AD 2020-12-03 -- Manufacturer Found That A P30 (Air Pressure) Sense Line Could Become Partially Blocked

The FAA is adopting a new airworthiness directive (AD) for all Rolls-Royce Deutschland Ltd & Co KG Trent XWB-97 model turbofan engines.

This AD requires updating electronic engine control (EEC) software. This AD was prompted by the manufacturer's finding that a P30 (air pressure) sense line could become partially blocked with a mixture of ice and water, which would cause a time-lag in the P30 signal, interfering with the fuel flow limit calculations. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective June 18, 2020.

Supplementary Information: The European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA AD 2020-0035, dated February 26, 2020 (referred to after this as “the MCAI”), to address an unsafe condition for the specified products.

The MCAI states: During ground tests, it was found that a P30 (air pressure) sense line could become partially blocked with a mixture of ice and water, which would cause a time-lag in the P30 signal, interfering with the fuel flow limit calculations. This condition, if not corrected, could lead to loss of thrust control, possibly resulting in reduced control of the aeroplane. To address these potential unsafe conditions, Rolls-Royce defined a new EEC SW, XWB_97-7.0, P/N RRY23XWB0001024, which corrects these issues. For the reasons described above, this [EASA] AD requires updating the EEC SW. This [EASA] AD also prohibits installation of affected SW on any engine.

FMI: www.regulations.gov