Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ATPL - BGS [Mod 1] Meteorology > 13. Microbursts and Standing Waves > Flashcards

13. Microbursts and Standing Waves Flashcards

1
Q

Microbursts and Standing Waves

“An extreme form of windshear generated by the slug of descending air that comes from a thunderstorm cell”

This is the definition of what

A

MICROBURST

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Microbursts and Standing Waves

Downdrafts generated by the slu of descending air from a thunderstorm cell, known as microbursts;

  1. average around ____ to ____ fpm
  2. When hitting the ground can flow out at ____kts
  3. The vector change over a short distance in surface wind can be ____kts
A
  1. 3000 to 4000 fpm
  2. 50 KTS
  3. 100 KTS

  • Have been measured at 6000 fpm

MICROBURST

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Microbursts and Standing Waves

Refer to the following diagram

  1. At point A, the headwind is inceasing radpily to 50 kts. IAS has INCREASED or DECREASED.
  2. As a result, the aircraft will go HIGH or LOW on the glidepath
  3. The pilot will INCREASE or DECREASE power and INCREASE or DECREASE flaps to compensate
  4. As the above changes take effect, the aircraft reaches point B. The headwind will rapidly INCREASE or DECREASE
  5. IAS will INCREASE or DECREASE
  6. The aircraft will will go HIGH or LOW on the glidepath
  7. At point C, IAS is INCREASING or DECREASING
  8. The pilot will be INCREASING or DECREASING power
A
  1. INCREASED
  2. HIGH
  3. INCREASE & INCREASE
  4. DECREASE
  5. DECREASE
  6. LOW
  7. DECREASING
  8. INCREASING

  • As the aircraft approaches and the headwind increase significantly by 50 kts, the IAS will significantly increase
  • The pilot compensates by reducing power and increasing flaps
  • Just as this takes effect, the downdraft pushes the plane down and the headwind drops off rapidly
  • As IAS decreases significantly, the pilot will apply thrust
  • Just as the aircraft passes through point B to point C, a rapid tailwind will pick up
  • There is an ongoing rapid drop off of IAS, the pilot is increasing power as a result of the drop off at point B, and the aircraft is given a significant push by tailwind
  • The aircraft will now start to fly high on the glidepath

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Microbursts and Standing Waves

A ____ microsburts is more intense than a ____ microburst

WET/DRY

A
  1. DRY
  2. WET

DRY > wet

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Microbursts and Standing Waves

Downbursts that occur at medium altitudes without reaching the surface are known as what

A

MIDAIR DOWNBURST

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Microbursts and Standing Waves

  1. Microbursts can be ____ to ____ km across
  2. They last for ____ minutes
A
  1. 1 to 4 KM
  2. ONLY A FEW MINUTES

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Microbursts and Standing Waves

  1. Downbursts that span greater than 4km are known as what
  2. Macrobursts last for ____minutes
  3. Macrobursts produce wind speeds in excess of ____kts
A
  1. MACROBURSTS
  2. 30 MIN
  3. 120 KTS

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Microbursts and Standing Waves

There are 2 principal systems used to give warnings of microsbursts at airfields, these are;

[ ] ATC visual checks
[ ] LLWAS
[ ] Low Frequency Doppler Radar
[ ] High Frequency Doppler Radar
[ ] Weather Balloon (radiosonde)

A

[ ] ATC visual checks
[X] LLWAS
[X] Low Frequency Doppler Radar
[ ] High Frequency Doppler Radar
[ ] Weather Balloon (radiosonde)

  • LLWAS - Low Level Windshear Alert System

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Microbursts and Standing Waves

Tornades can exhibit wind speeds that exceed;

[ ] 200 KTS
[ ] 250 KTS
[ ] 300 KTS
[ ] 400 KTS

A

[X] 200 KTS
[ ] 250 KTS
[ ] 300 KTS
[ ] 400 KTS

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Microbursts and Standing Waves

It is known that surface wind is slower than freestream wind (freestream wind conventionally called the 2000ft wind). and dependant on the hemisphere the wind will back or veer (Back in NH and Veer SH) towards the surface. Climbing or descending will take the aircraft through what sort of windshear

A

VERTICAL WINDSHEAR

  • This is not normally significant unless;
  • free-stream wind is very strong OR;
  • there is a temperature inversion present creating a very sharp boundary between airflow above and below inversion

VERTICAL WINDSHEAR

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Microbursts and Standing Waves

Which of the following are considered critical conditions that will indicate windshear or turbulence;

[ ] Cool calm conditions
[ ] Free-stream wind 40 KTS
[ ] Vector difference between surface and free stream wind of 40+ KTS
[ ] Temperature inversion of 10 or more
[ ] Costal breeze
[ ] Fog

