Comair, Inc.

Docket No FAA-2008-0643; Directorate Identifier 2008-NM-094-AD These comments are submitted on behalf of Comair, Inc. AD 2008-06-02 required the incorporation of Maintenance Requirements Manual Part 2, Appendix D for certain tasks. Three of these tasks 28-11-00-601, 28-11-00- 602 and 28-11-00-604 require inspections for Post-Modsum or post SB airplanes. Airplanes which do not have either the Mod-sum or SB incorporated have no inspection criteria. Tasks 28-11-00-601 and -602 are required for airplanes Post-modsum TC601R16091 (airplanes 7930 and subsequent) and Post-SB 601R-28-055 (effectivity 7003 – 7929). This SB is the subject of Transport Canada AD CF-2007- 34, with no FAA NPRM or AD equivalency. If the FAA issued an AD in the future and mirrors the TC AD compliance time of 5000 flight hours, when will the initial compliance time be required for these two above listed tasks? Using aircraft serial number 7011 as and example, as of this writing it has 35478:50 flight hours (FH) since new and it could have in excess of 40, 000 FH before this SB would be mandatory. Following common practices for the MRM, airplanes which are Pre-Modsum and Pre- SB, the initial tasks are not due until 20,000 FH after the incorporation of the SB. If aircraft 7011 incorporates SB 28-055 at 40,000 FH since new, the initial inspections for tasks 28-11-00-601 and -602 are due before 60,000 FH since new. The same logic would apply for task 28-11-00-604. In addition, since AD 2008-06-02 restates the Phase-In requirements listed in Maintenance Requirements Manual Part 2, Appendix D – Fuel System Limitations, the superseding AD should also contain the Effectivity statements.