How "big" is the pattern?

[EdFred]

Barry's post about making a right base into PHN in the "Heard" thread, and getting chewed out by someone on the ground because PHN is left traffic made me wonder...How big is the pattern? There isn't anything I am aware of that precludes one from making a straight in to a runway (not including obvious terrain or structures), so at what point does the turn to final make it part of the pattern and a base turn. Anything inside 1/2 mile? 1 mile? 3 miles? 5 miles?

 

[BruceAir]

The AOPA Air Safety Foundation Safety Advisor, "Operations at Non-Towered Airports," summarizes the most important information from the FARs, AIM, ACs and other sources (n.b. AC 90-66A Recommended Standard Traffic Patterns for Aeronautical Operations at Airports without Operating Control Towers).

Although specific distances aren't specified in the FARs or the AIM (or other sources that I know), the consensus among respected authorities* seems to be flying a pattern with legs offset from 1/2 to 3/4 mile from the runway, if you're in a typical single-engine GA airplane (larger, faster airplanes obviously need more room).

*Unfortunately, instructors seem increasingly to teach much larger patterns, but that's a rant I don't want to get into here.

 

[EdFred]

So, am I to interpret that to say I could make a right "base" 1 mile out for a straight in since I'm not "in" the pattern?

 

[Dave Krall CFII]

Barry's post about making a right base into PHN in the "Heard" thread, and getting chewed out by someone on the ground because PHN is left traffic made me wonder...How big is the pattern? There isn't anything I am aware of that precludes one from making a straight in to a runway (not including obvious terrain or structures), so at what point does the turn to final make it part of the pattern and a base turn. Anything inside 1/2 mile? 1 mile? 3 miles? 5 miles?

Generally, in a high wing on downwind your runway should be "mid-strut" when you look out, or even a little closer. Why would anyone routinely go downwind wider than 1/2 mile ? Base leg should be turned when the RWY threshold is 45 degrees off your shoulder, or sooner. To widen or extend any of these outward from the RWY for no good reason at non-towered fields, or unless asked by a tower to do so, means you're probably behind the aircraft, or just poking around, or the worst, pretending and believing your own BS in your subconscious that your piston plane is just so damn fast that you have to have more room.

Take pride in controlling your aircraft within certain time/distance constraints. It's an insult to your piloting skills NOT to fly a tight pattern unless there's a good reason not to, and it's unsafe to fly a big pattern that extends out of glide range to the RWY, particularly in light of the fact the a large percentage of engine failures occur when descending &/or reducing power.

If people are flying wide patterns, radio & ask what's the problem why they're flying so wide. Any CFI that does so must need the extra minutes, I figure.

 

[BruceAir]

Your question doesn't have a single, simple answer. If you review the references I cited earler, you'll have a good understanding of the fundamentals. Obviously, what works at one airport may not apply strictly at another (conflicts with nearby airports, airspace, noise-sensitive areas, IFR approaches, non-standard patterns, skydiving or glider operations, etc.).

The following guidance from the Advisory Circular seems relevant in a general sense, however:

e. The FAA encourages pilots to use the standard traffic pattern. However, for those pilots who choose to execute a straight-in approach, maneuvering for and execution of the approach should be completed so as not to disrupt the flow of arriving and departing traffic. Therefore, pilots operating in the traffic pattern should be alert at all times toaircraft executing straight-in approaches.
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I think it's also important here to emphasize airmanship. Anyone who flies at non-towered airports regularly knows that there's a wide range of knowledge about and ability to fly the recommended, "standard" traffic pattern. Although you may be able to cite chapter and verse to demonstrate that flying a wide base leg to join a 1-mile final is legally OK, common sense and safety suggest that if there are other aircraft in the pattern, it's generally best to join the flow. You won't save that much time by taking shortcuts anyway.

 

[EdFred]

Don't get me wrong Bruce I'm not trying to demonstrate bad airmanship, but when it is obvious there is no one else in the pattern and I am straight in after being in the clag for 3 hours, I am probably not going to make another circuit around the pattern, and I make take the wide "base" from the opposite pattern direction. If someone is in the pattern and my straight in will interfere, I will defer to them, throw a 360 or S turn in there, or fly the circuit correctly.

Dave -

I know the size of a taught pattern, but that wasn't the question I was asking.

 

[poadeleted20]

So, am I to interpret that to say I could make a right "base" 1 mile out for a straight in since I'm not "in" the pattern?

No. Too many airplanes are going out to one mile or more before they turn final, sometimes because of traffic, sometimes because they just need a longer final to stabilize (e.g., jets). As a matter of personal practice (not from any book or regulation or manual, it's just the way I do things), I won't shoot a straight-in unless I can be established on final at least three miles from the runway, and nobody's ever questioned me on doing that.

 

[Richard]

As a matter of personal practice (not from any book or regulation or manual, it's just the way I do things), I won't shoot a straight-in unless I can be established on final at least three miles from the runway, and nobody's ever questioned me on doing that.

Ron, why so far out? Now, if it's a safety feature for operations at non-towered aprts I can understand. (I avoid straight-in app at non-towered flds, period.)

 

[poadeleted20]

Ron, why so far out? Now, if it's a safety feature for operations at non-towered aprts I can understand.

That's just what it is. At towered airports, the controller is supposed to be keeping folks from running each over on the runway, and informed about who they're following, so if at all safe/possible, I'll do whatever Tower asks, including simultaneous patterns from opposite sides to the same runway.