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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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Looking Bach at the Joy of Simple Flight
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An old-school reader, annually I must winnow my collected ink-on-paper titles to make shelf room for Christmas newcomers. As they have for decades, the works of Richard Bach survive every purge.
Like many others, I met Richard through the pages of Jonathan Livingston Seagull, a Christmas present from my parents in 1972. He articulated a kindred outlook on life I was then struggling to define. We met again in his other works and in subsequent titles that now wait on my shelf for our next reunion.
It’s been awhile since Richard and I met on new pages, so I sought out his digital being. He’s sharing his philosophy and love of flight through a blog born this December. It’s a home “for short little bits of ideas, funny things that happen, a place to show the pasts and futures of what I care about, dear reader, if you should happen to be interested.”
As aviation—especially GA, the portal for flight’s newcomers—seeks its way in the 21st century, it should be of interest to all concerned about the future. The critical message is the theme that unites all of Bach’s aeronautical prose, that aviation’s sustaining joy and rewards are found in the adventure of simple flight.
Isn’t that what first drew us into the sky? For Richard, the simple act of looking up at a passing airplane led him skyward in the mid-1950s. And the joy of simple stick & rudder flight sustains him still, a point well made in A Different Family. Its final paragraph offers aviators this poignant observation:
“We come together, we meet because we share common interests, common values, we laugh at common joys, cringe at common dangers.
“Not blood, that runs this deep.
“Only child, last survivor, orphan, black-sheep outcast from your clan?
“You want to find your family, first you find your love.”
As we seek our way forward, perhaps the successful solution is to remember when we were newcomers enthralled with the sky. Instead of the technology and procedures that now define the maturity of our flying lives we should focus on the compelling and attractive challenges and rewards of simple flight. — Scott Spangler
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Pitch & Power and the Margin of Error
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A recent issue of AOPA’s Flight School Business included this story: FAA Updates CFI Renewal Clinic Guidelines. It referenced the updated advisory circular that covers FIRCs and noted that the FAA added angle of attack (AoA) to the list of core subjects the renewal clinic must address.
That should be interesting because angle of attack is the root of an enduring aviation debate that correlates pitch & power with altitude & airspeed. This requirement will certainly lead to some spirited discussions and diagrams at FIRCs nationwide, but what was behind its addition?
The answer was in Appendix 1 of AC 61-83G, under Item 5: Safety Trends in GA: How CFIs Can Directly Contribute to Aviation Safety. To summarize, the non-commercial, non-corporate general aviation accident rate has been trending lower over the past two decades. To continue that trend, the FAA added A0A because it’s related to seven of the top 10 ways pilots kill themselves—low altitude maneuvering and loss of control.
Everyone involved has done an admirable job in making aviation safer, and the low rate we’ve had for decades suggests that it is the margin of error. In statistics I learned that this margin is an unavoidable fact of life. My prof said it grows as the data pool shrinks, so it makes sense that the accident rate—aviation’s margin of error—is up a tick. The shrinking pilot population is flying fewer hours. Explaining the statistical version of a pilot-induced oscillation, the prof also said trying to eliminate the margin usually makes it worse.