Axalta

Much has been written all over the world about Takata, a company with diverse interests in supplying the automotive industry. Like Toyota the Takata Corp were initially focused on the production of textiles, and made two critical decisions on the back of huge external pressure to feed a rapidly expanding market – production of airbags and the change of gas generator technology.

For many years unlike companies such as Robert Bosch, Takata were only really known to the vehicle manufacturers – until a major global investigation into price fixing came to a head in Europe, Japan and the US during 2013. For the first time agencies from all three countries simultaneously investigated allegations of price fixing in a variety of commodities, including seat belts as well as airbags. Many companies were fined and executives jailed across the three prosecuting regions, including the major SRS suppliers – AutoLiv, Takata, TRW, Tokai Rika Co. The result for Takata was a fine of $71.3 million and three executives were jailed in the US.

However, bigger trouble was brewing for Takata – a situation which was recognised internally by late 2001 but it took until early 2015 for the company to admit in public.

Airbags And What They Do

The first commercial application for airbags came in the US during the 1970s, as a vital additional safety device. When used in conjunction with a seat belt the airbag can ensure the occupant cannot hit the steering wheel, dashboard or be hit by an obstacle from the side during an impact. The airbag is a deceleration device, so it has to:

1. Detect the severity of the impact – should any devices be deployed

2. Deploy the available devices for the best outcome

3. Each of the deployed airbags then has to inflate

4. The occupant then makes contact with the airbag as it deflates.

5. The whole process takes less than 0.2 of a second.

The integrity of the body shell and the major components fitted to it all influence the transfer of impact energy into the vehicle. The result is a series of deceleration curves for the vehicle taking into account the production tolerances for the body joints and equipment variations (ie, mass changes across a model range). Those curves, or ‘crash pulses’ are what the deceleration sensors detect, and the SRS control module then deploys the appropriate combination of airbags and seat belt pre-tensioners to ensure the best outcome for the occupants.

The crash pulse and supplementary restraint system (SRS) deployment is developed by the vehicle manufacturer – if the actual crash pulse is wrong then the airbags will deploy too early (the occupant will hit hard structures inside the vehicle anyway) or too late (the occupant will be severely injured or even killed because an inflating airbag has a skin speed between 140 and 320 km/h). The timing is critical – the occupant has to be moving in the direction of the airbag and contact it after it has started to deflate. Indeed the technology is finely balanced, and requires very accurate collision repair of the whole vehicle – not just the body panels – to restore the SRS performance.

By the 1980s seat belt technology had near universal fitment, but critically the US member states resisted the call for universal use by occupants. The result was to have two types of airbag structure – larger airbags for un-restrained occupants in the US, and smaller airbags for restrained occupants in the rest of the world. This meant developing two distinct SRS packages, and initially the SRS suppliers might have found they were building only one type of component for a given model range.

Now we can see that if the airbag is going to be inflated it has to occur quickly and precisely – and this goes to the heart of SRS technology.

Gassing Away

The airbag is folded carefully inside the cassette, with a talc or cornflower agent to ensure it will unfold very quickly even if it has not been used for 10 years. The bag is designed with carefully controlled fabric structure that allows the gas inside it to escape at the desired rate – so the airbag is a very carefully engineered component, dedicated to the vehicle application. The airbag is inflated by burning a chemical in a controlled fashion to generate the required volume of gas – again this is a very carefully engineered component dedicated to the vehicle application. Most of the airbag systems use nitrogen as the working gas.

The rate of burn, and thus gas generation, is controlled by the number of wafers or pellets inside the inflator cartridge. The particles of debris are captured by filters around the inflator cartridge case, and there are some traces of sodium azide (which is poisonous) also pass through into the car interior. The residue left in the inflator would contain sodium, so to negate this, additional chemicals were added to stabilise the remaining ‘ash’, including silica and potassium nitrate.

Production of the airbag inflator material (a mix of sodium azide and oxidising agent) was done in small batches in order to mitigate the risk of destroying the whole production plant should an accident occur, just as is the case for munitions. The inflator powder once prepared is pressed into either pellets or wafers, and then built into the inflator cassette. The advantage of this first generation ‘standard’ SRS inflator was the production process, adapted from a long established and mostly safe system (munitions), the chemicals were relatively stable and the end user benefits far outweighed the risks.

Enter Takata

In 1985 Takata took a momentous step, under pressure from Honda, to use the engineering fabric technology they had for the production of airbags. They quickly became an accepted global supplier for this technology, using the same inflator technology as the rest of the suppliers. The SRS suppliers were under pressure to eliminate sodium azide from airbags because the un-deployed materials is very, very toxic to humans. The search was on for a replacement technology.

