Unicom

September 2002 Issue




Turnback Technique

More pilots need a plan for handling this unenviable choice

An excellent article on turnbacks [Airmanship, July]. John Eckalbar discusses this in detail in his books: “Flying High Performance Singles and Twins”, and “Flying the Beech Bonanza”. I attended the Bonanza Pilot Profiency Program in April and had the pleasure of hearing John speak in person. Part of the study material was a chapter on “Turnbacks” written by Eckalbar. Out of curiosity I later asked several members of a flying club I belong to about turnbacks, minimum altitude, optimum bank angle and optimum airspeed. I was surprised that many had no clue. I was shocked at how few had a “plan” for engine failure at low altitude.

The BPPP approach to the problem is similar to yours, they found 45 degrees to be the optimum bank angle, however, 50 and 40 degrees produced only slightly greater altitude loss. They adopted an airspeed of 130 percent of stall speed for a given weight, and interestingly in the A36 at near gross weight that equates to 96 knots which is the same as Vy for that weight.

One other important point was that in the worst case scenario, ie a straight out departure, it will require nearly 360 degrees of turn (270/90, or more closely 250/70) to line up with the runway. Most people I asked assumed 180 degrees of turn was all that is necessary. The point being, if you go up to practice, it would be safer to assume 360 rather than 180 degrees . Other points to consider would be airport elevation, density altitude, wind direction and gross weight. It will take considerably more altitude to do the turnback at 3600 pounds than say 2800.

I think the most important point is to have a plan for every takeoff, especially the high weight ones. The BPPP comes up with 700 to 800 feet as the absolute minimum for a Bonanza at normal operating weights. And practice does help considerably just like any other maneuver.

-Jim Piper
Palos Verdes, Calif.


Good for you for pursuing this information on your own. We’d like to clarify two of your points, however.

First, making the turn at 1.3 time stall speed will get you there, but you will lose more altitude in the process than if you adopted the stall-speed-plus-five strategy because your turn radius will be greater. The faster speed does give you more of a cushion against a stall or stall/spin, so it does have some merit if conditions permit. We’d suggest practicing a maximum-performance turn at close to stall speed and from that develop a target height above terrain above which you’ll turn back. As you climb above that critical height, you can allow yourself a greater cushion above stall speed. Your turn will be of larger radius, so you’ll lose more altitude, but you’ll have more to play with.

Second, making a teardrop turnback isn’t a 360-degree maneuver. Runway length and altitude at failure will make a difference, but for an average consider the turnback about 225 degrees from runway heading, followed by about 45 degrees in the other direction to line up, for a total of about 270 degrees of turn. At least the 225 will get you back to the open airport space efficiently, even if it won’t line you up with the runway, which is especially important at airports that are surrounded by development.

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Spins and Splats
Although I’m not a real fan of spin training, Rich Stowell’s “Recovery Room” [Stick & Rudder, July] was very interesting and hit upon some apparent lack of instruction and testing of stalls and stall/spin awareness. Teaching and testing to the Practical Standards might be as benificial as the spin training he suggests, along with the use of sound judgement.

Ken Ibold’s “Trouble Times Two” was also a good article [Accident Probe, July]. A very good example of the classic case where “one” won’t get you but “two” or more team up to bite hard. However, Ken seems to have confused moments with inches. Extension of the envelope in the loading graph indicate that the plane would still be balanced within limits. Not having the complete weight and balance info, I am guessing that the “moments” shown really have been divided by 1,000. I think if the center of gravity was near nine inches aft of the aft limit, they wouldn’t have made it much beyond the end of the runway.

-Frank L. Miller
Ninilchik, Alaska


The NTSB report of the Mooney accident refers to the following calculations: Center of gravity at takeoff: 147.38 inches. Center of gravity at the time of the accident: 142.88 inches. CG range at max gross weight: 128 to 138 inches. But you are right that those numbers are the aircraft moment divided by 1,000 rather than inches aft of datum.

If you extend the CG envelope linearly, you’ll find the true center of gravity, at 48.5 inches aft of datum, would be within the envelope, but do you really want to make the leap involved with extending the envelope described in the loading graph?

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Ice? No Thanks
Regarding “Trouble Times Two” {Accident Probe, July], I think it’s important to note that, weight and CG issues notwithstanding, the critically important statement to make is that Mooneys will not carry ice, this being a function of the particular airfoil that contributes to the airplane’s speed.

Twelve hundred total hours – and 10 scary minutes in the 1980s – taught me this in a convincing manner.

-Lawrence Rayner
Lake Geneva, Wisc.

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Try This for Takeoff
I propose that we may be instructing incorrectly regarding the takeoff phase of flight. Since a disproportionate number of aviation fatalities occur in this phase of flight, we should be looking for explanations and teaching techniques to reduce those risks.

