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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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EAA AirVenture Stages Surprising Finale
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After its unusual start, EAA AirVenture Oshkosh returned to its predicable ways as the week passed the halfway mark. But is was just setting us up, out of the west, just above the trees and behind the backs of everyone facing the flight line for the National Anthem, came six blue and yellow F-18 jets arranged in the U.S. Navy Blue Angels’ rock solid delta formation. Everyone was like “Whaa….where’d they come from?” Reversing course, the Blues executed there Delta break, then rejoined in the delta and disappeared to the west just as magically as they had appeared. Clearly it was a well-planned (and timed) fly-by on their way to some other destination.
The second surprise came at AirVenture’s Press Headquarters on Thursday morning. On the media side of the event, this has not been the year for big announcements, and when there is a significant announcement, the orator shouts it from the stage early in the week. In other words, I wasn’t expecting much from the National Air & Space Museum’s presser at 0900 on Thursday morning. And then I saw Sean D. Tucker’s Oracle Challenger III parked in front of the press headquarters. Searching my midweek addled brain for any memory of another airplane so parked over the past 30 years I came up blank.
Let me cut to the chase. Air & Space is commencing a top-to-bottom makeover of the the visited museum on the National Mall in Washington, D.C. In the transformation of its 23 galleries, the museum will dedicate one of them—We All Fly—to general aviation, thanks to a $10 million gift from the Thomas W. Haas Foundation. And the Oracle Challenger III will soar above the portal to that gallery.
Tucker said he is closing out his solo air show career this season and is in the process of putting together a four-ship air show team and the sponsorship needed to make it work. While he’s gathering the second half of the necessary sponsorship, he said he would “campaign” the Oracle Challenger III to promote its new home, and then he will deliver it to the museum.
My final surprise was learning about an era of aviation I know little about, and to learn about it from roaring, burping, castor oil spitting engines that are a century old. Knowing that the crankshaft of a rotary engine is bolted to the firewall and that the prop is bolted to the crankcase and radial array of cylinders that spin as a unit is one thing. To see them actually operate is another. And I have a new appreciation for torque.
Kermit Weeks brought three of his World War I airplanes to Oshkosh, the Sopwith Pup, Sopwith Snipe, both with 80-hp and 230-hp rotary engines, and an Albatross, with a water-cooled Mercedes engine. All the engines are original, and their airframes are exact recreations created by Peter Jackson in New Zealand. Before starting each engine, Weeks explained the operating idiosyncrasies and operating parameters. For example, the 230-hp Bentley rotary on the Snipe burned about 13 gallons per hour of fuel, and about 3.5 gallons of castor oil, a vegetable-based lubricant. That’s important, because it doesn’t mix with the mineral based fuel, said Weeks. The lubrication system is one of constant flow; what friction doesn’t consume gets flung out of the engine, liberally lubricating the pilot and airframe. “It’s my beauty secret,” said Weeks. “Another benefit of the system is that you never have to change the oil. You just add more before every flight.” Unfortunately, Mother Nature didn’t allow any such excursions, and that was certainly no surprise. — Scott Spangler, Editor
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EAA AirVenture 2018 Has An Unusual Start
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No two repetitions of the the annual gathering of the aviation faithful at EAA AirVenture at Wittman Regional Airport in Oshkosh, Wisconsin, are the same. But in attending the event for the 40th time, I can honestly say that all of them share clearly defined family traits. Until this year.
What makes it feel really different I can’t exactly put my finger on, so forgive what is sure to be a wandering stream of consciousness puzzle piecing that is searching for a more focused picture. It was weird that no matter where I walked about on setup Sunday, aka AirVenture Day Zero, I didn’t see a lot of people.
Let’s start with the one above. That’s Row 331 in Homebuilt Camping at about 1300 on Sunday, Day Zero. Mother Nature is always a controlling factor, but I’ve never seen this area, and Homebuilt Showplane Parking, which parallels the flight line, so empty. Normally, there are lot more impatient pilots who see the bad weather forming and cut out of work to beat it to Oshkosh. But not this year.
Normally, even when the weather is bad, which it has been for the five preceding days, there’s always a throng of “civilians” (those not involved in setup, making the area defined by the exhibit hangars a dodge-em course for forklift drivers and others trying to get ready for the show.
Having spent two decades as an exhibitor, the civilians have always made setup complicated, but like many other aspects of Oshkosh, it was something you just had to deal with. This year EAA did something about it. The exhibit areas were a restricted area, unless you had one of these distinctive orange lanyards. (And the volunteers, who politely turned away the civilians who tried to enter the restricted area, did let me take a peak with my media pass.) Nice job, EAA! The exhibitors I talked to loved the new restrictions, and I didn’t hear any of the civilians griping that they could not wander among the grumbling beasts with the four little wheels and long steel tusks.
