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A total of 241 people were saved by firefighters after a Singapore Airlines Boeing 777 caught fire after an emergency landing at Singapore Airport early Monday. The aircraft was on a flight from Singapore to Milan when there was an oil leak in the right engine. The crew turned back to Singapore and the engine caught fire just after touchdown. Cellphone video shows the aircraft’s right wing fully engulfed in flame as the fire trucks, which were standing by, pour foam on the flames.

The fire was put out quickly but probably not soon enough to save the airplane. The 222 passengers and 19 crew apparently stayed on board while the firefighters attacked the blaze and can be heard chatting calmly while watching the drama outside in numerous videos posted to YouTube.


Flytenow Inc. is asking the U.S. Supreme Court to review its case against the FAA over pilots using the internet to seek cost-sharing flights with passengers. The company, which sued the FAA in 2014, has ceased operations and in December, lost its case in the U.S. Court of Appeals for the District of Columbia. Flytenow this week asked that the Supreme Court determine whether the circuit court erred in letting stand the FAA's definition of “common carriers,” although pilots using the online service “do not earn a commercial profit or indiscriminately offer to share their travel plans with the general public,” according to court papers.

The Goldwater Institute, which represents Flytenow, said in a statement Friday the FAA has also impeded the company’s First Amendment rights. “Flytenow is simply a communications hub; it connects pilots looking to share their flights with passengers interested in joining them." Jon Riches, the institute’s national litigation director, told AVweb on Friday the Supreme Court hears a small number of the cases requested, but "we think the issues that are raised are significant." The court can select to hear any of the legal questions Flytenow raised in its argument or send the case back to the lower court, Riches said.

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The comment period on a proposed rule that affects the ELTs on 14,500 U.S. aircraft will expire July 8. The notice of proposed rulemaking (NPRM) will require owners of some Ameri-King ELTs to have them thoroughly inspected for function and parts compliance. The rule was written after the agency issued a cease-and-desist order to California-based Ameri-King after it was determined the manufacturer was using non-certified components in the ELTs. The agency looked into the products after reports of 73 failures. Despite the cease-and-desist order, the FAA is not calling for the universal replacement of the ELTs.

If they choose to, owners can have the units thoroughly gone over by an avionics tech and checked for component compliance and functionality. Some defects can be repaired but others require the immediate replacement of the ELT. The agency is calling for repetitive inspections that it estimates will cost $170 but there doesn’t seem to be a schedule for the work.

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The Air Force is considering asking for a major modification to the F-35 that would further disrupt the delivery schedule of the complex program. Defense News is reporting the Air Force wants Lockheed Martin to cost out installing a different ejection seat. The current Martin Baker design can cause potentially fatal neck injuries to pilots weighing less than 136 pounds and put pilots weighing up to 165 pounds at greater risk from injury during an ejection. As a result, the Air Force has banned pilots weighing less than 136 pounds from flying the jet. Lt. Gen. Arnold Bunch confirmed that the Air Force has asked Lockheed Martin to look into the costs and other issues involved in switching to the United Technologies Aces 5 ejection seat. "We believe it's prudent to determine what it would cost, how much [impact on] the schedule, what the timeline would be, if something else happened and we wanted to go a different way,” he told Defense News.

The news comes a few days after the Marines announced they were pulling old F/A-18s out of mothballs in the Arizona desert to fill out their squadrons because of delays in getting their F-35s. Boeing has already made a couple of Hornets airworthy and there are plans to bring a total of 30 back to life. Only about 32 percent of its fleet of F/A-18s are airworthy and the Marines need at least 58 percent on the line to maintain operational readiness and do all the training and other flying the fighters have to do. Other F/A-18 users have bridged the gap between the 35-year-old Hornet and the F-35 with the Super Hornet but the Marines elected to gamble on the F-35, which was supposed to be available in 2006.

