While battling strikes from ground crew, baggage handlers, engineers and pilots, Qantas also signed on a contract on Thursday for the largest single commercial jet order in Australian aviation history worth $9.5 billion.

The company ordered 32 A320s and 78 A320 NEOs. Eleven of the new orders will be for a new Qantas premium service to be based in Malaysia or Singapore and 99 will be deployed to Jetstar to address the rising number of travelers and replace aircraft with leases that will soon lapse.

The purchase would likely anger the unions in Qantas which have been negotiating for better pay deals and have resorted to industrial action to pressure the air carrier's management to offer better pay packages.

On Monday at 3 p.m., members of the Australian Licenced Aircraft Engineers Association whose tasks are to inspect jets on the tarmac will walk off their jobs for four hours.

In anticipation of the industrial action, Qantas canceled 40 international and domestic flights, and delayed 24 flights by up to 3.5 hours and bring forward 14 flights. Monday's job walk-off is expected to affect 11,000 passengers, according to a Qantas estimate, but The Sydney Morning Herald made a larger estimate of 48,500 affected passengers.

On Friday, Qantas had to cancel 17 flights and delay 29 more because of a planned Transport Workers Union strike which was cancelled on the 11th hour. However, the cancellation of the strike still disrupted passengers' travel plans.

Outside, Qantas, more problems are in store for Australia's international gateways because of a planned customs inspectors' work stoppage on Thursday following the rejection by the Community and Public Sector Union of a federal government offer of 9 per cent pay increase spread over three years.

Prior to ordering 110 new jets from Airbus, Qantas planes had aviation accidents because of the old Rolls-Royce engines that need to be replaced. A Qantas A380 trip from London to Sydney made an emergency landing in November 2010 after a stopover in Singapore when one of its four engines blew out.

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