AD 2021-06-05 Airworthiness Directives; Airbus Helicopters Deutschland GmbH Helicopters

This AD replaces AD 2017-07-08, Amendment 39-18846 (82 FR 16895, April 7, 2017).

(1) For helicopters with an elastomeric bushing P/N 105-60386 installed, within 50 hours time-in-service (TIS) and thereafter at intervals not to exceed 50 hours TIS: (i) Visually inspect each elastomeric bushing for separation of the rubber from the metal or missing rubber by following Section 3.B.2 of Airbus Helicopters Alert Service Bulletin (ASB) MBB-BK117 D-2-71A-002, Revision 1, dated December 14, 2018. (ii) If any rubber has separated from the metal or if there is missing rubber, before further flight, inspect the elastomeric bushing for deformation, corrosion, and mechanical damage. (A) Replace the elastomeric bushing with an airworthy engine mount bushing if there is any deformation, separation of the rubber from the metal, corrosion, or mechanical damage, or repair the elastomeric bushing if the deformation, separation of the rubber, corrosion, or mechanical damage is within the maximum repair damage limitations. (B) If the inner and outer parts of the elastomeric bushing are separated with missing rubber, before further flight, replace the elastomeric bushing with an airworthy engine mount bushing. (2) For helicopters with a metal bushing P/N B712M10X1001 installed, within 100 hours TIS, and thereafter every 100 hours TIS, visually inspect the metal bushing of the inner and outer forward trusses for gapping between the inner and outer truss, contact marks on the inner and outer engine mount bushings, and worn out metal mesh. (i) If there is gapping between the inner and outer truss less than 1mm, within 50 hours TIS, replace the metal bushing with an airworthy engine mount bushing. (ii) If there is gapping between the inner and outer truss of 1mm or greater than 1mm, contact marks on the inner or outer engine mount bushings, or worn out metal mesh, before further flight, replace the metal bushing with an airworthy engine mount bushing. (3) For helicopters with an elastomeric bushing P/N 105-60386 installed, within 300 hours TIS, replace each elastomeric bushing P/N 105-60386 with metal bushing P/N B712M10X1001. (4) Performing the actions required by paragraph (f)(3) of this AD constitutes a terminating action for the repetitive inspections required by paragraph (f)(1) of this AD. (5) As of the effective date of this AD, do not install elastomeric bushing P/N 105-60386 on any helicopter.

(1) The Manager, International Validation Branch, FAA, may approve AMOCs for this AD. Send your proposal to: Matt Fuller, AD Program Manager, General Aviation & Rotorcraft Unit, Airworthiness Products Section, Operational Safety Branch, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110; email 9-AVS-AIR-730-AMOC@faa.gov. (2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 CFR part 91, subpart K, the FAA suggests that you notify your principal inspector, or lacking a principal inspector, the manager of the local flight standards district office or certificate holding district office, before operating any aircraft complying with this AD through an AMOC.

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.

This AD defines the unsafe condition as a delaminated elastomeric bushing. This condition could result in excessive vibration, which could lead to cracking and failure of the engine mount front support pins, and loss of helicopter control.