Editing Jet engine (section)

== Operation ==
[[File:ECAM.jpg|thumb|Airbus A340-300 [[Electronic centralised aircraft monitor|Electronic centralised aircraft monitor (ECAM)]] Display]]
In a jet engine, each major rotating section usually has a separate gauge devoted to monitoring its speed of rotation. 
Depending on the make and model, a jet engine may have an N{{sub|1}} gauge that monitors the low-pressure compressor section and/or fan speed in turbofan engines. The gas generator section may be monitored by an N{{sub|2}} gauge, while triple spool engines may have an N{{sub|3}} gauge as well. Each engine section rotates at many thousands RPM. Their gauges therefore are calibrated in percent of a nominal speed rather than actual RPM, for ease of display and interpretation.<ref>{{Cite book|url=https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/airplane_handbook/media/17_afh_ch15.pdf|title=Airplane flying handbook|publisher=FAA|isbn=9781510712843|pages=3|chapter=15 - Operating the Jet Engine|date=25 July 2017|oclc=992171581}}{{FAA.Gov}}</ref>