“Maintain Visual Separation”

[JNev]

Other than wake turbulence application, what use does this phrase have in ATC? I repeatedly hear coworkers and NCT controllers use it and I don’t really understand saying it to a VFR pilot after they have traffic in sight. They’re flying VFR so legally they always have to maintain visual separation and also they should if they want to not collide with other A/C. Isn’t it just wasted verbiage and redundant?

 

[r9s]

There's multiple topics going on in this thread and I think it's becoming intertwined. To clarify: OP was talking about the meaningless instruction some people say when issuing traffic to a VFR a/c.

Bob's talking about being told to maintain visual in the pattern, where wake from a previous departure comes into play. Which is effectively "waiving wake turbulence". He's correct, and the application is correct as well. The FAA implemented/withdrew/re-implemented this rule a few years ago with lots of headache over the usage of "maintain visual". I guess they couldn't think of another phrase and just reused that one.

Some others are referencing the actual usage for IFR A/C which philly explained pretty well above.

Mike. It is not meaningless. Stick with me here.


"Visual Separation" has a specific meaning in aviation beyond plain language. In fact it is in the Pilot/Controller Glossary.

VISUAL SEPARATION− A means employed by
ATC to separate aircraft in terminal areas and en route
airspace in the NAS. There are two ways to effect this
separation:
a. The tower controller sees the aircraft involved
and issues instructions, as necessary, to ensure that
the aircraft avoid each other.
b. A pilot sees the other aircraft involved and upon
instructions from the controller provides his/her own
separation by maneuvering his/her aircraft as
necessary to avoid it. This may involve following
another aircraft or keeping it in sight until it is no
longer a factor.

As opposed to the more generic "See and Avoid" (also defined in the PCG).

Any time a controller tells a pilot to "maintain visual separation", they are transferring the separation burden from the controller to the pilot.


So to answer the OP question- there are many times VFR aircraft have hard separation requirements. For example (and i will paraphrase here but with references...):
7-7-3 Separation
TRSA VFR separation requirement
target resolution or 500ft vertical

7-9-4 Separation
class B VFR separation requirement
b. 1.5 miles lateral or 500ft vertical (behind aircraft 19000lbs or more)
d. target resolution or 500ft vertical (behind aircraft 19000lbs or less)

7-8-3 Separation
class C VFR separation requirement
target resolution or 500 ft vertical


In addition each of these paragraphs require you to "apply the provisions of Para 5-5-4, Minima, subparagraphs g and h when wake turbulence separation is required"

5-5-4 Minima
g. behind super 1000 vertical plus
heavy -6 miles
large -7 miles
small -8 miles
ect...
h. small behind large- 4 miles
small behind heavy- 6 miles

4-8-11 Practice Approaches
Separation
a.2. IFR separation with 500ft vertical


I will let the tower guys discuss this one, but
3-9-7 b. 3.
no time requirement on successive touch-and-go provided the pilot is maintaining visual separation/spacing.

The rule literally says "visual separation" as well as referencing the visual separation chapter 7-2-1.



What does all of this mean? That there are indeed many separation requirements that controllers are required to maintain with VFR aircraft beyond the aircrafts ability to see and avoid. So whenever you hear a control say, "maintain visual separation", you must understand that the controller's separation requirement is now being transferred to the pilot.

For the OP, who is based at MRY under NCT's airspace. NCT is considered "Class C" airspace within their entire lateral boundary per their SOP (which goes waaaay beyond the usual 20 miles of the associated outer area). So as this increases their separation requirement, you may hear "maintain visual separation more often".

And for MJ. Yes - I am sure there are many controllers who say "maintain visual separation" when it is not necessary. Or when it is not required. Or when it is no longer applicable in the situation. I am sure it is overused and VFR pilots may cringe and wonder, 'why am I being to that?!?'.

But it is certainly not meaningless.

 

[MJ]

And for MJ. Yes - I am sure there are many controllers who say "maintain visual separation" when it is not necessary. Or when it is not required. Or when it is no longer applicable in the situation. I am sure it is overused and VFR pilots may cringe and wonder, 'why am I being to that?!?'.

You made that whole well researched argument only to agree with what I said

 

[Bob44zw]

When I first heard the phrase used in the pattern it made no sense at all. A Cub is downwind and a Learjet is departing. Even if I deliberately try to ram him, he will be in the next county by the time I turn around. Worse, if he deliberately tries to ram me, I cannot get out of his way. From my standpoint, separation is guaranteed even before the magic words were spoken.

It is different when a bunch of 737s are approaching. Clearing them for a visual approach does require some form of pilot separation. It has been a very long time ago for me, but we used to use a "contact approach" to get around some of the limitations of a visual approach.

 

[Termine]

A Cub is downwind and a Learjet is departing. Even if I deliberately try to ram him, he will be in the next county by the time I turn around.

