According to the definition given by Oblack (2018), “A tropical cyclone is a fast-spinning storm system that has a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain” (para.2). To be more specifically, if these phenomena occur in the Atlantic Ocean and the Northeast Pacific Ocean, they are called hurricane; if occur in the Northwest Pacific, they are called typhoon; and if occur in the South Pacific or the Indian Ocean, they are called cyclone.
A tropical cyclone is formed by several factors. As demonstrated by NASA science, the most important factor is warm ocean water near the equator. In the tropical ocean, due to direct sunlight, water on the surface easily evaporates and is scattered in the air. Since the wind near the equator is weak, the air could easily elevate and result in convection. The warm, humid air rises and the pressure decreases in that area. Air with higher pressure from the surrounding area is pushed into this lower pressure area. The newly injected air also becomes warm and humid, and then it rises. This action reoccurs as the warm air continues to go up, and the air around rotate in to constantly take its place. When rising to a certain height in the air, the warm and humid air cools down, thus the water vapor forms cloud in that position. At the same time, the flow of air moves from high pressure to low pressure, which forms ‘wind’. While the entire cloud and wind system swirls more and more violently, in the center form the eyes. The eye is very calm and the air pressure is very low. Air above the eye with high pressure flows down into it. When the wind speed reaches 74 mph, a hurricane is formed. (NASA Science, How do hurricanes form)
Hurricanes, in aviation’s perspective, are as highly destructive as discussed in other fields. Not only could they directly cause dramatic casualties and property damage in land facilities, but also influence pilots’ decision in flight. During these phenomena, heavy rain and floods may occur and squalls may roll up objects, create huge waves or overturn ships. The basic communication facilities and building will be destroyed. The impact of hurricanes on aviation mainly focuses on their destructions towards land facilities. The airport in the area of where the hurricane land in will be forced to close, but nevertheless, some airport ground facilities may be seriously damaged, and a large number of flights will be cancelled. However, with the continuous improvement of weather forecasting and sensing technology, and the fact that pilots are getting more and more real-time weather data in flight, storm navigation has become more common than in the past. Currently, most flights travel around the hurricane route, while a few flights may choose to fly over the top of the hurricane. As Rabinowitz (2018) in Thepointsguy said, “Allegiant Airlines 2237 flew well above Hurricane Florence on Friday, September 14, and was not affected by the storm” (para.9). In the quoted case, Allegiant flight was going over Hurricane Florence at 34,000 feet. However, while flying over the hurricane circle, in addition to bumps and passenger discomfort, pilots also need to face various safety issues, such as the possibility of hail attacks, and more seriously, possible power outages or even failures of the aircraft engines. Therefore, choosing a detour flight may be a safer way under such an extreme weather condition.
In general, the flight crew must be well prepared for severe weather conditions such as hurricane. when a flight is cancelled due to the impact of a hurricane, the crew should be standby to prepare for recovery flight. If the conditions permit take-off, before the flight, the crew should determine the location and track of the hurricane based on the meteorological cloud map, in order to prepare for a reasonable flight around the hurricane. At the same time, the crew must determine the amount of fuel required based on the route and prepare as much oil as possible. In flight, pilot must fully understand the weather conditions around the route and in the destination airport based on the weather radar, and communicate with the ATC constantly. During landing, if the captain believes that the condition of the destination airport is not suitable for landing, he must make a decisive go-around and choose whether to prepare for the landing depending on the circumstances.