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Sales of avionics for business and general aviation airplanes were up 2.7% in the first six months of 2017 over the same period last year, according to the Aircraft Electronics Association (AEA), but not because people are buying more airplanes. “Forward-fit” sales—those avionics systems intended for new aircraft—were down a remarkable 17.3%. The loss of forward-fit sales was overcome for GA avionics makers by strong sales for the retrofit market, up 26.3% to $644 million in the first half of the year. "It's encouraging to see a positive increase in year-over-year sales for two straight quarters, something we haven't experienced since 2014," said AEA President Paula Derks.

Sales are not broken out by system type, but the regulatory requirement for aircraft operating in Mode C airspace to be equipped with ADS-B Out by 2020 plays some role in the strong retrofit sales numbers. Based on product announcements at AirVenture 2017, avionics manufacturers, sensing the trend, seem also to be focusing more energy on the retrofit market. Dynon announced plans there to begin certifying its SkyView flight deck system. Garmin recently announced two new autopilots specifically for the retrofit market, the GFC 500 and GFC 600. TruTrak and Trio also announced new STCs for their autopilots for installation in more certified aircraft at the show.

Continental 'Factory new CM Magnetos at near-rebuilt pricing'

The Marine Corps has abandoned hope of finding alive three Marines missing after their MV-22 Osprey tilt-rotor aircraft went down off the northeast coast of Australia on Saturday. The other 23 personnel aboard the Osprey were rescued and only one of them had to be admitted to the hospital. The aircraft was taking part in a training exercise with Australian forces when the “mishap” occurred. At first, the Marines and Australians mounted a massive search but after about 14 hours it became a recovery mission.

"The transition comes after teams led continuous sustained search efforts supported by aircraft and ships," the III Marine Expeditionary Force, based in Okinawa, Japan, said in a statement. "As the sea state permits, recovery efforts will be conducted to further search, assess and survey the area ..." they said in a statement. Next of kin of the three missing Marines have been notified.


New flight recorder data says Air Canada flight 759 (ACA759), an Airbus A320, descended as low as 59 feet above ground level and the 55-foot tall 787 on Taxiway C before beginning to climb out on its go-around—coming potentially as close as four feet from a collision. At four minutes to midnight on July 7, ACA759, which had been cleared to land on Runway 28R at San Francisco International, instead lined up on Taxiway C, on which three aircraft were holding for takeoff. After prompting by one of the pilots of United Flight 1 (UA1), the first in line for takeoff on Taxiway C, who was well positioned to see that ACA759 was not headed toward a runway, the tower controller instructed ACA759 to go around. After advancing the thrust levers at 85 feet above ground level, the aircraft continued to sink to a minimum altitude of 59 feet, before overflying at least two more aircraft. Altitude figures in the NTSB report are likely based on the A320’s radar altimeter, according to an A320 pilot who spoke with AVweb about the incident. The extent to which the accuracy of the radar altimeter may have been influenced by extremely close proximity to aircraft underneath has not yet been reported by the NTSB.

According to initial interviews with the flight crew, both pilots appear to have been confused by the absence of lighting on Runway 28L, which had been closed for construction. Its lights were turned off at the time of the incident, and a 20.5-foot wide flashing X had been placed near the threshold. The Air Canada pilots reporting believing that Runway 28R was actually 28L and they therefore believed that Taxiway C was Runway 28R. According to the NTSB, the pilots “did not recall seeing aircraft on Taxiway C but that something did not look right to them.” At 0.7 miles from the runway, the Airbus crew had asked the tower to confirm there were no aircraft on 28R and that they were cleared to land. The NTSB only learned of the incident two days after the fact, at which point the cockpit voice recorder had been overwritten by subsequent flights.

BREAKTHROUGH! - Cubcrafters

The Canadian Transportation Agency (CTA) has ordered Air Transat to explain why passengers were driven to call 911 for help as they sat in packed aircraft for up to six hours on a hot afternoon and evening in Ottawa. The agency, an independent quasi-judicial body that rules on complaints about air, rail and marine transportation services, heard from people aboard the aircraft, who were supposed to land in Montreal but were diverted for weather. The packed A330 that had already spent seven hours in the air coming from Brussels sat on the ramp for another six hours with the doors shut tight on the more than 300 passengers and crew on board. The water supply ran out and the air conditioning was shut down when the aircraft ran low on fuel. At least one passenger called 911 and police, fire and ambulance personnel responded to treat people with breathing problems and other disorders associated with the heat.

