A halo around the moon

Warm front approaching - Lowering of cloud base - Cirrus, cirrostratus, altostratus, nimbostratus - Surface wind backing.

Stalled Wing

When the airflow is no longer moving over the top surface of the wing.2/3 lift has gone.

V.M.C below 3,000ft A.M.S.L

Airspace Class G. Clear of cloud, in sight of the ground, Flight visibility 1500 meters.

Q.N.H, Q.F.E

Questionble Nautical Height - Questionble field elevations

Cold Front

Clouds Cumulonimbus, cumulus, cu-nimbus. Drop in temp, wind veer, fall in pressure to rise once front has past.

CAVOK

Ceiling and Visibility Ok, no cloud at all below 5000 feet and vis greater than 10km (6 miles)

AIAA

Area of Intense Aerial Activity. These are marked on a chart as as a blue line made up of diamond shapes, there will also be an indication of its name and altitude restrictions. As paraglider pilots we can fly in these areas but an even better look out is required than normal as you should expect other aircraft to be around.

D306/10.0

Danger area, with designation 306 upto an altitude of 10,000 feet AMSL

MATZ dimensions

Military Aerodrome Traffic Zone: 3000feet up 5nautical miles radius plus 5nm long runway 4nm wide.

LOW PRESSURE

Rotates anti clockwise in the northern hemishere.

HIGH PRESSURE

Rotates clockwise in the northern hemishere.

Buys Ballots Law

Buys Ballot's law states that, in the Northern Hemisphere, if a person stands with his back to the wind, the atmospheric pressure is low to the left and high to the right. In the Southern Hemisphere, it is reversed.

Wind Veers.

When Surface winds turn clockwise.

ICAO Barometric pressure 0 km MSL

1013.25

Air Maps coloured Blue

Are for civil use.

Air maps with symbols coloured Magenta

Are used by Goverment

Cold Front

Clouds Cumulonimbus, cumulus, cu-nimbus. Drop in temp, wind veer, fall in pressure to rise once front has past.

CAVOK

Ceiling and Visibility Ok, no cloud at all below 5000 feet and vis greater than 10km (6 miles)

VMC ABOVE 3,000FT

When above 3,000ft or 1,000ft above terrain, whichever is higher: 1500m horizontally and 1,000 ft vertically from cloud; Flight visibility 5km below 10,000ft and 8km above 10,000 ft.

ACTIVE COLD FRONT

Stratus cumulus - cumulonimbus

APPROACHING WARM FRONT

C.A.N Cirrus - altostratus - Nimbostratus - Surface wind backing - Night before Halo around the moon and or Sun.

LOW PRESSURE

Rotates anti clockwise in the northern hemishere.

Air Flow

An areofoil shaped wing has 2/3 on top of the wing. This is known as Low pressure.

Bernoulli priceiple

Liquid passed through a ventuiri tube would increase the flow and reduce the pressure. Same as a areofoil wing. As of 2021 this idea has been challenged.