I don't understand the argument. Of course 121 is safer than 91/135. Are there outliers in there, yes. But as a general rule, 121 will be the safest.
That said, it isn't the pilots. It's the operating environment. And I don't mean the airports or the varied flying. It is less oversight, less structure, etc that allows for the bad apples to be, bad apples. The 121 environment simply doesn't allow it. Pinnacle was a great example. Two pilots who were safe in the structured 121 environment right up until that structure went away. An empty plane allowed for some bad behavior and we all know the result. Those 2 likely would have done the same thing, but earlier, in the 91 world.
Now that I've typed all that out, I'm going to go one step further. It should probably read 121=91 > 121=91=135 > 91 > 91 > 135 > 91
At 121 you pretty much know what you're going to get. At least at the large passenger operators. But there is entirely too much variety in 91 to lump it all together as unsafe. There are large Corporate operators. Multiple planes, dozen + pilots, FOQA, SMS, strict adherence to SOPs, full recurrent training every 6 months, and flying to big international airports. Then there are smaller corporate operators like mine. No FOQA going to small airports often, but a good focus on SMS and SOPs. There's 91k and there privately owned family accounts at the big management companies and accounts at small management companies. Some of those accounts may be on the 135 certificate at their management company and some are strictly 91. Then there are the big charter companies. Then there are completely self run one aircraft operations. 2 pilots with no oversight doing essentially whatever they want.
Obviously the pilots will have different amounts of oversight at all of these operators. Put the wrong pilots at the wrong operator and bad things will happen. This is true whether its 91, 121, or 135.
Agree with your premise that 121 is all held together by a formalized, dictatorial-regulatory environment that imposes some modicum of discipline, and sometimes, actual competence.
That said, 121 allows just as many, if not more, bad apples to inhabit its ranks as do 91 and 135. In 121, bad apples have a great deal of protection from poor health, lack of competence beyond the LCD, and just being seemingly impossibly horrible individuals.
In the absence of unions, doctors and lawyers, a 135 pilot's best protection is to be (
or pretend to be) a good ol' boy. The irony in 135 is that the best pilots are usually the ones who get fired or quit ... precisely because they
are the best pilots. As such, they just can't/won't abide BS. When they don't, they are deemed "not a team player" (read: a guy who will bend, break, or ignore rules for money).
In 121, operationally, the best pilots are not allowed to be any better than the the worst. The worst pilots are the ones who, while completely passionless, grossly overweight and out of shape, yet somehow sneak through medicals and then die of heart attacks sitting in their seats. Other examples include pilots who can't and won't do visual approaches. Still others include pilots who can't but will do non-precision approaches... right into the ground. Still others include all those "OH, Airline!" pilots who keep getting arrested for showing up
still drunk instead of just hungover like a proper airline pilot.
Training and assessing individuals AS individuals is time consuming and expensive. Folks whose primary interest is the highest profit margin possible will almost NEVER engage in those individual-focused activities.