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The restoration team for the B-29 “Doc” received Pentagon approval this week to use McConnell Air Force Base in Wichita for completing ground tests and future flight tests. The authorization allows Doc’s flight crew to work with base officials for arranging high-speed taxi tests, followed by a first flight. Josh Wells, a spokesman for Doc’s Friends, told AVweb that the ability to base the Superfortress at McConnell speaks to the significance of the bomber's wartime origins at the field, where workers – some volunteering on the project today – assembled B-29s. "It's important to keep that heritage here," he said.

Doc achieved two milestones in May, completing initial taxi tests then receiving an FAA airworthiness certificate. “We still have to run medium and high-speed taxi tests, as well as other ground, systems and instrument testing prior to first flight,” said Jim Murphy, Doc’s Friends restoration program manager. “Those tests will begin soon and we hope to have the plane in the air within the next few weeks. Our restoration volunteers have worked 16 years to get this far and we’re a few final steps away completing the first stage of Doc’s mission to honor those who built, flew and maintained the B-29 warbird.” 

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Landings with faulty gear are common and almost always uneventful but a Canadian seaplane pilot found himself in an unusual predicament on Saturday. The gear on the amphib floats on Paul Armstrong’s Cessna 206 only partly deployed so he was caught between a wet and a hard place. Landing on water would have flipped the aircraft because some of the wheels were down. Landing on concrete would have had the same result because some of the wheels were still tucked in the floats. So the pilot, air traffic control and officials at Buttonville Airport in Toronto cooked up a plan with the help of the local fire department.

While Armstrong did some sightseeing, the fire department showed up with a tanker and pumper and wet down a grass area beside the runway. After they poured a few thousand gallons of water on the grass, it was all up to Armstrong to make the best of the compromise and he did it in fine style. The plane slid to the shortest landing it had likely ever done, rocked forward, but remained upright and suffered little damage. Flight instructor Humberto Villalobos caught it on video.  A blown hydraulic seal was the culprit.

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Thirty years ago, the idea of carrying sophisticated digital radar in anything under a medium twin would probably have been met with roars of laughter, but technology has brought amazing advances. Now it’s possible for even an ultralight pilot to use the Internet to access essentially the same tools that are available to forecasters.

In the United States, the ground radar network has become so dense and reliable that it’s largely done away with the need for airborne weather radar for anything short of real-time dodging and weaving through an area of cells. Of course none of this radar technology will help a pilot flying to vacation spots in Cancun or St. Vincent, but on a typical cross-country flight, the amount of weather data at your fingertips can be overwhelming.

Radar Basics

Getting the most out of radar requires an understanding of how radar systems work. You may have once learned the basics of radar, possibly using the popular analogy of a bat emitting chirps in a dark room and judging distance by the time it takes for the sound wave to echo back.

The underlying principles of radar haven’t changed a bit. Radar antennas emit a directional pulse traveling at the speed of light. If it strikes a target, it is backscattered to the radar, which uses the elapsed time to determine the distance, or range. By rotating the antenna, it samples all azimuths in a full circle from 0 to 360 degrees.

This gives us a complete radar scan that is used to generate a map of all the echoes. Using digital processing, we can also use colors to highlight echoes that produced strong backscatter signals indicating that something denser than empty atmosphere is out there.

This describes how radar sites worked until the early 1990s. But engineers and research meteorologists developed another important technology called volume scanning. Older radar networks only looked at a single antenna elevation, usually half a degree above the horizon.

Instead of sampling the atmosphere on a single geometric plane, why not sample it volumetrically, in three dimensions? Using volume scanning, the antenna does a full sweep, taking about 20 seconds. Then the antenna elevates by about a degree and another sweep is performed. This scan-elevate-scan process is repeated until the antenna can’t point any higher. The maximum elevation for the U.S. WSR-88D radar is 19.5 degrees.

All of these elevation slices or “tilts” form what is called a volume scan.

