Test and Measurement Avionics Equipments Section

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Altitude Indicator | Altimeter

This page cover Altitude indicator known as Altimeter. The Altimeter is used to measure altitude.The altitude indicator is used in avionics domain. The vendors of altimeter used as altitude indicator are also mentioned.

The equipment which is used ro measure altitude of object above the fixed level (i.e. sea level) is known as Altimeter.

One of the major application is to know height of airplane flying above earth in order to avoid obstacles such as mountains as well as other airplanes. Moreover it is advisable to fly at high altitude due to thin air which requires lesser fuel as it asserts less resistance. This region can be found by knowing altitude level.


altimeter-Altitude Indicator

There are two methods to measure altitude as mentioned below.
Method-1: Measure air pressure and determine altitude from this.
Method-2: Transmit radio frequency wave from airplane towards earth and measure round trip time. We know that radio waves travel at the speed of light i.e. 3 x 108 m/sec. This will give us height of airplane above earth. The same is depicted in the figure-1.

The most common altimeters used in avionics are known as aneroid barometer. They display height by measuring pressure. This type of altimeter uses hollowbox which expands and contracts based on pressure decrease and increase. This will consecutively move the pointer based on change in air pressure.

Vendors of Altimeter or Altitude Indicator

Following are the vendors of altimeter or altitude indicator.
• HTC AL-7000 (measuring range: 0-5000meters/580-1040 hpa)
• Swastik Scientific Company, MUMBAI, INDIA
• L.J. Engineering, Inc. CA
• Apex Instruments, Inc., NC
• RIEGL, FL, USA



Avionics test and measurement equipments

ATE DME Test Set
Airflow Anemometer
Altitude Indicator
Directional Gyro




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