Thunderstorm operation Flashcards by Khanh Nguyen

What are the most important hazards to aviation in thunderstorms?

Turbulence
Icing
Hail
Low ceiling and visibility
Effect on altimeters
Lightning
Engine water ingestion

These hazards can significantly affect flight safety and operations.

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What is the primary characteristic of turbulence within thunderstorms?

Potentially hazardous turbulence is present in all thunderstorms, particularly due to shear between updrafts and downdrafts.

Turbulence can also occur outside the cloud, several thousand feet above and laterally from a severe storm.

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What should a pilot do to minimize aircraft stress during turbulence in a thunderstorm?

Fly at a constant attitude rather than attempting to maintain a constant altitude or airspeed.

This reduces stress loads on the aircraft.

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What conditions can cause clear icing on an aircraft?

Supercooled water freezing on impact with the aircraft, especially between 0°C and -15°C.

Clear icing can occur at any altitude above the freezing level.

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What is the primary hazard of hail in thunderstorms?

Hail can grow large due to supercooled drops freezing and latching onto each other.

Large hail occurs with severe thunderstorms and can be encountered miles away from the storm core.

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What happens to visibility within a thunderstorm cloud?

Visibility is generally near zero.

This can increase hazards and restrictions when combined with other thunderstorm hazards.

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How does thunderstorm activity affect altimeter readings?

Pressure usually falls rapidly before a storm and may rise sharply during the storm, potentially causing errors of more than 100 feet.

This pressure change cycle can occur within 15 minutes.

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What precautions should be taken after a lightning strike on an aircraft?

Conduct an in-flight serviceability check of all radio communication and navigational equipment.

Also check the compass system on all four quadrantal headings after landing.

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What is a microburst and its potential impact on aircraft?

A microburst is a violent, short-lived descending column of air capable of producing horizontal winds exceeding 60 knots within 150 feet of the ground.

Microbursts can last one to five minutes and may not be detected by airport anemometers.

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What is the recommended lateral avoidance distance from thunderstorms at 25,000 feet?

15 NM.

This distance helps to avoid potential turbulence and hail.

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What is the recommended lateral avoidance distance from thunderstorms at 20,000 feet?

10 NM.

This distance helps to avoid potential turbulence and hail.

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What is the recommended lateral avoidance distance from thunderstorms at 30,000 feet?

20 NM.

This distance helps to avoid potential turbulence and hail.

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True or False: It is safe to fly under a thunderstorm if you can see through to the other side.

False.

Turbulence and wind shear under the storm could be disastrous.

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What should be done if significant thunderstorm activity is approaching within 15 NM of an airport?

Consider conducting departure or arrival from a different direction or delaying take-off or landing.

Use all available information for this judgment.

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What should pilots do if winds are reported as gusting winds of ≥ 25 knots during approach?

Cancel the approach or reject the landing.

This is especially critical during adverse weather conditions.

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Fill in the blank: The safest path when flying parallel to a line of thunderstorm cells is on the ______ side.

upwind

This reduces the risk of encountering strong drafts and hail.

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What should pilots do if thunderstorm penetration is unavoidable?

Use radar to determine areas of least precipitation and maintain a straight course through the storm.

Avoid turning maneuvers, which increase stress on the aircraft.

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What is the best practice regarding weather radar usage in relation to ATC guidance?

Use ATC guidance in conjunction with the aircraft’s own weather radar to guard against inaccuracies.

Discrepancies should be reported to ATC.

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What should be monitored closely when thunderstorms are present near the airport?

Landing conditions with the tower to decide whether to continue or initiate a missed approach.

Frequent checks are recommended due to changing weather conditions.

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What altitude error may be encountered in strong drafts?

1000 ft

This altitude error can affect flight safety and navigation accuracy.

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What type of instruments provide the only accurate flight instrument indications during penentrate a thunderstorm?

Gyro-stabilized instruments

Gyro-stabilized instruments are crucial for reliable flight data.

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What should be avoided near the 0°C isotherm?

Level flight

The 0°C isotherm is associated with severe turbulence and lightning strikes.

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At what altitudes is severe turbulence, hail, and icing conditions generally found?

Between 10000 ft and 20000 ft

Violent weather can occur at all levels inside and outside an active thunderstorm.

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What can massive water ingestion lead to in an aircraft?

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Engine flameout and/or structural failure

High concentrations of water can severely impact engine performance.

What should be minimized due to changes in thrust during severe conditions?

Changes in thrust ## Footnote Minimizing thrust changes can help maintain aircraft stability in turbulent conditions.

What is the best policy regarding thunderstorms during flight?

Avoiding thunderstorms

Should visual appearance be trusted as a reliable indicator of turbulence inside a thunderstorm?

What is the minimum distance to avoid severe thunderstorms identified by radar?

At least 20 NM

What action should be taken if the area has 6/10 thunderstorm coverage?

Circumnavigate the entire area

What does vivid and frequent lightning indicate?

Probability of a severe thunderstorm

What is considered extremely hazardous in terms of thunderstorm altitude?

