Fly Me Friendly

I know I’ve said it before, but this latest news from Jon Ostrower (aka FlightBlogger) about the recent Boeing 787 delay being due to a design flaw in the tail really makes me wonder if the 787 isn’t doomed to become the De Haviland Comet of our time.

According to Jon’s report, the problem was discovered in December and is related to the unpressurised tail section of the aircraft. Apparently:

… the shear ties, those of which are made of aluminum, can pull away from the skin of the fuselage, potentially compromising the structural integrity of the aircraft.

The emphasis is mine to highlight that this is no small issue.

So what went wrong that could allow this problem to occur? According to Jon’s report:

… after the initial design failed to take into account thermal fatigue loading of the parts.

That’s a pretty serious design omission, don’t you think?

The 787 represents the same sort of technological leap in design & construction that the Comet represented in its day. Sadly, the design of the Comet was discovered to have catastrophic failures in whole new areas that hadn’t been encountered before (metal fatigue, the effects of repeated pressurisation cycles, etc).

The 787 project has been delayed repeatedly due to problems being encountered with its design and construction techniques. How many other problem areas will this aircraft encounter during testing? Will there be any others that escape testing but appear during operational use?

These are the risks that a company takes when it leaps so far ahead in technology. While Boeing is doing as much as they can to test & verify the aircraft, one cannot help but wonder if, like the Comet, the 787 will teach us about something entirely new that will be discovered at great cost.

With the recent announcement from Boeing that the first flight of their 787 was to be delayed due to structural issues in the wing box area, many of us knew right away it was a major show-stopper issue. Boeing made the announcement only a few days before people were expecting the first flight, catching many by surprise. With so much riding on this project and so many delays already experienced, Boeing were pushing hard to get the 787 in the air as soon as possible. That Boeing couldn’t start the test flights while addressing this problem in parallel showed us it was a big issue, something that would either lead to a structural failure in flight or would require so many changes that testing would have to start again after the modifications were made.

Subsequent to their announcement of a delay, it was confirmed that the issue involves wing flexing travelling into the fuselage leading to delamination of wing panels. This report and others do not paint a very pretty picture with many predicting that the 787 won’t fly until next year (2010).

All of this puts a major strain on the credibility of the programme, Boeing’s bottom line and their share price. They are eager to reach the first flight milestone and progress quickly towards delivery payments from customers. Anything that is feasible and safe will be done to get the 787 airborne ASAP, thus the longer the delays we’re seeing, the bigger the problem becomes.

The 787 is breaking new ground in many areas, from structures to systems to construction & assembly processes. In many ways this is similar to the de Havilland Comet that ushered in jet travel to an eagerly awaiting world.

While bringing in new technologies such as advanced alloys and new bonding methods, the Comet was also extensively tested prior to its entry into service. The Comet also utilised existing concepts such as large, square windows & hatches in the fuselage. As was tragically discovered, stress concentration occurred around the corners of the windows & hatches, leading to higher pressures in those areas and, eventually, metal fatigue that ruptured the fuselage with catastrophic results. By the time the problems were resolved, the Boeing 707 had eclipsed the Comet and, together with the Douglas DC-8, taken over the jet transport market. Boeing and Douglas both certainly benefited from the painful lessons learned from the Comet.

Returning to the present, Boeing discovered the 787′s structural problem during fatigue testing of a designated airframe. Despite countless computer simulations the issue was apparently never predicted and, like the Comet, took them by surprise.

Fortunately in this case the problem was discovered on the ground and without loss of life. Also fortunate for Boeing is that the Airbus A350 is still lagging the 787′s schedule, although the distance between them is rapidly decreasing. If the 787 doesn’t fly until 2010 and Airbus can hit the A350′s scheduled first flight in 2011, things could get very bad for Boeing.

While I doubt many 787 customers will be seriously considering converting their orders over to the A350 at this point, if the A350 continues on track and meets its target figures, further delays of the 787 will make the Airbus product start to look more interesting to 787 customers. If that happens, Boeing will be in big trouble indeed!