1AD/EC 120/3 Amdt 4 - Reinforced Coupling Tube Assembly

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AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/EC 120/3 Amdt 3 and issues the following AD under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

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Eurocopter EC 120 Series Helicopters

AD/EC 120/3

Amdt 4

Reinforced Coupling Tube Assembly 9/2004

Applicability: All Eurocopter EC 120B helicopters fitted with engine-to-main gearbox (MGB) coupling tube Part Number (P/N) C631A1101101 and/or fitted with the engine mount comprising the parts detailed in paragraph 1.A. of Eurocopter EC 120 Alert Service Bulletin (ASB) No. 04A005.

Requirement: 1. EC120B helicopters not incorporating an engine mount block modified in accordance with Eurocopter EC120 ASB No. 71.003 AND prior to serial number 1170 AND not incorporating Eurocopter EC120 Service Bulletin (SB) No.

71.005:

Perform a visual inspection of the engine to MGB coupling tube in accordance with Paragraph 2.B of Eurocopter EC120 ASB No. 05A003; and

b. Remove from service, MGB coupling tube P/N C631A1101101 assemblies found to be cracked; and

c. Remove from service, MGB coupling tube P/N C631A1101101 assemblies.

2. EC120B helicopters prior to serial number 1170 and not incorporating an engine mount modified in accordance with Eurocopter EC120 SB No. 71.003:

Remove from service, engine mount components detailed in Paragraph 1.A of Eurocopter EC120 ASB No. 04A005.

3. EC120B helicopters serial number 1170 and higher and EC120B helicopters incorporating an engine mount modified in accordance with Eurocopter EC120 SB No. 71.003, but not modified in accordance with Eurocopter EC120 SB No. 71.005:

Perform a visual inspection of the engine to MGB coupling tube in accordance with Paragraph 2.B of Eurocopter ASB 05A003; and

b. Remove from service, MGB coupling tube P/N C631A1101101 assemblies found to be cracked; and

c. Remove from service, MGB coupling tube P/N C631A1101101 assemblies.

4. EC120B helicopters all serial numbers which have modified in accordance with Eurocopter EC120 SB No. 71.005:

Remove from service, MGB coupling tube P/N C631A1101101 assemblies.

5. For MGB coupling tube P/N C631A1101101 assemblies held as spares:

Perform a dye penetrant inspection of the MGB coupling tube in accordance with paragraph 2.B of Eurocopter SB 71.005.