With a cloud top height of 40,000-50,000ft and a diameter of anything from 500km to 1500km, tropical storms are difficult to fly over, divert around, or, even worse, to fly through!
Although tropical storms are not a constant phenomenon, they affect a large area of the Earth’s surface at various times of the year. Their seasonal occurrence has a major impact on aviation, and trade routes and popular tourist destinations, such as Florida, USA, Bali and Indonesia are affected.
Inside the storm itself, multiple hazards are present that make flying through a storm a dangerous undertaking:
- strong winds and gusts can limit control of the aircraft and can consume large amounts of fuel trying to maintain course,
- severe turbulence from constantly rising, falling and circulating air, has the potential to dislodge internal and external fittings, or throw the aircraft sharply up or down by 1000’s of feet,
- hail, large enough to cause significant damage to the exterior of the aircraft, can cause windows to crack or damage to wings or control surfaces,
- lightning may not be the significant hazard it once was, but still has the potential to fry onboard electronic and communication equipment,
- and icing, at rates or extents that not all anti-icing equipment can manage.
Even if, like Concord, an aircraft has the ability to reach an altitude above a tropical storm, the turbulence and hail generated by the storm can reach heights well above the cloud top, potentially having a more significant impact than just a rocky ride!
Depending on the location of the tropical storm, re-routing around it may be a viable solution; however it is likely that more fuel will be required, making the alternate route more expensive to run.
But if there is a tropical storm approaching, or over, your destination (or departure) airfield then diversions might not be possible due to logistical impracticalities, and flights might need to be delayed or cancelled.
Tropical storms are quite possibly the most significant hazard to aviation due to the numerous dangers they present and their sheer size, making any contingencies an expensive option.
However, unlike other aviation hazards, tropical storms are seasonal and can be avoided; meaning that with a little meteorology and good planning, many of their negative impacts can be negated. More facts of tropical cyclones can be found here.
Sarah Bull- Operational Aviation Meteorologist