100 years of flight - Keep them flying : Navigation

The barometric altimeter invented by Paul Kollsman, a German, in 1928, was a pivotal instrument. It has a window into which pilots enter the local barometric pressure to calibrate it before takeoff. It is still widely known as the Kollsman window. This model was used on the first blind flight, takeoff to landing, in 1929.

Kollsman's latest altimeters might look similar to the older ones, but they are solid state, with several readouts. It is used on various Boeing 747 aircraft.

The 1975-era F-8 Crusader has the typical cramped, dial-filled cockpit common to many aircraft up to that time. The newest Falcon business jet from Dassault Aviation, however, features four large flat screens that can be set up by pilots to display just what they want. Note the alphanumeric keypad just forward of the blue oval-shaped "stationary mice" or cursor controls used to interact with the plane's computers.

Senior Editor

From dials and switches to flat screens and computers

When the Wright Brothers first flew, their plane carried an anemometer to measure wind speed, a revolution counter to track engine performance, and a stop watch. Today's airliners have hundreds of switches and controls, dozens of dials and displays, sometimes integrated into multiuse screens, several navigation systems, speed indicators, backup systems, autopilots, and a host of computerized devices.

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Over the years, cockpit instruments reduced flight-crew workload, provided redundant backups to critical systems, and accommodated new technology such as pressurization systems introduced in the 1930s. Others contributed to safety and tried to offset the spatial disorientation caused by misleading visual cues. For example, after flying through clouds or changing headings over long stretches of dark water, pilots might think they're flying straight and level but are actually in a banking rollout, banked at 30° and diving 1,000 fpm, the Graveyard Spin.

One of the earliest flight instruments for giving pilots an objective view of what their plane is doing was the turn-and-bank indicator (TBI). Bill Ocker, an army sergeant, "borrowed" one from a navy ship and eventually upgraded and patented a version for aircraft. The bank indicator is merely a curved tube with a steel ball in it. As the plane turns, gravity holds the ball at the lowest point as the tube rotates from side to side. The turn indicator contains a gyroscope that generates torque when the craft rotates, much like an inertial navigation unit.

Ocker also experimented to see if "flying blind" was possible, i.e., flying to a destination using only instruments and not looking outside the cockpit at all. So he and a colleague blindfolded pigeons and dropped them out of flying planes. After some spirals and rolls, the pigeons would eventually spread their wings and settle to Earth, convincing Ocker it was possible to fly without visual cues.