Number Two Engine
In the context of aircraft, "Number Two Engine" refers to the engine positioned to the right of the pilot's view, or the second engine from the left when facing the aircraft.
Engine Numbering
Aircraft engines are numbered starting from the left side of the pilot's view, with the engine farthest to the left being "Number One".
Pilot's Perspective
This numbering system is based on the pilot's perspective while seated and looking forward.
Example
If an aircraft has four engines, the engine next to the "Number One" engine on the right would be "Number Two", and the engines further to the right would be "Number Three" and "Number Four".
Why Start Engine 2 First?
Some aircraft procedures involve starting the right engine (Engine 2) first, as it powers the yellow hydraulic system, which is essential for parking brakes and steering during taxiing, and also powers an important transformer-rectifier unit. This reduces the risk of fire or damage to ground personnel or equipment near the left side of the aircraft.
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