We all know a majority of accidents occur in the traffic pattern; especially during descent and runway line-up. But the burning question is “why?” Basically, we fear the wrong things. Most pilots don’t understand the basic flight dynamics of descending turns and the real consequences and risks of unstabilized flying. With a little knowledge, practice and a committment to artful flying excellence, we all can do better and fly safer.
But instead pilots try to achieve safety by never banking over 20 degrees, flying huge patterns and becoming increasingly timid. Others advocate oval patterns to eliminate the steeper corners of the pattern (but fly a constant turn). Why not just “learn to turn” correctly and safely in the first place? I watch in amazement as pilots horse their planes around to final with varying bank angles and wildly changing airspeeds (hold on partner!) exhibiting a lack of stability, ground track control and overall discipline. The physical problems with patterns are obvious but they are driven by a lack of understanding risk and knowledge of the forces at work. This lack of stability and control continues directly into professional piloting where unstable approaches and overrun accidents are the #1 cause of accidents in corporate jets. As aviation educators (and pilots) we need to do better. Understanding some basic flight dynamics is critical to success.
Safety and a passion for pattern precision starts with an understanding of the invisible angle of attack (AOA) where the real risk hides. Simply presenting and thoroughly explaining a set of pictures like the ones above can jump start the conversation and clear up some very common misunderstandings. When asked which aircraft depicted above has the greatest angle of attack (AOA) almost every pilot (and many CFIs) pick the nose-high Cessna. The “a-ha” learning opportunity is that the AOA is the same on both of these aircraft. And that means the airplane in the glide is just as close to a stall as the nose-high plane on the left (now risk becomes clear). If we never demonstrate a stall with the nose *below* the horizon a new pilot in training will never understand AOA and how accidents occur. There is a “natural” (but erroneous) assumption that with the nose low, we are “safe” and “all stalls occur with a nose-high flight attitude” – wrong and reason #1 for pattern accidents! Even if this error is not stated verbally, practicing and demonstrating only nose-high stalls builds this myth and masks the true danger of descending turns.
In our initial flight instruction teaching the basic level turn, we emphasize that when a plane is banked, the lift vector is redirected to the horizontal (to create the turn) and no longer entirely opposes gravity. Consequently, some back-pressure is necessary to maintain altitude in a level turn. And during initial flight training, we build up this rote, muscle memory “bank and add pressure” response through repetition. But when we move on to the descending turns, is essential to emphasize this previously memorized script is incorrect.
A descending turn is completely different and requires “bank and release” because the added load of the bank will add drag and cause a decrease in airspeed (and greater AOA) unless back pressure is relaxed (and trim is a wonderful and underused tool here). Pilots descending tend to lose airpseed on every turn; they are banking and inappropriately adding back pressure (or failing to appropriately release). This is reason #2 of the “why” that explains many pattern accidents. This failure to understand the basic flight dynamics of the turn and AOA (also probably add some initial “ground fear” of being low) causes pilots in training bank to mishandle AOA. And once bad habits are extablished in training, they never go away.
Outside visual reference and proper trimming are also vastly undervalued in modern flight training. If the airplane is trimmed properly and the pilot in training knows the proper, predictible flight attitude for a descent in various configurations, the stabilized control of the aircraft is much easier. Unfortunately, many pilots in training are inappropriately focused inside on the panel chasing the airpseed indicator instead of setting a flight attitude with outside references. Personally, unless my pilot in training can fly the whole pattern visually, with eyes outside (and the instrument panel covered) I hesitate to even consider a solo. Fly safely out there (and often).
And of course, more on this and other key educator tools at our Oct. 2/3 SAFE CFI-PRO™ workshop at AOPA in Fredrick, MD. The registration form will be live in a week. This will have Hilton and Marriott rooms at a discount and a networking dinner at the National Aviation Community Center!
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8 thoughts on “The Secret of Pattern Safety!”
Again, read the 2014 Mar/Apr FAA Safety-Brief, page 13.
The recommendation in that Safety Briefing is to develop in-trim and hands-off flying skills. The recommendation in this article is to ‘bank and release’ in the descending turn. These are relatively subtle adjustments on the controls that I don’t think address the real issues. The base to final problem primarily involves judgement and control issues long before arriving at that turn, which include a poor pattern, inability to establish the proper descent performance, and missing the proper point to start the turn. The cumulative effect is to reach a point where the pilot panics and loses control. In a panic, these previously mentioned recommendations can be thrown out the window. So can hours and hours of study on what is the critical angle of attack. The pilot flew the pattern and initial descent poorly and didn’t start turning when he should have – the damage is already done.
A great article on trimming (I linked it into the blog). Careful trim relieves workload and stabilizes the aircraft. I *do* see people however flying the plane with the trim wheel; never a good procedure…
Yeah sure; every plane I’ve flown needs back pressure to avoid picking up speed during my 180 degree descending turn to final.
“A descending turn is completely different and requires “bank and release””. Not necessarily. It is extremely unlikely that the back pressure applied in a normal level turn in initial training is going to cause a problem in a base to final turn. The speed lost is very small – 2 to 3 knots, maybe 5. If you are anywhere near the proper speed on base, losing a handful of knots airspeed at base to final is not going to cause a problem. If there’s any concern about maintaining a little back pressure, just nudge in a little power. Releasing the back pressure will cause an increase in the rate of descent and airspeed, resulting in the airplane undershooting the aiming point and getting closer to obstacles, if any. So I don’t think it is a good idea.
We agree gentlemen…please read carefully. Trim correctly and do not inappropriately (by habit) apply back pressure. And *yes* there are many *other* ways to screw up the base-to-final turn (as mentioned). This is a blog though, not a book 🙂
Trimming is normally good but it will not fix a poor descent, only relieve control pressure. Since the transition to descent with lower power results in a nose-heavy airplane, I wonder if the emphasis on trimming makes things even worse because the trim adjustment is toward nose up. If the airplane were left nose heavy, wouldn’t there be less chance of a stall?
Careful trimming relieves workload in a busy environment. Many pilots inappropriately add extra speed on final as a safety cushion (5K for each kid?) but “on speed and stabilized” is the correct goal. Too much speed on final leads to all kinds of problems (excessive float followed by “plant and porpoise” is common) or overrun in a jet (#1 problem in turbine).
“On speed and stabilized” gives the same predictable performance every time and conforms with the published AFM data; physics!