and arriving air passengers board ferries at the pier for their ride back to the PRD. Passengers travelling both directions can bypass custom and immigration formalities, which reduces transit time. Four ports – Shekou, Shenzhen, Macau and Humen (Dongguan) – were initially served. As of August 2007, SkyPier serves Shenzhen's Shekou and Fuyong, Dongguan's Humen, Macau, Zhongshan and Zhuhai. Passengers travelling from Shekou and Macau can complete airline check-in procedures with participating airlines before boarding the ferries and go straight to the boarding gate for the flight at HKIA. In 2009, the permanent SkyPier Terminal opened. The permanent ferry terminal is equipped with four berths, but the terminal is designed to accommodate eight berths. Transfer desks and baggage handling facilities are included, and the terminal is directly connected to the airport automatic people mover system. Baggage and cargo facilities Ramp handling services are provided by Hong Kong Airport Services Limited (HAS), Jardine Air Terminal Services Limited and SATS HK Limited. Their services include the handling of mail and passenger baggage, transportation of cargo, aerobridge operations and the operation of passenger stairways. The airport has an advanced baggage handling system (BHS), the main section of which is located in the basement level of the passenger terminal, and a separate remote transfer facility at the western end of the main concourse for the handling of tight connection transfer bags. HKIA handles over five million tonnes of cargo annually. Hong Kong Air Cargo Terminals Limited operates one of the two air cargo terminals at the airport. Its headquarters, the SuperTerminal 1, is the world's second largest stand-alone air cargo handling facility, after the opening of the West Cargo Handling Area of the Shanghai Pudong International Airport on 26 March 2008. The designed capacity is 2.6 million tonnes of freight a year. The second air cargo terminal is operated by Asia Airfreight Terminal Company Limited, and has a capacity of 1.5 million tonnes a year. DHL operates the DHL Central Asia Hub cargo facility which handles 35,000 parcels and 40,000 packages per hour. Hongkong Post operates the Air Mail Centre (AMC) and processes 700,000 packages per day. It is envisaged that HKIA's total air cargo capacity per annum will reach nine million tonnes ultimately. Aircraft maintenance services Both line and base maintenance services are undertaken by Hong Kong Aircraft Engineering Company (HAECO), while China Aircraft Services Limited (CASL) and Pan Asia Pacific Aviation Services