It's apparently legal for pilots to fly over the top of clouds and fly VFR. However, I don't understand how it's possible to do so, especially since there is no visual reference to rely on to ensure that you are heading in the right direction. So, how exactly does this work, are there any limitations on this and is it possible to be done safely?
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asked Feb 9, 2014 at 14:46
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1$\begingroup$ Student pilots in the US are not allowed to fly over-the-top. §61.89 General limitations (a) A student pilot may not act as pilot in command of an aircraft: (7) When the flight cannot be made with visual reference to the surface; $\endgroup$– JScarryJan 16, 2017 at 23:31
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3$\begingroup$ Take a common situation hereabouts: fly from someplace in the clear SF Bay Area to Reno/Tahoe (or vice versa), travelling over the fog/low cloud obscurred Central Valley. You have a compass, VORs, GPS, and most of all, you can see the moutains on the other side of the valley. So you just point the nose at the appropriate mountain :-) $\endgroup$– jamesqfJan 17, 2017 at 3:03
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2 Answers
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I've flown VFR-on-top plenty of times. Navigation is simple: even the most basic airplane is required to have at the very least a compass, a clock and an airspeed indicator, which can be used to navigate much more accurately than you'd expect, given a reasonably good "winds aloft" weather report. Most airplanes also have some kind of radio navigation equipment as well. Furthermore, just because you are flying on top of a cloud layer, that doesn't necessarily mean you have no visual references for navigation. For example, mountains may poke through the cloud ceilings, or there may be an area of fog covering a portion of your route, with clear skies at your departure point and your destination. On one flight, I flew "VFR-on-top", but could see through the clouds to the streetlights below (it was dusk) even though my home airport was reporting IFR conditions (1/2 mile visibility, ceilings at ground level -- but it was a very thin layer of clouds).
Whether or not it can be done safely depends upon the circumstances. Getting lost typically isn't the issue, but rather whether you'll be able to descend in VFR conditions to land at your destination. Check the weather at your destination, paying attention to temperature and dewpoint spreads, and make sure you've got other options within the range of your aircraft. Also keep in mind that while you're on top, if you have an engine failure, you'll be making an engine-out IFR descent into unknown terrain below, unless you are within gliding distance of a suitable landing spot in clear weather nearby!
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2$\begingroup$ Welcome to Aviation SE! Thanks for the answer. $\endgroup$– reirabJan 30, 2015 at 5:12
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1$\begingroup$ Let us be very very precise. Are you talking about flying VFR-on-top, that is, you had an IFR clearance and were navigating solely by reference to instruments, and then the controller authorized you to fly "VFR-on-top"? Or were you flying VFR over the top, not on an IFR clearance, and were navigating by dead reckoning or occasional ground reference? $\endgroup$ Jun 20, 2022 at 1:18
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Perhaps the most important rule for a VFR pilot is "see and avoid" -- be able to see any immediate dangers (other aircraft, buildings, ground) and avoid them. When flying above the clouds, you can certainly see other aircraft and avoid them (as long as you're maintaining required cloud clearances), and the same for buildings. You cannot see the ground but on the presumption that your altitude is well above the ground and not significantly changing, this is not a factor.
As long as you're able to see the horizon, you're unlikely to become disoriented to the point of not actually knowing that the aircraft is or isn't flying straight and level. (Contrast that with flying in the clouds, where it's easy to become spatially disoriented and not be aware that you're starting to dive.) Limitations are basic: it's the PIC's responsibility to follow the regulations.
As to heading in the right direction and navigation in general, VFR flight does not mean one cannot rely on radio aids to navigation. VOR and GPS certainly make navigation very possible while on top, but to get to your question of "can it be done safely?" -- I suppose this comes down to a question of how reliable are your electronics and where are the weak spots; is the pilot under flight following or otherwise in contact with ATC, etc. If one were on top and were to lose the electrical system, there's certainly an emergency to be declared. If already in contact with ATC, it's an emergency that can likely be managed with the utmost of safety.
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$\begingroup$ There are variations between states and types. E.g. in the UK, amongst other criteria, helicopters must remain
in sight of the surfacewhich severely limits the options to fly on top. $\endgroup$– SimonFeb 9, 2014 at 15:50 -
1$\begingroup$ I wouldn't say that loss of the electrical system is an necessarily an emergency. There are still airplanes that don't even have an electrical system that fly VFR (even on top). They can use VFR GPS's or even time/speed/distance calculations to get them to a point where they do have ground reference. I think that the safety aspect is more about weather at destination and whether or not you could fly IFR if needed. $\endgroup$ Feb 9, 2014 at 19:55
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$\begingroup$ @Simon - are you talking about VFR rules only for helicopter? $\endgroup$ Oct 12, 2014 at 12:00
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$\begingroup$ @BurhanKhalid Yes, sorry, I should have made that clear. $\endgroup$– SimonOct 16, 2014 at 6:33
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1$\begingroup$ The only real hazard of VFR over the top is a forced landing, engine failure being the most obvious. If the cloud layer is broken and the ceiling a few thousand feet agl then this is not a huge risk factor. If solid overcast you will need basic attitude instrument proficiency (now taught as part of most private certifications) to let down, otherwise low risk. If overcast and the ceiling is low or it is a fog layer, then high risk, instrument training and an IFR equipped airport in glide distance is the only recourse.(for fog, it needs full ILS or LPV glide path, ALS lights are good too.) $\endgroup$ Sep 1, 2019 at 2:36