London-Chicago British Airways’ aircraft now grounded; check landing video

A BRITISH Airways flight heading to Chicago reportedly turned back after a pressurisation problem. Flight BA295 departed London Heathrow and was operated by a Boeing 777-236ER, registration G-VIIA.

According to FlightRadar24, the scheduled departure at Heathrow was 11:10 AM. But it took off at 12:14 PM. The scheduled arrival in Chicago was 1:50 PM. However, it is now expected to arrive at 11:02 AM.

The details about the British Airways flight were shared on X by Turbine Traveller, an aircraft technician based in Nairobi. The post was about a reported crew message explaining the decision to return.

The message said the aircraft was returning to Heathrow due to a pressure problem. It recorded cabin altitude reaching 10,500 feet. Cabin altitude refers to the altitude corresponding to the air pressure inside the aircraft.

According to the post, BA295 was cruising at 36,000 feet before descending rapidly. Soon, it reached around 9,000 feet. The 27,000-foot descent happened within seven minutes.

Turbine Traveller said this descent had matched Boeing's procedure for a loss of cabin pressurisation. The aim is to reach an altitude where additional oxygen is no longer required. At cruising height, the thin outside air cannot support normal breathing without additional oxygen.

The reported crew message also raised concerns about the aircraft's landing weight. It indicated the aircraft was around 30 tonnes above its maximum landing weight. The message said there was no way to release fuel.

This made fuel management another consideration during the return. Burning fuel during holding would help reduce the aircraft's weight before landing. Flightradar24 shows several loops along the aircraft's tracked route near southwestern Britain.

The post also explained how the Boeing 777 maintains cabin pressure. Its air-conditioning units supply air while valves control how much air leaves.

Two exit valves sit towards the front and rear of the aircraft. During automatic operation, they adjust as the aircraft climbs, cruises and descends. This helps maintain cabin pressure throughout different stages of flight.

The system normally limits cabin altitude to 8,000 feet. It also manages how quickly cabin pressure changes. Pilots can select manual control and adjust either exit valve when needed.

Airflow distribution changes depending on whether forward cargo air conditioning is operating. When switched off, about 20% leaves through the front valve and 80% through the rear. When switched on, the distribution is roughly equal between both valves.

Separate safety valves protect the aircraft against excessive pressure differences between its interior and the surrounding atmosphere. Other vents protect against the pressure inside becoming too low relative to the outside.

These systems work together to maintain suitable cabin conditions. When pressure is lost, reaching a lower altitude becomes the immediate priority. For BA295, the rapid descent followed the crew's decision to return to Heathrow.

“Heading back to Heathrow, too heavy for a normal landing, they’re currently dumping fuel over the Bristol Channel and will continue onto London once below max landing weight,” an ex-commercial and military Irish pilot posted on X.

“This is ALL regular practice in the simulation by the pilots and will be carried out entirely according to procedure. More than likely, that’ll be a BA paid night stop at the airport, for attempt number two tomorrow!” he added.

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