JULY 2010 LONG A STANDARD OPERATING principle in commercial aviation, the concept of redundancy has taken hold in light GA only during the past couple of decades with the advent of relatively affordable backup electric-powered attitude indicators. These backup attitude instruments provide the pilot not only with a redundant source of attitude information but also with one that has a different power source from the vacuum pump used by the primary instrument.
With the introduction of affordable solid-state attitude indicators, used in our flat-panel avionics systems, the state of the art has progressed even more, and redundancy, once thought to be financially unattainable for lower-end airplanes, is now an imperative.
he latest instrument to add to this safety picture is the L3 Trilogy, a standby instrument that takes the technology that L3 has used on high-end large bizjets and sensibly transfers it to the light GA cockpit. In the process it gives the pilot much more valuable safety-of-flight information all in a single location.
Whereas conventional electromechanical attitude backups provide you just that, backup attitude information from a source different from the primary, Trilogy gives the pilot that, plus a dedicated backup attitude source and air data computer, plus airspeed, altitude, barometer and heading instruments. In essence it provides a redundant source of information for the attitude indicator, the airspeed indicator, the altimeter and the compass and, just as importantly, it allows the pilot to get all of that information in a single instrument, offering a much improved scan, if you can still call it that with an instrument this compact.
Trilogy sells for $15,000 and features a remarkably self-contained design. With its 3.7-inch-diagonal active matrix LCD and four bezel-mounted buttons, Trilogy’s design is simple, which is a major part of the attraction. It features a built-in air data computer and attitude sensor, and it can link to an optional external magnetometer for the optional heading indicator. The instrument is standard 3-ATI format, so it can fit neatly into the hole vacated by another standard-size instrument, making installation in most cases a relative breeze. It weighs less than three pounds, so you’ll probably save a little weight over existing mechanical backups, and the LED backlighting has an automatic dimmer.
I recently flew the system in a remarkable Cessna 182 (with dual Garmin G500 and Aspen Evolution systems installed side by side) owned by Sarasota Avionics on a blustery late spring day in Central Florida.
I can truthfully report that there’s not much to say about Trilogy. The unit performed flawlessly on the hourlong flight, during which time I flew the airplane slowly, banked briskly from side to side and did slow turns while Trilogy faithfully mimicked the standby attitude indicator still mounted in the 182’s panel. It was easy, as I suspected it would be, to fly the airplane solely by reference to Trilogy. It is, in fact, orders of magnitude easier than trying to fly partial panel while telling your mind’s eye to ignore that failed instrument that led to the use of backups to begin with.
Trilogy is approved for installation in just about every Part 23 airplane, and it is TSO’d as well. It can be mounted in the panel, as it was in the 182 I flew, or it can be mounted on a subpanel, as it will be in the numerous Cirrus SR22s in which it surely will be installed.
For more information on Trilogy, visit L3 Avionics on the Web at www.as.l-3com.com.
