-
Making the Brazilian ATR-72 Spin
by
No Comments
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…)
-
How the FAA Let Remote Tower Technology Slip Right Through Its Fingers
by
No Comments
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.
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…)
-
N-Numbers, ICAO, and Your ADS-B Identity
by
No Comments
Many owners like to personalize their prized aircraft with an N-number that represents them, often with their initials. Before the advent of NextGen, painting the new number on the airplane, and professing it to ATC, covered the customization. Now, unless an airplane’s ADS-B identity matches its new N-number, a filter the FAA activated in January will likely scrub it from ATC’s scopes and the Traffic Information Services Broadcast to other aircraft with ADS-B.
Aircraft transmitting erroneous information, whose ADS-B identity doesn’t match the N-number painted on the airplane and processed to ATC, will not wander the sky at will. They will continue to receive ATC services based on secondary radar information when flying in radar coverage.
What’s this ADS-B identity, and where does one find it? Officially, it is the 24-bit ICAO address that is forever linked to an N-number, like a fraternal twin. It is otherwise known at the Mode S code, and when the N-number changes, so does the code.
If aircraft owners don’t have their avionics shops update their ADS-B systems with the new ICAO address (and call sign, if their aircraft officially operates with one instead of its N-number), when they get a new N-number, they will be spewing erroneous information. And should they get caught by the new filter, they will receive a notice of the errors of their ways and a request to contact the FAA’s ADS-B Focus Team, if the FAA can locate the owner of the offending airplane, that is.
When the ADS-B identity doesn’t match the physical N-number, making the aircraft registry connection to the owner is more involved. And if the FAA cannot make the connection, the offending aircraft is forever filtered without further notice.
There are several ways owners can ensure that their aircraft are broadcasting the correct ADS-B identity. They can have their avionics shop connect the appropriate test box and check all the numbers, correcting those in error. Or they can request a Public ADS-B Performance Report (PAPR), an automated online tool that emails a free ADS-B report card within 30 minutes after the conclusion of the specified flight in ADS-B airspace.
A PAPR examination highlights all of the erroneous data in red (check out the online PAPR user’s guide for all the details). If an owner requests a report but doesn’t receive one for the N-number he or she types into the online form, that means the system cannot find it in its inventory of flights, which means that the airplane’s ADS-B identity doesn’t match the number painted on its flanks.
Another common error is an improper emitter category, which identifies the aircraft size by weight. Its seven categories range from Light Airplane (max weight of 15,500 pounds or less) to Heavy (max weight of 300,000 pounds or more). It has three more definitive categories: Rotorcraft (all of them, regardless of maximum weight), High Performance (more than 400 knots true and 5 g), and Large Airplane with High Vortex (airplanes that weigh 75,000 pounds or more that generate high wake vortex; the Boeing 757 is the only current example).
There might be a third way, doing nothing. The only clue that there might be something amiss with the airplane’s ADS-B identity is a reduction of available ATC services. Equally important is the degradation of TIS-B traffic, which works in concert to mute the aircraft owner’s ADS-B investment. — Scott Spangler, Editor.
-
The Aesthetics of Collision Avoidance
by
No Comments
When it came time for Dennis Hutchinson to paint the Davis DA-2 he’d restored, he picked red and white with gold and blue accents, “because I like them and think they go well together.”
Aesthetics had little do with how he arranged those colors on the airframe. Collision avoidance was top of mind: “As small as the Davis is, I wanted it to be as visible as possible in flight, to pop out of the background, not blend in,” said Hutchinson, who’s based at the Indianapolis Regional Airport (MQJ) in Greenfield, Indiana.
Starting in gliders, Hutchinson has been a pilot for half a century. When Leeon Davis flew his prototype DA-2, with its 19-foot-3 wingspan and 17-foot-10 fuselage, in 1966, Hutchinson was two years away from soloing a glider, at age 14, after his 13th flight. He got his private at 15, before he was eligible for a driver’s license.
“Most sailplanes are painted white, to protect their composite structures,” he said. “What I’d observed from an early age was that sailplanes with even a small amount of darker, contrasting paint on the nose and wingtips were much easier to spot in flight that those with an all white finish.”
That’s why the tips of the Davis’s constant-chord wing and V-tail are red, because they contrast with the white inboard sections. The upper fuselage is white because it stands out against the darker earth when viewed from above, just as the red on the lower fuselage does against the sky when seen from below.
Going beyond this aesthetic contribution to collision avoidance, Hutchinson installed an AeroLED package of position/navigation/strobe lights on the wingtips and tail cone. “They are interconnected and flash simultaneously, to great effect.”
The landing and taxi lights are mounted in each wing, and they are capable of wig-wag mode. “They are not interconnected with the strobes, so they flash at a different rate,” he said. “Since all the lights are LEDs, the power they draw is minimal, and I highly value the extra visibility.”
Hutchinson said the combination of his collision avoidance paint scheme and lights is working, because when he arrives at a new airport, right after asking what kind of plane he’s flying (His initial answer? “It’s a freeze-dried Bonanza.”) pilots “tell me that the plane is lit up like a Christmas tree.” — Scott Spangler, Editor