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Volume 26, Number 13b
March 27, 2019
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AEA: Garmin Announces G3X Touch For Certified Airplanes
Paul Bertorelli

The already-warm competition in the low-cost glass panel market got hotter yet on Monday when Garmin announced at AEA in Palm Springs that the G3X Touch system will now be available for certified aircraft. The G3X Touch is a mainstay in the experimental segment and will now be installable under an approved model list for some 500 aircraft at $7995 for a 7-inch display version and $9995 for a 10-inch version.

Garmin clearly aims to compete with Dynon, which introduced its own line of experimental-cum-certified equipment last year to a limited list of aircraft under STC. While Dynon is supporting installations outside the established avionics shop network, Garmin will leverage its powerful presence in the dealer universe to market the G3X Touch to owners of certified aircraft.

The G3X Touch has four panel configurations to allow pilots to match their current panel or future purchases. Like its bigger brother, the G1000 series, the G3X Touch has vivid moving maps, synthetic vision, weather and traffic capability and wireless connectivity to portables.

The G3X Touch will also interface with the GFC 500 autopilot, the G5 electronic flight instruments and a range of navcomms. Garmin says production is underway and deliveries in April 2019 are planned.

AEA: Dynon Drops Prices on SkyView Classic and SE, Retires Touch
Marc Cook

Dynon Avionics has announced a slight reorganization of its product line with price reductions on two models, the SkyView Classic and SkyView SE, and the discontinuation of the SkyView Touch. Dynon has also said it’s close to receiving approval to fit the SkyView HDX to Beech 35-series airplanes via an STC.

Woodinville, Washington-based Dynon says the SkyView Classic and SE versions will be $200 to $500 less expensive, depending on screen size. Currently, the base Classic starts at $2395 with a 7-inch screen and $2995 with a 10-inch screen. The SE is $1495 with a 7-inch screen and $2495 with a 10-inch screen. Both are non-touchscreen versions of the company’s popular EFIS; the SE is aimed at the VFR pilot and so omits the synthetic vision, extensive mapping and other IFR-related features found on the Classic. As with the HDX, both the Classic and SE can be mated to engine-monitoring modules, autopilot servos and remote-mounted comm radios and transponders.

“We believe these [price] adjustments make for a more competitive lineup that accommodates a wider range of builder budgets and panel plans. Many builders want a reduced, simplified feature set and are targeting a lower budget. Dynon will help them get there,” says Dynon’s VP of Marketing & Sales, Randy Lervold.

The Touch was retired because “As the SkyView line has evolved over the years, it has grown to four different models, including SkyView HDX, SkyView Touch, SkyView Classic and SkyView SE. With SkyView HDX representing our state-of-the-art offering with its enhanced user interface, better display quality and a full touch interface, we felt there was unnecessary overlap in the model lineup. With the avionics market getting ever more competitive, we’ve decided to trim the line to make the product model steps clearer and at the same time sharpen the price points on our original SkyView family models,” says Lervold.

Meanwhile, the company continues to expand its base of STC-approved installations. Dynon already has STC approval to install the SkyView HDX in a long list of Cessna 172 models (and the D10A and D100 are approved as replacement attitude indicators or standby instruments now) but the company now expects to have approval in hand for installations covering Beech’s 35-series Bonanzas “in the coming weeks.” Next on the list are the Beech A36 models and the Piper Seneca; Dynon says the Piper should be approved in the first half of 2019. After that comes the Cessna 182 series, with an expected approval date “before the end of 2019.”

AEA: Garmin Rolls Out Two New Panel GPS Navigators
Paul Bertorelli

Although the standalone panel-mount GPS market has appeared moribund for several years, Garmin rippled the pond at the Aircraft Electronics Association show in Palm Springs Monday with the rollout of a pair of new touchscreen, approach-capable navigators, one of which incorporates ADS-B In and Out. The GPS 175—an entry-level IFR-approved GPS navigator—will sell for $4995 and the GNX 375, which adds ADS-B In and Out, will retail for $7995. Both fit the standard 6.25-inch rack width and are 2 inches high, meaning they’ll require minimal panel surgery.

Garmin plans an aggressive delivery schedule with units available to ship in April and with an approved model list totaling some 700 Class I/II aircraft that weigh 6000 pounds or less. Both navigators have a look and features similar to Garmin’s popular GTN 650/750 series navigators and the color touchscreen interface will be familiar to anyone who has used those boxes. Both include full GPS approach capability, including WAAS/LPV procedures, moving map, flight planning and nearest airport/waypoint capability. The GNX 375 adds traffic and weather pages to the mix.

