This Revised Special Airworthiness Information Bulletin (SAIB) corrects the serial number and alerts you, owners and operators of Hawker Beechcraft Corporation Model 60, 60A and 60B (Duke), equipped with a Lycoming TIO-541-E1C4 engine, of a potential discrepancy with a rebuilt Kelly Aerospace Energy Systems (KAES) T1879 model turbocharger, part number, 407540-9003; serial number, JAR00401. All other information remains the same. This rebuilt turbocharger was shipped from KAES to Aviall (a distributor) on December 19, 2006.
Incoming inspections of new KAES turbocharger backplates by a distributor revealed a production run of backplates that were machined without an oil galley, adjacent to a thrust bearing. All affected backplates which were individually distributed have been located and all but one turbocharger assembled with an affected backplate has been located. While the FAA is unaware of any safety
related issues with the turbocharger in question, functional and durability issues with the assembly might exist. These issues include, but are not limited to, the inability to achieve rated critical altitude
or engine performance, inability to achieve reliable and repeatable manifold pressure settings, sluggish and or unstable turbocharger operation, and the inability to meet expected component life.
SAIB attached below