Depending on the kind of weather taking place, an individual radar site will select the best volume scan strategy, known to forecasters as volume coverage pattern (VCP). The VCP largely determines how many elevations make up a volume scan and how long it takes to finish a volume scan.

This can take anywhere from 4 to 6 minutes in stormy weather and up to 10 minutes in fair weather. Thus, the images you view are not real-time. Add the time it takes to process and transmit the data, and you can see that the image you view can have data that’s 15 minutes old.

Weather radar from direct-broadcast satellite and Internet sources is built largely from the WSR-88D radar network of 159 sites across the U.S. Keep in mind that this is S-band radar, which operates at a longer wavelength (lower radio frequency) than airborne radars.

S-band radars use large antennas and powerful transmitters to provide excellent penetration through precipitation, minimizing attenuation and shadows. Their underlying images are inherently better than airborne radars that suffer from the restrictions on antenna size.

The classic radar image showing strong and weak echoes is depicting reflectivity. This is a measure of backscattered (reflected) energy from the targets.

It’s important to note that there are two types of reflectivity products. Base reflectivity is an image from a single elevation tilt. Composite reflectivity is a blend of all the tilts together in the entire volume. At a given spot, the composite-reflectivity value is a measure of the highest reflectivity that was detected at that spot on any of the elevation slices.

Reading the Radar

The best starting point to interpret your display is the type of reflectivity—base or composite. If the menus and labels aren’t clear and the vendor doesn’t specify it, dig until you find out. Base and composite-reflectivity displays are constructed differently and at times they can appear very different.

As a starting point, XMWX and WSI ADS-B show composite reflectivity. By contrast, WSI InFlight uses base reflectivity. Both are excellent products but each has its pros and cons that must be understood to be able to reap the maximum benefit from the information.

Why use two types of reflectivity? Composite reflectivity doesn’t miss anything. If it’s near the ground, it shows up. If it’s near the tropopause, it shows up. So why use anything else? Well, meteorologists need more granularity.

For example, the hook echo signifying a tornado only shows up in the lowest mile or two of the atmosphere. Using only one elevation at that level, it shows up beautifully, but if we use composite reflectivity, that hook echo is merged into all the hail and rain at higher levels and we just see a blob. So forecasters prefer to look at base reflectivity and page between the different elevations, though composite reflectivity helps with the big picture.

You should not be looking for specific shapes and features like hook echoes when assessing things on composite-reflectivity displays. But we do have intensity, which is quite useful even by itself, because the only weather phenomena capable of producing very high intensities are hail, particularly if it’s large and wet, and highly dense volumes of rain. Both of these usually signify a strong storm that should be avoided.

Caveat Emptor

Composite reflectivity does have its downsides. For example, anvils from storms have considerable ice content being carried up to a hundred miles downwind by the jet stream, and these plumes are easily picked up by higher radar tilts. This will cause composite reflectivity to “bloom,” showing much larger downwind depth than exists at most levels. This precipitation might very well be affecting a jet at cruise altitude, but a Bonanza near the ground might see only VMC, a broken layer of anvil overhead, and cumulus buildups to the west.

Another caution comes from winter weather or a cold-rain situation. If it’s just above freezing in the low levels, there will be a melting level at a specific altitude where ice is falling into warmer air and melting, forming a liquid coating around a solid.

This precipitation is highly reflective. On base reflectivity it forms a clear ring of reflectivity at a specific radius around the radar where the beam crosses through that level. The ring radius varies with radar tilt. As a result, composite reflectivity will stack all these different rings together, producing multiple concentric rings around a radar site, with some of these melting level artifacts incorrectly suggesting areas of intense precipitation.

While it’s difficult for anyone but a meteorologist to deconstruct a confusing composite-reflectivity image, being aware of how these effects get into your radar display will help you recognize them when they occur.

