Originally Posted by
Water pilot
I am not sure that I am understanding you. You can't be saying that it is compliant because of the difficulties in meeting the spec, but that is how I am reading what you wrote. In my world, "it was too hard to do it right" doesn't tend to satisfy the inspectors.
I'm saying that it's not black and white - the rotor burst requirements have 'judgement' involved. The one-in-twenty is not a
requirement, it's one method of showing compliance, but it's not the only way of showing compliance. People tend to treat what's in the ACs as hard requirements, but they are not. Reasonable people can disagree on what's required, and this wouldn't be the first time someone at the FAA got overruled by a higher up that determined that the specialist wasn't being reasonable.
I had a personal experience with this several years ago - we were certifying updated FADEC hardware which incorporated "Commercial Off The Shelf" (COTS) hardware. As others here know, mil-spec electronics are pretty much extinct now days - COTS has taken over (screened to a higher standard for aviation use than whats in you laptop or phone, but the same COTS components). The new hardware had been fully certified Part 33 by the engine company - all I was doing was certifying the installation on the aircraft (basically showing intended function with a flight test). We have a standard, FAA accepted (and actually FAA dictated) flight test program to do this. Yet this particular specialist rejected my plan - he wanted
dozens of hours of additional flight testing (at ~$50,000 per hour, so this was a big deal). I requested a face-to-face at the FAA. During the meeting, I finally got the specialist to admit that he didn't believe COTS hardware was acceptable and what he wanted was to do reliability testing. His manager was sitting right next to him and immediately stepped in and basically told the specialist to shut up - that he was completely out of line since the COTS hardware had already been certified Part 33 and the specialist was overstepping his authority. When the meeting ended, my original plan had been accepted with only minor comments. Oh, and if you're wondering, this was all pre-ODA.
Most of the specialists I had dealings with at the FAA were good, sharp, reasonable people. But not all. One of the FAA specialists quoted in the NYT article fell into that latter group.