Old Engineer
Good to have you back! It has been awhile since your last post, must be the winter weather...
I thought it would be interesting to post the certification requirements as presented in the US FAA regulations. You have noted a particular item that stands out and DERG did the same. I am sure there are more that seem applicable. As I see it, the OEM (original engine manufacturer) meets with the government regulator and submits a process for certifying a subject engine. During that meeting or subsequent meetings, it is decided exactly what the requirements will be for certification. Is it a totally new engine? If so, it requires all of the steps outlined for approval. Is it a derivative engine or growth engine from an existing family? Well, maybe this will be required but this will be waived based on history. And then the certification process begins and proceeds to engine type certification. Keep in mind that even if you go through a flight demonstration program on a different aircraft and a 150 hour endurance demonstration in a test cell, not all the potential problems may have surfaced or have been wrung out. So then, the engine receives its type certification, deemed to be flight worthy, and is ready for the real application, lets say on the A-380 aircraft.
The aircraft certification program is focused on the aircraft, although the same regulatory agency is in charge, just a different set of people and expertise are highly involved. So then, if during this aircraft certification program there are engine abnormalities along the way, how are they handled? What if there are, during the course of flight testing (1-2 yrs.), an abnormal number of engines removed off wing for various unnamed problems, beyond planned engine removals? Assume a significant number. Where do responsibilities rest, with the OEM, with Airbus, with the governmental regulatory agency? How was it handled? In my mind, this is where the breakdown occurred on the 900 and A-380. It wasn't during the original engine certification process, except for possible should have done but didn't possibilities. There was a lot of pressure by the producers to deliver the goods to the customers as the program was significantly behind schedule, viability of businesses rode on a favorable outcome of the flight test and aircraft certification program, so how were technical problems with the engines handled by the regulatory agency during the aircraft certification phase? I will let this up to the individual's imagination, I have mine.
Turbine D