People are accustomed to canceling activities due to rain. Whether you are at a baseball game or planning a picnic, being “rained out” is always a threat. But does rainy weather stop airplanes from flying? In general, aircraft can fly in many types of adverse weather including rain. However, if you are traveling in your own small airplane or flying on an airliner, there are many factors that determine whether the aircraft takes off or not.
IFR Flight Explained
For private pilots without instrument ratings, rain and other forms of poor weather can decrease visibility to the point where it is no longer legal for them to fly. Many pilots used to flying under visual flight rules (VFR) in fair weather may not be comfortable flying in the rain even when the conditions are VFR according to regulations.
Qualifying to fly under instrument flight rules (IFR) gives pilots more options when poor weather impairs visibility. An instrument-rated private pilot who trains to stay current can fly through zero-visibility weather conditions that would be likely to cause spatial disorientation in pilots who are not trained for instrument flying.
Airline pilots, on the other hand, essentially are “on instruments” constantly and are able to fly in conditions that would keep most private pilots, even those with instrument ratings, on the ground.
IFR vs VFR
To fly VFR, a pilot needs to see the horizon and use other visual cues to reliably maintain straight-level flight. Because rain affects visibility it can make VFR pilots uncomfortable even when the conditions are still VFR-legal. In training for IFR flight, pilots learn to use their artificial horizon and other instruments to determine their position, course, and attitude in the air.
How Do Airplanes Take Off in the Rain and Snow?
Even for the most experienced private and commercial IFR pilots, operating aircraft on the ground during rain and snow can be more problematic than flying. Because rain and snow result in less traction on the runway, pilots have to control their speed when landing and be especially adept at directional control during landing and takeoff to stay on the runway.
When conditions are snowy or icy, ground crews have to keep the runway free of snow and flooded areas that could cause airplanes to lose traction. They also have to ensure that aircraft are clear of snow and ice which could add weight to the airframe and interrupt the aircraft’s aerodynamics.
When bad weather includes low clouds and high winds, even IFR flights might not be possible if clouds are below the minimum altitude allowed by regulations or wind velocity and direction are beyond what the aircraft can handle. For airliners, weather conditions rarely become poor enough to keep them on the ground. But it does happen.
Impact of Rain on Airplanes
Rain alone rarely affects aircraft operations, especially for airliners and technologically advanced private aircraft that typically fly above the weather. Even taking off and landing in heavy rain, snow, and fog is possible for aircraft equipped with adequate instruments and automated control systems for the conditions. However, heavy winds and thunderstorms, which often accompany rain, can keep aircraft grounded and result in airline flight cancellations.
Airport Procedures for Inclement Weather
Inclement weather like thunderstorms, fog, icing, and wind shear tends to be the most frequent causes of airline flight delays, accounting for an average of 70 percent of delays each year, and a cost to airlines of billions of dollars, according to the FAA. The following are among the standard procedures airports use to minimize disruption while keeping air traffic moving.
- Ground stops: Air traffic control uses these to keep aircraft on the ground when controllers cannot safely keep track of them in crowded airspace.
- Ground delays: In these cases, controllers delay aircraft at the departure airport to ease or manage capacity at the planned arrival airport.
- Airspace flow program: This is used to identify aircraft that are scheduled to fly through storms and adjust their departure times. Doing so gives airlines the choice of delaying or canceling the flight, or directing it around the storm.
- Severe weather avoidance plans: These are designed to ease air traffic in areas expected to be affected by storms.
Weather Elements and Flying
Answering the question, “Can airplanes fly in the rain” is more complicated than it sounds because of the potential range of severity of rainy conditions and the variety of aircraft types. While rain alone rarely stops aircraft from operating normally, additional weather elements that typically accompany rain, such as wind gusts, thunderstorms, mist, and fog are more likely to keep airplanes grounded. Pilots have to tailor their planning and procedures for each individual flight and the weather conditions that might affect it.
How much snow causes flight cancellations?
A particular amount of snow will not necessarily cause flight cancellations at every airport. Some airports are known for excellent snow-removal capabilities and can continue to operate in conditions that would close other facilities. Ice, high winds, and other factors that often are present during snow storms could play a bigger role in canceling flights.
Can airplanes take off in thunderstorms?
While many pilots have taken off during thunderstorms, doing so is a bad idea because the severity of weather conditions around such storms makes taking off especially risky. It is almost always safer to wait for the storm to pass before taking off
Can small aircraft fly in the rain?
Yes, even small aircraft using basic equipment without advanced technology can fly in the rain as long as visibility is good and weather conditions overall are still within the limits of the aircraft you are flying.