Cooler heads observed that the majority of unintentional spins occurred in the traffic pattern, particularly on the base-to-final turn, where there was no room to recover even if the pilot knew how to. So knowing how to spin and recover served no purpose, besides its entertainment value—which, to be sure, was considerable.

Under the new dispensation, pilots were taught, in theory at least, not how to recover from a spin but how to avoid one. Nevertheless, stall spins, usually in the traffic pattern, still account for more than a tenth of all airplane accidents and around a fifth of all fatalities. Because they involve a vertical descent, stall spins are about twice as likely to be fatal as other kinds of airplane accidents.

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Why has the FAA’s emphasis on stall avoidance not done more to reduce the number of stall spin accidents? There are probably many reasons, but I think the lack of realism in the training environment deserves some blame. The training stall is a controlled maneuver, briefed in advance, approached gradually, calmly narrated, and recovered from without delay. The real-life, inadvertent stall is sudden, unexpected, and disorienting.

The pilot does not see it coming and so does nothing to prevent it. The training stall is so reassuring that pilots fail to develop a healthy fear of the real thing. After this preamble, you may guess that I am going to talk about a fatal stall spin.

The airplane was a Van’s RV-4, an amateur-built two-seat taildragger with a 150 hp Lycoming engine. It had first been licensed 13 years earlier and later sold by its builder to the 48-year-old pilot, a 1,300-hour ATP with single- and multiengine fixed-wing, helicopter, and instrument ratings. For the past six months, the pilot had been on furlough from regional carrier Envoy Air, where he had logged 954 hours in 70-seat Embraer ERJ-175 regional jets.

On the day of the accident, he added 24 gallons of fuel to the RV and flew from Telluride (KTEX) to Durango (KDRO), Colorado, a 25-minute trip, to pick up a friend. They then flew back to Telluride, where the temperature was 1 degree Fahrenheit, and a 10-knot breeze was blowing straight down Runway 27. The density altitude at the runway was about 9,600 feet.

Entering a wide left-downwind leg at about 100 knots, the pilot gradually decelerated and descended. By the time he began his base-to-final turn, he was about 200 feet above the runway and was going to slightly overshoot the extended centerline if he didn’t tighten his turn. His airspeed dropped to 50 knots, and the airplane stalled and spun. An airport surveillance camera caught the moment—a blur, then a swiftly corkscrewing descent. It was over in a few seconds. Both pilot and passenger died in the crash.

• READ MORE: Two Fatal Cases of the Simply Inexperienced

The National Transportation Safety Board’s finding of probable cause was forthright, though it put the cart before the horse: “The pilot’s failure to maintain adequate airspeed…which resulted in the airplane exceeding its critical angle of attack…” Actually, the opposite happened: The pilot allowed the angle of attack to get too large, and that resulted in a loss of airspeed. It was the angle of attack, not the airspeed, that caused the stall.

Still, it was an airspeed indicator the pilot had in front of him and not an angle-of-attack indicator, so to the extent that the pilot was consciously avoiding a stall, he would have had to use airspeed to do so. 

The published stalling speed of the RV-4 at gross weight is 47 knots. In a 30-degree bank, without loss of altitude, that goes up to 50.5. Individual airplanes may differ.

But in any case it’s misleading to make a direct, mathematical link between bank angle and stalling speed, although the NTSB frequently does just that. When you perform a wingover, your bank angle may be 90 degrees, but your stalling speed is certainly not infinite. In the pattern, you can relieve the excess G-force loading associated with banking by allowing the airplane’s downward velocity to increase—assuming that you have sufficient altitude.

On the other hand, with your attention focused on the simultaneous equations of height, position, glide angle, and speed that your mental computer is solving in the traffic pattern, you may not even be aware of a momentary excursion to 1.2 or 1.3 Gs.

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The RV-4, with a rectangular wing of comparatively low aspect ratio and no washout, stalls without warning in coordinated flight but is well-behaved and recovers readily. Uncoordinated, it can depart with startling abruptness. It resembles all other airplanes in being less stable when the center of gravity is farther aft, so maneuvering at a speed just a few knots above the stall may be more perilous when there is a passenger in the back seat. Like most small homebuilts, the RV-4 is sensitive to fingertip pressure on the stick and easily overcontrolled.

The NTSB’s report on this accident does not include any information about how many hours the pilot had flown the airplane or how many of those were with a passenger. The FAA registry puts the cancellation of the previous owner/builder’s registration just one month prior to the accident, suggesting the pilot may not have had the airplane for long.

The pilot never stabilized his approach. He descended more or less continuously after entering the downwind leg several hundred feet below pattern altitude—to be sure, the pattern at Telluride is 400 feet higher than normal—and never maintained a steady speed even momentarily. His speed decreased more rapidly as he entered the final turn, perhaps because he felt he was a little too low and instinctively raised the nose. Besides, the terrain rises steeply toward the approach end of Runway 27, possibly making him feel he was descending more rapidly than he really was.

A final factor that may have played a part in this accident is the altitude. The runway elevation at Telluride is at about 9,100 feet. Density altitude doesn’t matter for speed control in the pattern if you pay attention to the airspeed indicator, because all the relevant speeds are indicated airspeeds. But your true airspeed, which is 10 knots greater than indicated, can still create the illusion that you have more speed in reserve than you really do when you are making a low turn to final.

There’s a reason that students are taught to establish 1.3 V_s on the downwind leg, begin the descent abeam of the threshold, and maintain a good speed margin throughout the approach. It helps keep the stall-spin numbers down.

Note: This article is based on the National Transportation Safety Board’s report of the accident and is intended to bring the issues raised to our readers’ attention. It is not intended to judge or reach any definitive conclusions about the ability or capacity of any person, living or dead, or any aircraft or accessory.