Air Transat blamed the Ottawa Airport, saying it didn’t have enough services for all the aircraft that were diverted there. Ottawa Airport begged to differ and there were some tense tweets and countertweets going back and forth. Meanwhile, the CTA says it will sort through everyone’s stories and figure out how to avoid similar issues in the future. “This inquiry will determine, based on the evidence and the law, whether the treatment of passengers on the two flights was in line with the airline's obligations -- and if not, what corrective measures should be ordered,” CTA Chair and CEO Scott Streiner said in a statement.

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President Donald Trump has approved the sale of 12 Embraer Super Tucano light attack aircraft to Nigeria. Although the aircraft was designed in Brazil, the aircraft is being assembled in Jacksonville, Florida, and the weapons and sensor systems integrated by Colorado-based Sierra Nevada Corp. The supply chain was initially established for Embraer to supply the single-engine turboprop to the Air Force for use in counterinsurgency missions in the Middle East. This may be the first export of the U.S.-built counterinsurgency version of the aircraft for use by another military organization. The training version has been sold to Lebanon and Afghanistan as a trainer and is competing for other trainer contracts.

The sale to Nigeria is potentially controversial because of the country’s poor reputation on human rights and democratic process. Isaac Ikpa, executive secretary of Nigeria’s Centre for Social Justice, Equity and Transparency (CESJET), praised Trump for ignoring the “fraudulent mainstream media’s” accounts of Nigeria’s various transgressions against its own citizens and allowing it to buy the potent weapons system.  “On the strength of our work in Nigeria, we testify that the Nigerian military has reformed while its human rights record has tremendously improved under the current leadership, a development that was never acknowledged by Amnesty International and the international media circuit,” Ikpa said. He said the aircraft will be used to fight the terrorist group Boko Haram but the Indigenous People of Biafra (IPOB) claim “the aircraft will be used for aerial bombardment and mass murder of Biafrans." 


My wife, the captain, and I were flying to AirVenture 2017 in our C-152 in July.  We were on an IFR flight plan out of Gainesville, GA (KGVL) and cruising at 5000 feet.  We were talking to Atlanta Center. 

Centre: ”Cessna 1234, cleared to FL230.”

We just looked at each other and laughed.  Fairly quickly, we received this.

Center: ”Cessna 1234, disregard.  I'll bet you got a kick out of that one."


Dennis W. Wilt 


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The magnetos we’ve been relying on to fire our aircraft’s spark plugs may be the trailing edge of technology, yet if cared for appropriately, they are remarkably reliable. It’s the cared for part of the equation that matters—because they do require regular maintenance, otherwise some failure modes can mean engine stoppage or even catastrophic engine damage in a matter of seconds. The good news is that keeping your mags healthy usually costs less than two dollars per hour of engine operation per mag.

The purpose of a magneto is to provide enough electrical energy, at the right time, to fire a spark plug and ignite the fuel/air mixture in a cylinder. It operates on the principle that a rotating magnet will generate alternating electrical current in a coil of wire. By wrapping another coil of wire, with many more turns, around the primary coil, the voltage can be stepped up dramatically. The high-voltage current in the secondary coil—20,000 to 30,000 volts—is then mechanically directed to the appropriate spark plug as its piston reaches 20 to 24 degrees before top dead center (TDC). We’ll take a brief tour through the major components of a magneto, discussing what they do, how they can go bad, what happens when they do so and how to prolong their useful lives.

The heart of a mag is a permanent magnet, referred to as the rotor. It is rotated by a drive on the engine’s accessory case. On a four-cylinder engine, it rotates at the same RPM as the engine. On a six-cylinder engine, it spins at 1.5 times the engine speed. The magnet retains its magnetism for years, and is re-magnetized when the magneto is opened up for repair or overhaul.

As the rotor loses its magnetism, the electric current generated as it spins diminishes, leading to a less powerful spark and such things as hard starting or slight engine power loss. We strongly recommend following the manufacturers’ recommendations to pull mags at 500 hours time in service to replace them (Champion/Slick mags) or (Continental/Bendix mags) open them up, inspect and replace components as necessary (IRAN—more about IRAN later). 

