Basic Empty Mass (BEM) is the mass of the aircraft with the basic equipment, unconsumable fluids and unusable fuel and oil.

25°

-15°C

because:

-2°C per 1000 feet gives -30°C.

ISA: 15°C at sea level - 30°C = -15°C at FL150

IRS / GPS / VOR / DME

Alternate air is....

N1= Low pressure compressor spool or fan rotation speed. Usually expressed as a % of Max N1.

N2= High pressure compressor rotation speed.

EGT= Exhaust gas temperature, indicates the temperature at the first stage of the turbine, which is the most critical temperature in the engine.

EPR= Engine pressure ratio of the inlet to the jet pipe, displayed on the EPR gauge to use as a parameter for setting engine thrust

The position of the CG directly influences the fuel consumption of an aircraft. An aft position of the CG makes the aircraft less stable, requiring less lift to be generated in both the horizontal stabilizer and wings, reducing the overall drag of the aircraft, and increasing the max range.

You want to load the the aircraft so that the CG is at, or as close as possible, to the aft limit (Without exceeding it).

A Mach trimmer automatically compensates for Mach tuck above Mcrit.

Yes, with the modern high bypass turbofans the N1 compressor works as a huge propeller, it takes a big mass of air and gives it a relative small acceleration.

Around 70% of the air will bypass the core of the engine, only 30% of air will be compressed further and will eventually go through the combustion chamber.

At the tip