Image credit: Brandrodungswanderfeldhackbau [shifting cultivation] October 2007

The batteries are now contained in a fireproof steel box with a chimney that vents outside the aircraft.  That’s what you get for an extra 200,000 hours of engineers’ time.

The actual root cause of the problems previously experienced “may never be determined” but some 80 battery-related technical features have been upgraded.

Why try a new battery design

The Lithium-ion batteries on the 787 are characterised by being able to provide a large amount of electrical power in a short period of time.  They are about the size of a car battery and are much lighter than older types of battery.

By way of comparison, the 787’s batteries provide up to 150A of current and weigh 29kg (excluding the new modifications), whereas the older battery design used on the Boeing 777 weighs 49kg and provides just 16A of current.

What are the batteries used for?

There are two identical lithium batteries carried on the Dreamliner.  The one in the middle of the craft is used to start a small turbine at the tail of the aircraft, the Auxiliary Power Unit (APU).  And it powers the navigation lights.  The APU, in turn, provides the power (1100 shaft horsepower) needed to start the main engines.

The battery in the forward electrical bay, under the main cabin floor,  powers certain accessories when the aircraft is on the ground, and powers various electrical systems prior to the APU starting up.

All craft being modified

Ten teams of engineers, averaging 30 per team, are converting the 50 Dreamliners already delivered so they can be returned to service.  The modifications are scheduled to be completed mid-May.  The first commercial flights have resumed without incident.

The modifications are also being applied to aircraft that have been built but not delivered.  All deliveries scheduled for 2013 are expected to be delivered by the end of the year.

No problems have been experienced with craft that have been modified and returned to service.

Image credit: Altair78, 22 December 2009

The European Aviation Safety Authority (EASA) has followed the lead of the Federal Aviation Authority (FAA) in grounding the entire Boeing 787 fleet.  Ethiopian airlines are also grounding their planes on routes that do not fall under the EASA or FAA jurisdiction.

Concerns are focussed on the Lithium ion batteries, which we had identified as a risk in our previous article on the plane’s woes FAA questions safety of Boeing 787.

While Airbus make some use of Lithium ion batteries, they do not have the critical dependence on them that the Dreamliner has, because of its extensive use of electrical control of flight surfaces.

If investigation proves the problem to be a manufacturing defect in the batteries then the Dreamliner fleet will not be grounded for long.  If, however, the fault lies with the aircraft wiring or the design of the electrical systems themselves then there could be major delays.

If there are significant delays it will undermine operator confidence in the Boeing 787 and they will start cancelling orders, preferring perhaps to wait for the Airbus A350, which is currently scheduled to make its maiden flight in mid-2013.

In the mean time, The Guardian newspaper pleads, “Please do not call it the BinLiner”!

Image credit: Strower, 1 November 2012

Following a week in which there was a Boeing 787 safety incident each day, the FAA has ordered a safety review.  Though FAA inspectors spent 200,000 hours inspecting the design during the development process, they now have concerns about elements of the design as well as how the plane is built, and the safety of the electrical systems.

Many new aircraft designs experience a certain number of problems when they first go into production, and these often attract lurid headlines.  This seldom indicates major underlying problems.  However, it also seldom results in an FAA review.

There are only 50 Boeing 787 aircraft in service world-wide, six of which are operated by United Airlines in the USA.  Five incidents in a week therefore represents an alarmingly high problem rate.  It is 10% of the fleet!

Safety IS an issue

The FAA quote U.S. Transportation Secretary Ray LaHood as saying that “The safety of the travelling public is our top priority.  This review will help us look at the root causes and do everything we can to safeguard against similar events in the future.”

The Boeing 787 fleet has collectively logged 50,000 hours in the air – an average of just 1000 hours per aircraft.  In aircraft terms that is still factory-new.  (The now-resolved wing support problem in the Airbus A380 fleet only emerged at 1800 hours of service, so further surprises could still lie in store for Boeing.  Or not, as the case may be.)

Critical systems

It is clear that this is a serious review, not just a formal checking of the paperwork.  The FAA will check the design of critical systems.  Particular emphasis will be given to the electrical systems.  The interaction between electrical systems and mechanical parts of the aircraft will be examined in detail.  In addition to reviewing the design, the team (which includes Boeing engineers) will also examine manufacture and assembly.

Lithium ion batteries restricted

The fire hazards of Lithium ion batteries have long meant that they may not be shipped by air.  Since 1 January 2008 Lithium ion batteries have also been illegal for passengers to carry in checked-in luggage.  According to reports, in one of the recent Boeing 787 safety incidents a Lithium ion battery manufactured in Japan installed in a Boeing 787 exploded.  Fortunately there was no penetration of the hull.

How did Boeing get permission to install Lithium ion batteries as standard equipment in the Dreamliner?

Manufacture

The likely reason for the review of the manufacturing process is that the Boeing 787 relies on outsourced manufacture to a greater extent than for other planes.  There have been credible, serious allegations aired about outsourced manufacture at Boeing, in relation to structural elements of the 737 NT.  This has been linked to structural failure after minor runway incidents.

Boeing 787 aircraft will continue to fly while the review takes place.