Takata blew the opposition away by announcing in 1999 that they had a sodium azide free solid propellant inflator – tetrazole. The automotive world swamped Takata with orders, and the company underwent rapid expansion whilst building new production plants in Mexico, as well as in the US. Concerns soon surfaced as the supply of tetrazole was uncertain, and could not keep up with demand…. so by 2001 the company switched to ammonium nitrate instead. Commonly used in industrial explosives, this material was extremely sensitive to moisture content and prone to aging too. Critically, all the other SRS suppliers rejected this material due to instability, but Takata claimed they had a process that could stabilise the material.

What Went Wrong?

The first case of identifiable airbag failure occurred in 2009 when a seven-year old Honda had a low speed car park nudge which deployed the airbag. The driver’s jugular vein was severed – the accident investigation began. Three months later, the same thing happened, also on an older Honda. The investigation showed the debris, which had caused the fatal injuries, was parts of the driver’s airbag gas generator steel case – the gas generator had exploded, not producing gas as it was designed to do. Takata said nothing.

The number of incidents began to rise, and the US National Highway Traffic Safety Authority (NHTSA) started an investigation but closed it down by 2010 due to lack of evidence. The number of incidents continued to rise, and the vehicle manufacturers panicked. There was no sensible support from Takata, there was no logical reason for these problems – and yet the problem was occurring with greater frequency. The vehicle manufacturers had to act because their reputation was on the line.

NHTSA re-engaged with the investigation, and the Senate demanded a hearing. Recalls were sporadic, dealing with only the driver’s side airbag and only for the hot/humid states of the US – yet still the problems surfaced right across the US and beyond. Takata said nothing.

The Senate hearing committee demanded a public hearing. Takata appeared, said there was no fault and refused to allow investigators access to internal documents. The Senate hearing committee were angered by the delaying tactics and demanded co-operation, fining Takata $14 000 for each day they failed to give access. One former employee told the committee the issues were found back in 2001, and how the company knew of the instability issues certainly before 2004 – the point where Honda were informed.

Safety at all of the Takata plants was paramount and there were no significant breaches of the comprehensive safety rules – but the production process was not perfect. Company inspectors found as early as 2002 that ammonium nitrate production was left open to the atmosphere during extended shut down periods (weekends, holidays) instead of being put into dry storage. There were concerns about the life span of the gas generator, and demand was so high some of the gas generator modules were built with too few pellets/wafers. Finally the gas generator case design left some open design/function issues. All of these issues were flagged internally but not shared with all of Takata’s clients, or external agencies.

Takata admitted there was a problem for the first time on 19th May 2015.

What Was The Result?

As the panic raged the vehicle manufacturers – who had made it very clear that Takata gave them no answers – decided to replace the oldest modules with brand new ones. From the position in mid-2014 to March 2015, the replacement programme moved from driver’s side airbags in the hot/humid states to all airbags in most US states – and beyond.

On the 15th May 2015 the bombshell was dropped. Already younger vehicles were appearing with the same symptoms, and Takata finally admitted that there was an issue and theoretically even brand new units coming off the assembly line right now would end up with the same issue.

Of the 500 000 vehicles repaired in the US alone, all would have to be re-worked with an alternative technology. Takata alone had used ammonium nitrate – the other  SRS suppliers eventually found alternatives to sodium azide and had none of the issues Takata faced.

What Happens Next?

The recall programme across the world will roll out slowly. Each vehicle manufacturer will decide which vehicles (by VIN) and what parts should be replaced, and when – so the aftermarket is going to be 100% guided by the vehicle manufacturers/importers.

For the SRS suppliers the pressure is on. Already duplicate tool sets and in the case of older vehicles, re-commissioned tooling is underway. Inflator modules have been bought from competitor companies by Takata to help start working away at the enormous recall programme. Overall for the SRS sector, this whole affair has been very damaging in the eyes of the general public.

And For Repairers?

Unlike the normal service outlets collision repairers remove and refit SRS modules routinely. The rules around that are as strict as ever:

l Ensure the capacitor is fully discharged (wait around 10 minutes after disconnecting the battery).

l Remove the un-deployed SRS module without ever being directly in front of it.

l Keep the doors of the vehicle open.

l Place the un-deployed SRS module in a designated safety container, away from the main work area, sources of heat and lots of people.

There is an opportunity – to help customers, insurers and vehicle manufacturers understand – by asking the vehicle manufacturer or importer if the vehicle under repair is affected by a Takata-related recall.

An estimated 36 000 people are alive in the US alone, thanks to airbags deployed over the past decade and a half. But dozens of people have lost their lives because an issue raised within Takata during 2001 was not dealt with – an issue which was finally confirmed in 2015. For collision repairers there is no real operational issue as long as accepted work practice is followed without fail.

Auto Industry Consulting is an independent provider of technical information to the global collision repair industry. Products include EziMethods, our online collision repair methods system and Auto Industry Insider, our collision repair industry technical information website. For more information please visit the websites: www.ezimethods.com and www.autoindustryinsider.com or contact ben.cardy@autoindustryconsulting.com