An instructor and student are preparing for an early afternoon flight to conduct maneuvers out in the practice area. The student receives a weather briefing and the instructor asks how the weather conditions are for the flight. The student responds that the weather looks to be VFR. OK, that’s great, but remember, the instructor’s specific question was in regards to how the weather conditions were for the flight. A more appropriate response would have been, weather is currently VMC. What’s the difference you might ask?
Visual flight rules (VFR) are just that, a set of rules adopted by the FAA to govern aircraft flight when the pilot has visual reference. These were the rules outlined in Monday’s post. So when the student initially answered the instructor he stated that the weather was such that they would be able to operate under these prescribed set of rules for the training flight.
On the other hand, visual meteorological conditions (VMC) are expressed in terms of visibility, distance from clouds, and ceiling meeting or exceeding the minimums specified by VFR. To operate under VFR you must have VMC. Stating that the weather was VMC followed up by the current conditions would have been a much better initial response from the student.
For example, the same student checks a METAR for a Class D airport:
201353Z 00000KT 4SM HZ CLR 16/03 A2996 RMK AO2 SLP140 T01610028
Per 14 CFR §91.155 and AIM ¶3-1-4, VFR weather minimums for class D airspace require 3 SM visibility, 500 feet below, 1,000 feet above, and 2,000 feet horizontal distance from clouds. According to this METAR, VMC exists at this airport because we have 4 SM visibility which is more than the prescribed 3 SM and the sky is clear of clouds. So in this particular situation we can operate under VFR because VMC is present.
Understanding your weather briefing relative to VMC rather than VFR will also help you apply your personal limitations. VMC is required to maintain VFR, but it may not be enough to meet your personal limitations established for the circumstances specific to today’s flight. Personal limitations change with experience so there is no set of numbers you can memorize to make your go / no-go decision: you must evaluate the weather relative to today’s personal limits—it’s a unique evaluation every flight.
In this particular example, yes, visual meteorological conditions do exist, but do those conditions meet your personal minimums as a student pilot? That’s a decision that you as the pilot in command will need to make. You will need to ask yourself: is 1 SM above the prescribed VFR minimums is satisfactory for me to complete today’s training flight? Only you can make that decision.
Below is a five question practice exam on VFR weather minimums. Answers and explanations are included below.
1. Normal VFR operations in Class D airspace with an operating control tower require the ceiling and visibility to be at least
A—1,000 feet and 1 mile.
B—1,000 feet and 3 miles.
C—2,500 feet and 3 miles.
2. What minimum visibility and clearance from clouds are required for VFR operations in Class G airspace at 700 feet AGL or below during daylight hours?
A—1 mile visibility and clear of clouds.
B—1 mile visibility, 500 feet below, 1,000 feet above, and 2,000 feet horizontal clearance from clouds.
C—3 miles visibility and clear of clouds.
3. The minimum distance from clouds required for VFR operations on an airway below 10,000 feet MSL is
A—remain clear of clouds.
B—500 feet below, 1,000 feet above, and 2,000 feet horizontally.
C—500 feet above, 1,000 feet below, and 2,000 feet horizontally.
4. A special VFR clearance authorizes the pilot of an aircraft to operate VFR while within Class D airspace when the visibility is
A—less than 1 mile and the ceiling is less than 1,000 feet.
B—at least 1 mile and the aircraft can remain clear of clouds.
C—at least 3 miles and the aircraft can remain clear of clouds.
5. Which VFR cruising altitude is appropriate when flying above 3,000 feet AGL on a magnetic course of 185°?
Just because I know how much everyone loves standardized testing I will leave you with this bonus analogy question. First one to answer correctly in the comments section I will send an Oral Exam Guide of your choosing.
VFR : IFR :: VMC : (____)