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.

• READ MORE: A Cautionary Tale About Pilot Freelancing

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.

• READ MORE: Three-Mile Limit: Novice Pilots Succumb to the Perils of Total Darkness

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.

They were rare in general aviation airplanes until 2014 when the FAA simplified the requirements for installing them. A proliferation of aftermarket AOA systems followed, ranging in price from around $300 to more than $3,000. I don’t know how widely these devices have been adopted, nor do I know whether any study has been made of their impact on the GA accident rate.

Despite its well-known shortcomings as a stall-warning device, the airspeed indicator remains the only AOA reference in most airplanes. It has the advantages of being a mechanically simple system, intuitive, and familiar. Speed is an everyday experience, while angle of attack, for most pilots, remains in the realm of the theoretical.

Theoretical or not, I think, to start with, that we could improve the terminology. “Angle of attack” is really a proxy for something else, namely “the amount of the maximum lift available that is currently in use.” So it would be more meaningful to speak of a “lift indicator,” “relative lift indicator,” or “lift fraction indicator.”

• READ MORE: The Craft of Providing Variety in Airplanes

One of the advantages of thinking in terms of lift fraction is that almost all of the important characteristic speeds of any airplane—the exceptions are the nonaerodynamic speeds, such as gear-and-flap-lowering speeds—fall close to the same fractions of lift regardless of airplane size, shape, or weight. Best L/D speed is at around 50 percent and 1.3 V_s at exactly 60 percent. Stall, obviously, is at 100 percent. A lift gauge is universal: It behaves, and can be used, in the same way in all airplanes.

A few years ago, in a column titled “A Modest Proposal,” I suggested demoting the hallowed airspeed indicator to a subsidiary role and replacing it with a large and conspicuous lift indicator. I borrowed the title from a 1729 essay by Jonathan Swift, the author of Gulliver’s Travels, in which he satirically proposed that poverty in Ireland might be relieved if the populace were to sell its manifestly too numerous babies to be eaten by the rich. My appropriation of Swift’s title was meant to suggest that I considered my proposal was about as likely to be adopted as his.

At the time I wrote my article, I was not yet aware of a 2018 paper by a team led by Dave Rogers, titled “Low Cost Accurate Angle of Attack System.” Using a simple underwing probe and electronic postprocessing, Rogers and his group achieved accuracy within a fraction of a degree of angle of attack with a system costing less than $100. That’s more accuracy than you really need, but better more than less.

• READ MORE: Looking at the Physics of STOL Drag

The low cost is made possible by the availability of inexpensive small computers— Rogers’ team used a $20 Arduino—that can be programmed to do the math needed to convert the pressure variations read by a simple probe into usable AOA data. Processing is necessary because the airplane itself distorts the flow field around it and makes it all but impossible to read AOA directly with a vane or pressure probe situated close to the surface of the aircraft. Besides, configuration changes, like lowering flaps, alter the lifting characteristics of the wing.

Designing an accurate system is only half the challenge, however. There is also the problem, perhaps even more difficult, of how best to present the information to the pilot. Little agreement exists among current vendors. Some presentations use round dials, some edgewise meters, some various arrangements of colored lights or patterns of illuminated V’s and chevrons resembling a master sergeant’s shoulder patch.

In 1973, the late Randy Greene of SafeFlight Corp. gave me one of his company’s SC-150 lift indicators for my then-just-completed homebuilt, Melmoth. The SC- 150 used a rectangular display with a moving needle. There was a central stripe for approach speed flanked by a couple of dots for climb and slow-approach speeds, and a red zone heralding the approach of the stall. The probe that sensed angle of attack was a spring-loaded, leading-edge tab, externally identical to the stall-warning tabs on many GA airplanes.

Apparently, some people mounted the SC-150’s display horizontally, but that made no sense to me at all. Given that I wanted it vertical, however, Greene and I did not see eye to eye about which end should be up. Greene was a jet pilot used to a lot of high-end equipment (SafeFlight made autothrottles, among other fancy stuff, for airliners). He understood the device as a flight director—as you slowed down, the needle should move downward, directing you to lower the nose.

I, who despite having acquired in my younger days a bunch of exotic ratings, am really just a single-piston-engine guy, saw it as analogous to an attitude indicator and thought that as the nose went up the needle ought to do the same. Greene saw the display as prescriptive; I saw it as descriptive.

Recently, Mike Vaccaro, a retired Air Force Fighter Weapons School instructor, test pilot, and owner of an RV-4, wrote to acquaint me with FlyONSPEED.org, an informal group of pilots and engineers working on (among other things) practical implementation of a lift-awareness system of the type described in Rogers’ paper. The group’s work, including computer codes, is publicly available. Its proposed instrument can be seen in action in Vaccaro’s RV-4 on YouTube. 

The prototype indicator created by the FlyONSPEED group mixes descriptive and prescriptive cues. Two V’s point, one from above and one from below, at a green donut representing approach speed, 1.3 Vs, the “on speed” speed. The V’s are to be read as pointers meaning “raise the nose” and “lower the nose.” An additional mark indicates L/D speed. G loading, flap position, and slip/skid are also shown on the instrument, along with indicated airspeed.

Importantly, the visual presentation is accompanied by an aural one. As the airplane slows down, a contralto beeping becomes more and more rapid, blending into a continuous tone at the approach speed. If the airplane continues to decelerate, the beeping resumes, now in a soprano register, and becomes increasingly frenetic as the stall approaches. Ingeniously, stereo is used to provide an aural cue of slip or skid—step on the rudder pedal on the side the sound is coming from. The audio component is key: It supplies the important information continuously, without the pilot having to look at or interpret a display.

This system—it’s just a prototype, not a product—is pretty much what my “modest proposal” was hoping for, lacking only the 26 percent-of-lift mark that would indicate the maneuvering speed. Irish babies, beware.

