Aviation Safety Letter 2/2005

Flat Panel Displays - The Pros and Cons

by Ken Armstrong

Well, to cover the cons, we can start by saying these flat panel displays are virtually "con-less."

This scribe recently conducted flight test evaluations on the Cirrus Design SR22, Lancair 350 with Avidyne Entegra primary flight displays (PFD) in concert with a multi-function display (MFD). A week later, it was my pleasure to evaluate the even more advanced Garmin 1000 system in the Diamond Star. The Avidyne requires three minutes of power up time to be useable, and Diamond's Garmin about 30 seconds. So, pilots who power up the pounding pistons and immediately start to taxi will be forced to accomplish some of their checks at a standstill.

Owners of electronic cockpits need not live in awe of F-18 Hornet pilots or airline drivers, as the equivalent state-of-the-art instrumentation has arrived for general aviation (GA) aircraft. While I haven't met an airframe I couldn't tame, these new displays can be a handful for those of us accustomed mainly to the old, round, "steam gauges." It's not that the old equipment is better in any way - other than adding ballast up front to aircraft that are challenged by aft centre of gravity (C of G) conditions. In fact, the Diamond, Lancair and Cirrus aircraft all possess a modicum of old-style flight and engine instruments that provide back-up information lest one of the digital screens fail. This is slightly humorous because the electrical systems for the flat screens are typically dual-redundant and the mean time between failures (MTBF) for these displays make them far more reliable that yesteryear's equipment. However, until one fully converts to digital displays, it is occasionally beneficial to have the back-ups available for quick reference. To be really effective at using the huge amount of differently presented data takes a number of conversion hours, so don't plan to launch on major IFR excursions until your brain and digital data are "hard-wired" to each other.

Garmin G1000 Avionics System in a DA40-180 Diamond Star - Photo courtesy of Garmin Ltd.
Garmin G1000 Avionics System in a DA40-180 Diamond Star
- Photo courtesy of Garmin Ltd.

Cirrus runs a one-day course entirely dedicated to the PFD and MFD systems, and pilots tell me it is all they can do to absorb most of the information. The company will provide an additional training day as an option. Diamond runs a two-day course students can take to their motel rooms to simulate flights. On that note, Diamond is also building full-scale cockpit simulators to provide even more realistic practice. These are prudent measures that are considerate of customer needs and safety.

The classy glassy cockpit

The trend towards electronic flight instruments systems (EFIS) is becoming widespread as a costly option for many of the GA aircraft manufacturers. Airline pilots who fly in these light aircraft find little difference between the cockpit instrumentation used in GA compared to their airliners. Essentially, a PFD provides all the flight data commonly used during flights, in a visual manner that provides instant information - once one's brain adapts. The same is true for the engine instrumentation. A second 10-in. screen typically provides a host of other data, such as colour-shaded terrain clearance, moving map display, and a traffic awareness system (TAS) that mimics the traffic alert and collision avoidance system (TCAS) installations in the big kerosene burners. It should be noted that the TCAS function only operates when the transponder is within reach of American signals. Perhaps Canada will recognize the important safety considerations for GA aircraft, and improve their radar services to also provide this feature.

AIRMET, TFR and lightning updates - but only over the USA at the moment. Additionally, the MFD shows checklists, performance charts, emergency information and a host of additional information that enhances the ability of a pilot to comprehend his situation awareness. It should be noted that these computerized systems are essentially limitless in the information they can provide. I especially like knowing bits of information not commonly found in dated cockpits, such as the wind speed and direction as well as my true airspeed, fuel flow, fuel remaining and the estimate of fuel remaining at my destination.

Personally, I love all this useful information, and there is no question about the safety benefits of improving a pilot's situational awareness. One no longer needs to interpret the demon dials, as the displays paint a picture similar to what one would see through the windscreen. For flights in instrument meteorological conditions (IMC), this is a huge capability, as the risk of misinterpretation of instruments is virtually eliminated.

So, what's the total downside? Well, these panels are typically optional equipment that will on average add approximately $30,000 to the basic aircraft cost (about 10%). Additionally, you will have to invest some time in learning how to handle this huge amount of useful data, and perhaps have a refresher from time to time if you fly infrequently. In my opinion, these are all small prices to pay for the augmented information capabilities, enhanced aircraft performance and increased safety.

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