A British Airways Boeing 777 turned back to London on Monday after a steep, sudden descent over Ireland. The flight was on its way from Heathrow to Chicago. It landed safely, and no one was hurt.
Read on to find out what an emergency descent is and why the cause is still not clear.
Flight BA295 left London Heathrow around midday on Monday 5 October. It was flying to Chicago O’Hare. Over Ireland, at a cruising height of about 36,000 feet, something went wrong.
Reports say the crew began an emergency descent. This is a fast, planned drop to a lower height, where the air is thicker and people can breathe normally. Flight-tracking data show that the plane went down to about 9,000 feet. That is a drop of roughly 27,000 feet in just a few minutes.
The sudden drop would have been frightening for the people on board. One passenger described sudden turbulence as the masks dropped. At 36,000 feet the outside air is very thin and very cold, so a crew has very little time to lose when the cabin air is a problem. For that reason, pilots follow a clear drill. First, they put on their own oxygen masks. Then they begin the descent and tell air traffic control what is happening.
Passengers’ oxygen masks reportedly fell from the ceiling. Aircraft carry these masks in case the cabin pressure falls. Cabin pressure is the air pressure inside the plane. The air outside is too thin to breathe at high altitude, so the plane pumps air into the cabin to keep it safe. If the pressure drops, people can quickly feel unwell. Some reports say the crew suspected a loss of cabin pressure, but British Airways has not confirmed this.
The crew also set the transponder to the code 7700. A transponder is a device that sends a signal to air traffic control radar. The code 7700 tells controllers that an aircraft has a general emergency. The pilots then turned the plane back towards London. The 777 landed at Heathrow at around 5 pm.
British Airways said that the flight had a “technical issue”. The airline has not said what failed. No injuries were reported, and passengers were reportedly booked onto later flights. The aircraft will be checked before it flies again.
Events like this are rare, and pilots practise the emergency descent drill regularly in a flight simulator. The Air Accidents Investigation Branch, the UK body that investigates serious aircraft events, may decide whether to look at this case more closely. For now, the main question is simple. Investigators and engineers must find out what went wrong, and the answer is not yet public.
Check your understanding
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What is an emergency descent?
The article says an emergency descent is a fast, planned drop to a lower height, where the air is thicker and people can breathe normally.
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True or false: British Airways has confirmed that a loss of cabin pressure caused the problem.
The airline only called it a technical issue. The article says some reports suspect lost pressure, but British Airways has not confirmed this.
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Why is the cause of the event still unclear?
British Airways said only that there was a technical issue, and the article says some reports suspect lost cabin pressure but nothing is confirmed.
- emergency descent (noun) – a fast, planned drop to a lower height so that people can breathe normally. Typical use: “Reports say the crew began an emergency descent.”
- cabin pressure (noun) – the air pressure inside a plane, kept higher than the thin air outside. Typical use: “Some reports say the crew suspected a loss of cabin pressure.”
- transponder (noun) – a device that sends a signal about the plane to air traffic control radar. Typical use: “The crew also set the transponder to the code 7700.”
- technical issue (noun phrase) – a problem with the aircraft’s equipment, often described without details. Typical use: “British Airways said that the flight had a technical issue.”
You can practise what pilots say in a pressure emergency in our listening exercise Cabin Altitude Warning Over the Atlantic.
