Commentary

November 2014 Issue




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Letters: November 2014

ASPEN’S RED X UPDATE
I have a single-screen Aspen Avionics EFD1000Pro installed in my Piper Arrow since July of 2012 and it is amazing. Unfortunately, I learned that if the system loses pitot input (if it’s clogged, for example), you completely lose most all critical data, even non-pitot-sourced data. This results in a black screen with two red Xs covering the upper and lower halves. This means no attitude, airspeed, altitude, heading, HSI or GPS overlay from an external navigator, like a Garmin GNS530 or 430.

If the pitot resolution shows less than 30 knots and the GPS speed is indicating greater than 50 knots, all of the PFD data blanks out.

What really surprises me is that Aspen still hasn’t programmed the unit to be able to retain data and display capability that are unaffected by the pitot failure. I can see no reason that my GPS navigational overlay (and weather overlay) needs to disappear during a pitot input failure.

I understand that GPS data can take the place of pitot data if the units are programmed to use it. I do hope that they correct this soon and utilize the quality GPS data that I and most others are streaming to the Aspen units at all times. For Aspen to make its entire critical display system dependent on a single pitot and not fashion a backup that appropriately utilizes GPS data is nuts.

John Rooks
via email

Aspen’s Perri Coyne responds: “The EFD1000 AHRS solution is derived from gyro and accelerometer inputs, and stabilized with magnetometer and air data. These inputs are fed into a Kalman filter, which uses the various sensor data to derive a stabilized attitude output. While other low-cost AHRS for light aircraft rely upon GPS ground speed as a corrector, we chose pitot rather than a GPS to allow our system to be installed without requiring a GPS input. With the loss of pitot input, the attitude solution would be degraded, so the attitude is flagged as invalid and the pilot should refer to backup instrumentation. This is the reason the backup airspeed, attitude and altimeter instruments are required.

We are evaluating other attitude solutions that will reduce or eliminate the need for pitot pressure. If there is no hardware change required, we will make this available to our existing customers as we have done with other enhancements.”

PORTABLE RADIO TECH
Thanks for another great article on handheld transceivers in your October 2014 issue. I wonder if you might consider adding another criteria to your bench tests.

Several years back I bought the model SP-200 from Sporty’s. Unfortunately, I discovered that I couldn’t get within 100 feet of my FBO without the AWOS bleeding over all comm frequencies. As always, Sporty’s stood by its products and swapped the radio with an ICOM IC-A6 without even charging me for shipping. I can’t rule out the possibility that what I experienced was just a fluke with that one radio, but I’m much more leery of the frequency bleedover now. I thought you might want to consider that in future tests.

Bob Simmons
Xenia, Ohio

Frequency splash could either be a selectivity issue (depending on how narrowly-designed the band width is for each frequency) or another issue called spurious response, which is the receiver’s ability to reject harmonics. You didn’t specify if the AWOS frequency was close to the one you were monitoring (not physically close, but its location in the frequency band relative to the desired frequency). If AWOS was at 126.450 MHz and the tower was 126.600 MHz, it would be a selectivity issue. If AWOS was 118.000 and the other was 136.000, it would be a spurious response.

ANGRY ‘SUMBITCH'
I have no political party affiliation, but my wife says I’m a member of the “angry ‘sumbitch” party. The FAA frustrates me with its fossilized bureaucracy. For decades, automobiles had electronic ignition, anti-lock brakes and airbags with proven safety, yet because of the FAA’s bureaucratic, lethargic, red-tape-strangled processes, there are few options for safety enhancements on my TB20, such as vortex generators or air bags.

In your October 2014 issue, you reported on Dynon’s Touch that’s only available for experimental and LSAs. It is an oxymoron that FAA promulgates general aviation safety, yet obstructs the availability of enhancements that would save pilot lives. New airframes have many of these safety enhancements, but in this economy, I doubt the average owner can afford a $500,000 plane.

Art Watanabe
Liberty Lake, Washington

We’re honored the Dynon Skyview Touch article brought out the best in you, Art. With any luck, the proposed changes to Part 23 will someday bring affordable safety solutions to certified aircraft.