a measuring instrument for measuring variations in a magnetic field
an instrument used in gliders to detect changes in air pressure due to sudden changes in altitude
a very sensitive instrument which measures how fast a glider is gaining or losing height and the altimer records the height of the aircraft above the ground
instrument that measures vertical speed of sink or climb. Commonly abbreviated as vario.
an instrument that displays your rate of descent or ascent. usually has a changing sound indicating rise/fall & rate with tone change.