What are minimums on a plane?

2) “Minimums” is an aural warning advising you that you have reached the lowest altitude to which you can descend on the approach without seeing the approach lights or the runway, again depending on the type of approach.

What will happen to radio altimeter indication when airplanes fly over 2500?

In almost all cases, the display of radio height ceases when an aircraft climbs through 2500′ above ground level (agl) and recommences when it descends through 2500′ agl.

What does radio altimeter indicate?

A radar altimeter (RA), radio altimeter (RALT), electronic altimeter, or reflection altimeter measures altitude above the terrain presently beneath an aircraft or spacecraft by timing how long it takes a beam of radio waves to travel to ground, reflect, and return to the craft.

How accurate are radar altimeters?

Taking into account that the radar altimeter accuracy is of the order of 3\% of the measured altitude (see Section 2.2), the difference in distance from the ground between ALT and GNSS antennas (0.71 m) is negligible.

What frequency does a radio altimeter operate?

The radio altimeters operating in the 4200-4400 MHz band typically have a center frequency of 4300 MHz. Based on the frequency assignment data in the GMF, the emission bandwidths for a large majority of the radio altimeters used on Federal aircraft range from 20 MHz to 170 MHz.

Where is the radio altimeter?

The radio altimeter sometimes referred to as a radar altimeter is designed to provide an accurate reference, in some cases within 2 feet, of the aircraft above the ground. In most cases in general and commercial aviation this device is operational up to 2,500 feet above ground level (AGL).

What is the principle of operation behind the radio altimeter?

The radio altimeter measures the distance of an aircraft above the ground rather than above sea level. The altitude is equal to one-half the time that it takes a pulse of radio energy to travel from the aircraft to the ground and back multiplied by the speed of the pulse (equivalent to the speed of light).