Airworthiness Directive · Amendment 39-21176 · Hydraulic power system
Airbus Helicopters Deutschland GmbH Helicopters
This AD applies to Airbus Helicopters Deutschland GmbH Model MBB-BK 117 C-2 helicopters, serial numbers up to and including 9750, and Airbus Helicopters Deutschland GmbH Model MBB-BK 117 D-2 helicopters, serial numbers up to and including 20110, certificated in any category, with a hydraulic module plate assembly part number B291M0003103 with a single locking attachment point installed or with a double locking attachment point installed before the effective date of this AD in accordance with Airbus Helicopters Alert Service Bulletin (ASB) No. ASB MBB-BK117 C-2-29A-003 (ASB MBB-BK117 C-2-29A-003 Rev 2) or ASB No. ASB MBB-BK117 D-2-29A-001 (ASB MBB-BK117 D-2-29A-001 Rev 2), both Revision 2 and dated February 1, 2017, as applicable to your model helicopter.
The FAA is superseding Airworthiness Directive (AD) 2017-02-07 for Airbus Helicopters Deutschland GmbH (Airbus Helicopters) Model MBB- BK 117 C-2 and Model MBB-BK 117 D-2 helicopters. AD 2017-02-07 required a repetitive inspection and a one-time torque of each hydraulic module plate assembly attachment point (attachment point). This new AD retains the initial inspection and torque requirements of AD 2017-02-07 and requires replacing the attachment point hardware. This AD was prompted by a terminating action has been developed to address the unsafe condition. The actions of this AD are intended to address an unsafe condition on these products.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
Comply with either paragraphs (f)(1) and (2) of this AD, or paragraph (f)(3) of this AD, as applicable to your helicopter.
(1) For helicopters with a hydraulic module plate assembly with a single locking attachment hardware installed, within 100 hours time-in-service (TIS):
(i) Visually inspect the split pins, castellated nuts, plugs, nuts, and hexagon bolts of each attachment point for a crack and for proper installation by following the Accomplishment Instructions, paragraphs 3.B.1.3.a. through 3.B.1.3.d., of Airbus Helicopters ASB No. ASB MBB-BK117 C-2-29A-003 (ASB MBB-BK117 C-2-29A-003 Rev 3) or Airbus Helicopters ASB No. ASB MBB-BK117 D-2-29A-001 (ASB MBB-BK117 D-2-29A-001 Rev 3), both Revision 3 and dated December 19, 2017, as applicable to your model helicopter. Replace any part that has a crack before further flight. If the split pins, castellated nuts, or hexagon bolts are not as depicted in Figures 1 and 2 of ASB MBB-BK117 C-2-29A-003 Rev 3 or ASB MBB-BK117 D-2-29A-001 Rev 3, before further flight, properly install them.
(ii) Apply a torque of 9 to 10 Nm to the left-hand (LH) and right-hand (RH) nuts of each forward attachment point. If a torque of 9 to 10 Nm cannot be applied, replace the affected nut before further flight.
(2) For helicopters with a hydraulic module plate assembly with a single locking attachment hardware installed, within 300 hours TIS:
(i) Replace each forward single locking attachment hardware with double locking attachment hardware by following the Accomplishment Instructions, paragraphs 3.B.3.3. through 3.B.3.6. on page 11 of ASB MBB-BK117 C-2-29A-003 Rev 3 or ASB MBB-BK117 D-2-29A-001 Rev 3, as applicable to your model helicopter, except you are not required to discard old parts.
(ii) Replace each aft single locking attachment hardware with double locking attachment hardware and reposition the LH and RH aft grounding straps by following the Accomplishment Instructions, paragraphs 3.B.3.1. through 3.B.3.7. on page 13 of ASB MBB-BK117 C-2-29A-003 Rev 3 or ASB MBB-BK117 D-2-29A-001 Rev 3, as applicable to your model helicopter, except you are not required to discard old parts.
(3) If you have replaced the attachment hardware with double locking attachment hardware before the effective date of this AD in accordance with ASB MBB-BK117 C-2-29A-003 Rev 2 or ASB MBB-BK117 D-2-29A-001 Rev 2, as applicable to your model helicopter: Within 300 hours TIS, inspect the clamping effect of the LH and RH aft screw joints (bolts) of the hydraulic module plate by following the Accomplishment Instructions, paragraph 3.B.5., of ASB MBB-BK117 C-2-29A-003 Rev 3 or ASB MBB-BK117 D-2-29A-001 Rev 3, as applicable to your model helicopter, except you are not required to discard old parts.
Note 1 to paragraph (f)(3) of this AD: Airbus Helicopters refers to bolts as “screw joints.”
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.
