A Japan Airlines order for 20 Boeing 747-400 airplanes is one of the top Boeing orders of all time and makes JAL the largest customer for the jumbo jet, Boeing officials said Thursday. The order, worth $3.1 billion, brings to 40 the number of firm orders placed by JAL for the 747-400s. JAL also has options for 34 more of the aircraft. If all options are exercised, the order would be worth more than $7 billion, said Tom Cole, spokesman for Boeing Commercial Airplane Group. The jet, which can seat 600 people, has a range to 8,400 miles and a computer-aided cockpit that requires a crew of only two. The JAL planes will be configured to carry 375 to 404 passengers in three classes and will be outfitted with General Electric CF6-80C2 engines. Following JAL in firm orders for the 747-400s are Singapore Airlines with 29 and All Nippon Airways Co. of Japan with 26, Cole said. ``We call the Pacific a `747 ocean,''' he said. ``We do expect the airplane to sell well. It really has no competition.'' The order brings to 1,002 the total number of orders for the 747 series jets, making it the fourth civil airplane type in history to surpass the 1,000-mark in sales, Boeing said. The other models are Boeing's 727 and 737 series and the McDonnell Douglas MD-80 series. In dollar terms, the deal puts JAL in a four-way tie for fourth place among all Boeing orders with All Nippon Airways, United Airlines and Delta Airlines. The largest Boeing order ever was made by GPA Ltd. in May 1989, with 182 planes worth $9.4 billion. That order did not include any 747s, Cole said. Boeing has delivered 70 of the 747-400s since the model was first rolled off the assembly line in January 1989. A total of 279 of the jets have now been ordered. The JAL order brings to 138 the number of firm orders for Boeing planes this year, worth $11.4 billion, Cole said. The company sold a record 887 jets worth $46.7 billion last year, he said. Sumitaka Kawamura of JAL said that if the airline exercises all 34 options, its total investment in 747-400s will be nearly $12 billion. JAL plans to increase its fleet from 100 planes to 170 by 1999 to meet an expected increase in passengers. Kawamura said JAL had received five of the 747-400s planes by March, and would receive the rest by 1999 ``if our plans are not changed.'' Japan Broadcasting Corp. (NHK) said the orders would help reduce Japan's trade surplus with the United States.