• remotelove@lemmy.ca
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        5 months ago

        It’s likely aux power. A cable that big is carrying a ton of current so it can power most of the instruments and maybe even hydraulic pumps. If that jet doesn’t have an APU, it needs something to get the engines started. (Jet engines aren’t always self-start. They need something to turn them over while also getting fed a fuck ton of air. The exact mechanics are lost on me, but that is basically what is going on.)

        If fixed wing aircraft are remotely similar to the piece of shit helicopters I worked on, they spend most of their life in a perpetual state of just barely being good enough to fly. This means they need plenty of power during troubleshooting sessions so hungover airmen can break even more shit.

        Edit: An APU (aux power unit) on my helicopters (SH/HH-60’s. Basically a Black Hawk, but dumber.) was a third engine. It provides electrical power and also provides the air needed to start the other two engines. It’s also there to catch on fire at least once a year, as required by Navy regulations since all the leaking oil and fuel needs to be burned off on occasion.