Escalation and Bridging
Section 12: Continued Airworthiness & Maintenance
Definition
Escalation is the process of extending scheduled maintenance task intervals beyond the initial intervals established in the MRBR/MPD, based on accumulated in-service reliability data demonstrating that the current intervals are conservative and that safety is maintained with longer intervals. Bridging is the transitional process of extending intervals from the current approved interval toward a target interval in defined steps, with reliability monitoring at each step to confirm that the extended interval remains adequate.
Where This Shows Up
Escalation is a key element of the MSG-3 maintenance philosophy: initial maintenance intervals established during the MRB process are intentionally conservative because they are based on engineering judgment and limited test data. As in-service experience accumulates, the reliability program provides the data needed to justify interval extensions. The escalation process typically requires a formal proposal to the certification authority, supported by statistical analysis of reliability data, and is approved through a revision to the operator's approved maintenance program. Bridging programs define intermediate interval steps (e.g., extending a 5,000 flight hour inspection to 6,000, then 7,000, then 8,000 hours) with data collection and analysis requirements at each step.
Primary Sources
The MSG-3 process includes provisions for interval adjustment based on in-service data.
Maintenance Review Board Procedures — includes guidance on interval escalation processes.
Related Terms
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