We are presently performing a major inspection to a MS5001 GE Heavy Duty Gas Turbine Generator and we noticed that the exhaust cooling air for the exhaust frame has been eliminated due to an output increment. This gas turbine was originally MS5001N and after an upgrade to New Technology, one modification implemented the blanking off the cooling air to the exh frame. The customer has reported frequent exhaust frame heat shield cracking. Is this cooling air elimination commonly implemented after upgrading to new tech machinery?

 

What does the supplier of the "New Technology" upgrade that eliminated the exhaust frame cooling air to improve performance say about the repeated cracking?

How is the cracking repaired?

Does the cracking extend into the hot gas path area?

Is this negatively impacting operations? (Maintenance, surely, because some repair is likely done?)

Is the cracking a safety concern?

Again, what does the supplier of the upgrade that eliminated the cooling air say about the cracking?