Airlines resisted putting in stronger cockpit doors

Airlines resisted putting in stronger cockpit doors, too, to protect against hijackers. If you wait for a business to do the right thing...Modern airplanes like the Boeing 777 are full of sophisticated devices to municate with air traffic controllers and broadcast their position, including two transponders, several VHF radios, a satellite phone and text and data-link systems. One of them, the Aircraft Communications Addressing and Reporting System, or ACARS, handles textlike transmissions over radio or satellite links.
This handout from the Australian Maritime Safety Authority shows the satellite images of the two objects that officials say could possibly be related to Malaysia Airlines Flight 370. Credit Australian Maritime Safety Authority

But those systems can be vulnerable to tampering by outsiders or can just be turned off by pilots, or anyone else knowledgeable with airplane operations. Industry officials say pilots need to be able to turn off any transmission system in case it starts a fire.Similar concerns emerged after the 9/11 attacks,
Part of building stronger munications capacity is having the technology to support it when terrorists turned off transponders that broadcast a plane's identification number and other information, hiding the planes' identities from civilian controllers. Once an airplane is outside radar range, usually 200 miles from the coast, American airlines insist on getting munications from pilots at least once an hour to track their aircraft. Without these updates, a plane might fly hundreds of miles beyond its last point of munications before anyone was even aware it was missing.

These shor ings could e to an end thanks to a long-planned transition from radar to satellite-based systems that are expected to greatly increase tracking accuracy by the end of the decade.But in the meantime, Robert W. Mann, an aviation consultant in Port Washington, N.Y., said rescue operations could be considerably accelerated if airplanes were required to automatically send basic flight information via satellite such as position, altitude, speed and direction at much shorter intervals.Such a system could also be designed to keep transmitting as long as an airplane was airborne or generated power.