AirTran Airways

NPRM 2007-NM-294-AD was issued by the FAA to propose a new rule to supersede existing AD 99-04-11. The new rule would add additional aircraft to the effectivity of the existing rule, mandate the replacement of the aft strut insulation blanket, and install a new cover plate on both the left and right side engine struts. This rule is proposed to prevent damaged heat insulation blanks which would expose the strut lower surface to extreme high temperatures which could act as a source of fuel ignition leading to possible uncontrollable fire and fuel tank explosion. AirTran Airways has 42 aircraft affected by this proposed rule. AirTran Airways agrees with this rule but offers the following comments. Paragraph (f) of the proposed rule states to install a new heat insulation blanket part number (P/N) S315A213-57 within 60 months of the effective date. While Boeing does recognize P/N S315A213-57, it is a specification number with which supplier P/N 99A9257M is approved under. Boeing is selling the insulation blanket under supplier P/N 99A9257M, and the supplier part number is identified in the B737-700 Illustrated Parts Catalog as an acceptable part. AirTran Airways request the FAA update the proposed rule to indicate the supplier part number in addition to the Boeing specification number in order to prevent future compliance issues for the airline. Similarly, paragraph (g) of the proposed rule prevents installation of a P/N S315A213-42 or -47 insulation blanket. These blankets are provided under supplier P/N 99A9242M and 99A9247M. AirTran Airways request the FAA update the proposed rule to address these part numbers to prevent possible occurrences of installing a P/N S315A213-42 or -47 insulation blanket which is identified under the supplier P/N.