EASA SIB NE-13-31
Pratt & Whitney PW4000 Engines — Scavenge Oil Tube Coking and Proper Cleaning at Overhaul
Summary
The Special Airworthiness Information Bulletin (SAIB) NE-13-31 issued by the FAA on May 9, 2013, addresses potential scavenge oil tube coking and nozzle blockage in Pratt & Whitney PW4000 series turbofan engines. This issue affects engines installed on aircraft such as the Airbus A300, A310, A330, Boeing 747-400, 767, 777, and McDonnell Douglas MD-11. The bulletin provides guidance on proper cleaning and inspection procedures during engine overhaul to prevent reduced oil flow and possible engine damage.
What Changed
SAIB NE-13-31 introduces updated cleaning and inspection recommendations for the No. 4 bearing oil supply tubes and nozzles on PW4000-100 and PW4000-94 engines. It highlights the importance of removing all varnish and coke contamination and specifies a borescope inspection to verify cleaning thoroughness, as detailed in the revised Pratt & Whitney Cleaning, Inspection and Repair (CIR) manual.
Why It Matters
This information is critical for operators, maintenance, repair, and overhaul (MRO) facilities to prevent oil nozzle blockage that can lead to reduced oil flow, bearing distress, internal engine fires, and potential turbine shaft fractures. Proper cleaning and inspection help maintain engine reliability and safety, reducing the risk of in-service failures and costly repairs.
What To Do
Operators and certified repair facilities should perform thorough cleaning and borescope inspections of all oil supply and scavenge tubes and nozzles during overhaul, following the guidance in Pratt & Whitney CIR Manual P/N 51A357. There is no mandatory compliance deadline, but adherence to these recommendations is strongly advised to prevent engine damage.
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