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Making the Brazilian ATR-72 Spin
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Note: This story was corrected on August 10th at 10:23 am, thanks to the help of a sharp-eyed reader.
Making an ATR-72 Spin
I wasn’t in Brazil on Friday afternoon, but I saw the post on Twitter or X (or whatever you call it) showing a Brazil ATR-72, Voepass Airlines flight 2283, rotating in a spin as it plunged to the ground near Sao Paulo from its 17,000-foot cruising altitude. All 61 people aboard perished in the ensuing crash and fire. A timeline from FlightRadar 24 indicates that the fall only lasted about a minute, so the aircraft was clearly out of control. Industry research shows Loss of Control in Flight (LOCI) continues to be responsible for more fatalities worldwide than any other kind of aircraft accident.
The big question is why the crew lost control of this airplane. The ADS-B data from FlightRadar 24 does offer a couple of possible clues. The ATR’s speed declined during the descent rather than increased, which means the aircraft’s wing was probably stalled. The ATR’s airfoil had exceeded its critical angle of attack and lacked sufficient lift to remain airborne. Add to this the rotation observed, and the only answer is a spin.
Can a Large Airplane Spin?
The simple answer is yes. If you induce rotation to almost any aircraft while the wing is stalled, it can spin, even an aircraft as large as the ATR-72. By the way, the largest of the ATR models, the 600, weighs nearly 51,000 pounds.
Of course, investigators will ask why the ATR’s wing was stalled. It could have been related to a failed engine or ice on the wings or tailplane. (more…)
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How the FAA Let Remote Tower Technology Slip Right Through Its Fingers
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In June 2023, the FAA published a 167-page document outlining the agency’s desire to replace dozens of 40-year-old airport control towers with new environmentally friendly brick-and-mortar structures. These towers are, of course, where hundreds of air traffic controllers ply their trade … ensuring the aircraft within their local airspace are safely separated from each other during landing and takeoff.
The FAA’s report was part of President Biden’s Infrastructure Investment and Jobs Act enacted on November 15, 2021. That bill set aside a whopping $25 billion spread across five years to cover the cost of replacing those aging towers. The agency said it considered a number of alternatives about how to spend that $5 billion each year, rather than on brick and mortar buildings.
One alternative addressed only briefly before rejecting it was a relatively new concept called a Remote Tower, originally created by Saab in Europe in partnership with the Virginia-based VSATSLab Inc. The European technology giant has been successfully running Remote Towers in place of the traditional buildings in Europe for almost 10 years. One of Saab’s more well-known Remote Tower sites is at London City Airport. London also plans to create a virtual backup ATC facility at London Heathrow, the busiest airport in Europe.
A remote tower and its associated technology replace the traditional 60-70 foot glass domed control tower building you might see at your local airport, but it doesn’t eliminate any human air traffic controllers or their roles in keeping aircraft separated.
Max Trescott photo Inside a Remote Tower Operation
In place of a normal control tower building, the airport erects a small steel tower or even an 8-inch diameter pole perhaps 20-40 feet high, similar to a radio or cell phone tower. Dozens of high-definition cameras are attached to the new Remote Tower’s structure, each aimed at an arrival or departure path, as well as various ramps around the airport.
Using HD cameras, controllers can zoom in on any given point within the camera’s range, say an aircraft on final approach. The only way to accomplish that in a control tower today is if the controller picks up a pair of binoculars. The HD cameras also offer infrared capabilities to allow for better-than-human visuals, especially during bad weather or at night.
The next step in constructing a remote tower is locating the control room where the video feeds will terminate. Instead of the round glass room perched atop a standard control tower, imagine a semi-circular room located at ground level. Inside that room, the walls are lined with 14, 55-inch high-definition video screens hung next to each other with the wider portion of the screen running top to bottom.
After connecting the video feeds, the compression technology manages to consolidate 360 degrees of viewing area into a 220-degree spread across the video screens. That creates essentially the same view of the entire airport that a controller would normally see out the windows of the tower cab without the need to move their head more than 220 degrees. Another Remote Tower benefit is that each aircraft within visual range can be tagged with that aircraft’s tail number, just as it might if the controller were looking at a radar screen. (more…)
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Champ Ornament of Aviation Appreciation
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Each year for as long as I can remember, Sporty’s Pilot Shop has sent its annual crystal airplane ornament with the Christmas card it sends to members of the aviation media. We hung our growing collection of them each year until our boys moved on and out to start their own families, and our downsized tree wasn’t robust enough to sustain them. Instead of creating a Charlie Brown Christmas tree of airplane ornaments, we passed along the ornaments to friends and family who look up when they hear an airplane above them.
