Airworthiness Directive · Amendment 39-17764 · Turbomeca S.A. Turboshaft Engines
Turbomeca S.A. Turboshaft Engines
Superseded. A later AD replaced this one: AD 2021-17-05. Comply with the one in force.
This AD applies to all Turbomeca S.A. Arrius 2B1, 2B1A, 2B2, and 2K1 turboshaft engines.
We are adopting a new airworthiness directive (AD) for all Turbomeca S.A. Arrius 2B1, 2B1A, 2B2, and 2K1 turboshaft engines. This AD requires 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 HMU if it fails inspection. This AD was prompted by in-flight shutdowns caused by interrupted fuel supply at the HMU. We are issuing this AD to prevent in-flight shutdown and damage to the engine.
(1) On the effective date of this AD, for those HMUs that have not previously been inspected using Turbomeca Mandatory Service Bulletin (MSB) No. SB 319 73 2825, Version G, dated January 24, 2013, or earlier versions; perform an initial visual inspection of the HMU high-pressure pump drive gear shaft splines for wear, corrosion, scaling, or cracks, and clean and inspect the sleeve assembly splines for wear, corrosion, scaling, or cracks, at the following:
(i) For HMUs that have accumulated more than 150 operating hours (OHs) since new or since last overhaul, within 50 HMU OHs after effective date of this AD.
(ii) For HMUs that have accumulated 150 or fewer OHs since new or since last overhaul, before exceeding 200 HMU OHs.
(1) On the effective date of this AD, for those HMUs that have been previously inspected per Turbomeca MSB No. SB 319 73 2825, Version G, dated January 24, 2013, or earlier versions; perform a visual inspection of HMU aft splines of the high pressure pump for wear, corrosion, scaling, or cracks, and clean and inspect the sleeve assembly splines for wear, corrosion, scaling, or cracks, at the following:
(i) For HMUs that have accumulated 300 OHs or more since last inspection, within 200 HMU OHs after effective date of this AD.
(ii) For HMUs that have accumulated fewer than 300 OHs since last inspection, before exceeding 500 HMU OHs.
(1) Thereafter, repetitively visually inspect the HMU aft splines of the high pressure pump, and clean and inspect the sleeve assembly splines for wear, corrosion, scaling, or cracks, at intervals not to exceed 500 HMU OHs.
(2) If, during any initial or repetitive inspection required by this AD, an HMU does not pass inspection, then before further flight, replace the sleeve assembly on the affected high pressure pump drive gear shaft or replace the affected HMU.
After the effective date of this AD, do not install any engine on any helicopter unless the HMU was inspected as required by 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.