A

[ ] Cool calm conditions
[X] Free-stream wind 40 KTS
[X] Vector difference between surface and free stream wind of 40+ KTS
[X] Temperature inversion of 10 or more
[ ] Costal breeze
[ ] Fog

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Microbursts and Standing Waves

The conditions required for the production of standing waves (aka mountain waves or lee waves) are;

  1. A wind of ____kts or more over a small mountain
  2. A wind of ____kts or more over a large mountain
  3. Wind speed INCREASING or DECREASING steadily with height up to the tropopause
  4. Wind direction CONSTANT or ERRATIC at the tropopause
  5. Wind direction within 30° or 50° of the perpendicular to the ridge line
  6. A STABLE or UNSTABLE air mass
A
  1. 15 KTS
  2. 30 KTS
  3. INCREASING
  4. CONSTANT
  5. 30°
  6. STABLE

  • Waves are generated when wind blows over the ridge (perpendicular) not along the ridge line (parallel)
  • If there is a very strong stabel layer i.e. inversion, at ridge height, this will create the strongest waves

LEE WAVES

5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Microbursts and Standing Waves

When the right conditions are met for lee waves to form over a mountain, the area of maximum tubulence typically occurs where

A

AROUND RIDGE HEIGHT ONE WAVELENGTH DOWNWIND

LEE WAVES

6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Microbursts and Standing Waves

  1. Flying with the wind over the ridge of a mountain is preferable to flying against the wind TRUE or FALSE
A

TRUE

  • Flying into wind means the aircraft is trying to climd to clear a ridge and fighting downdrafts

7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Microbursts and Standing Waves

  1. The name given to a cloud that looks like a vortex on the leeside of a mountain
  2. The name given to a cloud that looks like the concave of glasses formed on the leeside of a mountain
  3. The name given to a cloud that sits over the top of the mountain ridge
A
  1. ROTOR CLOUD
  2. LENTICULAR CLOUD
  3. CAP CLOUD

MOUNTAIN CLOUDS

7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Microbursts and Standing Waves

Turbulence behind hills, rotors and rotor streaming are confined only to when conditions are right for standing waves TRUE or FALSE

A

FALSE

  • These hazards can occur in any strong winds over hills. Standing waves does not have to be a prerequisit

7

17
Q

Microbursts and Standing Waves

Dependant on the size of the mountain and the windspeed, the wave effects for standing waves can persist as far as ____nm downwind

A

100 NM

8

18
Q

Microbursts and Standing Waves

The name given to turbulance created as a result of large aircraft on high angles of attack on take off or landing

A

WAKE TURBULENCE

9

19
Q

Microbursts and Standing Waves

Wake turbulence rotors move outwards at around ____kts. Turbulence is therefore most dangerous in LIGHT or MODERATE cross winds

A
  1. 5 KTS
  2. LIGHT

  • Light crosswinds are unable to dissipate the wake turblance
  • The wake turbulence pulls one of the wakes back onto the runway
20
Q

Microbursts and Standing Waves

The current ICAO regulation requiest ____min or ____NM clearance for heavy aircraft behind heavy aircraft on approach or departure to avoid wake turbulence

A
  1. 2 MIN
  2. 4 NM

9

21
Q

Microbursts and Standing Waves

Hazards associated with turbulence include;

[ ] Structural damage
[ ] Paint work scratching
[ ] Airspeed fluctuations
[ ] Excessive fuel consumption
[ ] G-loading - High altitude upset
[ ] G-loading - Low speed buffeting
[ ] Fire
[ ] Injury to persons

A

[X] Structural damage
[ ] Paint work scratching
[X] Airspeed fluctuations
[ ] Excessive fuel consumption
[X] G-loading - High altitude upset
[X] G-loading - Low speed buffeting
[ ] Fire
[X] Injury to persons

10

22
Q

Microbursts and Standing Waves

What is the most reliable source of information relating to turbulance;

[ ] METAR
[ ] PIREP
[ ] AIRMET
[ ] VOLMET

A

[ ] METAR
[X] PIREP
[ ] AIRMET
[ ] VOLMET

  • PIREP is a pilot report
  • Pilot reports of turbulence are a very valuable source of information
  • Other turbulence forecasting methods are not very reliable

11

23
Q

Microbursts and Standing Waves

What is the difference between a SIGMET and AIRMET

A

AIRMET - less significant weather advisory
SIGMET - Very significant weather advisory

SIGMET v AIRMET

11

24
Q

Microbursts and Standing Waves

The name of the radar system that can measure position and relative velocity of aerosols and can be used to detect turbulence, in particular can be used to detect CAT

A

LIGHT DETECTION AND RANGING
(LIDAR)

11

ATPL - BGS [Mod 1] Meteorology (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions