This is a brief update and guidance on maintenance topics for the Pratt & Whitney PW307A, PW306A, and PW305A engines.
First Stage HP Turbine Blades have shown missing material from the platforms during scheduled borescope inspection, as shown in the picture. While some missing material is acceptable with an increased borescope schedule, an excessive amount of missing material may require engine entry.
Pictured are the Combustion Liner Heat Shields. The left picture shows individual heat shields with holes burned through. These individual heat shield panels are depicted as items 40 and 50 in the right picture from the PW307A IPC. These panels make it easier to repair the Combustion Liners while keeping costs down. It is always a good idea to plan ahead for the scheduled events to avoid parts shortages.
The HP Turbine Blades on these engines are a mandatory replacement during the hot section inspection. These blades have shown a lot of back orders causing longer downtime. It is advisable to plan ahead when approaching your scheduled HSI event. There is a 250 hour cushion allowed for planning purposes that can help with ensuring availability of these blades.
We are still seeing IBR NDT inspections. These will continue until all of the first stage compressors have been replaced. For ESP customers the labor to do the inspections is covered with parts being covered by the CSPN. Non-ESP customers will have to pay for the labor but the parts are covered by the CSPN.
The CSPN has been extended through November 2017. As a side note for non-ESP customers, the CSPN that covers the cost of the replacement IBR is now expired.