AD FAA-2012-1181

We are revising an existing airworthiness directive (AD) for certain Piaggio Aero Industries S.p.A. Model P-180 airplanes. That AD currently requires replacement of any firewall shutoff or crossfeed valve with a serial number in a certain range even if it has been previously modified. The way the applicability was written includes valves that should not be affected and are not included in the referenced service information. This AD requires the same actions as the current AD, but only affects those firewall shutoff valves referenced in the referenced service information. We are issuing this AD to clarify the affected parts required to correct the unsafe condition on these products.