About 200 turns of heavy-gauge copper wire make up the primary coil. One end of the wire is grounded to the mag’s case. The other end is attached to a set of breaker points that are operated by a cam. The breaker points spend most of their life closed so that the current generated in the coil by the spinning rotor flows around the coil—producing a strong magnetic field.

Magnetic Field Collapse

The cam is set to open the breaker points the moment ignition is desired. With the circuit suddenly broken, the magnetic field in the coil collapses and causes a voltage spike in the primary coil of 200 to 300 volts.

As the breaker points begin to separate and the voltage spike occurs in the primary coil, the electrical energy will attempt to arc across the widening opening between the points—they can’t get to their full-open position instantly. Any arcing will cause the breaker points to pit and erode, one of the causes of magneto failure. 

To prevent arcing across the points and cause a faster, more predictable magnetic field collapse—generating a greater voltage spike—a capacitor is included in the primary coil circuit. When the points start to open, the initial voltage spike charges the capacitor for a few microseconds rather than jumping across the widening point gap. By the time the capacitor is charged, the points are far enough apart that the 300-volt spike in the primary coil can’t jump the gap.

If the capacitor goes south, there will be arcing and pitting of the breaker points and eventual magneto failure. Breaker points do wear in normal use, however; they should last five to seven years.

Once the sudden voltage surge in the primary has been stepped up to 20,000 to 30,000 volts in the secondary coil, the energy needs to be routed to the appropriate spark plug. This is carried out mechanically by a distributor. A rotating wiper electrode on a plastic gear inside the distributor passes very near—but does not touch—the individual electrodes that connect to the individual spark plug lead wires.

The distributor components, other than the wires, are made of insulating material that can withstand the high voltages involved, although the materials can be damaged by heat.

The interior of the distributor must remain almost surgically clean as contamination will allow arcing between the rotating wiper electrode and the electrodes connected to the spark plug lead wires. Arcing will cause potentially damaging engine misfire. When arcing occurs, it leaves a trail of carbon from the burned contamination. That trail of carbon facilitates further arcing—making the misfire problem worse.

High-Altitude Misfire

Air helps prevent arcing between the electrodes in the distributor—it’s a natural insulator. As the airplane climbs and the air gets thinner, its insulating properties diminish, making arcing and engine misfire more likely. We’ve experienced misfire when flying in the flight levels—and we can say with certainty that it’s a scary event. The immediate solution is to reduce power and descend.

Reducing the power reduces the combustion chamber pressure and makes it easier for the spark plug to fire, reducing the potential for arcing in the distributor. As the air density increases, the insulating effect increases and should stop the misfiring. Once you land, have the mags pulled and opened up to inspect for carbon tracking inside the distributors—once it’s started, it’s easier for arcing to occur the next time. Any carbon tracking should be cleaned off.

For airplanes regularly being flown in the flight levels the method of preventing misfiring is either to use the largest magneto possible—so there is the greatest distance between spark plug lead electrodes—or install pressurized magnetos. Our research indicated that using large mags is preferable, although there is not enough space on some engines. Pressurizing the mags works, but adds complexity to the system and often introduces contaminants into the mags—increasing the risk of arcing and misfiring. If the pressurization system malfunctions at high altitude, it can cause both magnetos to arc, inducing misfire. Because of contamination risks, pressurized mags need to be pulled and inspected much more frequently than their non-pressurized brethren.

Additional protection against high-altitude misfire involves tightening up the gap on the spark plugs to make it easier for the spark to occur.

Arcing within the distributor generates heat, which can damage the plastic gear that rotates the main electrode, causing misfiring. Over time, the plastic gear can become brittle and lose teeth, throwing off the timing and causing the plugs to fire at the wrong time. Pulling the mag for IRAN every 500 hours of service allows a technician to check on the health of the distributor components and replace those that are at risk.

Dealing With Misfire

If you experience an engine that starts running rough, do a mag check. If the engine smooths out on one mag, but continues to run rough on the other—shut off the mag that is causing the engine to run rough. A failure within a mag that causes the engine to misfire is potentially serious. Misfiring can lead to detonation and catastrophic failure of the engine. We’re aware of a number of accidents as well as wrecked engines caused by a mag problem in which the pilot did a mag check, identified the problem as related to one magneto and then continued to run the engine on both mags. If the engine is misfiring on one mag, don’t keep using that magneto—that’s one reason why there are two mags on the engine.

