In-flight entertainment has come a long way since passengers craned their necks to catch a glimpse of the flickering films shown in 1980s aircraft. Today’s passengers expect on-demand video systems, telephones and even broadband internet access.

Unfortunately, that’s not all they can do. The technology used by the new generation of aircraft is now so advanced that aviation officials fear that terrorists could use it to fly the plane.

Aviation regulators have refused to certify Boeing’s new 787 Dreamliner passenger jet until it redesigns its computer system to protect against such an event, The Times has learnt.

The Federal Aviation Authority is concerned that terrorists could use the Dreamliner’s in-flight internet system to connect to “systems critical to the safety and maintenance of the aircraft”.

In a report released last week, the FAA said that Boeing had left the pilots’ computers open to attack by connecting the Dreamliner’s entertainment system to the pilots’ controls.

A hacker with a computer and some IT training potentially could hijack the system from his seat.

“The proposed architecture of the 787 allows new kinds of passenger connectivity to previously isolated data networks connected to systems that perform functions required to the safe operation of the airplane,” the FAA report says.

“This new passenger connectivity may result in security vulnerabilities from intentional corruption of data and systems critical to the safety of the airplane.”

Boeing now has to fulfil special conditions before the Dreamliner is certified safe. The 787’s maiden flight is scheduled for March with deliveries supposed to begin in November.

David Learmount, safety editor of Flight International, said: “The FAA is obviously very concerned about this. It’s not the kind of organisation that fires shots across the bows if it doesn’t think it was needed.

“It’s not good enough to have systems which can be hacked into and then disabled by the pilot. The hacker might have put a bug into the system which screws up the navigation. The FAA don’t want a system like that.

“They’re saying: don’t bring us an aircraft someone can hack into.”

On the message boards of the Professional Pilots Rumour Network website, pilots also expressed their concern. One wrote: “The possibility of a wired connection between passenger internet services and flight systems is really scary! No sane person would implement this.”

The Dreamliner is the most successful new commercial airplane in Boeing’s history. It is Boeing’s response to the Airbus A380 super-jumbo and is crucial to the company’s success.

Lori Gunter, a Boeing spokeswoman, said that Boeing had designed a system to counter the threat but admitted that it had not yet been tested.

Ms Gunter said that data could pass between the passenger and flight networks, but said there were “protections in place to ensure that the passenger internet service doesn’t access the maintenance data or the navigation system under any circumstances”.

Boeing’s highflier

— The carbon-composite, aluminum and titanium Dreamliner is Boeing’s most successful new aircraft, with more than 600 orders

— The use of lightweight composites makes the aircraft 20 per cent more fuel-efficient than similar-size rivals

— Moisture in the cabin air is higher than average, promising a more pleasant flying experience

— The 787 seats between 210 and 250 people and flies at Mach 0.85, about 570mph

— There will be four variants. It is scheduled to enter service in May. The shorter-range 787-3 and the stretched 787-9 are scheduled to enter service in 2010

— Prices will range from £74 million to £100 million, depending on model and configuration

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