Tower Instruction?

paflyer

paflyer

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Say you're going VFR into a towered A/P, and the tower says something like "report 3 mile base"; do they mean fly a base leg three miles long (before turning final), or a base segment that ends three miles from the runway?:dunno:
 
i usually interpret that as 3 miles away from the airport on base leg.
 
They would like you to approach the airport in a manner that has your flight path being an extended base leg and when you are three miles away let them know that is where you are at.
 
There is no published guidance whatsoever on what this means. Some controllers may want you to report when you're on base three miles straight line from the airport center, some may want you to report on a base leg which intersects the final three miles out, and some may want you to report on base leg with three miles to fly to the runway (e.g., one mile from turning a 2-mile final). No way to be sure which it is. The good news is that I've never heard a controller quibble about exactly which one they wanted, so keep your eyes open, and do what seems right at the time.
 
If you're ever unclear what the instruction means, just ask.

Many Class D towers will use local landmarks and you may not be familiar. At MGW, for example, when approaching from the north VFR you'll usually hear "Report 3 mile final over the stacks."

If you don't know what the "Stacks" are, just ask.

Rich, Jim, John, and the new guy (don't know his name yet!) always explain.
 
tonycondon said:
i usually interpret that as 3 miles away from the airport on base leg.
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I would guess that Tony is right. Aurora usually has us report 2 out on base. I do what Tony says and they never complain.
:blueplane:
ApacheBob
 
I've talked to a few tower controllers around here and the unanimous opinion was that it really doesn't matter. This is not a vector or clearance to a fix, it's a combination of an instruction to enter the pattern on a base leg (vs downwind or straight in) for sequencing and a request to give the tower a heads up when you're close enough that they will be able to see you and fit you into the flow. If the report is supposed to be at 3 miles and you report at 3.5 or 2.5 they're not going to complain because the arrivals who lack GPS typically aren't that accurate anyway. IOW if you are on a base leg (preferably in line with any traffic you see ahead of you on base although that's not required), and close enough that they can see you (hint: if you can see the tower, they can see your airplane) but not so close that you could be conflicting with traffic on downwind they won't care that you're not precisely 3 nm from anything.
 
I've always interpretted it to mean a 3 mile base leg .. so I'd report on base
3 miles from the base to final turn. I learned at a towered airport ... was a
control zone back in the 70s and that's how it was explained to me way
back then.

RT
 
My interpretation is 3 miles from the airport. But as mentioned, I don't think there is any one "right" answer.
 
Bob Gardner's book "Say Again, Please" dedicates a paragraph to this topic:
"57X, cleared as requested, report two mile left base"
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This instruction means to report when your course is 90deg to the extended runway centerline and you are two miles from the centerline, not when your course will intersect final two miles from the threshold. The reason for this is twofold: First, the controller wants to make visual contact and needs to know where to look; second, the controller wants to receive the report before you are close enough to mix with other traffic.
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My Second Edition also includes what appears to be an earlier (and way more confusing) revision of the same paragraph a couple of lines down, where downwind entry is discussed, not base. So take it with a grain of salt.
 
Since I'm an air traffic controller, Pete's explanation is correct. However, here's another example of what you might get asked to report. "N1234, report a 2 mile base for a 3 mile straight-in." A call like this one would help the controller sequence you with a couple of aircraft already in the pattern on downwind.
 
CardinalTom said:
Since I'm an air traffic controller, Pete's explanation is correct.
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According to what FAA publication? I've been searching for the official FAA answer to this question for several decades without success, and if it's written somewhere, I'd sure like to know where so I can reference it in the future.
 
CardinalTom said:
Since I'm an air traffic controller, Pete's explanation is correct. However, here's another example of what you might get asked to report. "N1234, report a 2 mile base for a 3 mile straight-in." A call like this one would help the controller sequence you with a couple of aircraft already in the pattern on downwind.
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So... what does that mean?
 
EdFred said:
It means you are 3.6055512754639892931192212674705 miles from the runway when you make the call.
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And you are at 33.6900675259798 degrees off of the extended centerline of the runway.
 
AuntPeggy said:
So... what does that mean?
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Seriously, it means the controller wants you to set up a base leg that will give you about a 3 mile final rather than one closer in (as would be SOP for most light airplanes) and they want to hear from you when you're about 2 miles from turning final so they can visually confirm that you're going to fit into the flow.