Because a magneto is always “hot,” there has to be a way to disarm it to avoid the engine firing when it’s not desired. To do so, a wire called a “P-lead” is connected from the ungrounded end of the primary coil (“P” is short for “primary”) to the ignition switch to allow it to ground the primary coil. So long as the P-lead grounds the primary coil, the mag cannot generate electrical current and fire a spark plug.

P-leads are subjected to the environment of heat and vibration within the engine cowling, so they can and do come loose or break. If the P-lead fails, that mag remains hot at all times and can cause the engine to fire if the prop is moved, a potentially dangerous event. Turning the engine off, briefly, with the ignition switch while idling just prior to shutdown will allow a broken P-lead to be detected.

The mag check you do during the pre-takeoff engine run-up will usually only reveal gross problems with the ignition system. Which means, if the max RPM drop or difference in RPM drop between the mags doesn’t fall within the engine manufacturer’s parameters, you’ve got something wrong that is significant enough that it needs to be dealt with prior to flight.

To find more subtle problems, before they become big ones, we recommend conducting a mag check in flight, when the ignition system is working harder, under more stress. We also highly recommend installing a digital engine monitor as it can save you more money than it costs in catching magneto problems before they become serious. 


There are two manufacturers of magnetos and, depending on the type of engine on your airplane, you may or may not have a magneto choice. Bendix mags, now manufactured by Continental, come in three main types. The S-1200 series are large, robust, hot-sparking mags that are often used on airplanes that fly at high altitude—although they do not fit on all engines. The S-20/S-200 series are older, smaller-style mags that have a good reputation in service. The D-2000/D-3000 series are “dual magnetos”—two magnetos driven via a single shaft. They are only used on Lycoming engines and Continental no longer supports them. Parts availability is reportedly still good.

Slick magnetos, now manufactured by Champion, are smaller than comparable Bendix mags, however, they are significantly less expensive. Due to price, some models are considered throwaway—after 500 hours in service, the cost of buying a rebuilt exchange mag is often the same as opening up and repairing the existing mag. Our review of prices for rebuilt exchange Slick/Champion mags from the national specialty shops revealed prices in the $600 to $800 range. Prices for new Slick mags we saw were twice that of rebuilt units.

IRAN v. Overhaul

When your Bendix mags hit 500 hours in service, we recommend yanking them and sending them out to a specialized magneto shop for IRAN. For Slicks, we suggest getting an estimate for IRAN versus checking prices for rebuilt units—as they may be comparable and it can be faster to simply get rebuilt mags.

We do not recommend overhauling a magneto. To tag a magneto as overhauled, a shop must replace all of a specific list of parts, even if they are perfectly serviceable. Our research into prices showed it was generally twice as expensive to overhaul a mag as to inspect and repair and replace parts as needed. Depending on the parts that have to be replaced, we figure on $500-$700 for IRAN of a big Bendix mag—the smaller mags are less expensive. Bendix mags can be IRANed indefinitely. They do not need to be overhauled.


Magnetos are reliable, robust devices that nevertheless need to be precisely timed—and the timing checked regularly. Accept that the components wear, and that a mag is not going to last until engine TBO, so plan on pulling and having them IRANed (or, for Slicks, replaced) every 500 hours.

Rick Durden holds an ATP with Douglas DC-3 and Cessna Citation type ratings, is an aviation attorney and the author of The Thinking Pilot's Flight Manual or, How to Survive Flying Little Airplanes and Have a Ball Doing It Vols. 1 & 2.

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I heard a comment the other day from a researcher at one of the big flight academies: “Cessna competes with Cessna, not with Piper or Diamond.” He was directly referring to the $400,000-plus price tag for the new Skyhawks that still constitute the mainstay of the training fleet.

Consider that stratospheric number against a good used model that can be had for $50,000, with no penalty in performance and probably not much in reliability if the older model is refurbished. In that context, he figured Dynon’s newly announced soon-to-be approvals for its Skyview HDX in certified airplanes could be market shifters. (I am constitutionally restrained from using the phrase “game changer.”)

Well, maybe. But in order for this to be true, the big academies will have to show interest, as will the smaller schools that form the backbone of Part 61 training. A smattering of interest from private owners would help.

