12.100.8. Explain how to determine pressure altitude by using an altimeter.

Set to 1013 hPa on the subscale and read it off directly

12.100.6. Calculate aerodrome pressure altitude, given aerodrome elevation and prevailingQNH. 

Find the difference between QNH and the ISA MSL pressure of 1013hPa
This is converted to feet by multiplying x 30
and the correction so obtained is subtracted from or added to the actual altitude
If QNH is higher than 1013 – subtract and if lower than 1013 then add

12.100.4. Define pressure altitude.

Pressure Altitude
This is the altitude in the theoretical ISA which has the same pressure as the real altitude with which we are concerned

12.100.2. Describe the general effects of altitude on aircraft performance.

One of the most important determinants on performance of the aircraft
As air density decreases with altitude both aerodynamic and engine performance decrease.

12.76. Control Systems

12.76.6. Describe the normal operational use of flaps, including limitations.Performance Sub Topic Syllabus Item 

A small amount of flap is often used for take-off
– increases lifting ability of the wing
– little cost in additional drag

A larger amount of flap is used on approach and during landing
– lowered stalling speed and additional drag
– allows a slower airspeed and steeper fllightpath

Lower ing flaps in a low-wing aircraft can cause a nose down pitch
Lowering flaps in a high-wing aircraft can cause a nose-up pitch

12.76.4. Describe the function of control locks and precautions for removal before flight.

Control locks

12.76.2(c) . flap systems. 

12.76.2(b) . trim tab; 

12.76.2(a) . primary flight controls;