What is in those bulky black flight bags that pilots carry into the cockpit? Not a change of clothes but reams of reference material -- about 40 pounds of it -- for the flight, including the aircraft's operating manual, safety checklists, logbooks for entering airplane performance data, navigation charts, weather information, and airport diagrams.
But instead of carrying all that paperwork, a growing number of pilots are carrying a 1 1/2-pound iPad.
The Federal Aviation Administration has authorized a handful of commercial and charter carriers to use the tablet computer as a so-called electronic flight bag. Private pilots too are carrying iPads, which support hundreds of general aviation apps that simplify preflight planning and assist with in-flight operations.
"When you need to make a decision in the cockpit, three to four minutes fumbling with paper is an eternity," said Jim Freeman, a pilot and director of flight standards at Alaska Airlines, which has given iPads to all its pilots.
The e-manuals include hyperlinks and color graphics to help pilots find information quickly and easily. And pilots do not have to go through updating manuals by swapping out old pages with new because updates are downloaded automatically.
American Airlines won FAA approval last month for its pilots to use the iPad to read aeronautical charts. Executive Jet Management, a NetJets company owned by Berkshire Hathaway, received the FAA's permission in February for its pilots to read aeronautical charts on iPads.
Moreover, the FAA said pilots at the two airlines don't have to shut off and store their iPads during taxiing, takeoff, and landing because the devices won't impair onboard electronics. Alaska Airlines pilots, like passengers, still have to put their iPads away during those phases of the flight.
Private and corporate pilots do not have to go through the same approval process. FAA regulations state those pilots are responsible for determining what technologies are safe and appropriate for cockpit use.
As a result, iPads are becoming essential in planes ranging from Gulf Stream G650s to Piper Vagabonds.
"I don't remember a time when one product seemed to get so much buzz and acceptance," Ian Twombly, spokesman for the Aircraft Owners and Pilots Association, said. "Many pilots approach new toys with skepticism, and the iPad seems to be almost universally appreciated as a cockpit device."
More than 250 aviation apps are available for the iPad, with one called ForeFlight among the top-grossing apps on iTunes.
Jack Long, a technology entrepreneur in Austin, wanted to save the $1,414 a year he paid for paper map and chart subscriptions.
He bought two iPads in December for his Pilatus PC-12, which he flies for business and pleasure. One iPad is a backup.
He now gets the same maps and charts digitally delivered to his iPads for $150 a year.
"I never pull out paper anymore," Mr. Long, a pilot for more than 30 years, said. "It's about safety as much as convenience. I can get at information immediately to make critical decisions."