Realizing that there are a lot of old panels out there with even older equipment, Garmin engineered the interface to allow using indicators such as BendixKing’s KI209, as well as other common CDI/EHSIs and even Garmin’s newer G5 electronic flight instrument. The new navigators will also talk to Garmin’s GFC 500 and 600 autopilots and for experimental aircraft, the G3X Touch. Roll steering is available with those autopilots and select third-party autopilots, meaning procedures such as holds, radius-to-fix legs and missed approaches can be flown with the AP engaged.

Garmin didn’t forget the portable interface, either. Both boxes have the built-in Connext cockpit connectivity feature that enables wireless flight plan transfer via Bluetooth to and from portable devices running apps such as Garmin Pilot and FltPlan Go. The GNX 375, by the way, incorporates a 1090-ES transponder for ADS-B In/Out capability so pilots can also view ADS-B traffic and weather on either the screen or mobile devices.

VIDEO: Garmin's New GPS Navigators
Paul Bertorelli

At the Aircraft Electronics Association convention in Palm Springs, California, in March 2019, Garmin introduced two new standalone panel mount GPS navigators, the GPS 175 and the GNX 375. The latter includes both navigation and onboard ADS-B In/Out. In this video shot at the show, Garmin's Jessica Koss gives AVweb viewers a tour of the new product.

Boeing Reveals 737 MAX Software Changes To Pilots (UPDATED)
Marc Cook

On Saturday, Boeing met with pilots from several airlines to review changes to the 737 MAX’s MCAS software in preparation for a more public explanation of the alterations expected to remove the beleaguered airliner from its worldwide grounding. On Wednesday, Boeing is expected to bring together “pilots and officials” from the airlines with the affected 737s in their fleets.

In addition to reviewing the software, pilots from five airlines flew simulated failures of the MCAS and were able to disengage the system and safely complete the flight. The New York Times is reporting that pilots who flew the simulation with the original software had just 40 seconds to identify MCAS as the source of the trim movement and disable it. And it's worth repeating that these pilots had been aware of the controversy swirling around MCAS since the Ethiopian Airlines crash this month.

According to reports, Boeing is set to confirm changes previously reported as considered, which include changing the MCAS configuration to accept data from both angle-of-attack sensors rather than just one, limiting the number of times the MCAS can drive the stabilizer to affect nose-down pitch, and limiting the duration of the events to 10 seconds. Preliminary reports from both the Lion Air and Ethiopian Airlines accidents suggest that the MCAS continually tried to offset the pilots’ efforts to level the aircraft. In addition, new coding will make the MCAS disengage if it sees a differential in AOA sensor readings of more than 5 degrees.

Those same pilots few the 737 MAX simulator with the revised software and were able to diagnose simulated failures and land safely with less effort, according to reports.

“This is part of our ongoing effort to share more details about our plan for supporting the safe return of the 737 Max to commercial service,” Boeing says. “We had a productive session this past Saturday and plan to reach all current and many future Max operators and their home regulators.”

Meanwhile, Southwest Airlines, the U.S. airline with the most 737 MAX aircraft in its fleet, is canceling approximately 130 flights a day, while American is canceling roughly 90 flights a day. Southwest has 4000 daily flights exclusively on 737s, while American has 6700 flights a day across a wide range of aircraft types.

British Air Flight Bound For Germany Lands in Scotland
Marc Cook

Passengers bound for Dusseldorf from London City Airport Monday morning on board British Airways Flight 3271 were surprised by the landing announcement, “Welcome to Edinburgh.” After a delay of 2.5 hours, the aircraft, operated by WDL Aviation for British Air, eventually made the two-hour flight to Dusseldorf.

The BBC is reporting that the Embraer 170 was flown from London City to Edinburgh and back for its final flights on Sunday, the day before. The crew is believed to have followed the previous day’s flight route. WDL said that “At no time has the safety of passengers been compromised. We flew the passengers on the flight with number BA3271 to Dusseldorf after the involuntary stopover in Edinburgh.”

One passenger described the “involuntary stopover” as a “mystery travel lottery.” British Airways says it will be in contact with the passengers soon, though it has not said if it will be offering recompense for the unexpected trip north.

Separation Anxiety
Joseph E. (Jeb) Burnside

If there were some way I could make a series of trips back in time to change things, one of the stops on my itinerary would be to somehow infiltrate the small cadre of early pilots and airplane designers to convince them to use a word other than “stall” to describe what happens when a wing exceeds its critical angle of attack. The word obviously has numerous other applications, and using it for this purpose has confounded student pilots and television news anchors ever since. That said, I’m not sure what should replace it, and remain open to suggestions.

After all, what single word, if any, concisely describes what happens when air flows over an airfoil at low angles of attack but then separates and stops flowing as that angle of attack exceeds a specific value? How to explain that aerobatic and inverted flight depend on excess power and brute force as much as they do training and practice? That there’s no magic geometry exempting the wing from its behavior at high angles of attack? Why is any of this a concern to us?

