Airworthiness Directive · Amendment 39-18426 · Turbomeca S.A. Turboshaft Engines
Turbomeca S.A. Turboshaft Engines
This AD applies to Turbomeca S.A. Turmo IV A and IV C turboshaft engines.
We are superseding airworthiness directive (AD) 2006-23-17 for certain Turbomeca S.A. Turmo IV A and IV C turboshaft engines. AD 2006- 23-17 required repetitive inspections of the centrifugal compressor intake wheel (inducer) blades for cracks and corrosion, replacement of parts that fail inspection, and replacement of the TU 197 standard centrifugal compressor. This AD requires the same inspections, but at revised intervals, adds the replacement of the TU 215 standard centrifugal compressor, and requires replacement of parts that fail inspection. This AD was prompted by a centrifugal compressor inducer blade loss. This AD was also prompted by a Turbomeca S.A. review of the engine service experience and their determination that more frequent borescope inspections (BSIs) are required on engines not modified to the TU 191, TU 197, or TU 224 standard. We are issuing this AD to prevent failure of the centrifugal compressor inducer, which could lead to an uncontained blade release, damage to the engine, and damage to the airplane.
(1) Remove the TU 197 and TU 215 standard centrifugal compressors and install the TU 224 standard centrifugal compressor, within 30 days after the effective date of this AD.
(2) Perform initial and repetitive ultrasonic inspections (UIs) or eddy current inspections (ECIs) of the centrifugal compressor (inducer). Use Accomplishment Instructions, paragraph 6.B.(1)(b) of Turbomeca S.A. Alert Mandatory Service Bulletin (MSB) No. A249 72 0100, Version H, dated May 21, 2015 to do the inspections. Use Appendix 1 of Turbomeca S.A. Alert MSB No. A249 72 0100, Version H, dated May 21, 2015 for the schedule of inspections.
(3) Perform initial and repetitive borescope inspections (BSIs) of the centrifugal compressor inducer. Use Accomplishment Instructions, paragraphs 6.B.(1)(a) of Turbomeca S.A. Alert MSB No. A249 72 0100, Version H, dated May 21, 2015 to do the inspections. Use Appendix 1 of Turbomeca S.A. Alert MSB No. A249 72 0100, Version H, dated May 21, 2015 for the schedule of inspections.
(4) If, during any inspection required by paragraphs (e)(2) or (e)(3) of this AD, any crack, corrosion, or other damage is detected on the inducer, then before next flight, replace the centrifugal compressor.
(5) Accomplishment of a UI or ECI of the centrifugal compressor inducer, required by paragraph (e)(2) of this AD, is acceptable in lieu of a BSI required by paragraph (e)(3) of this AD for that engine.
(6) Replacement of a centrifugal compressor required by paragraph (e)(4) of this AD, does not constitute terminating action for the repetitive inspections required by paragraphs (e)(2) and (e)(3) of this AD.
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
