AD 2004-07-09 Airworthiness Directives; General Electric Aircraft Engines CT7 Series Turboprop Engines

This AD applies to General Electric Aircraft Engines (GEAE) CT7 series turboprop engines, with propeller gearboxes (PGBs) identified by serial number (SN) in Table 1 of GEAE CT7 Turboprop Service Bulletin (SB) CT7-TP S/B 72-0452, dated July 27, 2001, and Table 1 of GEAE CT7 Turboprop Alert Service Bulletin (ASB) CT7-TP S/B 72-A0466, dated April 17, 2003. These engines are installed on but not limited to SAAB 340 series airplanes.

You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done. (f) Inspect the PGB oil filter impending bypass button (IBB) for extension using the following schedule: (1) Initially inspect within 50 hours time-in-service (TIS) after the effective date of this AD. (2) Thereafter, inspect each operational day. The flight crew may inspect the PGB oil filter IBB for extension if maintenance personnel are not available. (g) If the PGB oil filter IBB is extended, replace the oil filter and perform follow-on inspections, using paragraph 3.A of the Accomplishment Instructions of GEAE CT7 Turboprop SB CT7-TP S/B 72-0453, dated July 27, 2001. (h) At the next return of the PGB to a CT7 turboprop overhaul facility after the effective date of this AD, replace left-hand and right-hand idler gears. Use the Accomplishment Instructions of GEAE CT7 Turboprop SB CT7-TP S/B 72-0452, dated July 27, 2001 to replace the gears. (i) If the PGB is mated to a Hamilton Standard propeller and the left-hand and right-hand idler gears have not been replaced using the Accomplishment Instructions of GEAE CT7 Turboprop SB CT7-TP S/B 72-0452, dated July 27, 2001, replace the PGB before accumulating an additional 2,000 engine flight hours after April 24, 2003, the effective date of AD 2003-06-03. PGB Oil Filter IBB Inspection, Authorization (j) For GEAE CT7 series turboprop engines, in exception to the limitations imposed by § 43.3 of the Federal Aviation Regulations (14 CFR 43.3), a flight crew member holding at least a private pilot certificate may perform the inspections required by paragraph (f) of this AD. You must record completion of the inspections in the airplane records to show compliance with this AD, in accordance with §§ 43.9 and 91.417(a)(2)(v) of the Federal Aviation Regulations 14 CFR 43.9 and 14 CFR 91.417(a)(2)(v). You must also maintain the records as required by the applicable Federal Aviation Regulation. Terminating Action (k) Replacement of left-hand and right-hand idler gears using paragraph (h) of this AD, or replacement of the PGB using paragraph (i) of this AD constitutes terminating action to the repetitive inspections required by paragraph (f) of this AD. Definition (l) For the purpose of this AD, an operational day is defined as a day during which the airplane has flown for any reason. Alternative Methods of

This AD results from reports of PGBs equipped with certain gears that do not meet design specifications, resulting in the same failure addressed in the AD being superseded. We are issuing this AD to prevent separation of PGB left-hand and right-hand idler gears, which could result in uncontained PGB failure and internal bulkhead damage, possibly prohibiting the auxiliary feathering system from fully feathering the propeller on certain PGBs.