Editing Boeing 707 (section)

====Turbocompressors====
The 707 uses engine-driven [[gas compressor|turbocompressors]] to supply compressed air for [[cabin pressurization]]. On many commercial 707s, the outer port (number 1) engine mount is distinctly different from the other three, as this engine is not fitted with a turbocompressor. Later-model 707s typically had this configuration, although American Airlines had turbocompressors on engines 2 and 3 only. Early 707 models often had turbocompressor fairings on all four engines, but with only two or three compressors installed.<ref>{{cite web |url=http://www.airlinercafe.com/page.php?id=72 |title=Ultimate Boeing 707 Guide |website=Airliner Cafe |access-date=February 17, 2016 |archive-date=March 17, 2021 |archive-url=https://web.archive.org/web/20210317031322/https://www.airlinercafe.com/page.php?id=72 |url-status=dead}}</ref>