Thunderstorm tops 35,000 feet or higher

What is forbidden when thunderstorms are operating in its mature stage within less than 5NM from each side of the flight path?

Departure and arrival ## Footnote This rule applies specifically during the mature stage of thunderstorms.

Under what visibility condition is take-off and landing allowed when thunderstorms are present at a distance of 5NM or greater?

Visibility is more than 2000m ## Footnote This applies when thunderstorms are operating at a distance of 5NM or greater from the flight path.

In which cases must the captain perform take-off and landing?

Conditions include: * X-Wind ≥ 15kts * Gusting > 10kts * Tail wind > 10kts or Tail wind ≥ 5 kts and RA * VIS ≤ 3000m with TSRA and Cross Wind ≥ 10kts (day time) * VIS ≤ 1500m with -RA (night time) * After the first Go-around

When must the flight crew cancel the approach or reject the landing during the daytime?

When VIS ≤ 1500m with TS/RA and Cross Wind ≥ 10kts ## Footnote TS/RA refers to Thunderstorm with Rain.

Under what conditions are approach and landing strictly prohibited?

Conditions include: * Reported ceiling or RVR or VIS is below minima * +TSRA or +RA, +SHRA present over the runway, along with: * either VIS < minima + 300m; * or RVR < minima + 100m ## Footnote RVR stands for Runway Visual Range.

What should the PIC do after a second go-around?

The PIC must: * Assess the prevailing weather conditions * Determine whether to proceed with another approach or divert to the designated alternate airport ## Footnote According to VNA SOP, diversion must be conducted after 2nd missed approach

What should crew do when weather is expected to worsen or a thunderstorm seems imminent?

Crew should frequently check the landing condition with Tower ## Footnote This is to decide whether to continue or to initiate the missed approach.

What is recommended for flight crews operating on wet or contaminated runways with tailwind?

Flight crews are recommended to: * Check aircraft tailwind limitation in AFM/FM * Check runway performance limitation * Full flaps setting is recommended (when landing)

Fill in the blank: Departure and arrival are forbidden when thunderstorms are operating in its mature stage within less than _____ from each side of the flight path.

5NM

What could be misleading under gust front conditions?

Tower-reported winds and the altimeter setting could be misleading.

What is the minimum altitude clearance to avoid overflying thunderstorms?

5000 ft clearance above the storm top

What is recommended when flying near a squall line?

Detour between the storm cells rather than directly above them

During an overflight of thunderstorms, how should the radar antenna be positioned?

Tilted down to properly assess the most severe cells

Why should the radar antenna be tilted down during overflight of thunderstorms?

To properly assess the most severe cells, which may be masked by clouds formations

What is the purpose of target turbulence speed?

Provide best protection against the effect of gust on structural limit ## Footnote Target turbulence speed helps in maintaining aircraft stability during turbulent conditions.

Can crew use manual thrust during turbulence?

Yes when thrust changes become excessive with autothrust ON. Except during approach, autothrust must be kept on ## Footnote Manual thrust can be necessary to manage excessive thrust demands in turbulent conditions.

How can you find the thrust setting equivalent to the turbulence penetration speed?

FCOM-PRO-ABN-MISC [QRH] Severe Turbulence ## Footnote This reference provides guidelines for pilots on managing thrust during severe turbulence.

What is the caution when using manual thrust during turbulence?

Only change thrust in case of extreme variation in airspeed, and do not chase MACH or airspeed

Can you determine the severity of a thunderstorm via its external visual appearance?

No ## Footnote Visual cues alone are insufficient for accurately assessing thunderstorm severity.

How many stages does a thunderstorm have in its life cycle?

3 stages: Initial, Mature, and Dissipating

How long does the initial stage of a thunderstorm last?

15-20 min ## Footnote This stage is characterized by strong updrafts without precipitation.

What are the characteristics of the initial stage of a thunderstorm?

No precipitation, only continuous and strong updrafts ## Footnote This stage sets the foundation for the development of the thunderstorm.

How long does the mature stage of a thunderstorm last?

20-30 min ## Footnote This stage is when the thunderstorm reaches its peak intensity.

What are the characteristics of the mature stage of a thunderstorm?

Heavy precipitation, both updrafts and downdraughts present, thunderstorm has the greatest intensity - phenomena such as lightning, hail, microbursts, roll clouds, and gust fronts are likely ## Footnote This stage is critical for pilots to be aware of due to its potential hazards.

What are the characteristics of the dissipating stage of a thunderstorm?

Precipitation, only downdraughts, external appearance is like of so-called 'anvil' at the top of CB cloud ## Footnote The dissipating stage indicates the thunderstorm is weakening.

What is the difference between CONF FULL and CONF 3 during turbulence?

CONF FULL provides better handling capability. CONF 3 provides more energy and less drag

What caution should be taken when crew flies aircraft manually during turbulence?

* May expect large variation in altitude, but should not chase altitude. * Should consider descending to or below OPT FL, to increase the buffet margin ## Footnote Maintaining attitude stability is crucial for safety during turbulence.

Thunderstorm operation Flashcards

(58 cards)