Without air conditioning some people become suicidal.
Passengers on a plane in Brazil opened the emergency exits as their flight prepared to take off in a desperate bid for fresh air after the air conditioning unit broke down.
Sitting in 40C heat, the angry passengers ignored directions from flight staff to prepare for take-off, instead opening emergency doors to cool down.
Luckily for those on board, the plane was still on the ground.
They were meant to be flying from Rio de Janeiro to Sao Paulo, according to the UK's Mirror newspaper which first published the story.
Captured on video, the passengers can be seen fanning themselves down as they all attempt to crowd around the only source of fresh air.
Speaking to the Globo television network in Brazil, one passenger said they felt as though they were sitting inside a sauna.
Another claimed that passengers were frustrated and losing their tempers, while one female passenger is reported to have fainted. Others were forced to splash water on their faces in a bid to keep cool.
In a statement the airline, Gol, said the air conditioning units used on the ground were defective but that "no measures were spared to minimise the discomfort to passengers." All travellers later boarded another fully-functioning aircraft.
Last month, one first time passengers stunned flight staff by opening the emergency exit to get some fresh air.
To see the video go to http://www.mirror.co.uk/news/world-news/angry-passengers-open-emergency-exit