AD FAA-2009-0948

We are revising an existing airworthiness directive (AD) for Thielert Aircraft Engines GmbH models TAE 125-02-99 and TAE 125-01 reciprocating engines. That AD currently requires replacing the existing rail pressure control valve with an improved rail pressure control valve. This new AD requires the same actions but relaxes the initial compliance time from within 100 flight hours to within 600 flight hours for TAE 125-01 reciprocating engines. This AD was prompted by the determination that our AD was inadvertently more restrictive than European Aviation Safety Agency AD 2008-0128. We are issuing this AD to prevent engine in-flight shutdown, possibly resulting in reduced control of the aircraft.