Definition
An onboard computer system that continuously monitors aircraft systems, records faults, and stores maintenance data for ground crews to retrieve and act on after the flight. It does not control the aircraft; it observes, logs, and reports.
Plain English
A computer on the aircraft that quietly keeps a record of anything that goes wrong with the systems, so maintenance staff can read the report later and fix the right thing.
Context Anchor
Seen in aircraft manuals, equipment descriptions, and acronym lists for aircraft systems or maintenance functions.
Derivation
‘Maintenance’ here means upkeep and repair. ‘Processor’ refers to the computer that handles the data. ‘Subsystem’ means it is one part within a larger avionics system. Together: a computer subsystem dedicated to maintenance information.
Why Pilots Care
Pilots rarely interact with it directly, but pilot reports of system behavior are cross-checked against MPS data. What the MPS recorded during the flight often determines what gets repaired before the next one.
Intuition Check
Do not read “processor” as a person processing paperwork. Here it means an electronic part of the aircraft system that handles maintenance information.
Example Sentence 1
After landing, the technician downloaded the fault log from the MPS to investigate the intermittent caution light reported by the crew.
Example Sentence 2
Maintenance crews downloaded the MPS logs to identify recurring system alerts.