When you say modern standards, would that also be ditching the yoke and going sidestick? Isn’t FBW better suited to a sidestick?
No. FBW is totally agnostic when it comes to the input method. The negative to the Airbus style of sidestick is that they don’t provide feedback from the other side. It can be done, but AB have chosen not to do so. On the other hand, interconnected yokes do provide such feedback, but their only real positive beyond that is that of pilot continuity and training. Having used both, I far prefer the AB implementation.
There don’t seem to be any complete listings of the sort of things that Boeing has managed to grandfather, and I can imagine that nobody would want to fly with them at all if such a list were out there.
FBW is not a requirement for new aircraft, but it offers massive safety and engineering advantages. It is hard to believe that new aircraft are being sold without envelope protection. MCAS was in some ways a poor attempt at this, but anything that uses the stab as a primary control is suspect at best (the stab has more power than the elevator, which is why it’s so dangerous).
The lack of an EICAS in a new aircraft, when Boeing first started delivering these systems 40 years ago, is beyond poor.
Noise level, particularly in the coughpit, is grandfathered.
Doors (and slide/rafts) do not meet modern standards.
And some rules give undeserved commercial advantage. For instance in the calculations for V1, the 737 is able to use a standard that was replaced prior to the introduction of the A320. The upshot is that it can gain a few thousand kilos of take off weight, over the AB, because it’s allowed to use a form of calculation that is less realistic. If the modern rules were applied, out of shorter runways, they’d have less weight available, or not be able to operate at all. It’s interesting that this annoys AB so much that they’re going to ask for their aircraft to be exempted as well. Of course, they don’t expect this to be allowed, but when it’s not, it will have placed the regulators on some thin(ner) ice.