In my previous post as maintenance manager back-up gas turbines at a power station. We simultaneously lost 50% of our gas turbines whilst they were on load supplying the national grid. This meant we would be below the required capacity to meet demand for a peak time that was only 3 hours away. I had to immediately organise my team to investigate and identify the defect whilst ensuring the other turbines did not suffer the same symptoms. Therefore, I split my workforce leaving 3 men to watch-keep on the remaining machinery and the rest were tasked to find the symptoms. The problem was found to be a combination of a blocked filter and a seized valve. The valve was changed and the filter cleaned, which brought the off-line plants back into service one hour before the peak time. Thus averting power losses throughout the grid. Due to this incident I instigated stricter time tables on checking filters and created a maintenance routine to test all valves periodically