During VFR operations, the pilot must always self-assure separation from other aircraft, and thus must maintain a visual lookout all the time.

For IFR operations but in VMC, are there any rules as to pilot visual lookout? Is the pilot still required to maintain visual lookout (might be difficult in clouds, though...). Even if ATC assures separation, some objects such as drones may not be known to ATC, so ATC cannot provide separation...

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    $\begingroup$ “Even ATC assures separation”, actually, it assures separation between IFR flights, but depending on airspace class may or may not assure separation from VFR ones. $\endgroup$
    – Jan Hudec
    Commented Feb 16, 2017 at 13:32
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    $\begingroup$ Knowing ATC's at fault as you fall to earth after a collision is small consolation. You should always keep a lookout no matter what the regs say. $\endgroup$
    – GdD
    Commented Feb 16, 2017 at 14:06
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    $\begingroup$ Possible duplicate of Who is responsible for aircraft separation in IFR (limited/no visibility)? $\endgroup$
    – fooot
    Commented Feb 16, 2017 at 17:08
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    $\begingroup$ Not just drones but parachutists, very small manned aircraft such as powered parachutes and ultralights, and so on. Also there are areas without radar coverage. And even if radar does spot another plane, it won't necessarily report that plane's altitude accurately if the plane doesn't have a transponder. Also, other planes not controlled by ATC may make sudden maneuvers or deviations and there's no guarantee ATC will get a clear channel to report it to you in time. $\endgroup$ Commented Feb 16, 2017 at 22:39

2 Answers 2


You didn't mention which country or jurisdiction you're asking about, but in the US 14 CFR 91.113(b) says:

When weather conditions permit, regardless of whether an operation is conducted under instrument flight rules or visual flight rules, vigilance shall be maintained by each person operating an aircraft so as to see and avoid other aircraft

I assume other countries have similar regulations but even if they don't, it's still common sense and good piloting to keep a visual lookout whenever possible.

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    $\begingroup$ See and avoid is the mantra in every jurisdiction I know of, whether IFR or VFR. $\endgroup$
    – GdD
    Commented Feb 16, 2017 at 13:26
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    $\begingroup$ Yup! In some airspaces, you will have IFR and VFR without separation to each other and will only receive traffic information where available, e.g. class E airspace in Germany. $\endgroup$ Commented Feb 16, 2017 at 14:00
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    $\begingroup$ "See and be seen" is another good one. e.g. landing lights in daylight. it's just as important do what you can to give the other pilot a chance of spotting you (and maintaining situational awareness through judicious use of the radio) and looking out yourself. $\endgroup$
    – Simon
    Commented Feb 16, 2017 at 14:05

ATC assures separation...

This is a pretty critical misconception. ATC does not necessarily provide separation, just because you are flying IFR. Let's do a quick recap of the different airspace classes.

In class D, ATC will provide separation between two IFR flights, but will not separate VFR flights. All flights are provided with traffic information, and must avoid collision by means of traffic information and a visual lookout.

In class E, ATC will provide separation between two IFR flights. Traffic information about VFR flights will be provided if possible - but VFR flights can fly in class E without any radio contact, so ATC might not know about all flights. It is up to the pilots to avoid collision by using traffic information and keeping a visual lookout.

In class F, no separation is provided, regardless of whether you are flying IFR or VFR. ATC will provide advisory service towards other IFR flights, and traffic information about VFR is possible.

In class G, no separation is provided. Traffic information can be provided as far as practicable. (In some countries, you are not allowed to fly IFR in class G airspace - but this varies).

So yes, pilots are expected to keep a visual lookout, also when flying IFR. Obviously, in bad weather, this does not really apply. This is also the reason almost all aircraft are equipped with anti collision lights and navigation lights - so that other flights can see them.

Additionally, ICAO Annex 2 (Rules of the Air) states:

An aircraft operated on or in the vicinity of an aerodrome shall, whether or not within an aerodrome traffic circuit, observe other aerodrome traffic for the purpose of avoiding collision.

Note that there is no mention of flight rules. This procedures applies to "An aircraft" - that is, any aircraft.


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