Neither distance needs to be surveyed or measured with anything besides your eyes. If the runway is about a mile long try to visualize a point three times that length along the centerline and arrange your path to be on a 90° intercept course by the time you are a couple runway lengths from the extended centerline. You will NOT be in trouble if your base leg is actual 3.2 nm from the threshold or you call ten seconds before or after passing the 2 nm from the centerline point.
 
CardinalTom said:
Since I'm an air traffic controller, Pete's explanation is correct. However, here's another example of what you might get asked to report. "N1234, report a 2 mile base for a 3 mile straight-in." A call like this one would help the controller sequence you with a couple of aircraft already in the pattern on downwind.
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Seems to me that ought to be "a 2 mile base for a 3 mile final" rather than using the "straight in" phrase since it's kinda contradictory to the base arrival. Is either version spelled out in 7110.65?
 
gismo said:
Seriously, it means the controller wants you to set up a base leg that will give you about a 3 mile final rather than one closer in.
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Not here at SBY -- these folks just want to know when you're three miles from the airport so they can spot you. Since it isn't written anywhere I can find, at any other airport, it could mean what Lance said, or what the SBY tower says, or something else entirely. If in doubt, ask, but the one absolute truth is that it's all guesswork anyway, so unless you think a conflict may develop, your guess is good enough.
 
Ron Levy said:
Not here at SBY -- these folks just want to know when you're three miles from the airport so they can spot you. Since it isn't written anywhere I can find, at any other airport, it could mean what Lance said, or what the SBY tower says, or something else entirely. If in doubt, ask, but the one absolute truth is that it's all guesswork anyway, so unless you think a conflict may develop, your guess is good enough.
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Ron, did you notice I was writing about this call:

"N1234, report a 2 mile base for a 3 mile straight-in."

Seems to me it's pretty obvious such an instruction is intended to get you to turn final about 3 miles out even though (as you and I both suspect) this isn't standard phraseology from 7110.65.

But for the more common "Report 3 miles on left base" call I agree there's no specific guidance and as I said in an earlier post, the exact position of such a report or distance reference point is immaterial.
 
gismo said:
Ron, did you notice I was writing about this call:

"N1234, report a 2 mile base for a 3 mile straight-in."
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No, I didn't -- buried too far back in the quotation links.

Seems to me it's pretty obvious such an instruction is intended to get you to turn final about 3 miles out even though (as you and I both suspect) this isn't standard phraseology from 7110.65.
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Agreed, although it may not be completely obvious to everyone -- I can imagine a lot of pilots hearing that and replying, "Say again?" so they can get the various pieces straight in their heads.

But for the more common "Report 3 miles on left base" call I agree there's no specific guidance and as I said in an earlier post, the exact position of such a report or distance reference point is immaterial.
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Concur.
 
zaitcev said:
Bob Gardner's book "Say Again, Please" dedicates a paragraph to this topic:
My Second Edition also includes what appears to be an earlier (and way more confusing) revision of the same paragraph a couple of lines down, where downwind entry is discussed, not base. So take it with a grain of salt.
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You've got me there, Pete. My desk copy is the fourth edition and I do not retain copies of earlier editions so I can't explain what you have encountered.

I have in my hand a letter from the Procedures Division at FAA HQ which says in pertinent part:

"It is our conclusion that pilots instructed to make the 'two-mile left base' report should do so when established on a base leg that is two nautical miles from the final approach course of the landing runway."

Bob Gardner
 
Ron Levy said:
According to what FAA publication? I've been searching for the official FAA answer to this question for several decades without success, and if it's written somewhere, I'd sure like to know where so I can reference it in the future.
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To paraphrase from the movie A Few Good Men...how do you know where the mess hall is if it isn't in the manual? Some things are just SOP without being written. My guess of course.
 
bobmrg said:
You've got me there, Pete. My desk copy is the fourth edition and I do not retain copies of earlier editions so I can't explain what you have encountered.

I have in my hand a letter from the Procedures Division at FAA HQ which says in pertinent part:

"It is our conclusion that pilots instructed to make the 'two-mile left base' report should do so when established on a base leg that is two nautical miles from the final approach course of the landing runway."

Bob Gardner
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Part of the problem is this comes out several different ways:

"Report a two mile left base"
"Report two miles out on left base"
"Report two miles south, left base for runway 27"
"Report on a left base, two miles out"

And probably a few I can't remember.

