Russian regulators are instructing carriers to take steps to avoid cabin discomfort when operating to destinations in warm climates, after an incident involving an Aeroflot Airbus A330-300 in Bangkok.

The aircraft had been departing the Thai capital for Krasnoyarsk on 26 March.

As the jet taxied, its pilots were notified of a fault with the thrust-reverser on the left-hand Rolls-Royce Trent 700 engine, and they opted to return to the apron.

But congestion at the airport meant the aircraft was directed to a cargo parking bay, and the crew had to wait 40min for an escort vehicle, according to a 23 April bulletin from Russian federal air transport regulator Rosaviatsia.

The cabin temperature was 30.5°C.

Operational regulations at Bangkok required the auxiliary power unit to be turned off, and ground-support personnel connected air conditioning equipment.

The increasing temperature of the cabin started generating complaints from passengers, and the crew restarted the APU with the agreement of ground services.

Inspection of the left-hand engine determined that a control unit had failed, and could not be listed as a deferred maintenance item.

VQ-BPI-c-Aeroprints Creative Commons

Source: Aeroprints/Creative Commons

Passengers on the A330 complained as the cabin temperature rose during the delay

As a result, the crew decided to disembark the passengers, but buses to transfer the passengers only arrived 1h 5min after being requested, claims Rosaviatsia.

“While waiting for the buses, several passengers approached cabin crew with complaints about their health,” it states, adding that a number of them were given assistance and an ambulance was called. The cabin temperature was 31.5°C.

Passengers were on board the aircraft for 3h 20min including almost 2h while the jet was undergoing ground services operations.

After disembarkation they were accommodated in Bangkok hotels. The aircraft (RA-73785) underwent maintenance and departed about 24h later.

Rosaviatsia says carriers should not operate aircraft to hot destinations with unavailable systems which could reduce cabin temperature control.

Passengers should also not be kept on board in the event of a departure delay, it adds, if an aircraft malfunction cannot be quickly identified, and operators should establish procedures for disembarkation – or avoiding embarkation – in situations where extreme cabin temperatures could emerge.