Definition
The airspeed value displayed on the airspeed indicator, derived from the difference between ram (pitot) pressure and static pressure. In a thunderstorm encounter, airspeed indications can become erratic or unreliable due to turbulence, rapidly changing pressures, and possible icing or water ingestion in the pitot-static system, so the pilot is advised to maintain a constant power setting and a level pitch attitude rather than chase the needle.
Plain English
The speed reading shown on the airspeed gauge in the cockpit. In a thunderstorm, that reading can jump around or become wrong, so pilots are told to fly a steady power and pitch instead of trying to hold a specific speed.
Context Anchor
Seen during the instrument scan, especially when flying in turbulence or an inadvertent thunderstorm encounter where the airspeed reading may change quickly.
Derivation
“Indication” comes from a word meaning “to point out” or “show.” That helps here because an airspeed indication is what the instrument shows the pilot, not necessarily a perfect measurement of every kind of speed.
Why Pilots Care
Erroneous airspeed indication in thunderstorms can prompt incorrect pitch or power changes that lead to loss of control.
Intuition Check
Do not read “indication” as “guaranteed exact speed.” Here it means the speed value displayed by the cockpit instrument.
Example Sentence 1
On entering the thunderstorm, the airspeed indication began to fluctuate wildly, so the pilot held a level attitude and a constant power setting rather than trying to correct it.
Example Sentence 2
Fluctuating airspeed indication during turbulence prompted the pilot to reduce power and maintain attitude.