The US Federal Aviation Administration (FAA) has ordered airlines to modify cockpits - at the cost of millions of dollars - to prevent the possibility of mobile phone and WiFi signals crashing cockpit screens.
The air safety regulator said tests had indicated mobile phone and computer signals could cause the screens to go blank. The screens are manufactured by Honeywell.
Boeing had previously warned in November 2012 that an airline and wifi supplier had noticed interference to the screens caused by the installation of an in-flight wifi system.
The Federal Aviation Administration (FAA) warned the screens could also be disrupted by air surveillance and weather radar systems, which will pose a difficult problem to overcome as airlines can't do without either.
The screens are required to provide pilots with data such as airspeed and altitude, so a screen problem could potentially cause a crash. The FAA says over 1,300 Boeing 737 and 777 planes will have to be modified to avoid any problems.
It said: "We are issuing this airworthiness directive to prevent loss of flight-critical information displayed to the flight crew during a critical phase of flight, such as an approach or take-off, which could result in loss of airplane control at an altitude insufficient for recovery, or controlled flight into terrain."
Boeing recommended to airlines that modifications should be made in 2012, but many have not done anything about it. Despite these laggards though, the FAA has still given them another five years to complete the changes. The FAA says the modifications will collectively cost airlines an estimated $14 million (£8.75 million) in total.
Honeywell took the position that airlines should only be forced to install new screens if wifi-enabled tablets or similar devices were used near the screens by the cockpit crew. An increasing number of airlines are supplying their crew with tablet-enabled flight information.
Several airlines told the FAA they did not believe passenger wireless devices were close enough to interfere with the screens.
But the FAA said it wanted to "eliminate" any risk of interference. The reported risk of screen interference will cause some confusion among some passengers. Earlier this month, airline passengers travelling on European flights, were told by the European Aviation Safety Agency (EASA) they would now be able to leave their mobile phones and other connected gadgets on throughout entire flights.