When Airbus started building its first long-haul plane back in the 1990s, the company designed two versions more or less in parallel. The A330 is a two-engine sister of the four-engine A340 – and one of the world’s most reliable commercial aircraft.
They both have the same wings, tail assemblies and fuselage modules. Their basic models are of identical length. They also have practically the same load capacity and accommodate practically the same number of passengers. But Airbus had its reasons for designing two versions of the same aircraft – the A330’s two engines consume less fuel than the four powering the A340, but the latter has a greater cruising range.
The A330 – like all twin-engine aircraft – is subject to certain restrictions. These are spelled out in the international regulations entitled Extended-range Twin-engine Operational Performance Standards (ETOPS). ETOPS stipulate that two-engine aircraft must operate on flight routes enabling them to reach the nearest airport within a specified time, the so-called ETOPS time. This is to ensure that they can land safely even if only one engine is still functioning. Back in the 1950s the ETOPS time was around 60 minutes, and this meant that many transatlantic and transpacific routes could only be flown by four-engine aircraft.
Advances in engine design have now made it possible to prolong the ETOPS time for two-engined aircraft. The A330 was even able to demonstrate its reliability by flying across the North Atlantic on one engine only in six hours. Its ETOPS time was 90 minutes when it came into service and was later extended to 180 minutes. And in 2009 the A330 was the first model to be licensed by the European Aviation Authority EASA for routes with an ETOPS time of 240 minutes to the nearest airport.
Lufthansa has cast its A330 and A340 aircraft in very clearly defined roles. The four-engine A340 mainly flies the classic long-haul routes with an average length of around 6300 kilometers (3915 miles) per flight, while the A330 is usually reserved for shorter routes covering an average length of 4300 kilometers (2672 miles) per flight.