“I bought a car with airbags just to ensure that my family and me are safe during an accident, but the airbags didn’t deploy when an actual crash happened”, is becoming more and more common on Indian roads. Airbags are passive safety devices that come into play in the event of a crash, protecting the occupants of the car from the harder elements of the car’s interiors. But why are there so many complaints about airbags not deploying even in very serious crashes? We give you the lowdown.
Meanwhile, here is the latest case of airbags not deploying on a vehicle. A Mahindra XUV500 recently aquaplaned, rolled over and then came to rest against a coconut tree. According to a first person account who was driving the Mahindra XUV500 W8, this incident happened when the crossover was doing about 90 Kph on a wet road. A puddle caused the XUV500 to aquaplane and control was lost, leading to a rollover. The vehicle came to a rest after it’s side collided with a coconut tree. Miraculously, all five passengers of the XUV500 survived without major injuries.
From the post crash images of the vehicle, it is clear that none of the six airbags present inside the XUV500 deployed. So, what could have been the possible reasons for airbags not to deploy?
Accelerometer sensors not triggered.
Let’s first understand how airbags work. Airbags are inflated and deployed when the airbag ECU sends a signal to the triggering circuit. The airbag ECU gets this signal from the sensor, which detects deceleration. Based on a specific amount of deceleration, the ECU decides on whether or not to deploy airbags.
If the deceleration is not hard enough, airbags will not deploy. This is the reason why you will have the airbags deploying when you hit a wall straight on at say 20 Kph. On the other hand, you can hit a large piece of sponge at 40 Kph and the airbags may not deploy due to insufficient deceleration sensed by the sensors.
In case of the Mahindra XUV500, the vehicle rolled over, which means that the front of the vehicle hardly took any deceleration impact. Due to this, the driver and passenger airbags were not deployed.
Conditions where a crash does not require an airbag activation.
There are many minor crashes that do not produce enough deceleration to activate the airbag circuit. During such minor crashes, airbags do not deploy as they would not be required to cushion the impact between the car’s occupants and its interiors. In such case, the seat belts do a fair job in restraining the occupants from actually coming in contact with the car’s interiors.
Seatbelts not worn.
The XUV500 involved in the crash is a W8 variant, which means that it is equipped with curtain airbags. Coming to the curtain airbags, they deploy upon a side impact or a rollover. These events are registered by sensors that detect side impacts through the doors, and of course roll overs. If seat belts are not worn though, none of the airbags will be deployed. This is because the airbag can do a lot of damage to the car’s occupants if a seatbelt is not worn.
The airbag is basically deployed through controlled explosion. If the seat belts aren’t worn, the occupants of the car can come into contact with high temperature gases used to deploy the airbags. This can cause serious burn injuries, which is why seat belts are mandatory for airbag inflation. In case of the XUV500, if the seat belts of the middle row passengers weren’t fastened, there is a good chance that the airbags didn’t deploy due to this reason.
Bullbar and other accessories added to the front of the car.
Car and SUV owners are frequently known to add accessories to the front of their vehicles. Bullbars, nudge guards and even bumper inserts that are not approved by the car manufacturer can interfere in the airbag deployment process. These accessories can interfere with the rate of deceleration that the sensor senses.
Due to this, larger impacts may be wrongly sensed as smaller impacts, causing the airbags to fail. In other circumstances, the impact assessment may take a split second longer, resulting in wrong timing of the airbag deployment, which is also very dangerous.
Airbags CAN just fail.
Airbags are not 100 % reliable components. They are known to fail occassionally. In this case, it could have purely been a case of airbags failing to deploy when required the most. In fact, the world’s largest airbag maker, Takata, is facing multi million law suits in the United States for producing faulty batches of airbags that have actually caused the death of car occupants than protecting them during crashes.
Closer home in India. Toyota had to pay up 25 lakh rupees to a Fortuner owner, whose SUV’s airbags didn’t deploy in an accident. Does this mean that you shouldn’t buy a car with airbags. Well, for every incident of airbags failing to deploy, there are 9 incidents where airbags have deployed at the right moment, saving lives. On the road, you need every bit of active and passive safety to stay alive.
So, you must opt for a car equipped with airbags. You must also remember that no safety device in this world can make up for stupid driving. So, drive cautiously and sensibly.
Aquaplaning or hydroplaning
Now, this is specific to the case of this particular Mahindra XUV500, whose curtain airbags didn’t deploy. The vehicle in this case, rolled over. For curtain airbags to deploy, the roll over sensors need to be activated, which will get the airbag circuit into action if needed.
However, the roll over happened due to aquaplaning/hydroplaning. When aquaplaning (total loss of wheel traction caused due to driving on large puddles water) occurs, the rollover sensors will not work as these sensors require traction.
Since the roll over sensor didn’t register the roll over, it is possible that the curtain airbags didn’t deploy. However, side impact sensors should have gotten into action and deployed the airbags during the roll over. Even this doesn’t seem to have happened.
In the past, Mahindra has even recalled the XUV500 to install new software for the curtain airbags’ deployment. It remains to be seen if that recall has any connection with the latest accident. The automaker has a few questions to answer here.
[Images courtesy Team-BHP]
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