Let’s look at some numbers. Bluebook values for mid-1980s Skyhawks (P-models) are in the mid-$50,000 range. Mid to late-70s versions are a little less. Add to that a thorough refurb to include an engine, paint, rewiring, upholstery and upgrades like LED lighting and improved panel lighting and you’ll spend another $60,000 to $70,000. Dynon says the Skyview HDX will come in around the mid-$20s, so not to cheap it, call it $30,000. That yields a range of $135,000 to $155,000 or right in the $150,000 sweet spot flight schools tell me they’re willing to spend.

That’s less than half the price of a new Skyhawk. Conversely, if you’re willing to spend $150,000, what else can you buy? How about a mid-2000s pre-G1000 Skyhawk, or maybe even a high-timer with early glass? That budget will also buy a Piper Archer III of similar vintage or a Diamond DA40 with some change back. But those models will be either pre-glass or original G1000 airplanes. Modern avionics may have more appeal. (Or not. I don’t pretend to know what buyers really want and they often don’t either until the market options are presented.)

There is a test case here and it’s Redbird’s Redhawk 172 introduced in 2013. It’s a ground-up remanufacture of the Skyhawk, converting it to a Continental CD-135 diesel with Garmin’s G500 and digital comms, plus an autopilot. At $250,000, it has achieved modest but not spectacular market success. I think there are several reasons for this and one is that North American buyers don’t see compelling advantage in the diesel engine’s fuel economy traded for less payload and slower climb.

I keep hearing that U.S. buyers are warming to diesel and I keep not seeing significant sales numbers to support this. The backdrop of diesel trending out of favor for cars might not help. The upward diesel trend in aviation, such that it is, is a trickle, not a torrent. It’s not lost on me that Diamond, the diesel pioneer, acknowledged this by announcing the Lycoming TEO-540 as an option for its planned DA50-VII. That airplane is aimed at North America.   

You probably noticed that AEA reported a massive increase in retrofit sales among its members. The data lacks the granularity to show if this is due to ADS-B installations or upgrades of other types, but it does show owners are again willing to spend money. The appearance of six new retrofit autopilots suggests that manufacturers are sensing demand out there. Then again, demand is often indistinguishable from blind hope.   

So the intriguing question of the day is this: Will a downward trend in the cost of full glass panels coupled with an upswing in training demand ignite refurb demand greater than what Redhawk has seen? And the follow-up question: Does a $25,000 glass panel upgrade appeal to you enough to actually order one? You can answer that in today’s question of the week.

And while you’re contemplating that, consider this: CubCrafters announced that Garmin’s non-certified G3X Touch will be an option in the XCub. (Except that putting it into a Part 23 airplane is certification, after a fashion. A fine point.) This further substantiates the trend toward less expensive major avionics suites. It also raises the question of whether Garmin will offer the G3X as a retrofit for certified aircraft.

I asked and the answer was a noncommittal statement about Garmin always looking for ways to leverage its products into additional markets. That’s what the late Ben Bradlee would have called a non-denial denial. It’s not a no, so I take it as a probably. I think Garmin will have little choice but to offer the G3X to compete with Dynon. Little did we know what far-reaching effects would transpire when Jack Pelton announced the D10A STC in conjunction with Dynon last year.

Interesting times.    

Today’s Important Date

Although you might not read this until August 7, it’s being posted on August 6. Any student of World War II history will remember that date for the Enola Gay’s historic mission to bomb Hiroshima with the first nuclear bomb used in combat. Today is the 72nd anniversary of that event.

With B-29s making such a high-profile appearance at AirVenture this year, I thought the date was worthy of mention. Here’s a brief interview with Paul Tibbets, who commanded the Enola Gay, on his thoughts at the time. Some who had the pleasure of not living through World War II, much less fighting in it, often seem to fault Tibbets as being cruel and thoughtless of his role that day. He was anything but. Like all World II vets, he deserves commemoration.  

DC One-X from David Clark - lightest full-featured ANR headset

At AirVenture, AVweb's Paul Bertorelli took a turn in the left seat of a DC-3 with Dan Gryder flying low approaches. Here's a video of the action, with some great outside shots by Nate Tennant. 

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Picture of the Week

Sometimes it's just the details that catch our eye. We don't want to know what was going on in that plane. Thanks to Frank J. Gadarowski.

Electronics International 'Aviation Alert! Short video on how EI saved this pilot's life

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