Definition
In attitude instrument flying, the supporting instruments are those that back up and confirm the primary instrument by showing the rate of change or trend of the aircraft's pitch, bank, or power. They help the pilot detect deviations early and verify that the primary instrument is reading correctly.
Plain English
These are the instruments you cross-check to make sure your main instrument is telling the truth. They show whether things are starting to drift before the change becomes large.
Context Anchor
Seen in instrument flying when learning how to cross-check the flight display instead of staring at only one indication.
Derivation
From the everyday word 'support,' meaning to back up or reinforce. In this context, these instruments back up the primary instrument by confirming what it shows and revealing trends before they become deviations.
Why Pilots Care
Relying on a single instrument is risky. Supporting instruments allow the pilot to catch errors, instrument failures, or developing deviations early — which is essential for safe instrument flight.
Intuition Check
Do not read “supporting” as meaning unimportant or optional. Here it means the instruments that back up and confirm the primary indication for the task.
Example Sentence 1
While holding altitude in level flight, the pilot used the airspeed indicator and vertical speed indicator as supporting instruments to confirm the pitch shown on the attitude indicator.
Example Sentence 2
During a constant airspeed climb the airspeed indicator became primary while the attitude indicator and vertical speed indicator served as supporting instruments.