JX104 T-Storms

Question 1

List the 3 requirements for t-storm development

Answer 1

Moisture, Unstable Air, Lifting Action

Question 2

What is the point called when lifted air continuous to rise freely (ie the cumulus cloud grow rapidly, forming into cumulonimbus clouds)

Answer 2

Level of free convection

Question 3

Describe the effects of turbulence

Answer 3

Can cause changes in altitude, can cause structural damage, extra stress on the airframe, and the effect depends on severity of turbulence and speed of aircraft

Question 4

What is a gust front?

Answer 4

Forms on the surface at the leading edge of an advancing t-storm

Question 5

Describe Roll and Wall Clouds

Answer 5

They are typically fast moving cold fronts that occur in severe fast moving t-storm; they indicate the presence of low level wind shear and extreme turbulence

Question 6

What are the characteristics of hail?

Answer 6

They circulate in updrafts and downdrafts; hailstones larger than 1/2 to 3/4 of an inch can cause significant damage to aircraft in a few seconds; has been encountered as high as 45,000 feet in clear air, and carried 10 to 20 miles downwind

Question 7

Describe lightning hazards

Answer 7

Static charge builds up in the aircraft while in the clouds; can strike a/c flying in the clear; structural damage is possible; catastrophic fuel ignition possible; pilots can experience flash blindness; static buildup sometimes released through St. Elmo’s fire (purple/blue lights)

Question 8

Name the tornado cloud types

Answer 8

Tornado touches ground; funnel cloud (not touching surface); waterspout (touches water surface)

Question 9

Define a Microburst

Answer 9

An intense, highly localized downward atmospheric flow with velocities of 2,000 to over 6,000 fpm; outflow produces wind shear of 20 to 200 knots

Question 10

Describe characteristics of microbursts

Answer 10

Small area (1/4 to 2.5 miles wide; short duration (lasts only 5-10 minutes); emanates from cumuliform cloud, not necessarily a t-storm

Question 11

Describe dry microbursts

Answer 11

Form when there are large temperature (dew point) spreads at the surface; rain evaporates as it descends (virga), which cools the air; colder air accelerates as it descends

Question 12

T/O during microburst

Answer 12

Edge of vortex ring produces wind blowing upward from ground; increase in HW causes IAS to jump upward rapidly; in center of downdraft, a/c descends, but soon enters other side of outflow; HW shifts to TW, IAS drops rapidly, causing stall

Question 13

LDG during microburst

Answer 13

Natural reaction to reduce power and re-est descent; removes power and wastes valuable time to get a/c away from ground before entering outflow; *MAX SPEED AND CLEAN

Question 14

What are visual cues of microbursts?

Answer 14

Virga, localized blowing dust, shaft of rain which diverges closer to ground, severe t-storms

Question 15

Define virga

Answer 15

Precip that evaporates before reaching the ground

Question 16

What are some ways to detect microbursts?

Answer 16

Doppler radar, low level shear alert systems, PIREPS, and Departure and Arrival Weather Reports

Question 17

Techniques for avoiding t-storm hazards

Answer 17

cirCUMnavigate, NEXRAD, airborne radar

Question 18

What is airborne radar used for?

Answer 18

Used to cirCUMnavigate and avoid scattered t-storms; not used for t-storm penetration (lol)

Question 19

T-storm Hazard Avoidance steps

Answer 19

CIRCUMNAVIGATE; Overtop (avoids most hazards; altitude margin for turbulence and hail, at yeast 1,000 feet higher for every 10 knots of wind speed at cloud top level), Underneath (not in the worst of hazards; altitude margin 1/3 distance from ground to cloud base…4,000-6,000AGL

Question 20

T-storm penetration procedures

Answer 20

Penetrate perpendicular to minimize storm; Penetrate storm below the freezing level (altitude wise, warmer air) or above the -15 C level (to avoid icing); Minimum altitude should be 4,000-6,000AGL above the highest terrain; Establish recommended turbulent air penetration airspeed; Expect deviations in altitude and attitude; disengage autopilot; Avoid abrupt control movements; Turn up cockpit lighting to prevent temporary blindness; Turn on pitot heat

Question 21

What do roll and wall clouds indicate?

Answer 21

The presence of low level wind shear and extreme turbulence

Question 22

A _____ front forms on the surface at the leading edge of an adv t-storm

Answer 22

Gust

Question 23

What methods can be used to detect a microburst?

Answer 23

Visual cues, wind shear alert systems, PIREPS, Departure/Arrival weather reports

Question 24

Why should you fly over the top, at least 1,000 feet per knots of wind speed at cloud top level, to avoid a t-storm?

Answer 24

Because it allows an altitude margin for turbulence and hail

Question 25

Why should you penetrate the lower 1/3 of a t-storm?

Answer 25

Because most storms are most severe in the top 2/3 of a cell

Question 26

What combination of atmospheric conditions is necessary for the formation of a t-storm

Answer 26

Moisture, Unstable Air, Lifting Action

Question 27

What effects can turbulence have on an a/c?

Answer 27

Changes in altitude, structural damage, extra stress on the airframe, effect depends on severity of turbulence and speed of a/c

Question 28

What hazards are associated with lightning?

Answer 28

Static charge builds up in the a/c, can strike a/c flying in the clear, structural damage, catastrophic fuel ignition, pilots can experience flash blindness

Question 29

Why should you penetrate a t-storm in a perpendicular manner?

Answer 29

To minimize time in the storm

Question 30

What hazards to flight are associated with t-storms?

Answer 30

Hail, turbulence, and lightning