Are you the Cub in this scenario? This one is the "three minute rule" people have mentioned.

If a smaller aircraft departs a runway from an intersection (rather than full length) behind a larger aircraft, they must be separated by three minutes after the larger rotates. (The FAA says wake turbulence becomes a problem at rotation.) A touch-and-go or stop-and-go is considered an intersection departure once it touches down/comes to a stop (respectively), so the three-minute timer applies.

If the larger aircraft is a small+ or large, the three minutes can be waived if the second aircraft has the first in sight and will maintain visual separation. The idea is that you adjust your own rotation point so as to avoid the wake turbulence of the prior departure. It's not about avoiding a collision, it's about avoiding the wake.

 

[Phillyman2633]

This is not always true. Visual separation procedures (i.e. "maintain visual separation") for VFR aircraft do apply in B, C, and TRSA airspace. This is specifically addressed a few times in the appropriate sections of chapter 7. Even student and VFR-only pilots -- particularly those who routinely fly to/from airports in B, C, or TRSA airspace -- are supposed to be familiar with this procedure.

Visual separation procedures always apply for VFR aircraft because they're operating under VFR...but the phrase "Maintain visual separation" does not apply to aircraft operating under VFR. I am well aware of the separation requirements within Class C and B airspace and this has nothing to do with those regulations.

 

[Acquired Taste]

Phillyman2633 side question, why do all the big towers, yours included I'm pretty sure, tell a/c "caution wake turbulence, luaw" when departing behind a heavy? Pretty sure it's not required right? You guys are gonna make sure you have the mileage or minutes before you launch them anyway

 

[GulfBravoPapa]

Just because you have the milage or minutes required for wake turbulence doesn't mean the aircraft won't still hit it. There have been a number of enroute cases where separation has been legal and aircraft have been nearly flipped due to wake turbulence.

 

[Acquired Taste]

GulfBravoPapa yeah, but is it required? Same argument you're making could be said if you work approach and no one over there is saying caution wake turbulence regularly unless they're running visuals right?

 

[CF]

GulfBravoPapa yeah, but is it required? Same argument you're making could be said if you work approach and no one over there is saying caution wake turbulence regularly unless they're running visuals right?

In my opinion no, you're providing the separation so the wake shouldn't be a factor. Though I do issue it anyway when I'm aiming for the minimum in trail distance.

 

[colombia_atc]

Visual separation procedures always apply for VFR aircraft because they're operating under VFR...but the phrase "Maintain visual separation" does not apply to aircraft operating under VFR. I am well aware of the separation requirements within Class C and B airspace and this has nothing to do with those regulations.

The statement that visual separation procedures always apply for VFR aircraft is incorrect. "Separation" is a positive, well-defined requirement that obligates ATC to specific defined minima (i.e. 1.5 miles radar, 500 feet vertical). The pilot's obligation to "See and Avoid" is not the same thing as visual separation. If the controller wishes to discontinue radar or vertical separation, then visual separation procedures are required to be used by the controller, even for VFR aircraft, in B, C, and TRSA airspace -- and yes, that includes saying "maintain visual separation," even to VFR aircraft. If the controller does not use those words then he is obligated to apply the applicable radar or vertical minimum. note: does not apply to VFR/VFR in C airspace as there is no separation requirement between aircraft in class C if they are both VFR

On another note, see-and-avoid is not specific to VFR aircraft. Rather, it applies to all aircraft operating in VMC (technically, whenever weather conditions permit). Yes, even IFR aircraft are required to see-and-avoid as well. Per the FAA:

The flight rules prescribed in Title 14 of the Code of Federal Regulations (14 CFR) part 91 set forth the concept of “See and Avoid.” Part 91, § 91.113 prescribes that when weather conditions permit, regardless of whether the operation is conducted under instrument flight rules (IFR) or visual flight rules (VFR), each person operating an aircraft shall maintain vigilance so as to see and avoid other aircraft.

 

[CaptainObvious]

Are you the Cub in this scenario? This one is the "three minute rule" people have mentioned.

If a smaller aircraft departs a runway from an intersection (rather than full length) behind a larger aircraft, they must be separated by three minutes after the larger rotates. (The FAA says wake turbulence becomes a problem at rotation.) A touch-and-go or stop-and-go is considered an intersection departure once it touches down/comes to a stop (respectively), so the three-minute timer applies.

If the larger aircraft is a small+ or large, the three minutes can be waived if the second aircraft has the first in sight and will maintain visual separation. The idea is that you adjust your own rotation point so as to avoid the wake turbulence of the prior departure. It's not about avoiding a collision, it's about avoiding the wake.

