Editing Uncontrolled decompression (section)

===Gradual decompression===

Slow, or gradual, decompression occurs slowly enough to go unnoticed and might only be detected by instruments.<ref name="FAA-OPS2">{{Cite web |url=http://www.faa.gov/pilotos/training/airman_education/media/ac%2061-107a.pdf |title=AC 61-107A - Operations of aircraft at altitud above 25,000 feet MSL and/or mach numbers (MMO) greater than .75 |date=July 15, 2007 |work=[[Federal Aviation Administration]] }}</ref> This type of decompression may also come about from a failure to pressurize the cabin as an aircraft climbs to altitude. An example of this is the 2005 [[Helios Airways Flight 522]] crash, in which the maintenance service left the pressurization system in manual mode and the pilots did not check the pressurization system. As a result, they suffered a loss of consciousness (as well as most of the passengers and crew) due to [[hypoxia (medical)|hypoxia]] (lack of oxygen). The plane continued to fly due to the autopilot system and eventually crashed due to fuel exhaustion after leaving its flight path.