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How to Install an Airspeed Indicator

In aircraft, an accurate reading of how fast your are moving relative to the air you're flying through is as important as knowing how high you are. Airspeed is vital for maintenance of proper flight attitude to avoid stalling the wings, a potentially dangerous event, particularly in critical phases such as climbout and landing. Unlike a ground speed reading, the airspeed calculation takes into account the wind forces of the air mass surrounding the plane and acting on its velocity. An airspeed indicator is a differential pressure gauge which compares pressure input from two sensors. One, called a Pitot tube and faces directly into the airstream, while a static sensor samples pressure out of the airstream. The differential between the two pressure sources is mechanically calculated into an airspeed reading displayed in knots.

Things You'll Need

Screwdriver
Combination wrench
Torque wrench

Instructions

- 1
  Verify that the airspeed indicator cut-out in the instrument panel accommodates the dimensions of the airspeed indicator. Most light aircraft instrument panel cut-outs are standardized at 2 1/4 inches by 2 1/4 inches. Most airspeed indicators are supplied in that standard size.
- 2
  Mount the indicator face-out to the rear of the instrument panel. Secure with four mounting screws appropriate to the thickness of the particular aircraft's instrument panel.
- 3
  Locate the differential port fitting on the rear of the airspeed indicator case. It may be marked "P," for Pitot.
- 4
  Screw the aircraft Pitot tube's fitting onto the airspeed indicator differential port. Tighten to 45 inch pounds of torque.
- 5
  Locate the static port fitting on the rear of the airspeed indicator case. It may be marked "S."
- 6
  Screw the aircraft static line fitting onto the airspeed indicator's static port. Tighten to 45 inch pounds of torque.
- 7
  Connect wires of appropriate voltage to the gauge light tray on the underside of the gauge if the particular aircraft accommodates illuminated gauges.

Aviation