Definition
Malfunctions in cockpit instruments that cause them to display incorrect information, stop working, or behave erratically. Failures may stem from the instrument itself, its power source (electrical or vacuum/pneumatic system), its sensing inputs (such as the pitot-static system), or blockages and damage to external probes and ports.
Plain English
When a cockpit gauge or display stops working properly or shows the wrong information. The needle might freeze, drift, swing wildly, or the screen might go blank.
Context Anchor
Seen in emergency and abnormal-procedure discussions, especially when a pilot must recognize a bad cockpit indication and fly using other reliable information.
Derivation
Instrument comes from a Latin root meaning something used to prepare or equip for a task. Failure comes from an old word meaning to fall short or not perform. Together, the words point to cockpit equipment that is no longer doing the job the pilot needs it to do.
Why Pilots Care
Loss of reliable instrument data forces use of partial panel techniques or visual references and can quickly lead to loss of control if not addressed.
Grounding Statement
If a cockpit indication does not match what the airplane is actually doing, the pilot should treat that instrument as suspect until confirmed.
Intuition Check
Do not assume an instrument failure always means a gauge goes blank. It can also mean the instrument is still moving but showing wrong or unreliable information.
Example Sentence 1
During the climb, the pilot noticed the airspeed indicator was reading lower than expected and suspected an instrument failure caused by a blocked pitot tube.
Example Sentence 2
A vacuum pump malfunction is a frequent cause of instrument failures affecting the attitude indicator.