But we still hang with honored appreciation the annual ornament, in 2023 an Aeronca Champ. “Produced in large volumes in the late 1940s, the simple high wing design with fabric-covered wings was used primarily for training,” reads the card that describes each year’s airplane. “The Champ was one of the few taildragger airplanes that could be flown solo from the front seat, which greatly improved the visibility for the pilot in command. With Aeronca’s Cincinnati roots, the Champ is a favorite for many of the Sporty’s flight crew.”
Beholding the Champ’s etched outlines recalled some of my most cherished flight time and the teachers, Paul King and John Coplantz, who really taught me how to fly in December 1996, two decades after passing my private pilot practical test at Eagle Aviation in Long Beach, California. Seeking an endorsement, I was enrolled in the 15-hour tailwheel transition course at Stick and Rudder Aviation’s “Academy of Flight and Taildragmanship” in Watsonville, California.
Their three-ship training fleet consisted of a Champ, its military sibling, the L-16, and a clip-wing L-4, a Piper J-3 Cub drafted for liaison service during World War II. Battery-powered intercoms and handheld transceivers were the only things electric in all three airplanes, so how to safely hand-prop their 85-horse Continental engines was an early lesson. If you are a 1940-sized human, yes, you can solo the Champ from the front seat, but as an oversize mid-century monster, I barely fit in the cushionless back seat. My futile attempts at gracefully folding myself into the Champ always drew a flightline audience.
My first six flights were in the Champ, and its lessons served me well on every flight since in which I’ve been the sole manipulator of an airplane’s controls because it calibrated the seat of my pants. In flight, the Champ handled quite like the Cessna 172 in which I learned to fly at Eagle Aviation. And then Paul asked me to make a no-rudder turn to the left. Easing the stick over, the right wing fell back a good three feet and my hip moved smartly to the left as the Champ made a slipping left turn. So, this was adverse yaw.
Paul encouraged me to experiment, so I played with the rudder and concentrated on the seat of my pants. My butt became the turn-and-bank’s ball. With deft rudder inputs I could put it where I wanted — centered, half a cheek out, or full displacement. Cool. This is but one of the many lasting lessons I learned at Stick and Rudder, all of them clear, concise, and often unique, like the bicycle wheel with a screwdriver axel that taught gyroscopic precession. Before spinning the wheel, Paul asked me to hold my “fuselage” (arm) in a nose-high, three-point attitude. When I raised the tail, the prop twisted my wrist to the left. After another spin, the prop forced my fuselage to the right when I lowered the tail to a three-point attitude.
Sadly, Stick and Rudder in Watsonville is no more, but it lives on in those who continue to appreciate the lessons it taught. And at this time of year, it seems only right that we make time to appreciate all the gifts of life and learning, and the people who gave them. Thank you. Scott Spangler—Editor
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Dynamic Flight Maneuvers: Stop, Look, Remember
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Given the traffic seen on my daily stroll around town, except for the EAA AirVenture Oshkosh late summer interlude, the sky over Omro seems to be a no-fly zone. When the wind is right, I’ll see a regional jet whining its way north to Appleton International, and there’s the occasional business jet or turboprop on its way to Wittman Field, roughly 10 miles to the east. But when I hear a piston engine, I stop and look. If I’m lucky, like I was last week, it is a Cessna 172 from the Fox Valley Tech program out practicing maneuvers and other essential stick and rudder skills. On this day the lesson was clearly stalls and slow flight.
Rooted at a standstill in the middle of the sidewalk, I watched and heard the pilot work though the roster of approach and departure loss of lift attitudes, and after each of them, the Cessna recovered smoothly with no wah-wah of uncertain power changes. The Cessna demonstrated the same sure smoothness as it eased into slow flight, extended full flaps, and then slowly retracted them with little or no apparent loss of altitude. With the lesson apparently over, the Cessna and I turned east for our respective homes.
