the sides while climbing or descending to ensure you run into someone opposite direction, and make the change. You do not need a clearance, or permission, from ATC to change altitude while VFR outside of certain airspaces. I'll go into more detail about requirements for different classes of airspace in a future topic.

Minimum Altitudes for VFR

For the minimum altitudes, VFR are much less restricted than IFR aircraft. Basically, the aircraft must be operated at such an altitude that if a forced landing becomes necessary, the aircraft can glide far enough to avoid endangering persons or property on the ground. So if you're overflying a large city, you would have to be higher than if you're operating over a small village. In any case, if you're over a built up area, you have to be at least 1,000 feet above the highest obstacle within a 2,000 foot radius of the aircraft. If you're not over a built up area, you must operate a minimum distance (this may be considered horizontally, too) of 500 feet from any person, vessel, vehicle or structure, according to CAR 602.14. If you happen to be operating for the purpose of saving a human life (SAR duty, MEDEVAC helicopter, etc), firefighting, or other similar activities that are pretty specific in CAR 602.15, the above minima do not apply.

Clearance Readbacks

Many pilots, real world and otherwise, don't actually know what clearances they are supposed to read back to ATC and what ones they don't. In fact, many pilots, again online and real world, will read back things like winds issued by ATC. For VFR flight, the AIP RAC 5.2 tells us that a VFR pilot is only required to read back the text of ATC clearances when requested by an ATC unit. There are airmanship issues to consider when thinking about this statement, as well as some other regulations.

"Hold Short" Instructions

When operating at an airport, any time ATC issues taxi instructions including a "hold short" statement, the pilot must read this back. Not necessarily the whole clearance, but certainly the hold. If ATC says, "Taxi A, B, C and hold short of runway 24", the only critical part to be read back is, "hold short of runway 24". Most pilots will read back the entire taxi instruction, and that's OK. It gives ATC a chance to catch an error if the pilot recorded the wrong taxiways in the instruction.

Additionally, some airports will use Simultaneous Intersecting Runway Operations, where two aircraft will land on intersecting runways at the same time, and one will be required to hold short of the other. The landing clearance will sound something like, "cleared to land runway 33, hold short of runway 24". Many pilots will read back the landing clearance, but the "hold short" is the part that must be read back. This is an attempt to emphasize to the pilot that this action is required. If the pilot doesn't read it back, ATC will pursue the readback. If the pilot refuses to read it back, he should be ready to overshoot, as ATC will be forced to cancel the landing clearance.

Acknowledging Take-Off and Landing Clearances

Unless requested to read back specific instructions that accompany a take-off or landing clearance, the pilot needs only to acknowledge such a clearance. How does one do that? Simply by using the callsign of the aircraft. ATC says, "Lima Oscar Papa, winds 240@10, cleared take-off runway 24." To which the pilot can reply, "Lima Oscar Papa." That's it. Same for a landing clearance that doesn't include a "hold short" instruction. The winds definitely don't need to be read back, even though many pilots will readback the "cleared for take-off" or "cleared to land" parts.

Information

ATC will, upon request and workload and equipment permitting, relay information to VFR aircraft. Such information could include weather, either observed on radar or visually by ATC, traffic information, airport conditions, etc. Pilots, IFR or VFR, need not read any of this back. One way of confirming something you weren't quite sure you heard correctly is to read it back, and hope ATC will catch the error and correct you, but really, there is no shame in asking for information to be said again if you miss something. Saving radio time is good airmanship, so simply asking to have one piece said again is often quicker than reading back information unnecessarily, and it also removes the chance that ATC will miss your readback. Since it's not a clearance, he may not be quite so keen to listen to your readback as he is to listen for a clearance readback.

Radar Flight Following

While VFR aircraft en route outside of Class B, C and D airspace need not talk to ATC, Flight Following is provided by the IFR ATC unit responsible for the airspace where a flight is operating. If workload and equipment permit, ATC may, upon request, provide radar surveillance to a VFR aircraft en route. This means ATC will provide you with significant observed weather information (radar equipment permitting), traffic information on observed radar targets nearby, and so forth. It's also good if you have an equipment problem, if you get disoriented or lost, or other such situation. ATC can provide radar navigation assistance to get you back in line. I work in Moncton ACC, and one of our pet peeves is VFR aircraft who request flight following and then tune out from ATC's frequency. I can't provide you with traffic information if you're not listening. If you have to leave the frequency to make mandatory frequency calls, amend a flight plan, pick up an ATIS, or whatever, let ATC know you'll be leaving the frequency, give them an idea of how long you think you'll be off, and let them know when you're back. If you do call up for flight following, remember that you must maintain VFR, so stay in visual contact with the ground, and remain clear of cloud, and keep alert for other aircraft. Sometimes other traffic will not show on radar, and ATC can only report known traffic.

As always, feedback and suggestions are always welcome. I'd like to thank those who take the time to read, and especially those who take the time to write. Your interest is what keeps mine. My e-mail is moxner@nbnet.nb.ca.