Definition
Electrical plug-and-socket connectors that allow an avionics unit (such as a radio or transponder) to be slid into and out of a mounting tray in the instrument panel without unscrewing individual wires. The wiring harness terminates at a fixed connector in the back of the tray, and a matching connector on the rear of the unit engages it automatically as the unit is seated.
Plain English
A built-in plug at the back of a holder in the panel. When you slide the radio or other box into its holder, it plugs itself in. When you pull the box out, it unplugs itself.
Context Anchor
Seen in preventive maintenance rules for replacing certain self-contained panel-mounted navigation or communication units.
Derivation
The 'tray' refers to the metal sleeve or rack the avionics unit slides into; 'mounted connectors' simply means the electrical connectors are fixed to that tray rather than to the unit itself.
Why Pilots Care
Reliable connections prevent intermittent failures in navigation, communication, and flight instruments while allowing quick unit swaps without rewiring.
Analogy
Like a docking station for a laptop. You drop the laptop into the dock and every cable connects at once; lift it out and everything disconnects cleanly.
Intuition Check
Do not picture a loose household-style plug or a serving tray. In this aviation use, the “tray” is a fixed mounting frame in the instrument panel, and the connectors are built into it.
Example Sentence 1
Because the comm radio used tray-mounted connectors, the owner was able to slide it out and send it for repair without disturbing the aircraft wiring.
Example Sentence 2
Corrosion on tray-mounted connectors can cause loss of navigation data during flight.