The track changes constantly.

30 minutes, I would land as soon as possible.

-15°C

because:

-2°C per 1000 feet gives -30°C.

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

Induced drag and its wing tip vortices are a direct consequence of the creation of lift by the wing.

Since the Coefficient of Lift is large when the Angle of Attack is large, induced drag is inversely proportional to the square of the speed whereas all other drag is directly proportional to the square of the speed.

The effect of this is that induced drag is relatively unimportant at high speed in the cruise and descent where it probably represents less than 10% of total drag. In the climb, it is more important representing at least 20% of total drag. At slow speeds just after take off and in the initial climb, it is of maximum importance and may produce as much as 70% of total drag.

Finally, when looking at the potential strength of wing tip vortices, all this theory on induced drag must be moderated by the effect of aircraft weight. Induced drag will always increase with aircraft weight.

Lift is the component of the total aerodynamic force perpendicular to the relative airflow.

Lift is generated when a streamlined body, such as an aerofoil, is placed in a flow of air.

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 angle between between the chord line and the aircraft's longitudinal axis. It's a fixed angle for wings, but variable for variable incidence tailplanes.

A swept wing makes the velocity vector normal to the leading edge a shorter distance than the chordwise resultant.

Advection fog occurs when moist air passes over a cool surface by advection (wind) and is cooled.

It is common as a warm front passes over an area with significant snowpack, but it is most common at sea when tropical air encounters cooler waters, including areas of cold water upwelling, such as along the coast of California.

Fuel, speed and holding entry.