November 2019 – June-Young Lee

Inflight weather advisories

Posted on November 14, 2019November 14, 2019 by JYLEE in Flight Diary

There are 5 in-flight weather advisories that are forecast based on actual weather conditions.

1. Convective sigmet [WST]

advises of weather that is convective in nature and is issued for every thunderstorms with hail greater than 3/4“, surface winds greater than 50 knots
tornadoes, embedded thunderstorms, lines of thunderstorms
thunderstorm producing precipitation
Convective sigmet also implies severe turbulence, icing, and low-level wind shear
valid for 2 hours

2. Sigmet [WS]

advises of non-convective weather that is potentially hazardous to all aircrafts
issued for severe turbulence and icing not associated with convective activity, dust storms and sand storms reducing visibility below 3SM, and volcanic ash
valid for 4 hours

3. Airmet [WA]

advises of weather that is lower in intensity
valid for 6 hours
there are 3 types of Airmet

Sierra – IFR or mountain obscurations.
Tango – moderate turbulence, sustained surface wind of 30 knots or greater, and non-convective low-level wind shear.
Zulu – moderate icing.

4. CWA(Center Weather Advisories)

is issued on an unscheduled basis as supplementary information to an existing WA, WS, or WST
valid for 2 hours

5. WW(Severe Weather Watch Bulletins) / AWW(Alert Weather Watch Bulletins)

issued in areas of severe thunderstorm or tornado activity
severe activity is defined by greater than 3/4“ hail, wind gusts greater than 50 knots
a tornado watch defines an area where possible tornado activity exists

Fog

Posted on November 14, 2019November 14, 2019 by JYLEE in Flight Diary

Definition

a cloud that is on the surface
usually occurs when the temperature of air near the ground is cooled to the air’s dew point

Types of fogs

**Radiation fog**, *image from PHAK 12-21*

Radiation fog : On clear nights, with little to no wind, radiation fog develops. It usually forms in mountain valley. It occurs when the ground cools rapidly due to terrestrial radiation, and the surrounding air temperature reaches its dew point.
Advection fog : When a layer of warm, moist air moves over a cold surface, advection fog occurs. Wind(up to 15knot) is required to form advection fog. It is common in coastal areas where sea breezes can blow the air over cooler landmasses.
Upslope fog : When moist, stable air is forced up sloping land features like a mountain range, upslope fog occurs. Wind is required to form it.
Steam fog : When cold, dry air moves over warm water, steam fog occurs. Steam fog is common over bodies of water during the coldest times of the years.
Ice fog : When the temperature s much below freezing and water vapor forms directly into ice crystals in cold weather, Ice fog occurs.

Microburst

Posted on November 14, 2019November 14, 2019 by JYLEE in Flight Diary

Defnition

a small-scale, intense downdraft that spreads outward in all directions from the downdraft center when reaching the surface

**Effects of microburst wind**, *image from PHAK 12-17*

Characteristics

especially dangerous during landing if the pilot has reduced power and lowered the nose in response to the headwind shear
leaves the aircraft in a nose-low, power-low configuration when the tailwind shear occurs, which makes recovery more difficult
can cause the airplane to stall or land short of the runway

Thunderstorm

Posted on November 14, 2019November 14, 2019 by JYLEE in Flight Diary

Definition

a local storm, always produced by a cumulonimbus cloud, and always accompanied by lightning and thunder, usually with strong gusts of wind, heavy rain, and sometimes with hail.

How to develop

Unstable air, high moisture, and uplifting force are all required for thunderstorm to form

3 stages of thunderstorm

**Life cycle of thunderstorms**, *image from PHAK 12-28*

Cumulus is marked by a large billowing clouds with extensive vertical development, which is caused by updrafts from surface heating, terrain, pressure system or fronts
Mature is marked by the beginning of rain at the surface. During this stage, updrafts are at their maximum and extreme vertical shearing occurs between the updrafts and the cooler downdrafts following the precipitation
Dissipating is marked by downdrafts. The cool downdrafts eventually terminate the uplifting forces. When the downdrafts end and the rain has stopped, this signifies the end of the dissipating stage

If a radar indicates thunderstorm activity, pilots should avoid the cells by at least 20 miles.

Two different categories

Airmass TS is generally caused by surface heating (at desert or sea)
Steady state TS is associated with weather systems and frontal movement

Three principal types

Single cell (=ordinary cell thunderstorms) consists of only one cell. It easily circumnavigated by pilots except at night or when embedded in other clouds. Single cell thunderstorms are rare. Almost all thunderstorms are multi-celled.
Multicell cluster and line consists of a cluster of cells at different stages of their life cycles. As the first cell matures, it is carried downwind, and a new cell forms upwind to take its place. A multicell may have a lifetime of several hours (or more), which makes it tougher to circumnavigate than a single-cell thunderstorm. May have supercells embedded within them.
Supercell consists primarily of a single, quasi-steady rotating updraft that persists for an extended period of time. Updraft speeds may reach 9,000 fpm (100 knots). They may persist for many hours (or longer) and their size and persistence make them tough to circumnavigate.

