On Feb. 21, Internet users broadcast the news that flight MU5414 from Shanghai Pudong International Airport to Chengdu Shuangliu International Airport was struck by lightning as it took off. The China Eastern Airlines flight quickly returned and landed at 5:46 p.m., just half an hour after takeoff. Luckily, all passengers on the plane were safe.

The passengers on flight MU5414 said there was a flash of light when the plane took off, and many lights suddenly turned on in the cabin. Very soon, an announcement was made about the emergency landing. 

After a preliminary examination of the plane, no abnormalities were found. 

Generally, lightning occurs most frequently in China during spring and summer.

It was rainy in Chengdu on Feb. 21; visibility at the airport was 5,000 meters and the plane was able to take off and land normally. But weather conditions at high altitudes often differ from those near the ground. 

Statistics show that an aircraft is mostly likely to be struck by lightning while it is ascending or descending, between the height of 3,500 meters and 5,000 meters. Also common is when a plane flies through layers with a temperature between minus 5 degrees Celsius and zero degrees Celsius, especially near cumulus congestus and cumulonimbus clouds. Aircraft may also be struck by lightning when encountering moderate turbulence or flying through precipitation.

When it comes to cumulonimbus clouds, pilots do their best to avoid them. But when the clouds are too large to bypass, pilots sometimes are forced to return or land at alternate airports. 

According to statistics, on average, a plane is likely to be struck by lightning once for every 10,000 hours of flying. If a plane flies seven hours per day, it will hypothetically encounter lightning once a year; if it flies 10 hours per day, it may be hit once every 10 months.