Automakers Find Three Root Causes for Defective Takata Airbags

Automakers plagued by the Takata airbag recalls have found three specific root causes for some of the inflator ruptures, according to preliminary results from a study coming in the next few weeks.

Phase-stabilized ammonium nitrate without a moisture-absorbing desiccant is but one factor, according to the Independent Testing Coalition, a group of 10 automakers formed in December 2014 after they were named in the Japanese supplier’s recalls (BMW, Fiat-Chrysler, Honda, Ford, General Motors, Mitsubishi, Mazda, Nissan, Subaru, and Toyota).
When moisture is present, “long-term exposure to repeated high temperature cycling" and airbag inflator assemblies that do “not adequately prevent moisture intrusion" were also identified, the group said, “all of which contribute to the rupture of Takata airbag inflators."

The testing, conducted over 20,000 hours by Virginia-based defense contractor Orbital ATK, which builds rocket engines and ammunition, focused on the roughly 23 million inflators recalled in 19 million cars in the U.S. Orbital will run more tests to include an additional five million Takata inflators recalled within this month, as well as inflators produced with desiccant and brand-new inflators intended as replacement parts for the recalls–which the National Highway Traffic Safety Administration has admitted may not work long term. For that problem, Orbital will run an aging test.

In a separate, earlier report, NHTSA vehicle integrity chief Scott Yon said that “long term" means more than five years. The propellant wafers enlarge over time, at which point they become too large and begin to cause ruptures, Yon wrote.

“This is not short term exposure to high absolute humidity like during a 2 week vacation or even for 5 months each winter," he wrote. “It is continued exposure to high absolute humidity year round for multiple years in a row."

In light of the test results, NHTSA’s November consent order with Takata, in which it was fined $70 million over several years, may need to be amended. That’s how minority staff in the Senate Committee on Commerce, Science, and Transportation put it in a new report after reviewing internal company documents.

“To protect the public from an unreasonable risk to safety, Committee minority staff believe that NHTSA should immediately exercise its authority under the Consent Order and Coordinated Remedy to accelerate the phase-out schedule for non-desiccated ammonium nitrate-based inflators and to create a phase-out schedule for desiccated ammonium nitrate-based inflators."

According to the consent order terms, Takata has until 2018 to cease production of all non-desiccated ammonium nitrate inflators and until 2019 to prove that ammonium nitrate is safe within its most current products. While Takata agreed to stop entering new contracts for desiccated ammonium nitrate inflators, there is no production cap on those inflators.

Orbital has shared its results with Takata, which has not released any of its own test results since December 2014. Takata has yet to complete an internal audit and still has not identified the root causes of its own defective products. More than 24 million vehicles from 24 brands have been recalled in the United States. Clifford Atiyeh, Car & Driver

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