Now I just have to figure out what we’ll do with all those discarded airspeed indicators.

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

The post Ultimate Issue: AOA Gets Revisited—Again appeared first on FLYING Magazine.

It was about 1 o’clock in the morning. The air on the surface was warm and humid. If he checked the weather—there was no evidence that he did—he would have expected to find widespread but patchy cloudiness over the route of flight and at the destination. In some places clouds were broken or scattered with tops at 3,000. Elsewhere buildups climbed into the flight levels. Ceilings and visibilities under the clouds were good, at worst 700 feet and 5 miles. The temperature and the dew point were only 3 degrees apart, however, and there was a slightly increased risk of fog formation owing to, of all things, particulate pollution from dust blown in from the Sahara.

During the short flight, he climbed to 3,600 feet, probably to get above some cloud tops. It was pitch-dark as the crescent moon was far below the horizon. As he neared his destination he descended to 1,500 msl, 1,300 feet above the terrain, and reduced his groundspeed from 175 knots to 100 knots.

The airstrip at which he intended to land was 3,500 feet long, 40 feet wide, and had a light gray concrete surface oriented 4/22. Other than a hangar on an apron at midfield, there were no structures on the airport and no edge lights along the runway.

The only lights were red ones marking the runway ends. The surrounding area was largely dark. Sam Rayburn Reservoir sat close by to the north and east, a vast region of uninterrupted black. Parallel to the runway, about half a mile north, was State Highway 147, lighted only by the headlamps of infrequently passing cars.

• READ MORE: Two Fatal Cases of the Simply Inexperienced

For almost an hour, the pilot flew back and forth over the airstrip, tracing a tangled path of seemingly random right and left turns. His altitude varied between 350 and 1,100 feet agl and his groundspeed between 65 and 143 knots. His ground track, as recorded by ATC radar, suggested no systematic plan, but it was broadly centered on the northeast end of the runway.

The last return from the Saratoga, recorded 54 minutes after it arrived over the field, put it 9,700 feet from the northeast end of the runway on a close-in extended left downwind leg for Runway 22 at a height of 350 feet agl and a groundspeed of 94 knots. The Saratoga was below radar for the remainder of the flight.

Its burned wreckage was found at the southern edge of the clear-cut area surrounding the runway, several hundred feet short of the threshold. A trail of parts led back across the clear-cut to its north side, where the airplane had clipped a treetop at the edge of the woods. From the orientation of the wreckage path, it appeared that the Saratoga may have overshot the centerline on base and was correcting back toward the approach end lights when it struck the tree.

In the course of the accident investigation, it emerged that the airplane was out of annual, its last inspection having occurred in 2017, the registration had expired, and the pilot’s medical was out of date. The pilot had 400 hours (estimated) but did not have an instrument rating and, in fact, had only a student certificate. The autopsy turned up residues of amphetamine, methamphetamine, and THC (the psychoactive component of cannabis), but investigators did not rule out the possibility that the drugs could have had a therapeutic purpose.

• READ MORE: Three-Mile Limit: Novice Pilots Succumb to the Perils of Total Darkness

The National Transportation Safety Board’s report on the accident declines to speculate on whether the drugs impaired the pilot in any way. In fact, the NTSB report concedes that “the pilot’s aircraft handling was not deficient relative to his limited experience of flying in night instrument conditions and the prolonged period of approach attempts.” The finding of probable cause cited only the pilot’s “poor decision-making as he attempted to land at an unlit airstrip in night instrument conditions.”

The pilot bought the Saratoga in 2016 and then took flying lessons, but he stopped short of getting the private certificate. His instructor said he had never given him any instrument training. The pilot’s wife said that he “normally” flew to the airport at night and circled down until he could see the runway.

The airport was in Class G airspace. What the cloud conditions were we don’t know—the nearest automated reporting station was 24 nm away—and so we don’t know whether the Saratoga was ever in clouds and, if so, for how long. Maneuvering around at low level for nearly an hour in darkness and intermittent IMC would be taxing even for many instrument-rated pilots, and so it seems likely that if the pilot was in clouds at all, it was only for brief periods.

• READ MORE: Fatal Cirrus Accident Shows That Some Knowledge Doesn’t Translate

Two things strike me about this accident. First, how close it came to not happening: If the pilot hadn’t clipped the tree, he might have made the turn to the runway successfully and landed without incident, as he apparently had done in the past. Second, that he had ever managed the trick at all. I can only suppose that the contrast between the runway clear-cut and the surrounding forest was discernible when there was moonlight and that he was able to use GPS and the runway’s end lights to get himself to a position where his landing light would illuminate the runway.

Rugged individualism being, supposedly, an American virtue, I leave it to you to applaud or deplore the nonconformist aspects of this pilot’s actions. Perhaps a certain amount of freelancing is inevitable in an activity like flying. But I deprecate his persistence. One of the essential arrows in every pilot’s quiver should be knowing when to quit. He set himself a nearly impossible goal, and after flying half an hour to his destination, he spent an hour trying to figure out how to get onto the ground.

If it was that difficult, it wasn’t worth doing. There were other airports—with runway lights—nearby.

At the time of the crash, the pilot was awaiting the decision of a Houston court in a wrongful  termination lawsuit that he had filed against a former employer. Five months later, the court found in his favor to the tune of $143 million. Thanks to a terminal case of “get-homeitis,” however, he wasn’t there to enjoy it.

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 May 2024/Issue 948 of FLYING’s print edition.

The post A Cautionary Tale About Pilot Freelancing 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.

• READ MORE: Three-Mile Limit: Novice Pilots Succumb to the Perils of Total Darkness

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.”

• READ MORE: Fatal Cirrus Accident Shows That Some Knowledge Doesn’t Translate

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.

