AIRWORTHINESS DIRECTIVE On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/ERJ-170/10 Amdt 1 and issues the following AD under subregulation 39.001(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. Embraer ERJ-170 Series Aeroplanes AD/ERJ-170/10 Amdt 2 Firewall Hydraulic Shutoff Valves 10/2009 Applicability: Embraer ERJ-170( ) aircraft fitted with firewall hydraulic shutoff valves (FWSOV) part number (P/N) 975287-3 or P/N 975287-5. Requirement: Perform an operational check in accordance with Embraer Service Bulletin No. 170-29-0013 original issue 12 December 2006, or further ANAC approved revisions, for proper operation of the firewall hydraulic shutoff valves P/N975287-3 or P/N 975287-5. If necessary, replace the faulty hydraulic shutoff valve with a serviceable FWSOV. For the purpose of this AD, an operational check is: "A task to determine that an item is fulfilling its intended purpose. The check does not require quantitative tolerances. This is a failure finding task." For the purpose of this AD, a suitable FWSOV is a firewall hydraulic shutoff valve P/N 975287-3 or 975287-5 that has passed the operational check described in Embraer SB No. 170-29-0013 or either the replacement of these valves by others bearing a new P/N. Note: Agência Nacional De Aviação Civil - Brazil Airworthiness Directive AD No. 2007-02-01R2 dated 17 July 2009 refers. Compliance: Remains unchanged as detailed in the original issue of this AD as: Within the next 600 flight hours after 7 June 2007, and thereafter at intervals that do not exceed 600 flight hours. This Amendment becomes effective on 24 September 2009. Background: Periodic operational check of the firewall hydraulic shutoff valves, made during routine maintenance, has revealed that the failure rate of that component is significantly higher than expected. Such a dormant failure, when combined with further possible failures, such as engine fire, may lead to an unacceptable reduction of safety margins. Amendment 1 added an additional part number valve to the applicability section with no change to the requirement section. This amendment removes the requirement to replace the FWSOV with one bearing the same P/N. The original issue of this AD became effective 7 June 2007. Amendment 1 of this AD became effective on 25 October 2007. James Coyne Delegate of the Civil Aviation Safety Authority 14 August 2009