Document ID: chunk:federal_register_of_legislation:F2025C00050:body:0:p313
Version: federal_register_of_legislation:F2025C00050
Segment Type: other
Provision Reference: 
Character Range: 1089949–1094334

conditional instability;
(iv)          stability changes caused by:
(A)          radiation;
(B)          turbulence;
(C)          convection;
(D)          advection;
(E)          subsidence;
(F)           convergence;
(G)          divergence;
(H)          precipitation.
2.1.3              Humidity:
(a)           water vapour in the atmosphere;
(b)           vapour pressure, effect on density;
(c)           dry/wet bulb temperature:
(i)             dewpoint;
(ii)            relative humidity.
2.2                    Clouds and precipitation
2.2.1              Cloud:
(a)           types of cloud and level at which found:
(i)             stratus;
(ii)            cumulus;
(iii)          cirrus;
(b)           variations of basic types:
(i)             strato-;
(ii)            cumulo-;
(iii)          nimbo-;
(iv)          alto-;
(c)           hazards (if any) presented by different types.
2.2.2              Formation of cloud:
(a)           methods/mechanisms by which clouds form;
(b)           conditions favourable to formation:
(i)             atmospheric;
(ii)            topographic.
2.2.3              Precipitation:
(a)           cause of precipitation;
(b)           types:
(i)             drizzle, rain, snow, hail;
(ii)            distinction between showers and rain;
(c)           characteristics of precipitation:
(i)             orographic;
(ii)            frontal;
(iii)          showers;
(d)           hazards presented by precipitation:
(i)             reduced visibility (for example, landing);
(ii)            icing;
(iii)          radar masking (water layer on radome);
(iv)          weight and impact (severe rain on large aircraft).
2.2.4              Thunderstorms:
(a)           development of a single cell:
(i)             prerequisite conditions;
(ii)            stages of development;
(iii)          structure of mature cell;
(b)           hazards presented by a thunderstorm:
(i)             down-draught (near ground);
(ii)            turbulence;
(iii)          icing;
(iv)          lightning;
(c)           flight in or near thunderstorms:
(i)             hazards in flight close to thunderstorms:
(ii)            optimum flight paths/flight levels if penetration of a thunderstorm is necessary.
2.3                    Motion of the atmosphere
2.3.1              Wind and pressure:
(a)           relationship between isobars and wind:
(i)             Buys Ballot's Law;
(b)           primary cause of wind:
(i)             pressure gradient;
(ii)            coriolis force;
(iii)          gradient wind;
(iv)          convergence and divergence;
(c)           diurnal variation of wind;
(d)           turbulence and gustiness:
(i)             factors affecting turbulence;
(ii)            effect of turbulence on lapse rate.
2.3.2              Local winds:
(a)           land and sea breezes;
(b)           anabatic, katabatic and fohn winds;
(c)           low-level jet.
2.3.3              Mountain effects:
(a)           standing waves, rotors;
(b)           conditions favourable to development;
(c)           hazards presented by mountain effects.
2.3.4              Microbursts:
(a)           structure of a microburst;
(b)           meteorological conditions conducive to microburst formation;
(c)           visual identifying features;
(d)           hazards presented by microbursts:
(i)             windshear;
(ii)            effect on IAS and groundspeed;
(iii)          sink rate;
(iv)          turbulence;
(e)           windshear reporting procedures.
2.3.5              Variation of wind with height:
(a)           general/common characteristics:
(i)             loss of mechanical turbulence;
(ii)            tends to increase speed;
(iii)          tends westerly;
(b)           elementary knowledge of contour charts.
2.4                    Visibility
2.4.1              Measurement of visibility:
(a)           brief outline of difficulties:
(i)             practical measurement of visibility;
(ii)            visibility versus RVR;
(iii)          visibility at night;
(b)           reduced visibility:
(i)             distinction between fog, mist and haze;
(c)           hazards presented by reduced visibility:
(i)             in flight;
(ii)            on take-off or landing;
(iii)          unseen obstacles on runway;
(iv)          directional control, especially asymmetric roll control;
(v)           obstacle avoidance if