• READ MORE: Only Assumptions Can Be Made About What Took Down a Curtiss C-46 in Alaska

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.

In one of his books, Austerlitz, the title character goes flying at night with pilot friend Gerald Fitzpatrick in a “Cessna.” He describes the mesmerizing sight of the familiar constellations overhead. Now, looking up at the stars from an airplane is an entrancing experience, but no one ever had it in a Cessna.

The corresponding photograph, though somewhat distant and blurred, is clearly not of a Cessna but of a small twin-engine, twin-finned airplane that does, however, have a transparent canopy. I got the explanation for this apparent authorial fumble from a Swiss friend: Among nonpilots in Germany, “Cessna” would simply mean a private airplane, no particular brand.

The twin was actually a Miles Gemini, an airplane brought into being, like the original Beech Bonanza, by the anticipated postwar explosion in demand for personal air travel. It had four seats and was equipped with two 100 hp engines of the inverted in-line variety, housed in those nice narrow cowlings that many British and French aircraft of the 1930s and ’40s had. One of its unusual features was a big external airfoil flap.

Despite the flap, however, the published stalling speed of 35 knots cannot have been a calibrated airspeed—45 is more plausible.

Whatever its real landing speed, the fictional Gerald Fitzpatrick crashed fatally in his Gemini. His friend Austerlitz gloomily comments that this was bound to happen, since he was so fond of making sightseeing flights in the south of France.

• READ MORE: Looking at the Physics of STOL Drag

Novelists just won’t give private planes a break.

I wondered how the 3,000-pound Gemini would do on one engine. Late designer John Thorp, contemplating a trip to Europe with his wife, Kay, once propped up a couple of small Lycomings in front of his two-seat Sky Skooter. His friend George Wing, creator of the ubiquitous Hi-Shear rivet, happened to walk in, and thus was conceived the Wing Derringer.

Wing was not taking any chances on O-235s, however. The two-seat Derringer, with 160 hp O-320s, could definitely climb on one engine. The question of how a twin with 100 hp engines climbs on only one was answered, however, by the Champion Lancer, whose woeful single-engine performance was, like Sir John Falstaff, a cause of wit in many men.

Like many other early aviation enthusiasts, Frederick George Miles began in the 1920s as an amateur builder. Miles then started manufacturing small airplanes and eventually turned out a series of products that recalls, in its variety and inventiveness, the career of another homebuilder-turned-professional, Burt Rutan. Like Rutan, who started the Rutan Aircraft Factory with his then-wife Carolyn, Miles found a business partner in his remarkable wife Maxine, nicknamed Blossom, who, in addition to being his beloved, was a pilot, aeronautical engineer, stress analyst, and businesswoman.

In some respects, the paths of Miles and Rutan were different. Miles made airplanes for military and commercial use. Rutan, after leaving the homebuilt plans business that had launched his career, mainly produced one-off prototypes and never certificated any of his designs. (Beech ruined the Starship, he complained, in the process of certificating it. Beech engineers naturally took a different view of the matter.) But the two shared a wide-ranging versatility. Some designers, like Thorp and Dick VanGrunsven, turn out incremental variations and improvements on a basic theme.

With Miles and Rutan, you never knew what might come next. In Miles’ case the variety may have been due in part to his employing other designers, whereas Rutan designed all of his airplanes himself. Both men mastered the art of fast prototyping: Scaled Composites, the company Rutan founded, exploited foam-cored composites for that purpose; Miles’ medium was resin-bonded wood.

Miles’ greatest commercial success came during the pre-World War II years. He developed a number of training and transport airplanes and manufactured them in large numbers for the Royal Air Force. His efforts to produce a fighter were less successful. A 1940 prototype of a small wooden “emergency” fighter, proposed to stop the gap in the event that Hurricane and Spitfire production were hampered by German bombing, had a bubble canopy and a stock Merlin “power egg,” and looked just like a miniature Hawker Typhoon. Despite fixed landing gear, it rivaled the Hurricane in armament and performance, but it was never produced, mainly because the anticipated emergency did not materialize.

During the war, Miles produced a design remarkably similar in conception to Rutan’s first homebuilt. Like the VariViggen, Miles’ original Libellula—Latin for dragonfly—had a single pusher propeller, low wing, and high canard. The configuration was supposed to solve several problems associated with shipboard fighters, but the British Admiralty didn’t bite. A second version, this one with a high wing and low canard, was conceived as a bomber, with the idea that the tandem wing arrangement would provide an unusually large CG range. That airplane also ended up on the scrap heap.

The little Gemini twin, the one illustrated in Austerlitz, was a commercial success, as was a side venture the resourceful Miles got into: ballpoint pens. But the most striking Miles design from the wartime period was something completely different.

• READ MORE: Recalling a Good Pilot Friend and One Curious Character

The M.52, born in 1943, is said to have been the offspring of a ridiculous error. An intercepted German communication referred to the 1,000 kph speed of one of the jets then being developed. Someone failed to perform the conversion, and the belief took root that the Germans were perfecting a 1,000 mph airplane. Inevitably, the British felt they needed to follow suit, and Miles Aircraft earned the contract. (If it isn’t true, at least it’s a good story.)

The result was a 5-foot-diameter cylinder with thin, straight wings and a then-unprecedented, and prescient, powered all-flying stabilizer. Air for its centrifugal-compressor jet engine came in through an annular intake surrounding a shock cone, à la the MiG-17 or SR-71. The pilot sat inside the shock cone. In retrospect, the design looks sound except for its lack of area ruling, and it could probably have gone supersonic, given sufficient thrust. But in 1946, with the first prototype nearly complete, the U.K.’s Air Ministry suddenly canceled the project.

