AD 2023-06-06

(1) Within 90 days after the effective date of this AD, revise the existing maintenance or inspection program, as applicable, to incorporate the information specified in figure 1 to the introductory text of paragraph (g)(1) of this AD. The initial compliance time for doing the task is at the applicable time specified in paragraph (g)(1)(i) or (ii) of this AD.

Figure 1 to the introductory text of paragraph (g)(1)— AMM Task for the Ram-Air Valve

(i) For airplanes that have accumulated less than 1,800 flight hours since the last operational check of the ram air shutoff valve was performed as specified in AMM Task 21-52-04-710-801-A01, and for airplanes that have accumulated less than 1,800 flight hours from the date of issuance of the original airworthiness certificate or original export certificate of airworthiness: Within 90 days after the effective date of this AD, or before accumulating 1,800 total flight hours, whichever occurs later.

(ii) For airplanes that have accumulated 1,800 flight hours or more since the last operational check of the ram air shutoff valve was performed as specified in AMM Task 21-52-04-710-801-A01, and for airplanes that have accumulated 1,800 flight hours or more since the date of issuance of the original airworthiness certificate or original export certificate of airworthiness and for which no operational check of the valve has been performed: Within 90 days after the effective date of this AD or before accumulating 3,000 total flight hours, whichever occurs later.

(2) Within 90 days after the effective date of this AD, revise the existing maintenance or inspection program, as applicable, to incorporate the information specified in figure 2 to the introductory text of paragraph (g)(2) of this AD. The initial compliance time for doing the task is at the applicable time specified in paragraph (g)(2)(i) or (ii) of this AD.

Figure 2 to the introductory text of paragraph (g)(2)— AMM Task for the Pack Discharge and Ram-Air Supply Ducts

(i) For airplanes that have accumulated less than 17,600 flight hours since the last detailed inspection of the pack discharge and ram air supply ducts was performed as specified in AMM Task 21-51-00-220-801-A01, and for airplanes that have accumulated less than 17,600 flight hours since the date of issuance of the original airworthiness certificate or original export certificate of airworthiness: Within 90 days after the effective date of this AD, or before accumulating 17,600 total flight hours, whichever occurs later.

(ii) For airplanes that have accumulated 17,600 flight hours or more since the last detailed inspection of the pack discharge and ram air supply ducts as specified in AMM Task 21-51-00-220-801-A01, and for airplanes that have accumulated 17,600 flight hours or more since the date of issuance of the original airworthiness certificate or original export certificate of airworthiness, and for which no detailed inspection of the pack discharge and ram air supply ducts has been performed: Within 90 days after the effective date of this AD.

After the existing maintenance or inspection program has been revised as required by paragraph (g) of this AD, no alternative actions (e.g., inspections) or intervals, may be used unless the actions and intervals are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (i)(1) of this AD.