Rapid Depressurisation Actions

Recognising Rapid Depressurisation

Rapid depressurisation, also known as explosive decompression, is characterised by a sudden and dramatic loss of cabin pressure. Typical signs include a loud noise, a rush of air, fog or mist forming in the cabin, a rapid drop in temperature, and physical discomfort such as ear or sinus pain. Cabin altitude warnings and automatic deployment of passenger oxygen masks may occur.

Immediate Crew Actions

The first and most critical response is for all crew to don oxygen masks and establish communication using the interphone system. This is vital because the time of useful consciousness at high altitude can be extremely short—sometimes only seconds.

Once oxygen is secured, the crew must:

• Initiate an emergency descent to a safe altitude (below 10,000 ft cabin altitude)
• Engage seatbelt and no smoking signs
• Communicate with ATC, declaring an emergency
• Brief cabin crew and passengers as soon as possible
• Follow the aircraft’s rapid depressurisation checklist

Causes and Detection

Rapid depressurisation can result from structural failure (e.g., window or door failure, fuselage breach) or malfunction of the pressurisation system. Detection is usually immediate due to the physical effects and warning systems, but slow decompression may only be noticed via cockpit alerts or oxygen mask deployment.

Effects on Occupants

Rapid depressurisation exposes crew and passengers to hypoxia, decompression sickness, and physical trauma from flying debris or blast effects. Immediate use of supplemental oxygen is essential to prevent incapacitation.

Emergency Descent and Evacuation

After stabilising the situation, the aircraft must descend rapidly to a safe altitude. If a landing or evacuation is required, engines must be shut down and the aircraft brought to a halt before evacuation to avoid injury from moving parts or fire risk.