Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
NE-10-47
August 30, 2010
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) alerts you,
owners, operators, and certificated repair facilities of airplanes
equipped with Pratt & Whitney Canada Corp. PT6A-114 and PT6A-114A
series turboprop engines of the potential for engine in-flight
shutdowns (IFSDs) as a result of premature failure of compressor
turbine (CT) blades. These engines are installed on Cessna Aircraft
Company 208 and 208B Caravan airplanes. At this time, the airworthiness
concern is not an unsafe condition that would warrant airworthiness
directive action under Title 14 of the Code of Federal Regulations (14
CFR) part 39.
Background
The potential engine IFSDs addressed by this SAIB, are due to
operating the engine beyond the power settings specified in the
respective Aircraft Flight Manual (AFM) and/or inadequate maintenance
practices. Operating the engine above the specified AFM limits during
climb and cruise has largely contributed to incidents of accelerated CT
blade creep and a reduction in the operating life of the blades.
Failure to comply with operating procedures is a significant
contributor to CT blade failure.
Recommendations
To prevent CT blade failure and reduce blade distress, we recommend
the detection and control of hot section sulfidation, oxidation, and
blade erosion. This is done in accordance with the Engine Maintenance
Manual recommendations for periodic fuel nozzle maintenance, concurrent
borescope inspections of hot section components including CT blade and
vane airfoils, engine condition trend monitoring, and regular turbine
washing per engine maintenance manual recommendations.
For Further Information Contact
James Lawrence, Aerospace Engineer, Engine Certification Office,
FAA, Engine & Propeller Directorate, 12 New England Executive Park,
Burlington, MA 01803; e-mail: james.lawrence@faa.gov; phone (781)
238-7176; fax (781) 238-7199.
For Related Service Information Contact