McDonnell and Boeing Land Big Airliner Orders : Aerospace: The orders for more than 75 planes are worth up to $8.5 billion. And NWA Inc., the parent of Northwest Airlines, made a $4.6-billion deal with Airbus Industrie of Europe.

U.S. aircraft giants Boeing Co. and McDonnell Douglas Corp., touting their planes at Britain’s Farnborough International Air Show, Monday announced orders for more than 75 new jetliners valued at $8.5 billion.

At the same time, Minneapolis-based NWA Inc., the parent of Northwest Airlines, said it has converted options on 75 A320 aircraft from the U.S. plane makers’ European competitor, Airbus Industrie, into firm orders and had taken new options on 30 A321 aircraft in a deal worth $4.6 billion. Airbus is a four-nation consortium comprising Aerospatiale of France, Deutsche Airbus of West Germany, British Aerospace and CASA of Spain.

Irish-based GPA Group Ltd., the world’s largest aircraft leasing company, said it ordered up to 25 MD-11 long-range aircraft worth about $2.5 billion from St. Louis-based McDonnell Douglas.

The group made 13 firm orders for the aircraft and took options on 12 more, due for delivery between 1995 and 1999. The order brings GPA’s total orders and options for the MD-11 to 45 planes.

The GPA order is the largest MD-11 sale McDonnell Douglas has made and comes after a hiatus in which the firm did not receive any major orders. But the McDonnell Douglas order was still substantially smaller than those received by both Boeing and Airbus, continuing a trend in which McDonnell Douglas has seen its market share erode significantly.

Graham Boyd, GPA’s managing director for new aircraft acquisitions, told a news conference at the air show being held this week near London that the company has no leasing customers yet for new planes.

McDonnell Douglas, the largest U.S. defense contractor, is striving to expand its commercial aircraft production in the face of cutbacks on military spending. It has received 379 orders and 32 additional commitments for the MD-11, including the new GPA order.

Seattle-based Boeing, the world’s largest maker of commercial aircraft, said South Korea’s Asiana airline had placed orders and options for 51 Boeing planes worth almost $6 billion.

Asiana’s firm orders were for 10 medium-range Boeing 767-300s, eight short-haul 737-400s, six long-range 747-400s and three 747-400 freighters, Boeing said. Asiana also took options on eight 737-400s, six 747-400 passenger jets and freighters. Boeing said the 27 firm orders were worth about $3 billion.

NWA said its Northwest Airlines unit would operate 100 A320s by 1995. It already has eight of the 150-seat short- to medium-haul airliners in operation and says it would be operating up to 170 Airbus aircraft by the end of the decade.

Northwest said the new options for the A321 were convertible into A320s before 1994 and were for delivery after 1996. The planes will be powered by CFM56-5 engines.

Asiana, formed in 1988 by the South Korean conglomerate Kumho Group, already operates 10 737-400s and two 737-500s.

It has previously announced orders, worth $1 billion, for two 767-300s to be delivered next month, two 747-400s for late 1991 delivery and five 737-400s, with options for another five 737- 400s.

The independent Korean carrier has not yet chosen which engine will power the newly ordered 747s and 767s. All its 737 variants are powered by CFM56-3 engines, built by General Electric of the United States and SNECMA of France.

Boeing said the latest order brings its total firm orders in 1990 to 283 aircraft valued at $27 billion.

Privately owned Asiana competes with South Korea’s national carrier Korean Air Lines--also privately owned--on most domestic routes. It began domestic flights in December, 1988, and launched international flights to Tokyo and three other Japanese cities earlier this year.