I believe this is a false dichotomy. There's nothing that says that night cargo has to be riskier, we just all assume it must be riskier because of the environment and the costs. Do you think Cape Air stays on the ground when the weather is bad? No, I've seen those airplanes out plodding around in all sorts of crummy weather, especially in North East icing. Amflight and Cape Air probably even have most of the same OpSpecs, and are governed by mostly the same rules - so why does one company put one every couple years and why doesn't the other? And, this isn't my Amflight bashing, Amflight is what it is, but they face the realities of UPS more than they face the realities of their own business model. It's my opinion that on time performance pressure to fly in less than acceptable conditions is a result of the UPS system in freight most of the time, rather than what the company wants. That said, the reality of the job is that Amflight puts airplanes into the ground at a higher rate than CapeAir. Why is flying at Ameriflight "less safe" than flying at Cape Air? Let's use the PAVE model, and do some thinking about risk.
Pilots: Ameriflight can hire pilots as low as 1200hrs, Cape Air needs 1500hrs and an ATP to hire pilots. I doubt this is a contributing difference, but it could be (seems unlikely to me). Pilots for Ameriflight often fly weirdly disjointed schedules (created to please UPS) this is almost certainly a cause of fatigue. Regardless, both places higher younger, less experienced pilots. The only difference is that I'd bet more Amflight guys fly fatigued than Cape Air guys because of the type of flying. I'd also posit that everything I've heard about Cape Air leads me to believe that the training there is a little bit more rigorous than Amflight - again, not a bash, just a reality from my experience.
Aircraft: This is what we've been discussing. TAWS, or GPS equipment, or better equipment in some way shape or form - obviously, Cape Air has the jump on Amflight.
enVironment: The terrain Ameriflight commonly operates in is obviously more difficult than Cape Air's. Exposure to bad weather is probably about the same.
External Pressures: UPS creates a stupid amount of pressure. More than it should. Also, I'd suspect that just generally freight companies tend to push their pilots more than people-flying, but that's anecdotal on my part. Regardless, I bet that flying at both places has it's external pressures and headaches - realistically, Amflight may have more due to UPS, but I can't prove it.
Well, we're not going to change the external pressures (as late freight is unacceptable!), and we can't change the environment we operate in (1800RVR and VV001! Freight's gotta move, go give it a shot!) so what are things we can EASILY change to reduce risk? I posit that you can reduce risk quite easily at Amflight by adding more equipment, and training the pilots better. Equipment like GPS and TAWS are probably the most reliable way to make things safer, with revisions to training coming next. Either way, the flying is more challenging than Cape Air in terms of terrain, and the external pressures are probably greater at Amflight, but there are ways to help mitigate other risks in the job. You don't have to have everything stacked against you all the time! No, you don't need moving map GPS and TAWS to fly around in the mountains, and yes these don't do any good if pilots ignore them - but saying "F-it, this job is dangerous," misses the point. How do we fix the problem that guys keep hitting mountains in the middle of the night? How do we stop guys from making the same mistakes that countless pilots have made over the years.? How do we mitigate the risk in a way that keeps the airplanes moving just as much? The answer: better equipment and training will help, those are the only two things we can easily change, so why the hell hasn't Amflight changed them? Is it money? UPS is stingy, so any company that flies for them generally has to be stingy too, sure, but I don't think that's it. Is it the culture? Probably, every Amflight guy I know talked about how cool it was that this was the "most challenging flying they'll ever do." That doesn't help that the pilots create their own pressure to fly minimalist in the worst weather they can, that probably rubs off on management and the training department. Regardless, equipment which could make that kind of flying safer is available, reasonably priced, and easy to use. Why isn't it installed? We're not talking about a Mom & Pop 135, we're talking about the largest 135 operator in the country, with airframes and operations in almost every state, Canada, and Mexico. It's not like the money isn't there - rather the will isn't.