Stalls And Losing Control

These semantics are important because pilots regularly demonstrate they either don’t understand the fundamental concepts of lift and an airfoil’s angle of attack or believe these aerodynamic laws don’t apply to them or their aircraft. The accident record is our evidence, specifically those accidents attributed to loss of control in-flight, or LOC-I as the terminology has developed. Sure—not all LOC-I accidents involve stalls. But a stall is a precipitating event in many of them. It follows that preventing and avoiding a stall also helps us prevent and avoid losing control. If only it was that simple.

To me, the classic LOC-I accident involves maneuvering, probably at a relatively low altitude. For some reason—showing off, inattentiveness—a pilot manages to put the airplane in an attitude from which it is unable to sustain flight. It’s the so-called Moose Turn, where an ever-tightening circle is flown above an object of interest until the combination of greater than 1G loading and reduced power lead the pilot into critical-angle territory. The airplane stalls and probably spins, and another accident report is born.

In our hypothetical, this outcome likely isn’t expected by the pilot, but is predictable. And repeatable: Every time the wing exceeds its critical angle of attack, separation occurs, it loses lift and the airplane’s trajectory diverges from the pilot’s intentions. Every. Single. Time. And that’s true for other maneuvers pilots may perform from time to time, some of which can only be described as showing off and buzzing something or someone on the ground.

Angle of Attack Illustrations

Stalling Speed Skepticism

The other thing I’d try to change by going back in time is how we have adopted the concept of stall speed, as if there is one and only one indicated airspeed at which a given airplane will stall. The curious part of using airspeed to measure how close we are to flow separation is that it’s directly contradicted by even minimal understanding of angle of attack. The only time a published stalling speed is relevant is in the conditions listed, most of which involve level, unaccelerated flight. Yes, some manufacturers publish stalling speeds at various bank angles, but that’s kind of the point. Stalling speed has evolved into the one universal way we can measure and discuss the airplane’s attitude when it nears or exceeds the critical angle of attack. It’s imperfect and it’s indirect, but it’s a tool all cockpits have.

Instead, directly measuring the wing’s angle of attack (AoA) is a cheap and reliable way to find out how close we are to flow separation. Since most personal airplanes were certificated without one, a mini-boom industry was created a few years ago when the FAA lightened up on its paperwork rules to allow relatively painless installation of AoA indicators for advisory purposes. Lacking a formal requirement for AoA indication, our airplanes were engineered to provide warning of an impending stall, either through aerodynamic buffet or a dedicated system—sometimes both. The problem with both aerodynamic stall indication and dedicated systems is that they only provide adequate warning in unaccelerated flight—straight and level. Start throwing in some G-loading and the time between warning onset and an actual stall gets shorter as G increases. This is true for both types of warnings. It’s true for the Moose Turn scenario, also.

The graph below both perpetuates the stalling speed concept and puts some bank angle into the equation. But the graph’s real purpose is depicting the relationship between bank angle and load factor, and how they contribute to a greater angle of attack until reaching the critical point. Another way the graph is useful is to think of a 60-degree bank and the 2G load resulting as the maximum acceptable unless engaged in aerobatics (forget pitch angle for the moment and assume a constant altitude). By banking no more than 60 degrees and ensuring airspeed is at least 150 percent of the published 1G stall speed, we’ll remain below the wing’s critical angle of attack and flow separation won’t occur. For Cessna’s 172S Skyhawk SP and its flaps-up, wings-level stall speed of 53 KCAS, that means flying an airspeed of at least 80 KIAS (53*1.50 = 79.5) at no more than 60 degrees of bank to keep the wing below its critical angle of attack. Your mileage (and 2G stalling speed) may differ.

Turns And Flow Separation

In and of themselves, banking and turns don’t contribute to flow separation as much as we might think. They become more important, however, whenever we enter a bank while maintaining a constant altitude.

The graph above presumes that’s what we’re doing, which in most airplanes means adding nose-up input to the pitch control as compensation for the reduced lift being generated. And what does pitching the airplane up do? It increases the wings’ angle of attack.

The graph on the right, meanwhile, helps us understand why a bank of any significant angle increases the load factor. Not only is the airplane supporting its 1G, level-flight mass but additional loading is being applied, thanks to centrifugal forces. The additional G-loading depends on the bank angle and, as both graphs on this page show, a 60-degree bank results in a load factor—G-loading—twice what the airplane encounters in wings-level, unaccelerated flight. But that’s not the only way entering a bank closes the distance to the wing’s critical angle of attack.