The abrupt cancellation, which was never persuasively explained, fueled a persistent notion among British airplane buffs that their government had abjectly bowed to U.S. insistence on being the first to “break the sound barrier.” Indeed, the Bell X-1 rocket aircraft, which did so in 1947, was being developed at the same time as the M.52.

However, the M.52 may have been shelved simply because of the distinct possibility that its still-unproven afterburning turbojet might not be powerful enough to propel it past Mach 1 in level flight—let alone to 1,000 mph.

This column first appeared in the May 2024/Issue 948 of FLYING’s print edition.

The post The Craft of Providing Variety in Airplanes appeared first on FLYING Magazine.

Familiarity in flying has several components. There is the foundational element of general familiarity with airplanes and how to fly them. There is familiarity with systems; this may be of a general kind (knowing how to lean the mixture or adjust a constant-speed propeller, for instance) or specific to a particular airplane or type (such as knowing to use the left main tank of an old Beech Bonanza for takeoff when both mains are full because all return fuel from the injection pump goes to the left tank).

There is familiarity with handling characteristics: whether, for example, a certain type pitches up or down with flap deflection. There is muscle memory, knowing how much effort will be required to pitch or roll, and where to reach to lower the gear or switch fuel tanks. There is knowledge of cruising performance, clean and dirty descent rates, quality of stall warning, and post-stall behavior.

Although FAA regulations set quite precise requirements for familiarity and currency—becoming more rigorous for more complex and higher-performance airplanes—it is really hard to tell how much familiarity is enough and, for that matter, whether there is such a thing as too much familiarity. A pilot may know an airplane very well but usually fly a different type. Habits acquired from the more recently flown, or more familiar, airplane might be unconsciously applied to the other. The key word is “unconscious.” Familiarity is the thing that allows you to act without thinking. “Without thinking” is commonly a reproach, but instinctive, unconscious flying is also the hallmark of a natural and skilled pilot. There is a middle ground to be found between too much thought and too little.

How to make the first flight in a homebuilt airplane is a subject of ongoing debate, with one school arguing for short runway hops, reasoning that a few feet is not very far to fall, and another for immediate up-and-away flight, in order to get far from the rocks and hard places as quickly as possible. The impatient purchaser of a Lancair 235 tried to have it both ways.

What Happened

The pilot, 81 years old, had not flown in six months. He had about 450 hours total time. He had no experience whatsoever in the Lancair, which was turned over to him by a broker who asked him not to fly it until he had found someone with experience in the type to fly with him. The pilot promised he would not; however, he wanted to taxi-test the airplane. On his second taxi run down the runway, as the surprised broker looked on, the airplane took off and flew away.

Most likely, the pilot did not intend to break his promise to the broker, who was his friend. The airplane probably became airborne unexpectedly, and he thought it best to get familiar with it before attempting a landing.

He was gone for an hour. When he finally returned, the pilot made two landing approaches, each time going around. A witness observed that the pilot was having trouble with pitch control: “Nose up, nose down…nose up, nose down.” On the third approach, he landed long, bounced twice, climbed to 100 or 150 feet, stalled, and spun.

The National Transportation Safety Board identified the pilot’s lack of familiarity with the airplane as a contributing factor, the cause of the fatal accident being simple failure to maintain flying speed. It’s possible, however, that the pilot was not only unfamiliar with the Lancair 235 in particular but also with airplanes in general that are flown with fingertips rather than a fist. An extremely sensitive airplane is difficult for an inexperienced pilot to cope with because anxiety makes you more ham-handed and likely to overcontrol.

Some airplanes have design quirks that set them apart from others. One is the Piper Comanche, whose manual pitch trim—like that of the Ford Trimotor—consists of a crank handle in the ceiling. Early Comanches did not have electric trim, the operation of which is intuitive: forward button means nose down/go faster. Vertical trim wheels are similarly natural. The overhead crank, however, has built-in unfamiliarity.

The 3,000-hour pilot of a Comanche 250 was observed adjusting the overhead trim control as he taxied out to depart. During the takeoff roll, the propeller struck the runway surface. After breaking ground, the airplane pitched up, stalled and crashed vertically, killing all three aboard.

In principle, it should be impossible to strike a prop even with a flat nosewheel tire and a fully compressed nose strut. However, the nose-strut drag links and torque link were fractured “as if the nose gear had been forced rearward while extended.” Whether this damage arose from the crash or preceded it could not be determined; what was determined, though, was that the pitch trim was set in the full nose-down position, which would have the effect of lifting the tail as the airplane gained speed.

• READ MORE: Previous editions of Peter Garrison’s ‘Aftermath’

Another Comanche crashed somewhat similarly, although the fragmentation of the wreckage was such that the trim setting could not be determined. It was the 700-hour pilot’s second solo flight in the airplane, which he had bought two weeks earlier. He had taken the precaution of getting 15 hours of dual in it in the meantime. A witness reported the pilot appeared to intend to perform a short-field takeoff: He ran up to full power before releasing the brakes. The airplane seemed to rotate prematurely, and the witness, who was an experienced pilot, judged that it looked slow. Rather than level out to gain speed, however, it kept climbing “steeper and steeper” until it stalled and spiraled to the ground.

Although this was an early Comanche, manufactured in 1959, it was equipped with electric trim. The overhead trim is faster-acting, however. The inexorable increase in pitch angle is suggestive of an airplane that was either mistrimmed in the first place or whose pilot is inadvertently applying trim in the wrong direction while trying to get the nose down.

Fuel systems, especially ones in low-wing airplanes, which do not have a “both” position, can be a source of trouble. There are many instances of pilots using an empty tank for takeoff when there was fuel in another. Opportunities for confusion multiply as tanks become more numerous.

