Common Cockpit Instruments and Their Functioning
There are six cockpit instruments that can be found in most aircrafts. It is true that most of these instruments have evolved with time, however even the most recent aircrafts have these traditional instruments, as a source of back-up. This “six-pack” set of instruments are the chief source of cockpit information. Anyone who is interested in getting Aeronautical engineering admission must know that these instruments have a special importance in the engineering curriculum.
These cockpit instruments are divided in to two categories: static or pitot-static instruments and gyroscopic instruments.
Let’s start with static or pitot-static instruments first:
Airspeed Indicator
As the name suggests, the airspeed indicator is an instrument that tells a pilot about the airspeed either in knots or Mach number. The airspeed indicator operates by comparing air pressure from the pitot tube to air pressure from one or more static ports. The instrument has a diaphragm that measures the pressure differential and displays the same on the instrument pointer.
Altimeter
The instrument aim at measuring the airplane’s vertical height above mean sea level (MSL) adjusted for air pressure outside the aircraft. The pilot makes appropriate setting for air pressure and the altimeter will show the corresponding vertical height above MSL. Just like a basic barometer, altimeter compares the static pressure inside the aircraft to the contracting and expanding pressure surrounding it. The reading on the instrument fluctuates with airplane’s fluctuating altitude.
Vertical Speed Indicator
The rate at which the airplane ascends or descends is known as its vertical speed and the instrument that measures this rate is known as the Vertical Speed Indicator(VSI). Usually showed in feet per minute (fpm), in flight that is levelled, the VSI reading is ‘0’ feet.
Just like static or pitot-static instruments, there are three instruments that fall under Gyroscopic Instruments.
Attitude Indicator
The most important instrument for pilot is the ‘Attitude Indicator’, which helps the pilot in analysing if the aircraft is ascending, descending, straight or turning and level. The instrument has an artificial horizon, which is a backdrop for a miniature airplane. In most cases, the miniature airplane moves with the aircraft, as it is attached to the instrument viewing case. The attitude indicator is meant to show the sky in blue colour and the ground in brown, with a miniature airplane positioned with a white line, which is an artificial horizon in a level flight.
Heading Indicator
The instrument aim at providing the directional information to the pilot. A gyroscopic instrument, the heading indicator can be electrically powered or vacuum driven. As the airplane makes changes i.e. turns left or right, the heading indicator changes to show new reading, which on compass card is between 0 and 359 degrees.
Turn Coordinator
Just like heading indicator, turn coordinator can be either electrically powered or vacuum driven. The simplest instrument that has a miniature airplane that descends its wings to show the rate of turn. With pilot taking a roll on the airplane, the miniature airplane will depict its corresponding roll. The instrument also has an inclinometer that when flight is turning reacts like a pendulum and helps the pilot in avoiding skidding or slipping turn.
For a layman, understanding these instruments can be challenging, thus these are covered in detail in aeronautical engineering. Want to learn more, make yourself eligible for Aeronautical engineering admission today.
