Having been on the Elliot, Charlie could see that everything from the tech to the design of a research vessel was twice as complex and sophisticated than what one would see in two modern ships put together.
In other words, it didn't make sense that it would break down that easily.
Furthermore, the research crew had been using helicopters without informing the ministry, even turning off trackers while they did. It gave the sense that they weren't stranded, but were staying in the Antarctic deli