Picking your way through storm echoes has long been a familiar game of dodgeball for pilots, but there is danger in doing this because the most intense vertical motions are associated with the updraft. Unfortunately the updraft is actually a relatively dry part of the storm, meaning it is non-reflective to radar. An updraft core is made up mostly of cloud droplets in the lowest 5 to 10 thousand feet, with progressively larger droplets and higher reflectivity as you ascend to the top of the updraft. The danger is that in the strongest storms, this process is shifted to higher elevations, often 20 to 30 thousand feet off the ground, leaving the lower elevations with no reflectivity.

Fortunately, composite-reflectivity products actually offer an advantage in terms of safety, because some of the highest intensities in the storm tend to overlie the updraft. So while a Learjet pilot at only 10,000 feet might glance at a base-reflectivity product or her own on-board weather radar and see an echo-free region where a dangerous updraft is located, a Mooney pilot with composite reflectivity from XMWX will see this area saturated with high intensities and give it wide berth.

Composite reflectivity has an advantage here, but if upper winds are particularly strong, the updraft may be tilted, shifting the upper parts of the storm downwind and lowering the composite reflectivity’s margin of safety. Keeping away from the upwind (usually southwest) side of the storm will help keep you safe when upper winds are strong. That said, the AIM’s advice of staying at least 20 miles away from the storm is sound advice indeed.

Radar Network Shortfalls

The ground-based radar network has a couple of vulnerabilities. One is weather directly over the radar site. Imagine wearing a wide-brimmed hat and not being able to look up. You’d be blind to the storms overhead, though you would be able to see all the rain near the ground at short distances around you.

This is the same sort of problem that affects the WSR-88D radar, which can only tilt upward 19.5 degrees. It forms a volume known as the cone of silence, which cannot be sampled. For all practical purposes, this cone only affects areas within 20 miles of the radar. Within this zone, we’re limited to only seeing the lowest parts of the storm. Even if we’re using composite reflectivity, very intense echoes aloft over the radar site will likely be missed and intensities will show up as being lower than they really are.

A good weather delivery network like WxWorx from Baron (XMWX weather source) compensates for this by using neighboring radars to illuminate each of the cones of silence and fill the gap. This is very effective in radar-dense areas like Illinois, Indiana, Georgia, and Oklahoma. But in radar-sparse places like the northern plains and the Rockies, there may not be a radar site close enough. So if you’re picking your way through weather and are heading directly over a radar site, you may not be getting the full picture.

Some areas are simply too far from a radar site. There are several well-documented areas in the contiguous lower 48 states that are poorly sampled—the four corners area (N.M./Ariz./Utah/Colo.), central Utah, southeast Montana, the high desert and central coast of Oregon, and the Big Bend region of Texas.

Here, the radars are far away or blocked by mountains, and they’ll only sample higher elevations. This means if you’re flying in these areas, you’ll need to use extra caution, particularly in IMC and at lower elevations.

WSI NOWrad uses the 248 nm products to fill in those distant areas, but even with that feature there’s still no technology that will get samples in the lower troposphere so far from the radar.

Of course, if you fly outside the service area of all those great radars, you have the same problem. To a certain extent you can use infrared satellite imagery as a crude substitute, though it’s sensitive to high clouds as well as rain clouds.

Getting the Most

We’ve only considered radar data itself for weather avoidance. Most of the systems on the market offer many other tools that are excellent for keeping you safe, such as lightning detection and storm track information. While a whole new article could be written explaining how to integrate all these tools, a firm understanding of radar basics, a timely and complete weather briefing and good situational awareness are more than enough to keep you safe.

That said, perhaps we can distill this article into a little simple advice. Remain clear of the red areas and of the updraft and downdraft cores. Keep in mind that they aren’t always one and the same.

Tim Vasquez is a professional meteorologist in Norman, Oklahoma. See his website at

This article originally appeared in the June 2014 issue of IFR magazine. 

