Definition
A malfunction of one or more traditional mechanical or electromechanical flight instruments, such as the attitude indicator, heading indicator, or airspeed indicator, in an aircraft equipped with a conventional analog instrument panel. Failures may be partial or complete, and may stem from loss of vacuum or pitot-static input, gyro spin-down, electrical loss, or mechanical breakdown. Recognizing the failure and continuing safe flight using the remaining trustworthy instruments is the pilot's responsibility.
Plain English
When one of the older needle-and-dial flight instruments stops working correctly, the pilot has to spot the problem quickly and fly using the instruments that are still reliable.
Context Anchor
Seen in instrument flying and abnormal-procedure training, especially when a pilot must compare cockpit indications and decide which instrument is unreliable.
Derivation
Analog refers to instruments that show information through continuous physical movement of needles, drums, or pointers, rather than through digital numbers or screens. The word comes from the Greek analogos, meaning 'proportional' — the needle moves in proportion to what it is measuring.
Why Pilots Care
Loss of these instruments forces immediate transition to partial-panel techniques or backup displays to prevent loss of control.
Analogy
Like a car dashboard where the speedometer and fuel gauge suddenly go dead—you must use other cues to keep driving safely.
Grounding Statement
An analog instrument failure means the airplane may be flying normally, but one of the cockpit gauges is no longer telling the truth about it.
Intuition Check
Do not assume “failure” means the instrument goes blank or obviously breaks. An analog instrument can fail by giving a believable but wrong indication.
Example Sentence 1
During the flight into clouds, the pilot suspected an analog instrument failure when the attitude indicator showed level flight but the turn coordinator and altimeter both indicated a descending turn.
Example Sentence 2
During the partial panel exercise the instructor simulated an analog instrument failure to train the student on using the magnetic compass and airspeed indicator alone.