May 18, 2006

Interactive Quiz #107:
SIGMET/AIRMET Savvy

Slam into a developing thunderstorm that shakes your dentures loose and you'll appreciate the significance of a good weather briefing. Or you can circumnavigate that learning step and test your severe weather planning skills here.

INSTRUCTIONS: Answer the questions as best you can, then click on the "Score my quiz answers" button to see your score and read the explanations. If you don't like your score the first time around, you can change some of your answers and resubmit. To get the most out of this quiz, we suggest you keep trying until you get a perfect score.

NOTE: When more than one answer is true, only the most complete, correct answer will be scored as correct. The answers are assumed to apply within the United States unless otherwise noted.

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1. First day on the job flying for hire. Shoes shined and deeply in debt, you force a smile when the dispatcher hands you enough briefing paperwork to put the airplane over gross. Not to worry; just look for key phrases in the weather data. One must-know term is SIGMET (WS), which stands for:

a. Significant Meteorological Conditions
b. Significant Meteorological Impact
c. Significant Meteorological Information
d. Significant Meteorological Forecast

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2. SIGMETs may have a convective quality to them, so are labeled -- you guessed it -- Convective SIGMETS (WST). Your flight today is from Mt. Rainever, Wash., to Caribou Innards, Alaska. Convective weather is a possibility just about anywhere, and even though Alaska is the closest thing to paradise this side of Terre Haute, you should check for Convective SIGMETs. The problem is, Convective SIGMETs are not issued for Alaska.
a. True
b. False

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3. Convective SIGMETs cover a wide range of aerial nastiness including severe thunderstorms. "Severe" isn't a casual term forecasters toss around the break room; instead, a thunderstorm meets the severe criteria for Convective SIGMET purposes when the surface winds are greater than or equal to (_____) knots, hail at the surface is greater than or equal to (_____) inch/inches in diameter or there's a tornado ripping through the Aviation Weather Center (AWC) parking lot in Kansas City. Please fill in the two blanks.
a. 35 knots; 1/2 inch
b. 55 knots; 1 inch
c. 60 knots; 2 inches
d. 50 knots; 3/4 inch

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4. While self-briefing on DUATS you read that Convective SIGMET 12C warns of thunderstorms roaming across the Iowa prairie, eating mobile homes and convincing you to arc around the storms by a wide margin or, perhaps, wait for the line of thunderstorms to pass over -- often the best choice. While waiting, you eat the last day-old doughnut in the FBO lounge and reread Convective SIGMET 12C. Suddenly, a new Convective SIGMET -- 13C -- is issued. What does the "C" in SIGMET 12C or 13C mean?
a. Center Weather Advisory
b. Central Daylight/Standard Time
c. Central United States
d. Charlie (alphabetic sequence)
e. Convective

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5. Convective SIGMETs go beyond warnings of severe thunderstorms or tornadoes and can be issued for embedded thunderstorms or lines of thunderstorms. Convective SIGMETs can also be issued when thunderstorms cover a large area. Fill in the blank to complete the AIM's (7-1-6) Convective SIGMET criteria for what constitutes a large area full of thunderstorms, worth of a Convective SIGMET: "Thunderstorms producing precipitation greater than or equal to heavy precipitation affecting (_____) percent or more of an area at least (_____) square miles."
a. 40 percent; 3,000 square miles
b. 50 percent; 4,000 square miles
c. 60 percent; 5,000 square miles
d. 70 percent; 7,000 square miles

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6. Refer to the picture below. It's mostly there to get your attention. IFR magazine's contributing editor Richard Coffey took it near Post, Texas (named for C.W. Post of Post Toasties fame -- no we're not making this up). Post is 50 nm southwest of Lubbock, home to the WWII Glider Pilots Association's Silent Wings Museum. You're viewing a snapshot of what happens when moist, Gulf air collides with dry air creating the ideal environment for severe weather, particularly in spring and summer. The line -- common in the High Plains -- is called a "dew point front" or:

a. Cold Front
b. Dry Line
c. Warm Front
d. Squall Line

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7. SIGMETs get all the glory -- what with the tornadoes and hail the size of Volkswagens -- leaving the modest AIRMETs (WAs) to be easily overlooked. AIRMETs, however, are included in any good briefing and -- like the beefier SIGMET -- advise pilots of significant weather. AIRMETs are divided into three categories for: 1) IFR conditions and/or extensive mountain obscurations; 2) moderate turbulence, sustained surface winds of 30 knots or greater, and/or non-convective, low-level wind shear; and 3) moderate icing and freezing level heights. How are these three AIRMET categories labeled?
a. AIRMET Alpha, AIRMET Bravo and AIRMET Charlie
b. AIRMET One, AIRMET Two and AIRMET Three
c. AIRMET C, AIRMET W and AIRMET E
d. AIRMET Sierra, AIRMET Tango and AIRMET Zulu

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8. An unscheduled, in-flight weather advisory issued by an Air Route Traffic Control Center (ARTCC) for developing weather that may affect the flow of air traffic (flow control) is called:
a. Center Weather Advisory (CWA)
b. Center Meteorological Advisory (CMA)
c. En Route Weather Advisory (EWA)
d. ATC En Route Weather Alert (AEWA)
e. Flow Control Advisory

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9. Enough violent weather. Let's put you solidly in the soup -- the clag, the scuddy low stuff -- where you can show off your instrument-scan technique to your passengers who, frankly, wouldn't know a proper scan from a can of Spam. Nonetheless, before you'll ever fly with us in Low IFR (LIFR), you'll need to identify the official AIM (7-1-7) definition of LIFR, please:
a. Ceiling less than 1,000 feet and/or visibility less than 3 miles.
b. Ceiling less than 500 feet and/or visibility less than 3 miles.
c. Ceiling less than 500 feet and/or visibility less than 1 mile.
d. Ceiling less than 1,500 feet and/or visibility less than 3 miles.
e. I've never heard of LIFR, I'm VFR-only!

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10. Not everyone flies IFR, but if you're going to restrict yourself to the VFR envelope, then you'll need to know what a Categorical Outlook means when it predicts Marginal VFR (MVFR). What is MVFR?
a. Ceiling 1,000 to 1,500 feet and/or visibility 1 to 3 miles inclusive.
b. Ceiling 1,000 to 1,500 feet and/or visibility 3 to 5 miles inclusive.
c. Ceiling 1,000 to 3,000 feet and/or visibility 3 to 5 miles inclusive.
d. Ceiling 1,500 to 3,000 feet and/or visibility 3 to 5 miles inclusive.

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