I don’t recall us ever saying “maintain visual separation” to the pattern guys though. “Report the traffic in sight” “roger, wind, runway cleared for whatever, caution wake turbulence” If not in sight cleared to land or we’d call their roll on the stop and go

 

[Robert_Boucher]

I don’t recall us ever saying “maintain visual separation” to the pattern guys though. “Report the traffic in sight” “roger, wind, runway cleared for whatever, caution wake turbulence” If not in sight cleared to land or we’d call their roll on the stop and go

I think it's a regional thing to do the maintain vis with a guy in the pattern. I started out in the great lakes region and nobody at the facility did that and I get to my new facility and it's a requirement.

 

[GulfBravoPapa]

GulfBravoPapa yeah, but is it required? Same argument you're making could be said if you work approach and no one over there is saying caution wake turbulence regularly unless they're running visuals right?

I don't work tower so I am unsure. As an approach controller I say it to anyone following a heavy, or most of the guys smalls depending what is in front of them. But I feel like that is leftover from when I was first hired and it was a requirement (at least at my facility). I briefly remember getting a briefing saying it wasn't required anymore when providing appropriate separation but it's habit now. I did also use it this week with a VFR outside the bravo flying below the finals when there was a heavy jet that was going to fly over top of him.

 

[colombia_atc]

is it required? Same argument you're making could be said if you work approach and no one over there is saying caution wake turbulence regularly unless they're running visuals right?

The .65 mandates a "caution wake turbulence" in a few situations, regardless of the distance involved or the type of approach -- even when approved non-visual separation (minutes or miles) is being applied. Chapter 3 (3-10-3 and 3-10-4) and chapter 5 list several occasions when a caution wake turbulence advisory is mandatory.

My facility asked for an interpretation on this once. Due to the fact that no specific distance is in the regs, how does the controller determine when the advisory is required? Typical response from the region... it basically said that if there's any doubt that wake is a factor, and particularly if it's going to be "anywhere near" minimum separation, then the advisory shall be issued. Our supervisors told us to err on the side of caution, so we basically just started saying it as a habit, anytime it might remotely be considered a factor.

 

[AZNLUVR69]

If the larger aircraft is a small+ or large, the three minutes can be waived if the second aircraft has the first in sight and will maintain visual separation. The idea is that you adjust your own rotation point so as to avoid the wake turbulence of the prior departure. It's not about avoiding a collision, it's about avoiding the wake.

757 and heavies can be waived too if they are maintain visual separation doing touch and goes.

 

[Phillyman2633]

Phillyman2633 side question, why do all the big towers, yours included I'm pretty sure, tell a/c "caution wake turbulence, luaw" when departing behind a heavy? Pretty sure it's not required right? You guys are gonna make sure you have the mileage or minutes before you launch them anyway

That's my interpretation, too. I think there's something saying that if the aircraft is at the departure point and they can see the aircraft that just departed, you dont have to say it...but there is 2-1-20 that says to issue when you believe it may be a factor. I get so many questions about "What type are we following" that I just preempt now and issue cautionaries whenever the leading a/c is a heavy.

 

[DankVectorz]

The .65 mandates a "caution wake turbulence" in a few situations, regardless of the distance involved or the type of approach -- even when approved non-visual separation (minutes or miles) is being applied. Chapter 3 (3-10-3 and 3-10-4) and chapter 5 list several occasions when a caution wake turbulence advisory is mandatory.

My facility asked for an interpretation on this once. Due to the fact that no specific distance is in the regs, how does the controller determine when the advisory is required? Typical response from the region... it basically said that if there's any doubt that wake is a factor, and particularly if it's going to be "anywhere near" minimum separation, then the advisory shall be issued. Our supervisors told us to err on the side of caution, so we basically just started saying it as a habit, anytime it might remotely be considered a factor.

I don’t feel like looking it up atm but pretty sure it says to use “best judgement” on when to issue wake turbulence now

 

[Bob44zw]

Out here it is a required speech. We understand it, and carefully explain it to our pattern students. In aviation, all I teach now is pattern work. Afraid to lose sight of the runway . . .

The first time it happens to a student, it can confuse them. Just like “line up and wait.”

 

[MJ]

its not a "location based" requirement... it's 3-9-7 b3

 

[Termine]

I think it's a regional thing to do the maintain vis with a guy in the pattern. I started out in the great lakes region and nobody at the facility and I get to my new facility and it's a requirement.

its not a "location based" requirement... it's 3-9-7 b3

I'm in AGL and not everyone at my facility does it, at least not consistently.

MJ, I brought up that paragraph the other day—my argument was, despite the fact that subpara c explicitly mentions a WT advisory and doesn't mention "maintain vis sep", subpara b references 7–2–1 which does. I was told there have been interpretations sent down over the past five years first one way and then the other, and (according to the controller I was talking to) the current interpretation is that you don't have to say it. I haven't seen that in black and white myself.