A variable pitch propeller provides an optimum angle of attack for the propeller blades for a longer range which reduces fuel usage, fixed pitch propellers only have a certain rpm.

A Mach trimmer automatically compensates for Mach tuck above Mcrit.

Asymmetric Committal Altitude/Height is the minimum height needed to establish a positive climb whilst maintaining adequate speed for control and removal of drag during an approach to a landing.

In the Seneca at Oxford we used 200ft AGL. At this altitude when continuing for landing you selected the landing flaps (check clear runway, on speed, on altitude, landing clearance received).

You now are committed to land, single engine G/A with flaps 40 and gear down is not possible in a Seneca.

Mach number

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.

Fusible plugs offer protection from tire blowouts caused by thermal expansion that is generated in the tire under extra hard braking conditions.

20.020 litres (twenty thousand and twenty litres), about 15 tons.

When an aircraft climbs, the static pressure in the instrument case decreases, which allows the enclosed capsule to expand.

This in turn moves the needle on the instrument to indicate a corresponding altitude.

During descent, the opposite function applies.

Altimeter errors can originate and vary from:

Instrument Pressure Time-lag Barometric Density Temperature Blocked static port

Decreasing speed, by reducing engine power or pitching up.

Meridians converge from their maximum distance apart (at the equator) to the poles where they meet.

Great circles are the shortest distance between two points and convergency represents the change in direction experienced between those points.