I’m guessing that the exhibitors were less happy with the relative absence of civilian traffic on Monday, Day 1. Walking through the four exhibit hangars this afternoon, they weren’t exactly empty, but they were not filled with a lot of people. Maybe that’s because it seems EAA has again widened the rows that separate the facing lines of booths. And the occupants of those booths continues their transition from aviation-related companies to more consumer products like jewelry and vibrating massage recliners.
Perhaps more important, Mother Nature threw off her blanket of clouds on Sunday afternoon and almost within minutes airplanes recreated what was close to an aerial version of the settlers’ invasion of the Oklahoma’s Indian territory in 1889. Making my way north through Homebuilt Showplane Parking, I waded through a sea of airplanes to reach Row 331 in Homebuilt Camping. As you can see, a few people and their airplanes showed up in the past 24 hours. Hats off the the air traffic controllers who funneled them to the marshaling crew that got them safely to their campsites. After the disconcerting start, the comforting family traits of airplanes and friendly people have reasserted themselves. But what will tomorrow bring? — Scott Spangler, Editor
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Cody Parkovich, Enstrom Helicopter Production Test Pilot
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Just six months on the job as Enstrom Helicopter’s production test pilot, Cody Parkovich traces his position to the night he was bartending in Marinette, Wisconsin, just across the river from Menominee, Michigan. “That night I found out, when I was 23,” that Enstrom was a hometown company. “And I grew up here.”
Just discharged from the U.S. Marine Corps and home from San Diego where he’d served as an F-18 mechanic, “I didn’t know that flying a helicopter was an occupation outside the military,” he said. His original plan was to “go to school and go back into the service, but I got the itch and started flight training in Duluth two weeks later.”
Then he moved around the country to build time and experience in a number of different helicopters, the Robinson R44, Bell 206, the A-Star 350 series, ” and I instructed in a new Guimbal Cabri G2,” he said.
After teaching, Parkovich flew commercial ops in Utah, flying aerial tours in Michigan’s mitten, some ag spraying, and some utility pipeline inspection around Louisville and railroad track surveying with LIDAR, so the Canadian National could measure the grade before they increased the cruising speed of their freight trains.
“This is the life of a professional helicopter pilot,” said Dennis Martin, Enstrom’s director of sales and marketing. “Airplane pilots fly airliners, Helicopter pilots do 25 different things.” In short, they have to be as versatile as the rotary-wing aircraft they fly.
When Parkovich started work at Enstrom two years ago, “I thought I was a halfway decent mechanic from working on fixed wings, and then I found out that helicopters were a whole other ball of worms.” Like most of Enstrom’s workforce of 150, Parkovich works in different areas that cross-complement his primary responsibilities.
“Because I still work on the floor as a mechanic, I know these ships like a doctor knows human anatomy. I’ve been hands-on with the rigging process.” As we talked, he was prepping a turbine-powered 480B, with a Garmin G1000 in the panel, for its final inspection, just across the aisle from the final assembly area. In front of it was the hangar door.
Summarizing the purpose of a production test flight, Parkovich said it takes, on average, 5 hours to demonstrate that the helicopter meets all of its documented performance numbers and that all of its equipment, regardless of how it is equipped for the customer, works as its documentation proclaims.
More specifically, this involves flights at different centers of gravity, making sure it has the same cyclic throws and maneuverability. Accelerating to VNE — the never exceed speed—he checks for adverse vibration and retreating blade stalls.
He also flies to track and balance blades and helicopters, a process that reduces the whole-ship vibrations to the absolute minimum. All of the helicopter’s rotating pieces can produce vibration, but they start with the main rotor, which can vibrate on both the vertical and lateral planes.
New blades are balanced chord-wise, the added weights written on the tips, and span-wise. Those balances are refined by flying the blade set in a known ship, said Parkovich. Putting them on a new helicopter would introduce too many variables, such as tail rotor vibrations.
This also saves start cycles on the Rolls-Royce turbines, said Martin. “They only get 3,000 cycles before they need hot-section maintenance, and when you’re making blade adjustments, you have to shut down, adjust, and restart. And if it takes 25 or 35 cycles, you don’t want to give that to a customer.”
Production flight test doesn’t involve a lot of test equipment, said Parkovich. His most important instrument? The seat of his pants. In another summary, his job is to “make sure very helicopter feels the same, flies the same way.” — Scott Spangler, Editor