Airworthiness Directive · Amendment 39-17373 · Turbomeca S.A. Turboshaft Engines
Turbomeca S.A. Turboshaft Engines
This AD applies to all Turbomeca S.A. Makila 1A2 turboshaft engines with an N2 sensor harness, part number (P/N) 0 301 52 001 0, installed, with:
(1) A serial number (S/N) 242 through 339, inclusive, or
(2) A S/N 691 through 705, inclusive, 707 through 728, inclusive, or 813 through 844, inclusive.
We are superseding an existing airworthiness directive (AD) for all Turbomeca S.A. Makila 1A2 turboshaft engines. That AD currently requires replacement of certain serial number (S/N) N2 sensor harnesses. This AD requires replacement of the same S/N harnesses, and requires replacement of additional S/N N2 sensor harnesses. This AD was prompted by corrosion detected in affected N2 sensor harnesses. We are issuing this AD to prevent inadvertent activation of the 65% N1 back up mode, resulting in N2 speed fluctuation, significant power loss, and emergency landing of the helicopter.
(1) For engines listed in paragraph (c)(1) of this AD with an affected N2 sensor harness installed on both engines of the helicopter, do the following:
(i) Replace one N2 sensor harness with an N2 sensor harness that is eligible for installation within 10 flight hours (FHs) after December 7, 2011, or before the next flight after the effective date of this AD, whichever occurs later, and
(ii) Replace the second N2 sensor harness with an N2 sensor harness that is eligible for installation within 50 FHs after December 7, 2011, or before the next flight after the effective date of this AD, whichever occurs later.
(2) For engines listed in paragraph (c)(1) of this AD with an affected N2 sensor harness installed on only one engine of the helicopter, replace the affected N2 sensor harness with an N2 sensor harness that is eligible for installation within 50 FHs after December 7, 2011, or before the next flight after the effective date of this AD, whichever occurs later.
(3) For engines listed in paragraph (c)(2) of this AD with an affected N2 sensor harness installed on both engines of the helicopter, do the following:
(i) Replace one N2 sensor harness with an N2 sensor harness that is eligible for installation within 10 FHs after the effective date of this AD, and
(ii) Replace the second N2 sensor harness with an N2 sensor harness that is eligible for installation within 50 FHs after the effective date of this AD.
(4) For engines listed in paragraph (c)(2) of this AD with an affected N2 sensor harness installed on only one engine of the helicopter, replace the affected N2 sensor harness with an N2 sensor harness that is eligible for installation within 50 FHs after the effective date of this AD.
(5) If an affected N2 sensor harness is installed on both engines of the helicopter, one from paragraph (c)(1) of this AD and one from paragraph (c)(2) of this AD, then within 10 FHs after December 7, 2011, or before the next flight after the effective date of this AD, whichever occurs later, replace the N2 sensor harness from paragraph (c)(1) with an N2 sensor harness that is eligible for installation and within 50 FHs after the effective date of this AD, replace the harness from paragraph (c)(2) with an N2 sensor harness that is eligible for installation.
(1) After the effective date of this AD, do not install on any engine any N2 sensor harness, P/N 0 301 52 001 0, with a S/N listed in paragraphs (c)(1) and (c)(2) of this AD, unless the N2 sensor harness has “SB 0815” marked on its identification plate.
(2) After the effective date of this AD, do not install in a helicopter, any engine with an N2 sensor harness, P/N 0 301 52 001 0, installed, with a S/N listed in paragraphs (c)(1) and (c)(2) of this AD, unless the N2 sensor harness has “SB 0815” marked on its identification plate.
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
