AD 2014-05-01 Airworthiness Directives; Eurocopter Deutschland GmbH Helicopters

This AD becomes effective April 14, 2014.

(1) The Manager, Safety Management Group, FAA, may approve AMOCs for this AD. Send your proposal to: Rao Edupuganti, Aviation Safety Engineer, Regulations and Policy Group, Rotorcraft Directorate, FAA, 2601 Meacham Blvd., Fort Worth, Texas 76137; telephone (817) 222-5110; email rao.edupuganti@faa.gov . (2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 CFR part 91, subpart K, we suggest 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.

The subject of this AD is addressed in the European Aviation Safety Agency (EASA) AD No. 2009-0106R1, dated November 3, 2011. You may view the EASA AD on the Internet at http://www.regulations.gov in Docket No. FAA-2013-0554.

(1) Within 100 hours time-in-service (TIS), and thereafter at intervals not to exceed 100 hours or 12 months, whichever occurs first, take an oil sample in accordance with the Accomplishment Instructions, Part 1, of Eurocopter Alert Service Bulletin EC135-63A-012, Revision 5, dated September 6, 2011 (ASB EC135-63A-012). (2) Within 25 hours TIS after taking the oil sample in paragraph (e)(1) of this AD, analyze the oil sample in accordance with the Accomplishment Instructions, Part 2.A. through Part 2.C. of ASB EC135-63A-012, except that you are not required to contact Eurocopter. (i) If the analysis indicates Stage II as specified by the Accomplishment Instructions, Part 2.B., of ASB EC135-63A-012, within 25 hours TIS, remove and inspect the oil filter element for a chip, defined as any solid piece of metal but not metallic fuzz or fine particles. (A) If there are no chips, clean the oil filter element and chip detector, inspect the drive stage toothing, perform a ground run, and inspect for leaking oil in accordance with the Accomplishment Instructions, Part 4.A through 4.G, of ASB EC135-63A-012. Change the oil. (B) If there is a chip, replace the MGB with an airworthy MGB before further flight. (ii) If the analysis indicates Stage III as specified by the Accomplishment Instructions, Part 2.B., of ASB EC135-63A-012 and if the water content is between 0.1 and 0.5 percent, within 10 hours TIS, remove and inspect the oil filter element for a chip. (A) If there are no chips, clean the oil filter element and chip detector, inspect the drive stage toothing, perform a ground run, and inspect for leaking oil in accordance with the Accomplishment Instructions, Part 4.A through 4.G, of ASB EC135-63A-012. Change the oil. (B) If there is a chip, replace the MGB with an airworthy MGB before further flight. (3) Before the MGB has accumulated 300 hours TIS, determine whether two or more chip indications have occurred. If two or more chip indications have occurred, inspect the drive stage toothing, perform a ground run, and inspect for leaking oil in accordance with the Accomplishment Instructions, Part 4.A through 4.G, of ASB EC135-63A-012. (4) Any time there is a chip indication, remove and inspect the chip detector for deposits (fine particles or metallic fuzz) or chips, and remove and inspect the oil filter element for a chip. (i) If there are no chips and a minimal amount of particles or metallic fuzz, corresponding to Figure 5, Stage A of ASB EC135-63A-012, clean the chip detector and the oil filter element and enter the chip indication on the MGB log card before further flight. (ii) If there are no chips and some particles or metallic fuzz, corresponding to Figure 5, Stage B of ASB EC135-63A-012, clean the chip detector and the oil filter element and enter the chip indication on the MGB log card before further flight, and within 10 hours TIS inspect the drive stage toothing, perform a ground run, and inspect for leaking oil in accordance with the Accomplishment Instructions, Part 4.A through 4.G, of ASB EC135-63A-012. Perform a ground run for 15 minutes at the flight-idle power setting, and then re-inspect the chip detector for a chip, particles, and metallic fuzz. (iii) If there is a chip, replace the MGB with an airworthy MGB.

This AD defines the unsafe condition as a tooth rupture in the MGB. This condition could result in failure of the MGB, loss of power to the main rotor, and subsequent loss of control of the helicopter.