N2

N2
The rotational speed of the high-pressure compressor in a dual-spool gas turbine engine.
NM
Nautical Miles. One nautical mile = 1.15 statute miles = 6,076 feet = 1.85 kilometers ...

The low local partial pressure of gases, principally nitrogen (N2) but including all other gases, may cause dissolved gases in the bloodstream to precipitate out resulting in gas embolism or bubbles in the bloodstream.

The green arcs depict the operating limits for the rotor and power turbine. The power turbine (N2) must be operated between 97% to 100%. The rotor (Nr) may be operated between 90% and 100%.

See also: Flight, Power, Aircraft, Speed, Landing