A 1,300-hour commercial pilot, flying a single equipped with aftermarket tip tanks, crashed while trying to return to land immediately after taking off. The pilot, who had only a few hours in the airplane, had taken off with the fuel selector on a tip tank, although use of the tip tanks was limited to whatever is meant by “level flight.” The NTSB’s report on the fatal accident does not provide information about the pilot’s previous experience, but the fact that he took off with a tip tank selected suggests he probably landed on his preceding flight with that same tank selected—also forbidden—and his previous experience may have been in airplanes, such as high-wing Cessnas, that do not require so much attention to tank selection.

Mistakes breed in the shadowy land between the systematic and the instinctive. Only by forcing our actions up into the realm of conscious procedure—for instance, by methodical use of checklists and each crewmember’s critical attention to the actions of the other—can we reduce our reliance on instinct and the unconscious errors that come with it.

This story originally published in the December 2019 issue of Flying Magazine

The post A Pilot Gets Caught Between Procedure and Instinct appeared first on FLYING Magazine.

Slowing down matters as much as accelerating in most auto racing, and the same is true of STOL Drag racing. Unlike traditional Reno-style pylon racing, which involves no slowing down whatsoever, STOL Drag requires starting and stopping twice while flying less than a mile.

I have never been to a STOL Drag race, and so I will probably be pummeled for whatever I say, but here goes anyway.

Two pylons and corresponding start/stop lines are set 2,000 feet apart. A third pylon is placed at the 1,000-foot mark, just for reference. The idea is to take off from the first line, fly to the far line, land, come to a full stop, turn around, and repeat the process without touching the ground between the lines. Two airplanes compete side by side, and the winner is the one that first comes to a full stop at the end of the race. Best times are just over 50 seconds, so, for a pleasurable activity, it’s brief.

In principle anyone can participate, but the really serious competitors use highly modified airplanes that can accelerate like mad and stop very short after touching down. However, competitors are paired off according to aircraft performance, so it wouldn’t be unusual to see a Skylane compete against a Beech Bonanza.

• READ MORE: Valdez Fly-In STOL Competition Celebrates 20th Anniversary

Since it’s a time trial, the race rewards acceleration, speed on the airborne segment, and deceleration after each landing. But the equation is complicated by the need to begin to slow down long before reaching the far pylon. Pilots accomplish this by chopping power, kicking in full rudder, and slipping toward the line. But even this phase isn’t as simple as it sounds. Airplanes decelerate quicker with wheel braking than aerodynamic braking, so while it may seem as if it’s best to touch down at minimum speed to reduce the rollout distance, it may actually be better to get the wheels on the ground as quickly as possible, even a few knots above the stall speed.

Initial acceleration is a function of the airplane’s mass and the engine-propeller combination’s thrust. Big thrust requires lots of power and a big prop. Two of the dominant competitors in the sport, Toby Ashley and Steve Henry, fly a Carbon Cub and Just Aircraft Highlander, respectively.

(Henry’s Nampa, Idaho, company, Wild West Aircraft, sells the Highlander as a light sport kit.) Neither racing airplane has much in common with its ordinary Lycoming- or Rotax-powered brethren. Both use liquid-cooled, geared, turbocharged, intercooled engines with very big props. They say the engines put out around 400 hp. The airplanes are stripped down, competing at weights less than 1,000 pounds. Since they are generating more than 2,000 pounds of static thrust, and therefore achieve an initial acceleration of 2Gs or more, it’s not surprising that both get airborne in a couple of seconds and a few dozen feet.

• READ MORE: The Ryan YO-51 Wowed with STOL Performance

The powerful initial acceleration does not last long, however, because thrust diminishes as speed increases, and drag grows in proportion to the square of speed. At 90 knots, which an airplane accelerating at an average 1G would reach in five seconds and 400 feet, drag has increased to more than 200 pounds and thrust is cut in half. Since the drag can be subtracted from the thrust to get the net force accelerating the mass of the airplane, it follows that the forward acceleration may already be well under 1G.

The actual segment times, based on videos of Henry racing at Reno last year, are, as you would guess, asymmetrical, reflecting the fact that it is easier to speed up than slow down. From brake release to throttle down at midcourse, about 10 seconds elapse. From there to wheels on, another 10, but at that point the airplane is still moving at around its stall speed of 35 knots. The rollout takes four seconds and another four to get turned around. The times going back are similar for a total of 52 seconds.

If the average acceleration up to the middle of the course were two-thirds of a G, the maximum speed attained would be about 125 knots. If the touchdown speed at the far end were 35 knots, the average deceleration in the slip would be a bit under under one-half G—more at the start and less at the end. By the time the wheels touch the ground, the rate of deceleration is pretty low. Wheel braking brings it back up to the half-G level.

• READ MORE: Valdez STOL Competition & Fly-In Air Show Marks 20 Years of Excellence

The Carbon Cub and Highlander regularly finish within a fraction of a second of each other, and successive heats also differ by small amounts. That consistency is a testament to the pilots’ skills, since, as you find when you watch any of Henry’s cockpit videos, quite a lot goes on during the brief race. Everything hinges on the deceleration timing, staying as low as possible, and amount of wheel braking that can be applied without nosing over.

Henry claims to use his airplane as a daily driver—probably at about 20 percent of power. But I suppose that if STOL Drag racing continues to be popular, it may eventually engender purpose-built airplanes. Very likely the slip-to-slow-down approach would be supplemented or replaced by large air brakes that would add several square feet to the airplane’s equivalent flat plate area. Maybe a slight edge in acceleration could be gained by cleaning up the front end, replacing the big intercooler radiator with a small tank of ice water, and getting engine cooling air to the main radiator with a scoop and duct. But aerodynamic refinement may be pointless, since so little time is spent at high speed.

