I’m not in the business of attacking Boeing, but the optics of a decision to remove lightning safety protections on the 787 are not helpful to the troubled aircraft manufacturer.
Boeing Removed Lightning Protection On 787 Dreamliner
“Lightning protection on an airplane like the 787 that’s fabricated largely from carbon composites is more elaborate than on a metal aircraft. When Boeing developed the Dreamliner, it included special measures to protect the wing fuel tank. It sealed each metal fastener in the wing with an insulating cap and embedded copper foil in strips across the carbon wing skin to disperse the current from any lightning strike.”
Five years ago, to cut costs, Boeing stopped adding insulating fastener caps. In March, Boeing stopped adding copper foil.
The U.S. Federal Aviation Administration (FAA) initially ruled that Boeing had not shown that the removal of the copper foil would still leave “extremely improbable” the chance of an ignition of the fuel vapor by a lightening strike. The standard for “extremely improbable” is “likely to occur no more than three times in a billion flight hours.”
But Boeing had already churned out 40 sets of wings without the copper foil and appealed the decisions. FAA managers reversed the earlier decision and the Dreamliner products sans cooper foil was allowed to proceed.
Days later the second 737 MAX, ET3o2, crashed.
FAA Engineers Objected To Removal Of 787 Safety Protections
FAA engineers objected to their safety determinations being overruled by managers. One filed a formal complaint, stating:
“I do not agree that delivery schedules should influence our safety decisions and areas of safety critical findings, nor is this consistent with our safety principles.”
Even in the initial aftermath of the ET302 crash, FAA was still delegating certain safety approval processes to Boeing itself.
Boeing: Extra Protections Were Unnecessary
Boeing argues the “extra” precautions were unnecessary to maintain the integrity of the aircraft and keep passengers onboard safe. It stressed “several other layers of protection from lightning strikes” and added that the removal of copper foil “was properly considered and addressed by Boeing, thoroughly reviewed with and approved by the FAA.”
That does not appear to be the case.
Boeing specifically noted that other 787 lightning protection measures remain.
“In addition to the various measures taken to reduce the chance of a spark, the 787 wing fuel tank has a nitrogen-generating system (NGS) that reduces flammable vapor by filling the space above the fuel with inert gas.”
Perhaps these extra layers of safety are indeed unnecessary – that is beyond my expertise. But the optics of this situation do not cast Boeing in a good light, especially the FAA engineer objection. I think there are all sorts of politics at play that are delaying the 737 MAX re-entering service. Perhaps politics are involved here too. But looking at the evidence raises more questions than answers.
image: John D. Parker / Boeing