Turning Base

mandm said:
I usually just pick a landmark on the ground that I like and use that. Especially if a highway/road leads up to it.
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That will work at home aerodrome, but not at an unfamiliar airport. For that reason, when I taught I always taught to use aircraft based references to arrange your pattern.
 
In the last several months, I've been doing almost exclusively multi-engine upgrade training, so by definition with experienced pilots only. Almost all of them mention "okay, there's 45 degrees, turning base" as we fly the pattern.

However, none of us has a protractor out to measure the angle, and I'm pretty sure that most of our estimates of 45 degrees are different. There's a lot of variability there. I prefer closer-in patterns, but is my estimate of 45 deg really any better than theirs? So I've been wondering if maybe my "45 degrees" is really more like 30 degrees.
 
In the RV-8, I fly downwind a bit under half a mile out, power to idle at the numbers and begin turning base, prop forward, keep the turn going instead of squaring the pattern, and hit my landing spot smoothly with no float - usually abeam the PAPIs.

I was taught the partial power stabilized approach, but the power off circling approach is stabilized as well. Airspeed is steady, decreasing at an even rate, descent rate stable and reasonable, flight path not wavering back and forth but smooth.

If there is traffic to follow, no problem keeping it wider and longer so to speak. Be ready to fly the right pattern for the situation and make it work.
 
I use 45 degrees, but keep in mind, if you use 45 degrees and you are 1/2 a mile from the ap on downwind you will end up turning a 1/2 mile final. If you are 2 miles from the runway, you will end up turning a 2 mile final.
 
I fly a loose pattern that drives CFIs nuts. My thinking is that there are way more stall/spin accidents in the pattern than engine out mishaps.
 
Not just loose pattern, but rounding corners instead of squaring downwind to base and base to final is what I am hearing from the Lancair folks.
 
apr911 said:
At 30 degree bank and 70kts, a 180-degree downwind to final turn will take you 1500ft or 0.25NM... Which leaves about 10 seconds for base with no wind.
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I think my standard pattern has a base leg shorter than 10 seconds. Just enough time to roll my wings level, check final for traffic and, usually, go to full flaps. I’d guess maybe 5 seconds but I may dig up a video and actually time it.

Like others, my turn to base is at roughly the 45° point. Works for me.
 
Just checked. This video has me trying out a rounded pattern, followed by a normal one. In this particular normal pattern my base seems to be about 10 seconds, which feels about right and not rushed at all.


Having tried “circular patterns”, I’m not yet a fan - I like that straight and level “pause” on base to look around and judge how things are going.
 
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I was trained to use 45 degrees also. I use FlyQ and one feature I love is the flight tracking history. After each flight, I can check to see how my patterns were, did I correct for the wind appropriately, was the upwind on the centerline etc? I assume other EFBs have a similar feature.
 

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FastEddieB said:
Just checked. This video has me trying out a rounded pattern, followed by a normal one. In this particular normal pattern my base seems to be about 10 seconds, which feels about right and not rushed at all.
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I looked at several of my landing videos and 10 seconds on level base seems to be average, and about 15 seconds from the end of base to final turn and the threshold.
 
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FWIW I currently fly an airbus and we use the 45deg as the base turn. It usually winds up being one continuous base turn to final.
 
the problem is, what ever the airlines do filters down to GA because A. the FAA only thinks 121/135 and B. most of the good old CFI's are either dead or retired and the new breed are all building time for the airlines. every CFI teaches stabilized approach, but they don't understand what stabilized approach really is. do you really need to be configured, on speed, power up at 1000 ft in a c150? there is really no reason to carry power all the way down final in a single engine trainer, all that will do is make you land short if it fails. the stabilized power up is needed in a airliner due to spool up time and inertia. power off 180's should not be a commercial maneuver, it should be a primary maneuver. its simple energy management. the technique of flying a wide pattern with a student to give them time is a bad technique, because it builds a bad habit that you must undo as they progress. the reliance on vasi's has also been a factor in wide patterns, a three degree glideslope is great when on gauges, but makes for a big pattern because of the math to intercept it off a base. i prefer to use an airport without a vasi for primary training if I can, it makes the student really visualize and understand what they are doing. it all comes down to the narrowing of the box that pilots perform in. the faa has been pushing pilots away from the corners of the envelope for years, thinking that if people dont fly out towards the performance envelope they will not exceed it and safety will improve. look at the "new" slow flight standards. all it does is make pilots more dangerous when they get out of that small comfort zone.

there was an earlier post about limiting bank angle to decrease the chance of a stall/spin. how does that increase safety? first, if your not uncoordinated there wont be a spin. second, stall speed only increases with a increase in bank angle with a increase load factor, so if increase the bank angle but keep the load factor constant no increase in stall speed.

As CFI's we are all failing, we are teaching people how to fly, not how to be pilots. most CFI's are a expert at programming the 430, but have never even cracked open aerodynamics for naval aviatiors.
 
FORANE said:
Not just loose pattern, but rounding corners instead of squaring downwind to base and base to final is what I am hearing from the Lancair folks.
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I was taught to fly a "Corsair" approach from day one. A continuous arc from base to final.
 
