"Join a 3-Mile Left Base"

TOGA9

TOGA9

OPS CHECK GOOD
I am inbound to your Class D airport. Runway 36 is active, and I am approaching from the southwest in a Cessna 172. I call the tower and you tell me to "enter on a 3-mile left base for runway 36." As a tower controller, which of these are you expecting?

(Let's say a normal C-172 pattern is legs within 1 mile of the airport)

1) Join base at a point three miles from the runway (resulting in a 1 mile final).
2) Join base at a point that will result in a three mile final.
3) Join base at a point that will result in a three mile long base leg (resulting in a 1 mile final).
4) Get completely lost and ask for vectors.
5) Something else?

Thanks for your input. It seems there are several opinions to this question, and I would appreciate a controller's input.
 
While I'm not willing to dig it up, I would join a 3 mile base to a "normal" final.

If the controller wants me on a 3 mile final, I would expect the controller to say "make a 3 mile final", which I have also heard.
 
Toobdrvr said:
While I'm not willing to dig it up, I would join a 3 mile base to a "normal" final.

If the controller wants me on a 3 mile final, I would expect the controller to say "make a 3 mile final", which I have also heard.
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^^^^^^ this
 
Picture a normal left base leg. Plan to be aligned with that three miles before the point you turn to final. All the controller is saying is that he knows you're pretty much setup for a base leg so plan to be on it when you're approximately three miles from the airport. Avoid over-thinking it.
 
Given those instructions and flying a piston single I would set up to join a 3 mile base leg. I always made a habit of flying a very short final while flying piston singles. So that is what I do.
 
I had something like this happen yesterday at honolulu. The controllers here tend to get ahead of themselves. Tracon said " join a right base runway 4R to intercept a 3 mile final" clear enough.

Then we switched to tower who gave this advisory to another plane "traffic for the parallel is on a 6 mile right base " at that point we were on the base leg and approximately 3 miles away from the intercept point. So maybe 6 miles refers the total pattern distance remaining (base + final). Or it could be the slant distance to the field from the aircraft ( hypotenuse) . It's gotta be one or the other.
 
Correct me if I'm wrong, but wouldn't a 3* GS mean that at 900 AGL you should be 3miles out on final? most pattern altitudes are 1000 AGL so whether entering on a base or flying a downwind, either way you end up 3 miles out. Or is this only a jet thing?
 
Cptnchia said:
Correct me if I'm wrong, but wouldn't a 3* GS mean that at 900 AGL you should be 3miles out on final? most pattern altitudes are 1000 AGL so whether entering on a base or flying a downwind, either way you end up 3 miles out. Or is this only a jet thing?
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Yes, a three mile final at 1000ft you would be on glideslope. So much of flying is improvisation when the aircraft are capable of it. Light Pistons don't need three mile finals because they are so manueverable. Typically in a standard pattern if you begin your descent with a power reduction abeam the numbers you can still intercept the vasi/PAPI on glide path when you turn to final 1/2 to 1 mile out.
 
Man I feel there is some over thinking here. I don't know if what i do is right but it has worked for me so far.

3 mile base. I just drive towards the airport until I am 3 miles away then enter a base.
 
Cptnchia said:
Correct me if I'm wrong, but wouldn't a 3* GS mean that at 900 AGL you should be 3miles out on final? most pattern altitudes are 1000 AGL so whether entering on a base or flying a downwind, either way you end up 3 miles out. Or is this only a jet thing?
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That would be assuming you don't begin your descent until final...
 
TOGA9 said:
I am inbound to your Class D airport. Runway 36 is active, and I am approaching from the southwest in a Cessna 172. I call the tower and you tell me to "enter on a 3-mile left base for runway 36." As a tower controller, which of these are you expecting?
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Agree, that instruction is a coin toss and I get it all the time. I'd say make your base 3 miles long to a normal final.

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I hear controllers give that instruction and then each controller expects something else. Which is one of the reasons I don't say things like:
traffic on a 3 mile left base (when he is 5 flying miles from the runway)
enter a 3 mile left base (when I want a left base to a 3 mile final)

I'll say:
traffic 5 miles out
enter left base to 3 mile final (or usually they're already on some sort of base leg already and I just say "join final no closer than 3 miles")

Basically it's very ambiguous and if you want to know what the controller wants, you should just ask on frequency. And more often than not, I've seen it used just as a memory jogger so the controller doesn't forget you're about to land when it's really slow.
 
After digging through the pilot/controller glossary and AIM for something official I finally just called the tower here today and asked out of curiosity, and they said 2 as well...make your base to join a 3 mile final.

And of course he followed up with the 'if you're ever unsure, just ask.' Nice guy.
 
JeppUpdater said:
After digging through the pilot/controller glossary and AIM for something official I finally just called the tower here today and asked out of curiosity, and they said 2 as well...make your base to join a 3 mile final.

And of course he followed up with the 'if you're ever unsure, just ask.' Nice guy.
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Interesting. I would have gone with #3. Don't know how many times I've reported to tower something along the lines of "Tower 1234 five mile left base runway XX" when I was on a five mile base.

Just draw the traffic pattern in your head; if the ask for a 3 mile base then that's what you give them. If they want a 3 mile final, they'll ask for that as well. AND you can be sure that if they tell you they want a five mile upwind, you had better now make a turn over the airport.
 
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