High wings and a tailwheel are taken for granted on STOL airplanes for a lot of practical reasons. But I wonder whether a low wing with some extra span—taking better advantage of ground effect—and tricycle gear with brakes on all three wheels might bring some advantages. Add lots of horsepower and an airfoil with a maximum lift coefficient of two, and then…off to the races!

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

The post Looking at the Physics of STOL Drag appeared first on FLYING Magazine.

Both pilots were in their early 30s and were Polish nationals. Both held FAA private pilot certificates based on their Polish certificates. They were relative novices, with 210 hours total time between them, only 130 as pilot in command (PIC). Neither was instrument rated, and only one was legally qualified for night VFR flying. (Their FAA certificates required them to comply with the limitations imposed by their Polish ones.)

After having dinner in town, they returned to Key West International Airport (KEYW) around 8 o’clock. It was dark, the sun having set an hour and a half earlier. The moon, new two days before, was now a smiling sliver on the western horizon. By the time they boarded the airplane, it too had set.

Presumably because he was the one who had done the rental checkout, the less experienced pilot of the two, with 30 hours of PIC time, took the left seat, and his companion took the right. It was the pilot in the right seat, however, who held the night qualification.

• READ MORE: Fatal Cirrus Accident Shows That Some Knowledge Doesn’t Translate

They began their takeoff roll at 8:33 p.m. When they were airborne, the tower instructed them to make a left turn northbound, remain clear of Navy Class D airspace, and contact Navy tower for transition. “Navy” meant Naval Air Station Boca Chica (KNQX), whose airspace abuts that of KEYW.

The tower frequency for KNQX is 118.75, but the pilot read back only 118.7, followed by a pause and then the last three digits of the Cessna’s call sign, “five eight niner.” The “five” was ambiguous, but it is possible that the pilot handling the radios missed the final “five” in the Navy tower frequency. In any case, that acknowledgement was the last communication heard from the Cessna.

In the early afternoon of the following day, some pleasure boaters noticed an object floating in the water. They thought it might be a manatee and approached it cautiously, only to find that it was a human body. The water was shallow, just 7 feet deep, and perfectly clear. Parts of an airplane could be seen resting on the bottom. The site was less than 3 miles from the Key West runway. 

Accident investigators found that an airport surveillance camera had recorded the airplane’s lights as it departed. Its flight path was erratic, descending, leveling off, descending again, leveling off, and then disappearing from view.

A witness, who had been fishing from a nearby bridge and read about the accident in the newspaper the following day, reported having seen what he thought at the time was a firework but now realized might have been a red light on the airplane descending rapidly toward the water.

• READ MORE: Only Assumptions Can Be Made About What Took Down a Curtiss C-46 in Alaska

The National Transportation Safety Board (NTSB) attributed the accident to “the non-night-qualified pilot’s improper decision to depart in dark night meteorological conditions, which resulted in his subsequent spatial disorientation…”

A direct line from Key West to Miami bears about 055 degrees, and about half the trip is over open water. On a dark night, the danger of disorientation is great. The brightly lighted line of the Keys recedes on the right, while the dark Everglades lie ahead. Miami is a pale glow beyond the northeastern horizon. The two pilots having just returned from the Bahamas, flying over open ocean in a single-engine airplane evidently held no terrors. (They had, nevertheless, taken the precaution of wearing life jackets.)

Most likely, however, they had no idea that the main danger of a night flight over open water was not that they might have to ditch after an engine failure, it was that they would lose the horizon and fly into the water before they even realized that something was wrong.

The fact that one of them was legally qualified for night flying meant only that he had logged a certain number of hours and takeoffs and landings at night with an instructor, not that he had any experience flying at night in this particular kind of environment. In any case, the pilot with the night qualification was sitting in the right seat, and to the extent that he might have made better use of the attitude indicator, he was not in a position to do so.

This is not an unusual kind of accident. I have written in this column about many similar ones, including two Barons and a Citation that flew under control into Lake Erie immediately after taking off from Cleveland Burke Lakefront Airport (KBKL); a Lancair 550 and a Cessna 210 that crashed immediately after taking off on moonless nights in desert terrain; and a Piper Cherokee, on another island of the Florida Keys, that went into the water a couple of miles from the runway from which it had just taken off.

Note the recurrence of the phrase “taking off.” The airplanes that took off over a pitch-dark lake or desert invariably climbed only a few hundred feet before they began to bank, then the bank grew progressively steeper, and the climb became a dive. The pilots were unaware that anything was wrong. Once the lights disappear, the rest lasts a matter of seconds, or at most 2 or 3 miles.

The two Polish pilots did fine at first, while they were over the lights of Key West. It was only when they left the lights behind that the insidious effects of darkness beset them. Neither pilot had instrument flying experience beyond the hood work required for the private certificate, which bears more resemblance to an arcade game than the real sensations, physical and emotional, of piloting an airplane in total darkness.

In pilots’ careers certain dangers are bound to arise for which it is very difficult for an instructor to prepare them. Many of those dangers are associated with loss of a visible horizon, whether because of fog, clouds, or darkness.

Warnings to believe the instruments, not bodily sensations, may be memorized, emphasized, and faithfully repeated, but they are never so persuasive as the sensations themselves. One must work hard to develop the discipline to level the tilting wings of the attitude indicator despite an overwhelming impression that the instrument has failed and the airplane is still in level flight.

Unfortunately, not every airport has an ocean or large lake handy with which to impress upon the student pilot the perils of total darkness—and Warsaw is far from the Baltic Sea.

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 March 2024/Issue 946 of FLYING’s print edition.

The post Three-Mile Limit: Novice Pilots Succumb to the Perils of Total Darkness appeared first on FLYING Magazine.

