Task C - Weather Information (Chap 12&13 PHAK) Flashcards
What is an FSS? What does it do?
Flight Service Station (FSS) (PHAK 13-4/13-9
* Primary source for preflight weather information.
* Call 1800-WX-BRIEF (FSS)
* Provides also provides inflight weather briefing services
* www.aviationweather.gov
* www.1800wxbrief.com
What is the difference between an Outlook, Standard, and Abbreviated Weather Outlook?
-Outlook briefing- 6 hours or more away, forecast.
-Standard briefing- provides the most complete information and more complete weather picture. Get it before departure. No more than 5 hours in advance.
-Abbreviated briefing- a shortened version of the standard briefing. Updates on the previous briefing
What is a TAF? What is the radius and valid period?
- TAF- terminal aerodrome forecast. Established for the 5 statute mile radius around larger airports. It is valid between 24-30 hour period. Updated 4 times a day, every 6 hours.
How long is an AIRMET valid for?
6 Hours
What is an AIRMET?
Hazardous weather, moderate in intensity that affects all aircraft.
What are the three different identifiers with an AIRMET? And describe what each one is.
-TANGO- turbulence, surface winds greater than 30 knots, low-level wind shear
-SIERRA- IFR conditions, mountain obscuration
-ZULU- Icing, freezing levels
What is a SIGMET?
Hazardous weather, severe to extreme in intensity that affects all aircraft
How long is a SIGMET valid for?
Valid for 4 hours unless it relates to a hurricane, it’s valid for 6 hours.
What is a Convective SIGMET?
- Severe thunders with surface winds greater than 50 knots
- Hail at the surface greater or equal to 3/4 inch in diameter
- Tornados
- Squall lines
- Thunderstorms with heavy or greater precipitation that affect 40% or more of a 3,000 square mile or greater region.
How long is a Convective SIGMET valid for?
2 Hours
What is a METAR?
An observation of current surface weather reported in a standard
international format. They are issued on a regularly scheduled basis unless significant weather changes have occurred. Then a special (SPECI) meter can be issued anytime between routine meter reports.
What is a PIREP?
Pilot weather reports. Provide valuable information regarding the
conditions as they exist in the air which cannot be gathered from any other source. Can confirm the weather, or tell about unforecasted weather
What is the weather delay on the MFD?
15 to 20 minutes
What are the percentages of gas that make up the atmosphere?
78% Nitrogen
21% Oxygen
1% Trace Gases
How much water vapor is in the air?
0-5%
What are the levels of the atmosphere?
Troposphere
Stratosphere
Mesosphere
Thermosphere
What is the standard lapse rate?
2 Degrees Celsius every 1000ft
How far does the Troposphere extend up to?
Around 20,000 ft.
How much does the pressure decrease per 1000ft altitude gain?
1 inch
What two layers have the most influence on weather?
Troposphere and Stratosphere
How far does the Stratosphere extend up to?
160,000ft
What is the definition of stability?
The air’s ability to resist vertical motion
What causes instability in the atmosphere?
Vertical air movements
What can instability in air lead to?
Significant turbulence, clouds with vertical development, and severe weather
What causes weather changes?
Currents and winds of atmospheric circulation
How does air flow?
High-pressure to low pressure
What are some examples of uneven heating at GMU?
385, the golf course, the patch of grass prior to 19, Lauren’s Road
What are some examples of obstruction of wind?
Large buildings, hangars, mountains, canyons can break up the flow of the wind and create wind gusts that changes rapidly in direction and speed