You're in a maze of twisty little passages, all different...
 
pilot_dude said:
To paraphrase from the movie A Few Good Men...how do you know where the mess hall is if it isn't in the manual? Some things are just SOP without being written.
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Not in this case -- that's why we have the AIM for pilots, 7110.65 for the controllers, and the Pilot/Controller Glossary for everyone.
 
gismo said:
Part of the problem is this comes out several different ways:

"Report a two mile left base"
"Report two miles out on left base"
"Report two miles south, left base for runway 27"
"Report on a left base, two miles out"

And probably a few I can't remember.

You're in a maze of twisty little passages, all different...
Click to expand...

Could be because the 7110.65 does not address this:

"3-10-1. LANDING INFORMATION Provide current landing information, as appropriate, to arriving aircraft. Landing information contained in the ATIS broadcast may be omitted if the pilot states the appropriate ATIS code. Runway, wind, and altimeter may be omitted if a pilot uses the phrase “have numbers.” Issue landing information by including the following:
NOTE-
Pilot use of “have numbers” does not indicate receipt of the ATIS broadcast.
a. Specific traffic pattern information (may be omitted if the aircraft is to circle the airport to the left).
PHRASEOLOGY
ENTER LEFT/RIGHT BASE.
STRAIGHT-IN.
MAKE STRAIGHT-IN.
STRAIGHT-IN APPROVED.
RIGHT TRAFFIC.
MAKE RIGHT TRAFFIC.
RIGHT TRAFFIC APPROVED. CONTINUE.
b. Runway in use.
c. Surface wind.
d. Altimeter setting.
REFERENCE
FAAO JO 7110.65, Para 2-7-1, Current Settings.
e. Any supplementary information.
f. Clearance to land.
g. Requests for additional position reports. Use prominent geographical fixes which can be easily recognized from the air, preferably those depicted on sectional charts. This does not preclude the use of the legs of the traffic pattern as reporting points.
NOTE-
At some locations, VFR checkpoints are depicted on sectional aeronautical and terminal area charts. In selecting geographical fixes, depicted VFR checkpoints are preferred unless the pilot exhibits a familiarity with the local area.
h. Ceiling and visibility if either is below basic VFR minima.
i. Low level wind shear or microburst advisories when available."

Bob Gardner
 
Isn't this discussion a little bit like measuring with a micrometer and cutting with a axe? At least before the advent of GPS no one could tell when they were exactly 3 miles from final or 3 miles from the end of the runway. Besides, by the time you get it out of your mouth, you will no longer be there, especially if there are other transmissions on the frequency.
 
+1. When I hear a controller tell someone, "I told you to report a 3-mile base, not 3 miles out on base," I'll start worrying about this. Until then, it's an undefined instruction, and your guess is as good as the controllers.
 
Ron Levy said:
+1. When I hear a controller tell someone, "I told you to report a 3-mile base, not 3 miles out on base," I'll start worrying about this. Until then, it's an undefined instruction, and your guess is as good as the controllers.
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Well, I remember coming into DuPage (KDPA) one day (I was copilot), we were told to report 3 miles out. Our GPS was showing 3.5 out and we called in, only to be yelled at because we were less that 3 miles from the airport boundary, and we were measuring, of course, from the center of the airport! There are some arguments that just aren't worth having. :no:
 
Everskyward said:
Isn't this discussion a little bit like measuring with a micrometer and cutting with a axe?
Click to expand...

"Report 3 mile right base" is not an uncommon call at KPAO (where I fly).

My interpretation: Please skip the downwind leg of the pattern, and if we forget to call you up when you get close enough for us to care, give us a shout to make sure we don't forget you.

They almost always give me further instructions before I am actually 3 miles away if the pattern has any other planes it.

Chris
 
Wow, who knew the level of controversy this would generate! In any case, thanks for all the replies, and now I don't feel like there was something that I should know after flying for 10- plus years, but didn't, since it's not written in stone (or the FAR's) anywhere!

On the relatively rare occasions I've received that instruction, I've flown it as a "distance to the turn to final" without getting a cranky call from the tower, but as you guys know assumptions in this business can create a smoking hole - or two - in the ground.
 
colohan said:
"Report 3 mile right base" is not an uncommon call at KPAO (where I fly).

My interpretation: Please skip the downwind leg of the pattern, and if we forget to call you up when you get close enough for us to care, give us a shout to make sure we don't forget you.

They almost always give me further instructions before I am actually 3 miles away if the pattern has any other planes it.

Chris
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Same here at KAPF, many times they've actually gone ahead and cleared me before I even had to report the 3 mile.
 
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