This column first appeared in the Summer 2024 Ultimate Issue print edition.

The post Ultimate Issue: Analyzing a Fatal Final Turn appeared first on FLYING Magazine.

The next day, the wreckage of the 140, its front end crushed, was found a few hundred feet northwest of the pilot’s private strip. Since the flaps were down, it had evidently been approaching to land when it stalled and spun. There was no way to know why the mishap occurred, but the National Transportation Safety Board (NTSB) report on the accident noted that conditions were such that carburetor icing was likely.

Stall spins are, and always have been, a common cause of fatalities in general aviation. They often occur during turns at the base-leg end of the pattern. What made this accident a little less usual than most was the history that led up to it.

According to the NTSB, the father, 39, was a student pilot. He had learned to fly from his grandfather, who had no pilot certificate at all. The father began logging time in 2007 and stopped in 2015. He got his last FAA medical in 2014 and his last fight review in 2015. He had a student endorsement for a Cessna 150 but none for the 140. The NTSB estimated his total time as 40 hours, of which 20 were as pilot in command and 20 were in the 140. These estimates were based, apparently, on the fact that the pilot used the 140 to survey local water towers from the air and report levels to their owners.

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The CFI from whom the pilot had received some flight instruction—and who described him as a “safe pilot”—reported that the pilot knew he was not allowed to carry passengers with a student certificate, but he was “anti-regulation with the government.” The NTSB attributed the accident to the “student pilot’s noncompliance and lack of experience” but noted it was impossible to know who was at the controls at the time of the fatal stall. The father could have been upholding the family tradition by teaching his son to fly.

Three weeks after that accident occurred, a Cessna 421 crashed in a wooded area near the DeLand, Florida, airport (KDED), killing its three occupants. A couple of witnesses saw the airplane flying at low altitude. One, who spotted the airplane on two occasions 10 minutes apart, described the engines on the second sighting as sounding as if they were idling. Another witness reported hearing popping or backfiring sounds. The latter witness also reported the airplane rolled to the left three times before he lost sight of it behind the treetops. It’s not clear whether by “roll” he meant a full roll or, more plausibly, a wing dropping and then coming up again.

The NTSB concluded “it is most likely the pilot lost control of the airplane while maneuvering” and added that the “pilot’s lack of any documented previous training in the accident airplane make and model contributed to his inability to maintain control of the airplane.”

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The pilot of the ill-fated 421 was a 500-hour SMEL CFI. His logbook lacked a “complex airplane” endorsement, but that was probably an oversight. A complex airplane is one with flaps, retractable landing gear, and a variable-pitch propeller. It would be difficult to earn a multiengine rating in an airplane without those features—there aren’t a lot of Champion Lancers left.

As pilots who have flown more than one type of airplane know, the actions required to keep them right side up are alike for all. This 500-hour CFI with 40 hours of logged multiengine time had managed to start the 421’s two GTSO 520s, taxi, take off, and fly for at least 10 minutes. He seemed to have demonstrated an ability to control the airplane.

The 421 had a somewhat checkered recent history. Its last annual inspection had been performed five years earlier, and its Hobbs meter had advanced only four hours in the meantime. Its previous owner had put it up for sale on eBay, and a Texas man had bought it for $35,000, sight unseen, intending to spend a few thousand dollars having it restored to airworthy condition and then resell it. The 50-year-old airframe had, according to aircraft.com, 5,713 hours, and both engines were well short of TBO.

NTSB investigators found nothing to suggest the engines had failed, but the condition of the propeller blades indicated “low rotational energy at impact.” Fire destroyed all fuel tanks, and the NTSB report does not comment on the quantity or quality of fuel residues or the presence or absence of water or other sediment in the engines or what remained of the fuel system.

The Texas A&P whom the owner had engaged to travel to Florida and restore the airplane to airworthy condition had located a pilot to deliver it for $4,500. That pilot, 32, was in the right seat when the crash occurred. With a private certificate and 155 hours, he was even less qualified than the left-seat pilot to fly the 421. The owner declined the suggested pilot and instead gave the job to a certain instructor whose name he did not recall.

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Most likely, this was the instructor who was flying the airplane when the accident happened. At the time of the accident the airplane had not yet been signed off by the A&P, and afterward everyone involved denied having any idea what the two pilots and their passenger were doing flying it. The NTSB speculated that the flight was probably of a “personal” nature—that is, a joy ride.

The NTSB blamed both of these accidents on inexperience. Although the South Dakota pilot owned his airplane and had flown, on and off, for a dozen years, his experience had been intermittent. The least one could say is that when the accident occurred, he was more experienced than he had ever been before. As for the other cause cited, noncompliance, it’s hard to see how it qualifies as a cause.

Plenty of experienced and compliant pilots stall and spin, and nobody says they did so because they were too experienced or compliant. In the case of the Florida crash, the NTSB cited the “pilot’s lack of training and experience in the accident airplane make and model.”

The analysis fails to even suggest the possibility of an external cause, such as, say, a partial power loss in the left engine. In fact, as an online bodycam video of the arrival of would-be rescuers at the accident site shows, the airplane came to rest right side up and was not severely fragmented.

Was it really out of control? Or was the pilot valiantly trying to cope with an emergency not of his own making?

Note: This article is based on the National Transportation Safety Board’s report of the accident and is intended to bring the issues raised to our readers’ attention. It is not intended to judge or reach any definitive conclusions about the ability or capacity of any person, living or dead, or any aircraft or accessory.

This column first appeared in the April 2024/Issue 947 of FLYING’s print edition.

The post Two Fatal Cases of the Simply Inexperienced appeared first on FLYING Magazine.