By SCOTT MCCARTNEY
The Wall Street Journal

When Air France Flight 447 crashed in the Atlantic Ocean in June, seven
hours elapsed before air-traffic controllers realized it was missing,
delaying search and rescue efforts and bewildering air travelers over how a
jumbo jet could be lost in an age when even simple cellphones can pinpoint
positions.

Could it happen in the U.S. and other parts of the world? Thanks to a
relatively new breed of air-traffic-control systems, that isn't likely.
Air-traffic controllers in the U.S., Europe, Canada, Australia and New
Zealand, who control most of the air traffic across oceans, now have modern
satellite-based systems that include frequent automatic position reporting
from airplanes and email-like communications between pilots and
controllers.

Besides just knowing where planes are with more-accurate and more-timely
position reports, the benefits of modern systems are numerous: Flights are
shortened by allowing more efficient routes, saving time for travelers,
money for airlines and reducing the carbon footprint of airliners. And
travelers get smoother flights because planes can fly closer together,
allowing more to use the least-turbulent altitudes.

What's happened in recent years over oceans offers a glimpse of what
governments and airlines hope will happen over land—a "Next Generation"
system that will be a vast improvement over the ground-based radar and
radio communications system in place for the past 50 years.

The Federal Aviation Administration's "NextGen" development program for the
continental U.S. has a history of delays and failures. But it is now on
track, according to government and industry groups, to produce in the next
10 years or so an air-traffic-control system with lots more capacity. With
satellite-based data links instead of radar, which is somewhat slow and not
precisely accurate, jets will be able to safely travel closer together,
reducing delays. Faster communications over data links will allow
controllers to handle more airplanes at one time. And with better computer
systems that can predict conflicts far in advance, planes will get to pick
their best route rather than be restricted to the set paths in the sky
today. Systems to handle busy skies over land will be different from the
oceanic system, but built with the same functions, communications and data
links.

"This is kind of a view into Next Gen," said Rick Day, senior vice
president of operations for the FAA's air-traffic organization. "It's a
total transformation from the controller's point of view."

The U.S. system, called Advanced Technology and Oceanic Procedures, or
ATOP, was adapted by Lockheed Martin Corp. from a system developed in New
Zealand (Australia's system was the other finalist). So far, ATOP has saved
airlines 330,000 flying miles per year—as far as flying to the moon and
half-way back—and nearly 10 million gallons of fuel.

The system has been in use in the U.S. for four years. Data come from
multiple sources on board aircraft, in case one fails, and multiple
computers run together on the ground to provide backup. Planes report every
14 minutes, though controllers can change that to more frequent reporting,
if necessary. If a position report is six minutes overdue, alarms go off.
And the system automatically warns controllers if planes stray off course.

Controllers say the system is a huge improvement, but all the kinks haven't
yet been worked out. ATOP gives them a radar-like picture of all planes in
the section of oceanic air space they are responsible for, accurately
showing position, direction, speed, assigned route and other information.Messages can be zapped back and forth with pilots. Any potential conflicts
get automatically flagged to controllers as much as two hours before planes
would get closer than separation standards allow. Problem flights are
marked with flashing orange lines, and controllers have to take action to
resolve conflicts before the lines go red 30 minutes before separation
standards would be violated.

"Once the bugs got worked out, and most have been, we've been very happy
with this," said Craig Troxclair, a controller at the FAA's oceanic traffic
room near Oakland, Calif.—a facility that controls a huge swath of the
Pacific Ocean, half-way around the world past Guam. "A lot of time used to
be spent processing position reports on strips of paper. That took away
from the service you could provide."

Indeed, controllers in Oakland used to have to keep track of planes with
strips of paper, plot aircraft positions with grease pencils on maps and
calculate flight paths using rulers and a plastic slide rule-like device
called a "wiz wheel." And you can still find one or two around the Oakland
facility.

Using ATOP, if a pilot requests an altitude or route change, the system
loads the new information, based on the data transmission from the plane,
calculates any possible conflicts and suggests responses from the
controller automatically. If there aren't any problems with the request,
approval can be sent with a couple of mouse clicks. And if any other
flights are in the way of the requested new route, they get highlighted on
the controller's screen in red.

"Previously if aircraft wanted to climb or reroute, it was a tedious
process and controllers often didn't have time," said Dennis Addison,
support manager for FAA's Oakland center. Now controllers can provide
better routes and altitudes for flights. "It's really changed the way we do
business," he said.

Controllers can allow airlines to design their own flight paths instead of
using one of the 16 routes drawn up each day by controllers in the U.S. and
Japan. (These are the routes that—based on winds, temperatures and other
factors—controllers think will be best for that day.) That flexibility
allows them to optimize each flight's route, based on the latest wind and
temperature reports (the colder it is, the more efficient a jet engine is).

Controlling planes over oceans presents all kinds of challenges because
aircraft are out of normal radio and radar range. For decades, controllers
relied on position reports over high-frequency radio every hour or so,
competing for air time with fishing vessels and all kinds of other traffic.

Because of the inaccuracies and time between reports, planes were spaced
far apart—often about 100 miles—to ensure safety. That added to delays
since flights had to wait for space in the stream of planes and made it
difficult for lots of flights to get on ideal tracks for winds, slowing
flights and increasing fuel burn. It also made it hard to change altitudes
when the ride got bumpy. Now, with more-accurate and timely position
reporting, separation between airplanes can be reduced to as little as 30
miles over oceans. (Over land, planes are kept at least five miles behind
one another, but that may well be reduced when satellite-based navigation
replaces radar.)

Not all planes across oceans have data-link capabilities, and
high-frequency radio is still used with some flights and as a backup with
others. Many aircraft also have satellite phones that controllers can call.
And some nations, notably Brazil and Senegal, which were handling Air
France Flight 447, don't yet have modern oceanic air-traffic-control
systems. The Airbus A330 jet with 228 people aboard crashed on June 1 about
930 miles off the coast of Brazil. Senegal never took control of the jet
from Brazil, and it wasn't until seven hours later that controllers in
Madrid and Brest, France, raised an alarm, investigators said.