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Weekly tips, technique and training from IFR.

October 2019

Full Issue (PDF)

Download The Full October 2019 Issue PDFSubscribers Only

I used to fly out of an airport on the coast just south of the San Francisco Class B. While controllers tried to permit transit, there was no guarantee. If they also have a §91.131(a)(2) problem, that Miami solution would seem attractive to San Francisco. The result for VFR traffic on a trip headed north might be to add up to 100 miles or more to bypass the Class B to the east, or a deviation far out over the Pacific Ocean, neither of which is an attractive alternative.

Briefing

Briefing: October 2019Subscribers Only

The Air Force and tech company DZYNE have created an ungainly-looking device that can take off, fly and land an airplane like a human pilot and without tearing the aircraft apart. The Air Force Research Lab (AFRL) Center for Rapid Innovation flew a Cessna 206 with the ROBOpilot at the controls for two hours on Aug. 9 and said the idea is to make the machine interchangeable with human pilots. “Imagine being able to rapidly and affordably convert a general aviation aircraft, like a Cessna or Piper, into an unmanned aerial vehicle, having it fly a mission autonomously, and then returning it back to its original manned configuration,” said Dr. Alok Das, senior scientist with the Center for Rapid Innovation, in a statement. A video with the news release shows the robotic pilot making corrections to keep the centerline during takeoff and a bounced, but ultimately safe landing.

Features

Skew-T RevisitedSubscribers Only

The Skew-T log-p diagram, typically just called a “Skew-T,” is an amazing tool for understanding what’s happening in the atmosphere at a given station. They are essential for understanding a precipitation regime or differentiating icing layers. Even after nearly three decades in meteorology I would find it almost impossible to understand an icing situation without this tool, and I often visualize the makeup of an environment with a sort of mental Skew-T image. I can’t underscore how valuable these diagrams are once you get to know them.

Clearing FlagsSubscribers Only

It’s certainly legal to fly through the AIRMET. These are advisories covering large areas. But it behooves you to determine that your flight plan won’t enter “known or forecast light or moderate icing conditions” as prohibited in §91.527. Here goes. There’s a stationary front just west of the route, bringing in cloud layers and scattered showers. Freezing levels will hit between 7000 and 12,000 feet. So, at 8000 feet, you do risk picking up ice. One lone pilot report from a single-engine turbine over Iowa shows negative ice in climb from 3000 to the tops at 11,000. This isn’t all that useful since you’re flying lower and slower, but you are willing to climb as high as 12,000 feet to be on top. Your Plan B, while not at all mission-friendly, is to turn back to warmer air and land in Iowa, or even return to Bowling Green if that’s best.

Why GPS Doesn’t WorkSubscribers Only

Dark clouds are looming on the horizon of our otherwise exciting GPS future. With increasing frequency, the military is jamming or spoofing GPS over huge swaths of airspace. A typical GPS NOTAM for Albuquerque center covers a radius of 237 NM at 10,000 feet, 207 NM at 400 feet and 165 NM at 50 feet daily for most of a week. Pilots in the Southwest have become accustomed to these NOTAMs, but they’re becoming more frequent and expanding to other areas of the country.

Canada’s ADS-BSubscribers Only

Just to make sure you understand what’s up, let’s review. In the U.S., we’ve got excellent radar coverage, so all those radar sites have been modified to understand your aircraft’s ADS-B out transmissions. In those areas where radar sites don’t quite have adequate coverage, the FAA has added ground stations specifically to receive your ADS-B Out. The bottom line is that the FAA has sufficient ground-based coverage to know where you are almost all the time, using your ADS-B Out.

Spotting TrafficSubscribers Only

TCAS II is the most comprehensive form of TCAS, but its range depends on what it is asked to do. Overall pulse detection range is 30 NM for Mode S transponders and 14 NM for Mode A/C units. Surveillance must be reliable within 14 NM, but TCAS II will only assess threats within 12 NM as possible RAs. TCAS II guarantees system reliability within at least 4.5 NM. Two TCAS II systems can coordinate RAs to maximize vertical separation, typically 300-700 feet. There is even a reverse RA if one aircraft fails to respond correctly in the latest version 7.1 software.

When Things Go WrongSubscribers Only

It should be obvious that we never say the words, “Declare,” “Emergency,” “Mayday,” or “Pan-Pan” unless we indeed have a dire situation. These words have the potential to flip a controller’s airspace upside down faster than a Vmc roll, so they should be used with discretion. Even saying “Declare” by itself could lead us to believe that assistance is needed, as well as “Pan-Pan” (Urgent condition). Because Pan-Pan is considered an urgent condition (maybe not a full-blown emergency), it has the potential to turn into “Mayday” (Distress) so we mostly treat it as such.

On the Air

On The Air: October 2019Subscribers Only

The ride over was smooth and generally clear on a recent flight, but there were intermittent clouds and bumps at 7000: Piper 28D: “Allentown Approach, Piper Two Eight Delta, request.” Allentown Approach: “Go ahead.” Piper 28D: “We are about to enter a cloud layer at 7000. Is 5000 available? I’ve got my 90-year-old dad with me and I’d like him to have a smooth ride.” Approach: “Both of you can godown to 5000.”

Readback

Readback: October 2019Subscribers Only

First, we checked with Garmin and their equipment actually decodes the Morse code identifier rather than rely on GPS and the tuned frequency to look it up in the box’s database. So far, so good. We next checked with Mark Kolber, our regs guru, and he pointed us to AIM 1-1-3.c. That paragraph talks about navaid identification in general, pointing out that merely hearing Morse code isn’t enough because it could be transmitting “TEST.” Likewise, live voice transmissions from FSS or ATC don’t indicate a valid navigation signal. The prize, though, is in the paragraph’s last sentence, “If your equipment automatically decodes the identifier, it is not necessary to listen to the audio identification.” So, Rick, you’re right. If the box decodes and displays the Morse code identifier, you can rely on that.

Remarks

Bigger Class B?

I used to fly out of an airport on the coast just south of the San Francisco Class B. While controllers tried to permit transit, there was no guarantee. If they also have a §91.131(a)(2) problem, that Miami solution would seem attractive to San Francisco. The result for VFR traffic on a trip headed north might be to add up to 100 miles or more to bypass the Class B to the east, or a deviation far out over the Pacific Ocean, neither of which is an attractive alternative.