Thank you Mr Stevens for an intelligent technical diagnosis and a prompt reply.

We were also thinking in the same line. We had adopted many methodology to identify the leak or any after combustion. We had used the explosive meter, we had analysed the GT turbine compartment air at defferent locaton with gas chromatograph, we had used thermal imaging and also pyrometer to identify varying range of gas and temperatures. In none of the methods we could find even traces of gas or oxydation tendency.
Based on these we had deciding to run the machine till M.I which is due in september 2010