Can the airworthiness review certificate (ARC) of the large aircraft be extended during the extensive maintenance/long term storage?

An ARC extension could be performed as long as:

1. the conditions established for controlled environment (M.A.901 (b)) are met. This means:

• continuously managed during the previous 12 months by a unique CAMO, and
• maintained for the previous 12 months by Part 145 organisations.

AND

there is no evidence or reason to believe that the aircraft is not airworthy, as stated in M.A.901(k).

Thus, the procedure for the extension established in the CAMO has to address verification of the compliance with 3 above mentioned conditions. An aircraft going through the lengthy maintenance/modification or long-term storage is not considered to meet the condition number 2.