Standard Conditions and Density Altitude
density altitude measures
air density
convective currents
The amount of moisture present in the air is dependent
of the
temperature
Usually forms in sheltered valleys, with little to know wind, near bodies of water
radiation fog
is an observation of current surface weather
reported in a standard international format
METAR
AGL stands for
above ground level
where updrafts occur
over sand, rock, plowed ground
this doubles the amount of moisture the air CAN hold
increase/decrease in air temp by 20 degrees
common in coastal areas, where sea breezes
blow moist air over cooler land & when air masses move inland from the coast
advection fog
METARs are issued (how often)
hourly
true altitude is
the altitude above sea level (MSL)
an increase in temperature as altitude is increased
temperature inversion
Amount of water vapor present in the atmosphere at a
given time
Relative Humidity
when moist, stable air is forced up sloping land
upslope fog
BR
mist
high density altitude's impact on perfomance
negative
a change in wind speed and / or
direction over a short distance
wind shear
the temperature in which the air can hold no more moisture
dew point
over bodies of water during the coldest
time of year
steam fog
18004kt
180 degrees
4 knots
standard conditions at sea level
- Temperature: 15°C (59°F)
- Air pressure: 29.92 inches of mercury (1,013 millibars)
Microburst
- Typically occurs in a space
of less than one mile horizontally and
within 1,000 feet vertically for about
15 minutes
- Can produce severe downdrafts of up to
6,000 ft per minute (fpm)
- Can also produce a hazardous wind
direction change of 45 degrees or more,
in a matter of seconds
spoils the smooth flow of air over the propellers or wings
frost
Flying in an environment with relative humidity readings of _______ & _______% would decrease performance of your aircraft
75 & 90
RAB35
ran began 35 minutes past the hour