Originally Posted by
atakacs
Thanks - very interesting an informative answer (at least to me). So bottom line there is no easy answer, especially with the case at hand (737 MAX).
I'd be really interested - and I'm certainly not alone - in the certification process for the MCAS. I really hope for all involved that it was not "self-certified "... Is this process publically documented?
Much of what an airframer provides during the certification is considered proprietary and/or commercially sensitive. So while the process is documented and available via the freedom of information act, the details and documentation typically are not. In fact much of the documentation submitted to the authority is either returned to the airframer or destroyed once the certification is finished.
When making a significant change to an existing aircraft model, there is something called the Changed Product Rule (CPR) - which was negotiated and 'harmonized' about 20 years ago based on input from Boeing, Airbus, FAA, EASA/JAA, and a host of others (harmonized means that the rules are identical between the FAA and EASA). It has specific rules regarding what would require an Amended Type Cert (ATC) vs. the normal ongoing changes (e.g. new interiors, updated flight control or FADEC software, etc.). Normal on-going changes use the cert basis as defined in the TC - an Amended TC opens up the cert basis. The details can get messy, but in general portions of the aircraft that are 'unchanged' can use their existing cert basis, while new or changed systems need to step up to the latest regulations.
I would assume that since MCAS was a new system for the MAX, it needed to be certified to the latest regulations. My educated guess is that MCAS wasn't given the hazard classification it really deserved (i.e. it was defined as Major or Hazardous, instead of Catastrophic) and hence wasn't given the level of attention it deserved.
BTW, it's worth noting that the push to "Delegated Compliance" wasn't Boeing's idea - it was dictated by the FAA in Washington DC and is being applied to all airframers and major suppliers in the US, not just Boeing. My understanding is that EASA has something similar with Airbus and the other airframers/suppliers in Europe/UK.
I was a DER - which became "Authorized Representative" or AR once Boeing became delegated - and almost to a person the DER/ARs hated it. It made the DER/AR job much, much harder.