2*110 = already 220
The 737 main exits are Type I. I’m not sure there is any narrow body with Type A exits, those are usually the main exits on wide bodies.
D’oh! I meant to type Type C. But if they are Type I, I’m not sure how the numbers add up: 45+35+45=125 for a 737-300/700?
When the 737 and A320 were certified, type C exits did not exist. This is why they are Type I.
However, for many aircraft, these exits are designated as Overperforming Type I, and depending on the aircraft and exit, they have higher passenger allowances than the standard Type I.
Those allowances are determined by analysis and/or testing for each aircraft. So for a 737-700, the allowance is 149. For the -800 it is 189 instead of 175. For the A321Neo, it is up to 200 when door 3 is deactivated, instead of 175.
For these increased allowances to happen, many aspects of the aircraft and door design are evaluated, such as door opening and size, provision of dual slides, aisle and exit path width, etc.
(Also keep in mind that a dual Type III overwing exit has a limit of 65 pax, not 2 x 35 = 70 pax).
How soon they forget: WN was operating the MD-95 / Boeing 717 as recently as 2015, but found it did not work for them and made the deal to get rid of them in 2012, basically paying DL to take them off their hands:
I think the 717 is not a good example. The 717 probably had similar or worse economics to the 737 while offering much more limited range, and hence flexibility within the network. On the other hand, the A220 can do pretty much everything the 737 can, for a lower cost (per seat and per trip). Having the 717 in the Southwest network was always going to be very hard to make it work. The A220 on the other hand, is a much more interesting proposition.
I'd rather die peacefully in my sleep, like my grandfather, not terrified and screaming, like his passengers