SP Guide Publications puts forth a well compiled articulation of issues, pursuits and accomplishments of the Indian Army, over the years

— General Manoj Pande, Indian Army Chief

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— Admiral R. Hari Kumar, Indian Navy Chief

My compliments to SP Guide Publications for informative and credible reportage on contemporary aerospace issues over the past six decades.

— Air Chief Marshal V.R. Chaudhari, Indian Air Force Chief

Dreamliner Delayed

Issue: 06-2009By Air Marshal (Retd) B.K. PandeyIllustration(s): By 293.jpg

Boeing recently announced that the first flight of the 787 Dreamliner would have to be postponed due to a need to reinforce an area within the sideof-body section of the aircraft. Preliminary analysis indicated that flight test could proceed this month as planned. However, after further testing and consideration of possible modified flight test plans, the decision was made late last week that first flight should instead be postponed until productive flight testing could occur. First flight and first delivery will be rescheduled following the final determination of the required modification and testing plan. It will be several weeks before the new schedule is available.

First passenger aircraft in the world made largely of composites, the Boeing 787 Dreamliner is much lighter than a metal aircraft of equivalent dimensions and is expected to be the most fuel-efficient in the world. Conceived in the late 1990s as a replacement for the Boeing 767, its maiden flight was originally scheduled for mid-2007. However, hurdles pertaining primarily to production derailed the event, which has now been postponed for the fifth time. Ironically, the inaugural flight was scheduled to coincide with the recently concluded 2009 Paris Air Show.

Repeated postponement of the test flight has tarnished the otherwise impeccable track record of the company, sent stock values plummeting and raised serious concerns among customers and shareholders alike. Reeling under the impact of slowdown in orders in the wake of the global economic downturn, recurrent troubles with the Dreamliner could seriously impinge on the credibility of the company. Moreover, the delay is agonising for customer airlines waiting eagerly for the Dreamliner to replace their fuel guzzling aircraft.

The latest hiccup was triggered by a disconcerting discovery of weakness at the wing-fuselage joint—a flaw that could have the potential to cause disintegration of the airframe should the airplane be subjected to high stress conditions in flight. During tests on the ground, it was discovered that the stress levels recorded at the wing joints were higher than predicted by the computer models. The airframe is fabricated on the basis of data generated through simulation models. The root of the problem may, therefore, lie either in the design or the manufacturing process, or worse still, in the software. In view of the recent disaster with the Air France Airbus 330 over the Atlantic, Boeing could ill-afford to ignore the problem. Hence, the decision to postpone the test flight is undoubtedly a sound one. Remedial action would involve reinforcement to strengthen the wing joints with attendant cost and time overrun as also weight penalty.

Displaying unflagging optimism, top company executives play down the problem as “localised structural reinforcement and is quite manageable”. Such imponderables, they argue, are often encountered in programmes related to the development of new aircraft. Boeing has been rolling out at hectic pace large number of other models such as the 737, 747, 757, 767 and 777 and has never faulted on delivery schedule. To that extent, the 787 programme is an aberration. But unlike the other models which have been built on well established processes, in the case of the 787, the manufacturing process is different—far more complex, ambitious and technologically challenging on account of the extensive use of carbon fibre.