TOULOUSE, France--Airbus aims to fly its new A350 for the first time in coming days, a milestone in achieving its target of getting the jetliner approved and into service next year.

For program manager Didier Evrard, the start of flight testing only increases pressure to ensure that Airbus and its suppliers are gearing up production smoothly.

Manufacturing missteps have recently tripped up Airbus, a unit of European Aeronautic Defence & Space Co. (EADSY, EAD.FR), and U.S. rival Boeing Co. (BA). Troubles developing and assembling the Airbus A380 superjumbo and Boeing's 787 Dreamliner have pushed those programs billions of dollars over budget and years behind schedule.

The A350, a two-engine intercontinental model designed to compete with Boeing's 787 and larger 777 models, is already more than one year late. Airbus has swallowed tens of millions of dollars in extra costs, in part due to troubles at its suppliers.

After problems with the superjumbo and Dreamliner, Mr. Evrard has made extra efforts to help Airbus suppliers, but concedes the process carries unknowns. "Taking on a supply partner is a bit like a marriage," Mr. Evrard said. "It's difficult to imagine how it's going to turn out on the first day."

Roughly half of the A350's structure is made from carbon fiber-reinforced polymer composites that are tricky to manufacture. Airbus and its suppliers have struggled to accelerate production of the precision parts.

One of the biggest headaches Mr. Evrard said he has faced is with Spirit AeroSystems Inc. (SPR). The Wichita, Kan.-based company has been building airplane parts for decades, but only for Boeing, from which it was spun off in 2005.

At one point last year, Airbus had more than 140 engineers and technicians working with Spirit to iron out problems.

"It took some time to realize the extent of the challenge, as [Spirit] had overestimated their capability," Mr. Evrard said at an Airbus technology presentation.

Spirit says the problems stemmed from the A350's novelty. "We believe that the issues we have been experiencing are normal at this stage of a program for bringing a brand-new airplane to market," said Spirit spokesman Ken Evans.

Issues at Spirit came as a surprise to Airbus, which selected the U.S. supplier largely because of its experience with Boeing. Mr. Evrard said Spirit hadn't fully adapted to independence and was accustomed to Boeing monitoring its suppliers.

To address this, Airbus commissioned an external audit of Spirit's internal processes. This allowed engineers and managers from Airbus to help Spirit improve its supply-chain management, Mr. Evrard said.

Spirit has "come a long way over the past two years and we have gotten rid of most of our headaches," Mr. Evrard said. "But we still have to keep an eye on them."

Airbus is ramping up A350 production as a boom in demand for smaller passenger jets is stretching aviation suppliers' capacity to meet increasing demands from Airbus and Boeing.

"Suppliers are dealing with a double squeeze from the ramp-up in production at Airbus and Boeing as well as the need to gear up for their new programs," said Christophe Menard, an aviation-sector analyst at Paris brokerage house Kepler Cheuvreux.

Supply-chain disruptions are "a real risk" for Airbus on the A350, Mr. Menard said.

Tom Williams, who oversees all Airbus programs, said the company experienced supply-chain problems last year as it increased production of its A320 single-aisle jet.

"We've had to inject a lot of additional resources into the supply chain and in some cases we've had to intervene directly in the supply chain, either actually taking a management ownership in some of suppliers, injecting money, injecting our managers and talent in order to help manage the problems and keep the suppliers afloat so that we could keep feeding our production lines."

Write to David Pearson at david.pearson@dowjones.com

Subscribe to WSJ: http://online.wsj.com?mod=djnwires

Spirit Aerosystems (NYSE:SPR)
Historical Stock Chart
From Mar 2024 to Apr 2024 Click Here for more Spirit Aerosystems Charts.
Spirit Aerosystems (NYSE:SPR)
Historical Stock Chart
From Apr 2023 to Apr 2024 Click Here for more Spirit Aerosystems Charts.