weather & aeromedical Flashcards
AIRMETS
hazardous for limited capability aircraft, valid for 6 hours, could be regarding turbulence, moderate icing, mountain obscurations
SIGMETS
significant meteorological conditions for ALL aircraft, valid for maximum of 4 hours, could be regarding severe icing, severe or extreme CAT (not. associated with thunderstorms), dust/sand storms
Convective SIGMET
convective weather significant to ALL aircraft. valid for 2 hours, could be regarding severe thunderstorms, tornadoes, etc.
METAR and TAF
Both are weather sources. TAF is the only forecast source (4x/day every 6 hours). METAR and TAF are NOT broadcasted on a frequency. Both cover 5 sm/nm around airport area.
ATIS, AWOS, ASOS
ATIS: towered airports only, broadcasted every hour, letter code, very comprehensive
ASOS: tow./non-tow. airports, broadcasted every minute, more comprehensive
AWOS: tow./non-tow. airports, broadcasted every minute, less comprehensive
three ingredients of thunderstorms
moisture, unstable air, uplifting force (i.e. a cold front)
three stages of thunderstorms
cumulus: lifting action of air begins
mature: precipitation, big updrafts and downdrafts, all hazards are at the greatest intensity
dissipating: strong downdrafts, cell dies rapidly
when does fog occur
when temperature = dew point
can happen by:
- temperature cools to its dew point
- dew point is raised to meet temperature (by added moisture)
types of fog (radiation, advection, upslope, steam)
radiation: nighttime causes ground to cool down to its dew point, occurs on calm clear cool night
advection: warm moist air pushed by wind over cooler ground surface
upslope: moist air is force upslope and cooled
steam fog: air temperature over water cools faster than the water temperature… great lakes
supercooled droplets
water droplets existing as liquid in temperatures below freezing (between 0 and -15 deg. cel.)
types of structural icing
clear: LARGE supercooled droplets of water, heavy, forms as a clear sheet of solid ice, occurs between 0 and -10 deg. cel.
rime: SMALL supercooled droplet of water, white and rough, occurs below -10 deg. cel.
mixed: both clear and rime
other types of icing (carburetor, instrument, intake)
carburetor: cooling effect of venturi causes ice to form in carburetor, forms in high humidity (>80%) and temps -7 to 21 deg. cel.
instrument: icing on instruments i.e. pitot-static, OAT gauge
intake ice: ice in the intake of an engine preventing air from flowing, reduces RPM
frost
both temp. and dew point are below freezing, can obscure windshield and antennas, increases stall speed, reduce lift, MUST be removed before flight
hypoxia
cause: insufficient supply of oxygen
remedy: breathe oxygen (time of useful consciousness decreases with altitude)
symptoms: fatigue, CYANOSIS
hyperventilation
cause: excessive amount of CO2 is removed from the body due to heavy breathing
remedy: breath into a brown paper bag
symptoms: similar to hypoxia but NO cyanosis