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If you’re a reader of current events—and these days, who isn’t?—you can’t have missed Friday morning’s seismic news about the U.K.’s vote to exit the European Union. It’s easy to compartmentalize that as being “over there” with little or no impact on the U.S. Pardon me, but I don’t think so, although no one knows for sure what the long-term effects will be. The Dow took a hardy three-point tumble, wiping out a year of gains. We’ll see if it shakes off the worries and recovers some ground on Monday.

If your current events reading has included any of the minutiae related to the increasing globalization of world aircraft markets then you also understand that the EU and its certifying agency, the European Aviation Safety Agency, are central to that trend. What the EU and EASA have done is to make Europe a single economic bloc for trade but, more important, a more predictable certifying and licensing agency for aviation products going in both directions. The alternative had been a hash of different requirements and barriers for every country in Europe and now the question becomes will it be again?

My guess is probably not, but no one knows. The political press in Europe is discussing the U.K. exit as the start of a contagion in which other countries will either want out of the EU entirely or will attempt to negotiate their own special relationships with the union that would provide all the benefits, but none of the burdens. If that were to happen—and it could—then by what rationale does a single European aviation agency survive? What priority would the U.K. or any other country place on restoring bilateral approval agreements with the U.S. or other European countries? In the midst of likely economic chaos, would aviation concerns just get kicked to the curb, like they have so often?

I fired off a quick email to GAMA’s Greg Bowles, who’s now working in Brussels as a liaison for U.S. aviation interests in Europe. Without commenting on the contagion aspect, he agreed that how the U.K. prioritizes restored bilaterals is the big-picture worry for the short term.

“We can only speculate but it is most likely that the U.K. will remain a party to EASA like a handful of other non-EU countries. With that said, the U.K. would need to sign an aviation bilateral agreement with the U.S. as the old agreement expired when the FAA-EU agreement was signed,” he said. GAMA had lauded EASA regulators for moving quickly on the CS23 revision and noted the FAA has done just the reverse.

A key question now is insularity, which seems to have driven the Brexit vote in the first place. According to exit polls, the leave-the-EU voters were anti-immigrant and anti-EU regulation and oversight. It’s illogical that such insularity would creep into the aviation oversight agency, the CAA, but then the vote to exit strikes me as illogical, too. What’s to be gained by doing it?

For the U.S. aircraft industry, exports are a robust part of the business. Not too long ago, more than half of Cirrus aircraft were exported. That percentage has declined, but exports are still important. Friday morning, the British pound took a horrible thrashing against the dollar, sinking to a 30-year low, and the Euro did little better. That’s great if you’re planning a London vacation, but horrible if you’re trying to sell a few Cirri, Cessnas or Mooneys across the pond. I’m not sure if this benefits Diamond, an Austrian company, exporting to the U.S. The same applies to the many European-based light sport manufacturers who may or may not enjoy a little tailwind from exchange rates. That could easily be neutralized by yet slower economic activity in Europe ignited by the U.K. exit.

For the past three decades, GA worldwide has faced barriers and headwinds—economic, regulatory and demographic. While the U.K. exit may not devastate our little struggling-to-survive niche, it’s impossible to see how it’s of any help. It’s easy to see how it could be just enough of a confidence sapper to make the difference between selling 25 airplanes abroad and selling 21. In other words, it might not be a stick in the eye, but rather a case of poison ivy. Who the hell needs either? No wonder then that by Friday, as the Brexit hangover set in, U.K. voters had a new hashtag: Regrexit.  

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Overheard while flying through the New York Class B airspace:  

Pilot:  Departure ABC 795 off 14L climbing to 5000'.  

Controller: Is this 725 or 795?  

Pilot:  What did I say?  

Controller:  795.

Pilot:  Oh sorry, I guess this is 725.

Controller:  Don't worry about it, I mix up call signs all day.

Pilot:  Yeah, but I only have one call sign to screw up.

Ed Abrams

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