Hyperventilation

Posted on November 14, 2019November 14, 2019 by JYLEE in Flight Diary

Definition

a state of carbon dioxide deficiency caused by an excessive breathing rate due to stress, fear, anxiety in flight.

Symptoms

Visual impairment
Unconsciousness
Light-headed or dizzy sensation
Tingling sensation
Hot and clod sensation
Muscle spasms

Treatment

descend to a lower altitude or use supplemental oxygen first because the symptoms of hypoxia and hyperventilation are similar
breathing into a paper bag, breathing normally, talking aloud
land at the nearest airport and seek medical help

Common symptoms of hypoxia and hyperventilation

drowsiness
headache
visual impairment
unconsciousness

Hypoxia

Posted on November 14, 2019November 14, 2019 by JYLEE in Flight Diary

Definition

a state of oxygen deficiency in the body
reduced barometric pressure(higher altitude) reduces the concentration of oxygen in each breath
medication, carbon monoxide, anemia, extreme hot&cold, fever, drugs, alcohol and anxiety increase the body’s need for oxygen
if we do not get sufficient oxygen, symptoms occur, followed by unconsciousness before die

Symptoms

Cyanosis
Headache
Euphoria
Drowsiness
Decreases reaction time
Impaired judgement
Visual impairment

Treatment

fly at lower altitude
use the supplemental oxygen
land at the nearest airport
seek medical help

Four types of Hypoxia

Hypoxic hypoxia – inadequate supply of oxygen to the body.
Hypemic hypoxia – inability of blood to carry oxygen(smoking )
Stagnant hypoxia – inadequate circulation of oxygen(cold temp)
Histotoxic hypoxia – Inability of the cells to use oxygen effectively (alcohol)

Special Use Airspace

Posted on November 14, 2019 by JYLEE in Flight Diary

Warning area

depicted with a blue border
warns non-participating aircraft of unusual hazards
starts at 3NM off the coast and extends outward to at least 12 NM off the coastal area
pilots must exercise extreme caution

Alert area

depicted with a magenta border
denotes an area having a high concentration of military student training
pilots must exercise extreme caution

Restricted area

depicted with a blue border
denotes an area having unusual and invisible hazards to aircraft such as artillery firing, aerial gunnery, or guided missiles
pilots must get a clearance from ATC(controlling agency, using agency) prior to entering

MOA(Military Operations Area)

depicted with a magenta border
separates an area containing military activities from IFR traffic
VFR pilots must exercise extreme caution
IFR pilots must get a clearance before entering

Prohibited area

depicted with a blue border
contains airspace where flight is prohibited
established for security or national welfare

Controlled firing area

not depicted
do not cause non-participating aircraft to change their flight paths
when a spotter aircraft, radar, or ground personnel determines and aircraft might be approaching the area, the activities are discontinued

Airspace

Posted on November 14, 2019November 14, 2019 by JYLEE in Flight Diary

Class A

Dimension : FL180-FL600 including airspace over the waters within 12 nm of coast of the 48 states and Alaska.
Equipment : mode C, two-way radio, IFR equipment.
Entry requirement : ATC clearance, IFR plan, Instrument Rating
Wx minimum : N/A

Class B

Dimension : It is indivisually tailored for each airport. (usually 10,000’msl)
Consists of usually 3 stages like upside down wedding cake.(not exceed 30nm radius)
Equipment : mode C, two-way radio
Entry requirement : ATC clearance, PPL(STUDENT PILOT W/T INDORSEMENT)
Wx minimum : Vis 3sm, COC

Class C

Dimension : It is individually tailored for each airport.
usually core area is up to 4000’AGL with 5nm radius. and shelf area is from 1200’ to 4000’AGL with 10nm radius
Equipment : mode C, two-way radio ( if mode C x, permission is needed)
Entry requirement : two-way radio communication, student pilot
Wx minimum : Vis 3sm 152

Class D

Dimension : It is usually up to 2,500’AGL with 4nm radius of circle
Equipment : two-way radio
Entry requirement : student pilot, two-way radio communication
Wx minimum : Vis 3sm, 152

Class E

Dimension : controlled airspace that is not designated as class A,B,C,D
Equipment : N/A
Entry requirement : N/A
Wx minimum : Vis 3sm 152 (below 10,000’msl), Vis 5sm 111 (above 10,000’msl)

Class G

Dimension : uncontrolled airspace located anywhere that class A,B,C,D,E has been not designated
Equipment : N/A
Entry requirement : N/A
Wx minimum : below 1,200’AGL = 1sm, COC (DAY), 3sm 152 (NIGHT) above 1,200‘AGL = 1sm, 152 (DAY), 3sm 152 (NIGHT) / above 10,000’MSL = 5sm, 111