“Wing warping,” as this approach was called, was satisfactory for very slow airplanes, but faster ones required more rigidity, and by around 1908 or 1909 the idea had arisen of replacing part of the trailing edge of a wing with a hinged, controllable flap. Actually, a prescient Englishman, Matthew Boulton, had patented the idea in 1868, when airplanes were still a thought experiment. His invention had been forgotten, however, by the time real airplanes came into being. Despite the early invention of the aileron, wing warping continued to be used, even on some fighters, as late as 1916.

That a hinged trailing-edge flap would have the same effect as warping the entire wing is obvious to us, because we have seen it in action. But it cannot have been quite so obvious then. The evolution of airplanes in the United States suffered from the Wrights’ unfortunate attempt to establish a monopoly on flight by patenting the very concept of lateral control. Litigation over that ambitious claim held back aeronautical development in America for years while it raced ahead in Europe.

The function of an aileron, or any hinged trailing-edge surface, is commonly explained in ground school by simple analogy to, say, a door opened on a windy day. The wind hits the deflected surface of the aileron and pushes on it. If the aileron is deflected downward, the wind pushes it upward, and if it’s deflected upward, the wind pushes it downward.

This explanation, while intuitively appealing, fails to capture what is really happening. The majority of the lift generated by an unstalled airfoil is always concentrated near the front, and moving a trailing-edge flap up or down changes the flow conditions at the leading edge. An aileron deflected downward impedes air passing below the airfoil, and as a result, the dividing line between air passing below the airfoil and that passing above it moves aft. More air now passes over the top, the velocity of air rounding the leading edge increases, and the pressure there is correspondingly reduced. In other words, the lift change that results from deflecting the aileron is not confined to the aileron itself. It affects the entire area ahead of the aileron as well.

• READ MORE: Recalling a Good Pilot Friend and One Curious Character

The effect of the aileron, like that of wing warping, amounts to a change in angle of attack. This understanding helps clarify what is happening in a steady-state roll. Why does an airplane with deflected ailerons settle at a steady-roll rate rather than roll faster and faster? It’s because the rotation reduces the angle of attack of the up-going wing and increases that of the down-going one. The change, which is opposed to the change caused by aileron deflection, is not uniform. It is greatest at the tip, where the rotational velocity of the wing, relative to the forward velocity of the airplane, is greatest. When the change of angle of attack due to rotation, integrated across the entire wing, is equal in magnitude to that resulting from deflection of the ailerons, the airplane is in equilibrium about its roll axis and rate of roll stops increasing.

Rate of roll is one of the “wow” numbers associated with a high-performance airplane. When we read that a T-38 or an A-4 rolls 720 degrees per second, we are amazed and wonder how the pilot knows which way is up. Arguably, roll acceleration—how quickly you get from zero to, say, 90 degrees of bank—might be more important in air combat maneuvering.

Roll rate is not a single number, however, as it increases with speed. Preferring a criterion that is independent of speed, engineers often refer to “peebee-over-toovee”—a (more or less) constant value represented by the ratio “pb/2V,” where “p” is the rate of roll in radians per second (a radian is 57.3 degrees), “b” is the wingspan, and “V” is the true airspeed (in the same units as the wingspan). Thus, for example, an airplane with a roll rate of 70 degrees per second (deg/sec), a wingspan of 35 feet, and a forward speed of 300 feet per second has a pb/2V of 0.071 radian.

In physical terms, that means that if the airplane flew past you while rolling, the path of its wingtip, in profile, would be at an angle of 0.071 x 57.3, or about 4 degrees to the flight path. That is called the “helix angle,” because the rotating wingtips form a double helix, like DNA.

• READ MORE: Gliders Are Form of Flight That Resonates Above Others

The rolling helix angle is theoretically a constant for any given airplane, determined by wing planform, aileron design, and various other subtler factors. In principle it allows you to predict an airplane’s roll rate at any speed. Things don’t quite work out that way, however, because at high speed deflecting the ailerons makes the whole wing twist, counteracting the ailerons themselves, and cables stretch, preventing the ailerons from deflecting completely. Still, helix angle remains a convenient criterion, at the very least for setting a minimum acceptable standard for rolling performance.

A 1941 National Advisory Committee for Aeronautics report set that minimum value at 0.07 for transports and bombers and 0.09 for fighters. According to some published figures with which pilots who flew the airplanes are bound to disagree, the Spitfire Mk.V and FW-190 were fast-rolling airplanes, and the P-40 was not far behind. The FW-190 rolled 151 deg/sec at 226 knots, the Spitfire 150 at 176, and the P-40 134 at 315. The P-47 rolled a mere 71 deg/sec at 250 knots, the P-51B 98 at 260, the P-38 78 at 260. The corresponding pb/2V values are 0.118, 0.163, 0.082, 0.060, 0.072, and 0.084 respectively. The T-38 scores around 0.26.

Neither helix angle nor rolling acceleration fully expresses the quality of lateral control experienced by the pilot. That has more to do with effort, linearity of response, and presence or absence of “hysteresis,” or slop. Pilots used to single out the ailerons of Bellancas for praise, but pb/2V had nothing to do with it. It was really all about the ailerons’ smooth, frictionless, instantaneous response, low forces, and lack of free play.

The fact that pb/2V is theoretically constant for a given airplane has a couple of corollaries. One is that a larger span results in a lower roll rate. Another is that roll rate in degrees per second, taken alone, is misleading.

The Sopwith Camel, one of the deadliest fighters of World War I, rolled at a mere 40 degrees a second. But if you judged it by its pb/2V of 0.083, it was equal to the P-40 and superior to the P-47 and P-51.

This column first appeared in the March 2024/Issue 946 of FLYING’s print edition.

The post There’s Something Essential in the Bank appeared first on FLYING Magazine.

