The Uncluttered Cockpit

THE UN-CLUTTERED COCKPIT

A Magnetic Compass, Airspeed Indicator, Altimeter accompanied by a Manifold Pressure Gage and Tachometer were at one time the entire scope of information on which a pilot would rely. This provided an uncluttered cockpit and uncluttered is good.

From an operational point, the more instruments available to the flight crew means the more places they have to include in the instrument scan. Not to mention the inconvenience to people like us who have to maintain these devices. I still have scars from having to replace an airspeed indicator where four other components had to be removed before I could get a wrench on the hardware that secured my target — it was rear panel mounted with rigid plumbing. Mechanical and electromechanical flight deck displays have been around since the beginning of aviation. With the changes taking place in technology a tremendous amount of information can be made available to flight crews. If electromechanical devices were the only means of presenting this information, aircraft manufacturers may find themselves in a situation where every inch of the instrument panel would be utilized and the blood of technicians would flow at each maintenance encounter.

Well as the saying goes, "What's old is new again." Many new production aircraft have gone back to the uncluttered look of yesteryear. However, flight deck information has not been sacrificed to achieve this clean configuration. This is accomplished by using an Electronic Flight Instrument System (EFIS). Such a system provides the flight crew the capability of displaying information never before available in the area of the central scan. The possibility exists to select or deselect data depending on the flight regime and provides the pilots with a means of easily seeing the interrelationship of ever-changing flight data.

Electronic Flight Instrument systems can be installed in a variety of configurations. Two to six tubes make up the most frequent flight deck displays. In many cases, an interface is made with the flight deck displays and the Automatic Flight Control System (AFCS).

Flight Deck displays sometimes include an Electronic Attitude Directional Indicator (EADI), Electronic Horizontal Situation Indicator (EHSI) and a Multi Function Display (MFD). In some systems, the ADI and HIS are combined within one display called a Primary Flight Display (PFD).

Engine instruments can even be part of the Electronic Flight Deck and may include the Annunciator warning system. EICAS is an acronym for Engine Indicating and Crew Alerting System, which can combine engine displays with various warnings or cautions for the flight crew. Some manufacturers refer to this as an Electronic Indicating Display (EID), while others use Electronic Indicating Engine Display (EIED). In all of these cases, the old analog display has disappeared and digital technology has taken over.

Several types of displays are currently in use with the most frequent being the Cathode Ray Tube (CRT) and the Liquid Quartz Display (LCD). In most systems, the flight deck displays are interchangeable between EADI and EHSI or between PFD and MFD. In fact, the majority of systems being installed today have the ability to electronically swap displays with the action of a single switch.