Readings from altimeter, variometer, airspeed indicator, attitude indicator — those were real.    From Wordnik.com.  [Typhoon Season]

The telegraph sending keys, field and battery switch, dry battery, variometer and antenna reel are the only units included inside the fuselage.    From Wordnik.com.  [The Radio Boys Trailing a Voice or, Solving a Wireless Mystery] Reference

The variometer emits an audible signal, and pilots can tell by the frequency and pitch how fast they're climbing or descending.    From Wordnik.com.  [Home] Reference

Potentiometer, variometer, variocoupler, radio frequency, amplification, loop aërials, audion and grids -- no, I am not saying these words to show off.    From Wordnik.com.  [Radio Boys Loyalty Bill Brown Listens In] Reference