Raised stakes

(The following article first appeared as the main leader in 22 January 2013 Flight International)

The US Federal Aviation Administration acted correctly to ground the Boeing 787 because of fears over battery fires, but the decision raises questions about the integrity of a certification process that declared the 787 airworthy less than 18 months ago.

The grounding seems at once slightly unfair and yet appropriate. Why unfair? With all new aircraft there are problems in service that cannot be anticipated in the controlled environment of a certification trial. But the 787′s unique high-power electrical system means that even the slightest glitch can raise concerns about onboard fires and containment measures.

The FAA’s certification process has always missed small problems that can only be discovered after an aircraft encounters the random conditions of a diverse group of operators. Hans Weber, owner of aviation consultancy Tecop, recalls how airlines protested against the initial reliability of the Boeing 747-400, especially in the galleys where a burner tended to melt the aluminium coffee pot. That glitch also posed a fire hazard, Weber says, but the FAA never felt the necessity to intervene.

On United’s first long-distance 777 passenger flight, crews found a passenger door frozen shut upon landing. A small channel of moisture inside the doorframe had gone undetected during flight testing.

What makes the 787 different is the severity of a few of its “teething” issues. A contained engine explosion in July and a battery meltdown and associated fire in January are serious safety alarms no-one expects after airworthiness certification. Both incidents triggered probes by the US National Transportation Safety Board, which usually focuses on incidents involving injuries and fatalities. And now the 787 is grounded around the globe while the battery fire investigation continues.

Airlines are rightfully demanding fuel-efficiency gains, driving manufacturers to design ever-increasing levels of performance from the turbofan and electrical system. On the 787, both of these systems are operating at extreme conditions never before experienced in commercial operation. Hence, even small mistakes – such as, say, switching to a lead-free coating and inadvertently triggering a contained engine failure – can have unexpectedly severe consequences.

The airworthiness process is not designed to screen for the risk of every random fault. As airframers assume more performance-driven risks, the kind of regulatory interventions required for the 787 are likely to become more routine.

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