A power failure after rotation is the ultimate stressor if you are unprepared. The ground is close, airspeed is marginal, and the pilot may well be terrified. Not surprisingly outcomes are too often bad.

For some time now I have been modifying my takeoff proceedure as follows. I start the roll with a slight nose-down trim, acelerate to liftoff speed, rotate to become airborne, and then stay in very close ground effect till I reach cruise speed (about 85 to 95 mph in my Kitfox). I then start the climb-out and although airspeed bleeds off somewhat with the climb, I keep the airspeed above the best rate of climb speed.

I have thought that this technique has two worthwhile advantages in the event of an engine-out emergency. First, if I am still in ground effect I can simply bleed off airspeed and land. Second, if the engine fails at, say, 200 feet, the extra margin of airspeed gives me a few moments to reign in the panic and hopefully lower the nose before the stall occurs.

I have also thought that staying in ground effect is also a good technique for clearing obstacles for the reason that flying in ground effect allows the aircraft to gain energy with the maximum efficiency and in the shortest time, allowing the aircraft to hop over the obstacle. I would be most interested in a discussion of these possibly whacky ideas. What would be the pros and cons?

-Paul Phillips
Scottsbluff, Neb.


We see a couple of problems with this approach. If you’re keeping the airspeed above best rate of climb, you’re going to have less altitude to work with in the event of an engine failure.

Using ground effect to help you accelerate is OK until you get to best rate of climb speed. Any faster than that and all you’re doing is getting closer to the end-of-runway obstructions than you have to be. Your high-speed “hop” over an obstruction may be unnecessary if you make the climb at the peak of the airplane’s efficiency – best angle or best rate of climb, depending on your objective.

It’s obvious you’ve given this some thought, so we recommend you take a stopwatch and an impartial observer and try each way. We think you’ll discover that your airplane’s performance has been disguising the shortcomings in your approach.

Accidents in the takeoff phase of flight are generally associated with overloading, poor crosswind control, fuel contamination and the pilot’s sleepy right foot not compensating for p-factor.

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Electronic Archives
I’m a long-time subscriber to this publication and I was wondering if it’s possible to get an electronic copy of Ron Levy’s article “Ready to Rumble” [Instrument Check, July]? It’s for personal use, of course.

-Tom Thomas
Santa Fe, N.M.


Funny you should mention it. As you may have noticed elsewhere in this issue, our web site is now up, complete with archives for the last couple of years, with more coming as we get them uploaded. Go to www.aviationsafetymagazine.com and follow the simple instructions. If you’re a subscriber you can create a logon and get whatever you want. Make sure you have a mailing label available because you’ll need the codes from it. If you’re not a subscriber, you can still buy articles individually.

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Outta the Way, Pal
Much attention has been rightfully given to proper airport and runway safety procedures in recent months. It has been my experience that controllers have been quite patient and helpful in giving progressive taxi instructions at unfamiliar airports, and all of them I have dealt with have cheerfully repeated clearances to cross runways when asked for confirmation.

It is time for pilots to look at their own behavior and see if it reflects the same willingness to embrace safety. I was recently departing North Las Vegas Airport for the first time. It was quiet and fairly early in the morning, because I wanted to avoid high density altitude and afternoon winds over the mountains to the west.

I received my clearances and began to taxi as instructed. At my home airport, I could taxi at rotate speed if I wanted to, but at an unfamiliar field I taxied at a conservative but not snail-paced 12 to 15 knots or so.

Near a well-marked intersection, I slowed a little to make my turn onto another taxiway and, through ANR headsets and over the sound of my I0-520, I heard a loud noise from directly behind me.

I glanced back and was surprised to see a commercial turboprop right on my rudder revving and cycling his props, presumably to speed me up. At the runup area, he did the quickest runup I’ve ever seen, and taxied by me at a ridiculous speed, giving me a surly look as he passed.

I should add that every window of his airplane had a face pressed against the glass. Undoubtedly, he’d given his apologies to the passengers for the holdup caused by the inconsiderate Bonanza pilot ahead of them. (I realize I’m making some assumptions here.)

The behavior of this pilot is akin to automobile “road rage” and is not something pilots should let creep into their routine. This type of action could have resulted in a flustered pilot blundering onto an active runway, making a taxi turn too quickly, or other accident.

Please remember that although you may be totally familiar with your airport, other pilots aren’t. Have some patience and expect the same patience from fellow pilots and we will be safer for the effort.

Al Browne
Salinas, Calif.


There’s no doubt that “runway rage” is alive and well. But in the interest of fairness we’d like to point out that all that revving and cycling of props may not have been intended to intimidate you. Many charter operations use a “rolling runup” while taxiing to speed things up.

We don’t want to suggest you’re just being paranoid, because we weren’t there. But we hope you consider the possibility that you were not the target of unfounded rage, but just the guy in front.