Thunderstorm Hazards – Ibex Aviation Academy

Aviation Hazards of Thunderstorms

Turbulence is caused by gusts, eddies, and strong updrafts and down-drafts within and around thunderstorms.
As air is drawn into a thunderstorm, strong updrafts may be encountered in clear air up to 10–20 km around the storm and as far as 25–30 km downwind.
Severe turbulence can occur inside Cumulonimbus (Cb) clouds as well as between adjacent Cb clouds.
Turbulence may also extend several thousand feet above and below the cloud.
If turbulence exceeds the aircraft’s gust load limits, it may result in loss of control, difficult landings, or structural damage.

Static electricity develops inside Cumulonimbus clouds due to the continuous movement of water droplets and ice particles.
Lightning is most likely to occur when the ambient temperature is between +10°C and –10°C.
Lightning strikes can puncture the aircraft skin and interfere with navigation and communication systems.
Possible effects include a burning smell, loud explosive noise, temporary blindness or flash blindness, and inaccurate navigation indications.

Strong updrafts may produce negative G forces, while strong down-drafts may produce positive G forces from middle levels down to the surface.
These vertical currents can cause sudden altitude changes up to approximately 1 km from the thunderstorm.
Down-drafts spreading across the ground generate squall winds with speeds ranging from 40 to 100 knots.
Strong gusts occur in the transition zone between updrafts and down-drafts and may cause structural damage or loss of aircraft control.
Air pockets are localized regions of rapidly changing pressure and temperature associated with strong vertical air currents.

Thunderstorm wind shear is produced when powerful down-drafts strike the ground and spread outward to heights of approximately 2,000 feet.
During landing, an aircraft may initially encounter a headwind followed suddenly by a tailwind, resulting in a rapid loss of airspeed and possible stall warning.

Clear Ice (Glaze Ice or Translucent Rime) may form between the freezing level and approximately 10,000 feet above the freezing level.
If aircraft icing protection systems are not activated, severe ice accumulation may lead to engine flameout and degraded aircraft performance.

Heavy rain significantly reduces flight visibility.
Heavy showers can cause water accumulation on runways, increasing the risk of aquaplaning (hydroplaning) during landing.
Water ingestion into aircraft engines during heavy rainfall may result in loss of engine power.
Hail is commonly encountered between the freezing level and approximately 25,000 feet above the freezing level and can cause severe structural damage to the aircraft.

Hail striking the aircraft or windshield produces loud noise and is usually accompanied by severe turbulence.
Darkness and loss of outside visual references near thunderstorms can lead to spatial disorientation.
Pilots should rely primarily on flight instruments, especially the Artificial Horizon (Attitude Indicator), to maintain aircraft attitude.

Rapid pressure changes associated with thunderstorms can produce errors in pressure-sensitive flight instruments.
The altimeter may over-read in the vicinity of thunderstorms.
Low-Level Significant Weather (SIGWX) charts help identify areas of Cumulonimbus development and associated hazards.

Micro-bursts and Macro-bursts are intense down-drafts that create severe wind shear and violent vertical air currents, typically lasting 1–5 minutes.
Wind speeds may exceed 75 km/h and are often associated with heavy rain or virga.
During approach, pilots may encounter a headwind, followed by a strong down-draft, and then a tailwind, creating a highly hazardous situation.
A Micro-burst affects an area less than 4 km in diameter, whereas a Macro-burst extends over an area greater than 4 km.
Micro-bursts and macro-bursts can cause rapid changes in angle of attack, roll, yaw, turbulence, visibility, aircraft attitude, noise levels, and may result in undershooting or overshooting the runway during approach.