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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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Einar Enevoldson Likes to Fly Gliders High
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High as in altitude. Wandering through the science section of the New York Times in the dying days of October, “A Quiet Trip to the Ozone Hole” caught my attention. It’s about the Perlan Project, which is building a pressurized glider that will ride the standing wave created by the Andes Mountains to 60,000 feet.
Riding the top of the altitude-sapped wave, the plan is to catch the polar vortex, “circulating winds that act like a giant cyclone during the austral winter, delivering a strong uplift.” That should carry the glider, whose wings span 84 feet, to 90,000 feet, where it can study the ozone hole, and set a new altitude record while doing it.
Learning about this private project and existence of the “polar vortex” drove my airplane geek meter into the red. But it didn’t come close to meeting (in print and through the accompanying videos) the project’s chairman, Einar Enevoldson. He started his aviation career by learning to fly gliders in 1947, the year Chuck Yeager, broke the sound barrier.
An Air Force pilot doing an exchange tour with the Royal Air Force, he attended the Empire Test Pilot’s School in Farnborough, England. He went on to fly some truly remarkable aircraft between 1968 and 1986 as a NASA research pilot at the Dryden Flight Research Center at Edwards Air Force Base. Among them were the YF-12 (predecessor of the SR-71), the X-24 lifting body, and the funky scissor-wing AD-1 that made its last eight flights in 1982 at EAA Oshkosh.
As I read, my right brain screamed, Why have you never before heard about Einar Enevoldson? My logical left brain replied with another question: Other than the few who are face-to-face friends, how many mass-market test pilots can you name, and how many of them are the World War II-era peers of Yeager?
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Are US Investors Trying to Tell GA Something?
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Time will ultimately confirm or deny the recent rumors that the Chinese will become the controlling investor in another venerable American manufacturer of general aviation aircraft. Looking at this possibility from another vantage point … is the US business community trying to tell the general aviation industry something by their lack of interest and financial participation?
Their action, or lack of it, speaks volumes. Given the pragmatic bottom-line focus of business and those who invest in them, clearly American investors see little or no return in GA. Ruminating on why this may be offers several possibilities that pose questions about the industry itself, and about the changing focus of American business.
On the industry side there is supply and demand: Interest in flying and aircraft ownership has been in decline for some time. Part of this is surely the result of social change and the willingness of each succeeding generation of Americans to invest the time and money to participate in what captures their attention and interest. An iPhone is easier to master—and is more useful—than learning to fly. GA is not the only one suffering here: today fewer American teenagers get a driver’s license.
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Asiana 214 Pilots’ Statement Ignore the Obvious
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The pilots of Asiana Airlines 214, a Boeing 777 that crashed at San Francisco International Airport in July, told investigators the auto-throttle system on their aircraft malfunctioned. They swear it was properly set prior to beginning their approach too, assuming of course that the system would adjust the engine’s power as necessary to maintain safe flight.
The problem is the auto-throttles didn’t work as expected, the airplane got too low and too slow and the pilots never noticed until it was too late.
The Boeing stalled on short final to SFO’s runway 28 Left and struck a dike near the approach end. The impact tore the aircraft into a number of pieces also killing three and injuring dozens of other passengers. The aircraft was a total write-off.
Asiana pilots on earlier flights had reported a few maintenance write-ups for the same problem — a series of “uncommanded auto-throttle disconnects” — as a potential culprit in the accident.
My question … so what? (more…)