Shepherd said:
I was taught to fly a "Corsair" approach from day one. A continuous arc from base to final.
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Same here when I got checked out in my Bonanza...my instructor was an old Navy pilot...carrier approach is what he called it .

When I fly a high wing I square up the tun to check for traffic.
 
To be serious for a moment....

Was taught that I needed to:
1) When abeam on downwind, pull power back (not off) and if you're really good you don't touch it again. Set correct flaps and get the right speed.
2) Turning Base is when you're 45 degrees from the threshold, AND assuming you're doing it right you've dropped 300 feet from pattern altitude AND you're at the right speed as well.
 
FORANE said:
Not just loose pattern, but rounding corners instead of squaring downwind to base and base to final is what I am hearing from the Lancair folks.
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As others have mentioned, the arc turn from downwind to final is the Navy way. But it also has its origins from landing other ground based planes with poor forward visibility before WWII.

I started using the continuous turn when I got my Waco. It allows you to make a nice steady descending approach while maintaining visibility on your landing spot. And you can indeed roll wings level briefly on the base portion to do a quick scan for traffic.

People have gotten this misguided idea that stabilized approach means long finals at constant airspeed and/or wide and perfectly square traffic patterns. I suspect that comes from overly conservative CFIs who themselves never had a good feel for mastering basic airmanship.
 
Arnold said:
That will work at home aerodrome, but not at an unfamiliar airport. For that reason, when I taught I always taught to use aircraft based references to arrange your pattern.
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True, I do get nervous at new airports hoping the one I see is the correct one. Almost best to just load up an approach.
 
about that continuous turn ... I tried that a few times, but that seem to block my view of that norad cub who might in final and my low wing is blocking it. is there a secret sauce i am missing?
 
WannFly said:
about that continuous turn ... I tried that a few times, but that seem to block my view of that norad cub who might in final and my low wing is blocking it. is there a secret sauce i am missing?
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As I posted above, nothing about the 'continuous' turn prevents you from briefly rolling wings level in the middle of it to scan for traffic.

Also, keep in mind those no radio cubs aren't typically flying long straight in finals.
 
mandm said:
True, I do get nervous at new airports hoping the one I see is the correct one. Almost best to just load up an approach.
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Foreflight and the G1000 perspective+ make this easy, and I agree. We have two closely aligned runways at Bedford that people apparently end up on the wrong runway enough that it is a permanent announcement to check runway alignment on final. Screwing up results in a violation now..... or worse if you are really unlucky.
 
I've read a few posts only and haven't seen mention of wind, glide ratio and distance from the runway on downwind. Maybe, with zero wind and enough experience to fly the appropriate distance from the runway on downwind for any preferred power setting, the approach can be managed where turning base at a 45° works out ok. But the OP asks about being "taught". From the very beginning it's landmarks and rote procedure, "Over this, do this, over that, turn to there, etc." Next, as descending, it's "Are you too high or too low?" "Make a small change." Rapidly, rinse and repeat. Over and over again and again. Then, after these lessons have sunk in, there's no need to think in terms of 45°. You've been "taught" to adapt and when life serves up lemons, you just make lemonade.
 
As to distance from the runway on downwind, I like to use the wing as a reference. Typically, the outer quarter covers the runway when I'm at TPA with wings level. I need to superimpose flight tracks on Google Earth to measure what the actual distance is. But it "feels right" and I can easily glide in if need be.

I only use the smallest amount of rudder in the scenario of overshooting base to final. As others have said, I crank in a little more bank angle, point the nose down and let 'er fall (the RV-9A has a ridiculously small amount of adverse yaw).

Edit: Just measured it; about 0.6-0.8 miles. At Cable in Upland, CA, our cutout from Ontario's Class C is pretty tight, and the bomber guys are no doubt busting airspace all the time!
 
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steingar said:
I fly a loose pattern that drives CFIs nuts. My thinking is that there are way more stall/spin accidents in the pattern than engine out mishaps.
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Most of those stall spins follow an engine out while stretching it because you’re too far away.
 
2 miles out abeam the runway on downwind is ridiculous. Just saying. I wasn't that wide in an F-111 on inside downwind.
 
mandm said:
True, I do get nervous at new airports hoping the one I see is the correct one. Almost best to just load up an approach.
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Load an approach to avoid flying a regular VFR pattern at an unfamiliar airport?? Whatever happened to visually gauging your aircraft's glide angle below the horizon and turning base when it looks right? The sight picture is the same at any airport, you don't need landmarks. Do you never fly into small private strips where you can't load an "approach"?
 
RoscoeT said:
Load an approach to avoid flying a regular VFR pattern at an unfamiliar airport?? Whatever happened to visually gauging your aircraft's glide angle below the horizon and turning base when it looks right? The sight picture is the same at any airport, you don't need landmarks. Do you never fly into small private strips where you can't load an "approach"?
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Well, the sight picture is different sometimes. Terrain, buildings, etc. can make an unfamiliar airport difficult to spot if you've already descended to near TPA. For me, the best course of action is to overfly the airport and get my bearings.
 
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