As the Cessna diminished to a muter pinpoint, I wondered if the pilot enjoyed the rewards of the practice of dynamic flight, the skillful manipulation of the flight controls and go-lever to achieve the desired three-dimensional goal. I hope so. Never a hundred-dollar hamburger guy, my most rewarding flights focused on perfecting the fundamental flight skills. And to challenge myself, I would combine a series of maneuvers and aim for predetermined goals with a plus-or-minus nothing deviation from the appropriate altitude or speed.
One of my favorite combinations was appending the slow flight flap exercise to the end of a chandelle. A climbing 180-degree turn introduced during my education for a commercial pilot certificate, it requires precision control that is more challenging than it at first seems. You enter the maneuver at a predetermined heading and airspeed. Rolling into a turn (left or right) starts the maneuver, gently banking to—and maintain—30°.
At the same time, you smoothy apply full power and increase pitch to control airspeed, with the goal being just shy of the critical angle of attack. I relied on the tenor range of the Cessna’s stall warning. The bass note told me I was getting close, and the soprano stridently told me I’d gone too far. Halfway through the 180° heading change (a predetermined plus-or-minus goal calculated on my entry heading) the challenge changes, from holding a constant bank while increasing pitch to maintaining the stall warning’s tenor pitch while gradually rolling out of the bank that exactly opposite of my entry heading.
Because I was already at the critical angle of attack at full power, slowly adding full Cessna barndoors without stalling really challenged the seat of my pants and visual scan, and it was a good way to practice recovering from stalls, as well. Success depends on smooth and precise inputs. More importantly (to me, at least), it was fun, as striving to be better usually is. Scott Spangler, Editor
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21st Century Airship Development Preserves History
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The most fascinating nugget of news in the announcement of the FAA’s issuance of special airworthiness certificate to Pathfinder 1, LTA’s prototype 21st century rigid airship, is the authorization to fly it in Class D airspace defined by California’s Moffett Federal Field (NUQ) and Palo Alto Airport (PAO), which is next door, so to speak. The nugget was nestled in LTA’s certificate application. The airship’s experimental flight test program would establish its flight envelope through “substantial indoor and outdoor ground testing.”
I emphasized indoor because rigid airships are not small flying machines. Pathfinder is 124.5 meters of carbon-fiber-polymer tubes connected by titanium hubs. You need some pretty good indoor space to fly something 136 feet long. Fortunately, LTA Research, founded by Google cofounder Sergey Brin, has options. And in acquiring them, he has saved significant parts of American lighter than air history and national historic landmarks that continue to make contributions to aviation, and would be nearly impossible to replace or recreate.
Moffett Field is south of San Francisco, established in 1931 as the Navy’s West Coast rigid airship facility. (Lakehurst, New Jersey, served America’s sunrise coast.) It is home to three airship hangars. The Navy built Hangar 1 in 1933 for the USS Macon, ARS-5. In 2011, Google’s founders saved Hangar 1 from demolition by underwriting its restoration. Three years later, Google subsidiary Planetary Ventures signed a 60-year lease with the General Services Administration to manage Hangar 1 and the surrounding airfield.
Across the main runways from Hangar 1 are the smaller Hangars 2 and 3, two of the world’s largest freestanding structures. They are two of the 17 wood blimp hangars the Navy built during World War II for its antisubmarine blimp fleet. Hangars 2 and 3 are two of the seven survivors (there are two more in Tustin, California, two at Lakehurst, New Jersey, and one at Tillamook, Oregon). Pathfinder 1 made its first flight inside Moffett’s Hangar 2 on May 12, 2023.
After Pathfinder 1 finishes if Moffett Field flights, it will move to Akron, Ohio, home of the 1175-by-325-foot Akron Airdock, which LTA bought in 2022. Once the world’s largest structure without internal supports (it covers 364,000-square-feet, roughly 7 football fields), the Goodyear Zeppelin Corporation built it in 1929. From it emerged the US Navy dirigibles Akron, ARS-4, in 1931, and the Macon, ARS-5, in 1934.
Pathfinder 1 is but a prototype, to be followed by larger iterations as the test program progresses. And, in time, it will offer aviation aficionados the unique opportunity to witness the past, present, and future of one (lighter than air) aspect of aviation. — Scott Spangler, editor