Airworthiness Directive · Amendment 39-21688 · --fuel controlling system
Safran Helicopter Engines, S.A. (Type Certificate Previously Held by Turbomeca S.A.) Turboshaft Engines
This AD applies to Safran Helicopter Engines, S.A. (Type Certificate previously held by Turbomeca S.A.) Arrius 2B1, 2B1A, 2B2, and 2K1 model turboshaft engines.
The FAA is superseding Airworthiness Directive (AD) 2014-04-06 for all Safran Helicopter Engines, S.A. (Safran Helicopter Engines) Arrius 2B1, 2B1A, 2B2, and 2K1 model turboshaft engines. AD 2014-04-06 required initial and repetitive inspections of the hydro-mechanical metering unit (HMU) high-pressure pump drive gear shaft splines, cleaning and inspections of the sleeve assembly splines, and replacement of the sleeve assembly on the affected high-pressure pump drive gear shaft or replacement of the HMU if the HMU fails inspection. This AD was prompted by in-flight shutdowns caused by interrupted fuel supply at the HMU. This AD requires revised inspections and continues to require cleaning of the sleeve assembly splines, and replacement of the sleeve assembly on the affected high-pressure pump drive gear shaft or replacement of the HMU if the HMU fails an inspection. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Within the compliance time specified in Table 1 to paragraph (g)(1) of this AD, as applicable, and before re-installation of the HMU after each removal from the engine, visually inspect the drive gear shaft splines of the high-pressure pump, and clean and inspect the sleeve assembly splines in accordance with paragraphs 2.4.2 and 2.4.3, or 4.4.2 and 4.4.3, as applicable, of Safran Helicopter Engines Mandatory Service Bulletin (MSB) 319 73 2825, Version J, dated March 15, 2019.
(2) Repeat the inspection required by paragraph (g)(1) of this AD at intervals not to exceed 500 HMU operating hours since the previous inspection.
Note 1 to paragraph (g)(2): A non-cumulative tolerance of 10% of HMU operating hours (hrs) may be applied to the timing of each repetitive inspection, with a maximum allowable tolerance of +50 HMU operating hrs. For example, counting from the initial inspection, the repeat inspections would occur at the following times, with the tolerance noted in parentheses; 500 HMU operating hrs (+50 hrs), 1000 HMU operating hrs (+50 hrs), 1500 HMU operating hrs (+50 hrs).
(3) If a rejectable indication is found during any inspection required by paragraphs (g)(1) or (2) of this AD, replace the sleeve assembly on the affected high-pressure pump drive gear shaft or replace the affected HMU in accordance with paragraph 2.4.2 or 4.4.2 of the MSB.
(1) A Group 1 HMU is an HMU that was first installed on or before January 31, 2013, and that has not previously been inspected in accordance with Safran Helicopter Engines MSB 319 73 2825 Version G or later.
(2) A Group 2 HMU is an HMU that was first installed after January 31, 2013, or a HMU that has previously been inspected in accordance with Safran Helicopter Engines MSB 319 73 2825 Version G or later.
The reporting requirements specified in the Accomplishment Instructions, paragraph 2.4.2, of the MSB are not required by this AD.
