- Industria: Aviation
- Number of terms: 16387
- Number of blossaries: 0
- Company Profile:
Aviation Supplies & Academics, Inc. (ASA) develops and markets aviation supplies, software, and books for pilots, flight instructors, flight engineers, airline professionals, air traffic controllers, flight attendants, aviation technicians and enthusiasts. Established in 1947, ASA also provides ...
An instrument used to measure and plot the strength and direction of the earth’s magnetic field. Magnetometers are often towed behind low-flying airplanes to find deposits of magnetic minerals by noting the change in the direction of the local magnetic field. These aerial surveys are referred to as MAD (magnetic anomaly detection) surveys.
Industry:Aviation
An instrument used to measure angles. The goniometer used in an automatic direction finder (ADF) uses the output of a fixed loop antenna to sense the angle between a fixed reference, usually the nose of the aircraft, and the direction from which the radio signal is being received.
An electronic goniometer measures the angle by comparing radio signals picked up on a nondirectional antenna with signals picked up on a directional antenna.
Industry:Aviation
An instrument used to measure atmospheric pressure. A glass tube about one meter long, with one end closed and the other end open, is filled with mercury, and the open end is submerged in a bowl, or cistern, of mercury. The mercury in the tube will drop down, leaving a vacuum above the mercury in the closed end.
Atmospheric pressure pressing down on the mercury in the bowl holds the mercury up inside the tube. The height of the top of the mercury in the tube above the level of the mercury in the bowl is an accurate measure of the amount of pressure produced by the weight of the atmosphere. Standard atmospheric pressure at sea level holds the mercury up in the tube to a height of 760 millimeters, or 29.92 inches.
Industry:Aviation
An instrument used to measure electrical current. A galvanometer measures the amount of current flowing in a circuit by measuring the interaction between two magnetic fields. One field is produced by a permanent magnet, and its strength is fixed. The other field, an electromagnetic field, is produced by current flowing through a moving coil, and its strength is determined by the amount of current being measured. The moving coil is restrained by a calibrated hairspring in such a way that its deflection is proportional to the amount of current flowing through it.
Industry:Aviation
An instrument used to measure high temperatures. Pyrometers usually begin measuring at temperatures above about 600°C.
Industry:Aviation
An instrument used to measure low values of air pressure. A manometer consists of a long glass tube mounted in front of a calibrated scale. The tube is filled with a liquid, and air pressure forces the liquid up in the tube where its height is measured against the scale.
Different ranges of pressure can be measured by using different liquids: water is used for low pressure, ethylene dibromide for medium pressure, and mercury for higher pressure. Differential pressure can be measured by forming the tube into the shape of the letter U and applying the two pressures to the two ends of the tube.
Industry:Aviation
An instrument used to measure quantities of heat released or absorbed during chemical reactions or physical changes of state.
Industry:Aviation
An instrument used to measure temperature. Some thermometers measure the change in the volume of a liquid caused by its expansion or contraction with changes in its temperature. Others measure the change in pressure of a confined gas as its temperature changes.
Electrical thermometers measure the current produced in a thermocouple as the temperature difference between the thermocouple junctions changes, and resistance thermometers measure temperature by measuring the current forced by a constant voltage through a resistance that changes with the temperature.
Industry:Aviation
An instrument used to measure the absolute pressure of the atmosphere. A mercury barometer measures the atmospheric pressure by the height of a column of mercury held up in a tube by the pressure of the atmosphere. An aneroid (no liquid) barometer measures the pressure by the amount an evacuated bellows is collapsed by the atmospheric pressure.
Industry:Aviation
