A deferred item on the autopilot system that is not documented to the correct authority — MEL, CDL, MPPM, AMM, or SRM — is not just an administrative failure. It is an airworthiness exposure. The Deferred field in this ATA Chapter 22 template is the classification that determines which maintenance authority governs the deferral, which operational limitations apply, and what the rectification interval is.
MEL deferral means the item is listed in the Minimum Equipment List with a specific category (A, B, C, or D) defining the dispatch interval. CDL means Configuration Deviation List — the item is a physical component that can be absent or modified without grounding the aircraft, within defined limits. AMM or SRM deferral means the rectification is governed by the Aircraft Maintenance Manual or Structural Repair Manual. Each classification triggers a different procedural response, and logging "deferred" without the authority type is not a log entry — it is a liability.
The ATA 22 Context: Auto Flight Systems
ATA Chapter 22 covers autopilot, auto-throttle, flight management systems, and related auto flight control. In a modern transport aircraft, a fault in this chapter may not prevent dispatch but will often impose operational limitations — altitude restrictions, reduced automation levels, loss of Cat III autoland capability.
The MEL Remark (Limitation) field is where those operational constraints are recorded. A Cat III B autoland capability that is MEL'd to Cat I limits because one of the two autopilot channels is deferred represents a significant operational implication — certain airports become impractical in low-visibility conditions, crew training requirements may change, some routes become restricted. The limitation has to be in the record, tied to the specific MEL item, before the aircraft dispatches.
The Reset field captures the preliminary reset procedure the mechanic or pilot is authorized to perform before escalating to maintenance. ATA 22 faults frequently have defined reset procedures in the TSM — power cycling components, pulling and resetting circuit breakers in specific sequences, running built-in test equipment cycles. If the reset is performed and the fault clears, the record captures what was done and confirms the fault did not return. If the reset fails, the TSM troubleshooting path begins.
The Manual Reference Architecture
TSM, Test Manual, and Replace Manual are three separate reference fields because each points to a different phase of the rectification workflow.
The TSM (Trouble Shooting Manual) reference gives the task number for the fault isolation procedure — the diagnostic sequence that isolates the failed line replaceable unit. The Test Manual reference covers bench or aircraft functional tests required to verify the repair. The Replace Manual reference identifies the AMM task for the physical replacement of the LRU.
Having all three references in the same maintenance log record eliminates the document-hunting step during troubleshooting. A mechanic who opens the log entry for a deferred autopilot disconnect warning fault at 02:00 AM during a line maintenance turn sees the TSM task number, the test procedure reference, and the replace manual task in the same record — not spread across three separate document searches that each require navigating the revision-controlled maintenance library.
The Figure1 and Figure2 image fields are where wiring diagrams, test point photographs, or screen captures of fault code displays go. A fault that generates a specific CFDS message with a specific fault code is documented photographically alongside the log entry — the maintenance record and the evidence of the fault condition are in the same place.
Note1 and Note2 handle the free-text context that no structured field accommodates: "fault cleared after power cycle but returned on ground after 45 minutes, correlating with FMS initialization cycle completing" — the kind of behavioral observation that narrows the TSM fault isolation path and saves two hours of troubleshooting.