Gh123 From , joined Dec 1969, posts, RR: Posted (3 years 1 week 1 day 7 hours ago) and read 2094 times:
I was under the impression that the air for the cabin came from the bleed system in the engines. If that is the case then what are these intakes for on the underside of the 777?
CdfMxTech From United States, joined Jul 2000, 1332 posts, RR: 34 Reply 4, posted (3 years 1 week 1 day 5 hours ago) and read 2021 times:
The air for the Air Conditoning/pressurization system does come from the pneumatics supplied by engines (and the APU of course). But these Ram Air Inlets are necessary to cool the bleed air in order for it to be used as conditioned air. The process of getting the air to the required temperature involes a process of taking hot air, then cooling it, heating it again, then cooling it again (to explain it in simple terms). This COLD (or better said cooler) ram air aids in doing that.