China Airlines' existing Sydney offering (arrive Taipei in early morning, leave at night) connects with the new London service (depart Taipei mid-morning, arrive back into Taipei late afternoon). From Sydney to London there is a 1h:25m layover in Taipei, while the return from London to Sydney has a less desirable 5h:00m layover.
Unlike its return from London into Taipei in the late afternoon, China Airlines returns into Taipei in the early morning from three of its four other European destinations: Amsterdam, Frankfurt and Vienna. Passengers on those flights would have a day-long layover before connecting to Australia.
The second Sydney flight will enable connections in both directions from Australia to those three European cities for the first time. China Airlines' Rome service arrives back into Taipei mid-afternoon, creating a long layover for passengers connecting onwards to Australia.
The second Sydney service also accommodates growth, as well as spillover from the first Sydney flight resulting from inventory being reserved for European connections.
China Airlines' existing Sydney service is a red-eye in both directions, resulting in morning arrivals and onward connections. This requires 10 hours of ground time in Sydney during the day (previously used for a tag service to New Zealand).
The second daily flight will reduce ground time and improve overall utilisation, but brings time challenges. The new second flight will depart Taipei at 08:10 and then arrive back into Taipei at 19:50, limiting Asian connections in both directions.
Although the flight will accommodate new connections to three European cities, Asia connections and local sales will be dampened. It will be challenging to travel from other Taiwanese cities (even on high-speed rail) to make the 08:10 Taipei Taoyuan departure.