The diagram on the right may be helpful. It depicts an airplane in a right bank as its wings approach their critical angle of attack. Beyond the airplane’s G-loading, it’s important to understand how banking can result in one wing being closer to its critical angle of attack than the other. This has major implications for understanding spin entries, which is what the diagram actually depicts.

Although the diagram appears to represent a constant bank, that’s not really what happens. Instead, a rolling moment is imposed about the airplane’s longitudinal axis—the one running from nose to tail. Unless rudder is applied to maintain heading, the airplane will turn in the direction of the lowered wing. One wing goes up while the other goes down. The top of the rising wing sees increased air pressure, delaying flow separation. Meanwhile, the top of the lowering wing sees the opposite—reduced air pressure—and the potential for flow separation to be realized at a reduced angle of attack.

But wait—there’s more. In a bank, the lowered wing—the one on the inside of the turn—is moving through the air at a speed lower than the raised wing, the one outside the turn. Less air flowing over the wing means less lift, and increases the likelihood of flow separation. In other words, the lowered wing is closer to its critical angle of attack than the raised one. The mere act of rolling into a bank momentarily increases angle of attack and the risk of flow separation on the lowered wing.

There’s a final point to be made about turning flight at angles of attack near the point of flow separation: Deflecting the ailerons changes the wings’ aerodynamics. The wing with its aileron deflected downward sees increased camber, which means increased lift (drag also increases as a byproduct). The opposite aileron, meanwhile, is deflected up, into the flow itself. This also increases drag but with the addition of decreasing that wing’s lift, essentially by acting as a spoiler and increasing flow separation.

Maintaining Control

As mentioned earlier, not all loss-of-control accidents involve turning flight, or even exceeding the critical angle of attack and encountering a stall. But a bunch do, perhaps with a spin thrown in for good measure. Any time we’re maneuvering— turning, banking, climbing and/ or descending—we’re changing the wing’s angle of attack. Sometimes we’re reducing it, sometimes not.

One key to understanding flow separation is to accept you can’t directly measure how close the wing is to its critical angle of attack without an AoA indicator. Until and unless you have one, indicated airspeed is the imperfect stand-in. It works well enough in level flight, but with almost any bank angle, the equations start changing and you must maintain a healthy margin above the wings-level stall speed.

Banking also has other effects, which may or may not increase the likelihood of exceeding the critical angle of attack and encountering flow separation. Do it right (wrong) and you’ve found the perfect recipe for a spin entry. Do it too close to the ground and you’ll end up an LOC-I statistic.

Jeb Burnside is the editor-in-chief of Aviation Safety magazine. He’s an airline transport pilot with a bunch of hours and owns a Beechcraft Debonair, plus half of an Aeronca 7CCM Champ.

This article originally appeared in the October 2018 issue of Aviation Safety magazine.

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Southwest 737 MAX Makes an Emergency Landing in Orlando
Marc Cook

Seems as though the Boeing 737 MAX can’t get a break. Southwest Airlines had one of its out-of-service 737s commit an emergency landing in Orlando today when the crew reported an engine problem. The ferry flight, SWA 8701, had only the cockpit crew on board and landed safely 10 minutes after departing MCO.

According to an FAA statement, “The crew of Southwest Airlines Flight 8701, a Boeing 737 MAX aircraft, declared an emergency after the aircraft experienced a reported engine problem while departing from Orlando International Airport in Florida about 2:50 p.m. today. The aircraft returned and landed safely in Orlando. No passengers were aboard the aircraft, which was being ferried to Victorville, Calif., for storage. The FAA is investigating.”

According to the FlightAware track, Flight 8701 never got above 2000 feet MSL and did not exceed 270 MPH.

That particular 737 was to join Southwest’s other MAX aircraft in Victorville, where the airline has chosen to temporarily mothball the fleet while Boeing, at the very least, works out software updates to the MCAS. Southwest, which operates 34 of the type, has the largest MAX fleet in the U.S. Victorville, in the high desert northeast of Los Angeles, has the parking space for the grounded aircraft and offers the benefit of dry desert air to reduce deterioration while they are idled.

Podcast: Paula Derks Reflects On Four Decades in Avionics
Paul Bertorelli

The 62nd annual Aircraft Electronics Association convention in Palm Springs, California, marked the official retirement of Paula Derks, the association's longtime president. In this podcast recorded at the show, Paula reflected on the changes she's seen in more than two decades overseeing AEA. Hint: It's a lot.

Podcast: AEA's Mike Adamson Says Finding Techs Still a Challenge
Paul Bertorelli

While the shortage of pilots gets most of the breathless press these days, avionics shops can tell you it’s no picnic finding technicians to install increasingly complex avionics. And with the avionics sector booming, newly installed Aircraft Electronics Association President Mike Adamson says it will take intense pressure on training just to keep up, much less growth the workforce.

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