Airworthiness Directive · Amendment 39-11981 · Rolls-Royce Spey 555-15, -15H, -15N, and -15P Turbofan Engines
Rolls-Royce Spey 555-15, -15H, -15N, and -15P Turbofan Engines
Rolls-Royce (RR) plc. Spey 555-15, -15H, -15N, and -15P turbofan engines. These engines are installed on but not limited to Fokker F.28 Mark series airplanes.
Note 1: This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment adopts a new airworthiness directive (AD), applicable to Rolls-Royce (RR) plc. Spey 555-15, -15H, -15N, and -15P turbofan engines, that requires modification of the low pressure (LP) turbine stage 2 nozzle guide vane (NGV) support ring seal assembly. This amendment is prompted by two instances of disk drive arm damage. In both cases, heavy damage to the stage 1 LP turbine-to-stage 2 LP turbine disk drive arm occurred as a result of an out-of-balance condition following the failure of a stage 2 LP turbine blade. The actions specified by this AD are intended to prevent damage to the disk drive arm which could result in loss of stage 1 LP turbine-to-stage 2 LP turbine disk drive, a turbine overspeed condition, and possible uncontained disk failure and damage to the airplane.
To prevent damage to the disk drive arm which could result in loss of stage 1 LP turbine-to-stage 2 LP turbine disk drive, a turbine overspeed condition and possible uncontained disk failure, and damage to the airplane, do the following:
(a) Within three years after the effective date of this AD, rework the low pressure (LP) turbine stage 2 nozzle guide vane (NGV) support ring seal assembly in accordance with paragraphs 2.A. through 2.C. of the Accomplishment Instructions of RR service bulletin (SB) No. Sp 72-1063, dated May 1999.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Engines