After taking off from North Las Vegas Airport (KVGT) and flying 60 miles, they landed at Mesquite, Nevada (67L), where they added 10 gallons of fuel. The pilot with the airplane rating, who had flown the first leg, now ceded the left front seat to one of his companions, evidently with the idea of giving him some flight instruction. He moved to the right seat, and they performed several touch-and-gos before continuing toward Bryce Canyon, 105 miles distant.

The terrain rises from around 4,000 feet msl near Mesquite to around 7,800 feet at Bryce. Between them is a pass at 8,500 feet. Shortly before reaching that pass, and still below 8,000 feet, the Cirrus stalled, flipped inverted, and crashed into a mountainside, killing all four men. The Cirrus was equipped with an Avidyne solid-state primary flight display that stored an array of flight and engine data. The memory module was undamaged, and investigators were able to reconstruct the flight in detail. The story it told was surprising.

To start, the airplane was about 225 pounds over gross weight when it left Mesquite. The air temperature on the ground near the accident site was 80 degrees, and the density altitude over 9,000 feet. At the time of the accident, the airplane was just a few hundred feet above the surface, barely climbing, and only 4 miles away from the 8,500-foot pass. Its indicated airspeed was around 70 knots, and for the three minutes before the loss of control, the stall warning had been sounding almost continuously. All the while, its 210 hp Continental engine was turning at a leisurely 2,300 rpm.

• READ MORE: Only Assumptions Can Be Made About What Took Down a Curtiss C-46 in Alaska

So many things are wrong with this picture that I hardly know where to begin. But let’s start with general mountain flying principles. The wind was from the southwest, so the airplane would not expect to encounter downdrafts in the pass. Nevertheless, because in mountainous areas winds close to the surface are unpredictable, it’s chancy to fly toward rising terrain with the idea that you will just make it over the next ridge. Better to circle and climb, and not approach the ridge until you have the altitude to safely clear it, and approach it at a 45-degree angle, in order to have room to turn away if you don’t have enough altitude. The Cirrus, which had reached as high as 7,847 feet, had actually begun to lose altitude, probably because of its very low airspeed, before the stall occurred.

Even overloaded, and despite the high density altitude, the Cirrus had sufficient power to climb at 375 fpm. But to do so would have required increasing the rpm to 2,700, the rated maximum. It would also have required maintaining the best rate-of-climb speed, which was 93 kias. At 2,300 rpm, the calculated rate of climb at 93 knots would have been 22 fpm. At the stall speed, it was zero or less.

As a helicopter professional, the airplane-rated pilot—he was legally the pilot in command, and we assume he was the pilot flying—may have felt comfortable flying from the right seat. But the instrument cluster was on the left, making it difficult for him to see the airspeed indicator. Still, the stall warning should have been airspeed indicator enough.

He was a very experienced pilot, with more than 5,600 hours. Only 160 of them, however, were in fixed-wing airplanes, and only 17 in the SR20. He had originally gained his airplane rating in an SR20 but then began renting an SR22, which has the same airframe but 100 more horsepower. He had not flown an SR20 for 18 months before this trip and used it only because the SR22 he usually rented was not available.

Two major errors, which are immediately obvious to a fixed-wing pilot, are the failure to fly at the best rate-of-climb speed and the failure to increase rpm to make use of all the power available. The low speed may possibly be explained by the pilot wanting to use the best angle-of-climb speed, or by the fact that the best rate-of-climb speeds of helicopters are generally lower than those of fixed-wing airplanes, usually around 60 or 70 knots. As for the rpm, main rotor rpm is not normally used in setting power in a helicopter. Rotor rpm is set at a customary value and remains there, while power is controlled by throttle and, in both turbine and most modern reciprocating-engine helicopters, some type of automatic correlation or linkage with the collective, which controls the average pitch of the main rotor blades. It’s not hard to imagine that fixed-wing power-setting practices might be eclipsed by the ingrained habits of a helicopter pilot with limited fixed-wing experience who flies helicopters daily but airplanes only seldom.

• READ MORE: A Night Flight Leads a Pilot to a Tragic End

That the stall warning could have been allowed to sound for several minutes also seems incredible, but helicopters do not stall. Perhaps the pilot imagined that he could safely fly at what he believed to be the best angle-of-climb speed and that the stall warning was a mere unavoidable nuisance.

The National Transportation Safety Board (NTSB) blamed the accident on the “pilot’s failure to maintain sufficient airspeed and airplane control,” to which his assumed lack of experience operating heavily loaded airplanes in a high-density-altitude environment contributed. The NTSB made no effort to explain the egregious failure to use an appropriate speed and all available power, to circle to climb, or to stay well clear of the terrain. The agency did, however, report that the pilot had previously been admonished for overloading an airplane, gone out of his way to conceal his overloading of this one, and was prone to “try to circumvent things” with employees of the rental firm. The NTSB may think that imperfect morals predispose pilots to accidents, but in this case the cause was not overloading by a few percent nor the intent to deceive the renters about it. It was the blatantly faulty management of the airplane.

I used to visit Robinson Helicopter Co. in Torrance, California, from time to time, and founder Frank Robinson, always very cordial and hospitable, would send up one of his pilots with me for a little jaunt to administer CPR to my four-decade-old, but seldom used, helicopter rating. Once he flew with me himself and cautioned me against a too-abrupt forward push on the cyclic. He said this was an error to which fixed-wing pilots were prone when startled, for instance, by the sudden appearance of conflicting traffic. It was harmless in a fixed-wing airplane but dangerous in a helicopter, because the main rotor blades could strike the tail boom. He preferred that helicopter pilots learn to fly in helicopters and not come to them polluted by fixed-wing habits.

It works both ways.

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 January-February 2024/Issue 945 of FLYING’s print edition.

The post Fatal Cirrus Accident Shows That Some Knowledge Doesn’t Translate appeared first on FLYING Magazine.