Beyond the six-pack
You are here. And here's where your rout is. And oh, by the way, here's where the traffic is, where the weather is, and where that new cell tower is. This knowledge is golden, and having it all on the same map is what the multifunction display (MFD) is all about.
The MFD as we see it in today's general aviation cockpits has its origins in the navigation displays on electronic flight information systems (EFISs) is large jets. When they first appeared in general aviation aircraft, MFDs fell into two camps — those with open architecture, capable of accepting inputs from a variety of sources, and those that displayed information from an integrated source (typically a GPS navigator).
Engineers of those MFDs destined to receive input from multiple sources targeted possible open space on the panel, such as radar displays; those designing screens for GPS navigators looked no further than the radio rack. The primary driver for screen size — because it was clear from the beginning that bigger would be better — was the cost of the display itself; the driver for what the unit could display depended on the capability of the screen. So the screens used today reflect this marriage, with the affordable color liquid-crystal display (LCD) making what we see possible.
The screen is still the most expensive component of the unit, and glass that's optimal for use in the cockpit is a specialty product. Economies of scale seen in a similar consumer products aren't yet available to the aviation market — and depending on whom you talk to, they may never be, though some in the know express hope that the explosion of in-dash automobile GPS navigators would help. conversely, no car manufacturer has to deal with the same environmental performance parameters (hot and cold, high altitude, constant vibration, and bright sunlight) found in light aircraft.
In the future, look for the roles of MFDs to meld with their brethren, primary flight displays (see "Primary Flight Display [PFD]: Information Central," below). You may not be able to distinguish between the two, as cockpits become more integrated, and functionality crosses platforms to ease pilot workload and reduce the number of reversionary — or failure — modes that glass-cockpit pilots train for today. That means the displays will look the same during a failure as they do during normal conditions.
And look for the information to keep getting better, richer, and even more accurate. Live weather for tactical use, perhaps, 3-D approach information, and traffic systems that rival today's traffic alert and collision avoidance system — all on the screen in front of you.— JKB
Primary Flight Display (PFD): Information Central
The primary flight display (PFD), although often in the same form factor as the MFD, fulfills a distinct task — displaying information from various flight instruments about the state of the aircraft (position, heading, and attitude) and integrating that information with inputs from other aircraft systems and avionics.
Although early PFDs replicated the round dials, improvements came quickly. Case in point? The wide horizon line. Being able to see attitude information at a glance or in your peripheral vision reduces pilot workload — so no matter where you're focusing your attention in the cockpit, your brain picks up on your position in space.
At this point, the autopilot and GPS are primary information sources that will display onto a PFD. But a simpler cockpit is a safer cockpit — and having to gather data from several places and with 30 button pushes is not as safe as it could be. So future PFDs will incorporate more information in an easily digestible form.— JKB
