Airbags not Deploying

[Mr E]

Casting my mind back to an accident near the village a couple of years ago - a Jeep hit an Astra that had failed to stop at the crossroads and crossed the main road. Jeep was doing about 50mph and had no chance to brake. Point of impact was the front nearside wing. Jeep's airbag deployed, nothing in the Astra.

The front of the Astra was rotated forwards in the direction of the Jeep's travel and span across the road into trees. The passenger in the Astra walked out, the driver had to be airlifted are being removed but recovered successfully.

The crew who extracted her said that there was no reason for the airbag to be deployed in her car as there was no frontal / near-frontal impact.

 

[television]

Side air bags have the sensors at the top of the door under the window, if the impact was below this, then they may not go off, most air bags are there to protect the head.

the said life span is 15 years but does anyone replace them, if you test them,, then it is like settinf off a fire work when you say "that one was good"

 

[grober]

Interesting point on the design lifetime of pyrotechnic safety devices such as airbags and seat belt tensioners. Many modern cars are now written off after a multiple airbag deployments incident. It seems the cost of replacing these devices and associated trim,seats, headlining etc pushes the repair costs over economic levels. A bit worrying how long it will be before insurance companies wise up to this. May be one more factor in determining the economic lifetime of modern cars i.e. you won't be able to ensure a car because the pyrotechnics are past their "sell by" date.

 

[DansSlk]

That's not an expected outcome though - a modern car is supposed to absorb the energy of the impact so that in even low speed impacts the car can look very damaged. If a car occupant wearing a seatbelt dies in 30MPH impact then I would suggest that that's extremely unusual - perhaps the person was already fragile.

I don't know what the person's health was like before hand to be honest with you mate but I've seen this more than once and I'm used to seeing mashed up cars that where involved in low speed incidents but that only applies when you hit a crumple zone, the nasty ones are where the car tends to look relatively undamaged.

Get an impact in the wing area like a glancing blow or a hit to the side and its very nasty, guess it helps if you have a wider car but its still one of the most dangerous places to get hit.

 

[DansSlk]

By the way I've only ever heard of one airbag deploying un-commanded and that was in an 80's model but the exact type escapes me.

Grober has a good point on the damage, if you've had your dash blown to pieces by one of these things firing then it can get very expensive but I'd prefer to fix that than run without the airbags.

 

[television]

By the way I've only ever heard of one airbag deploying un-commanded and that was in an 80's model but the exact type escapes me.

Grober has a good point on the damage, if you've had your dash blown to pieces by one of these things firing then it can get very expensive but I'd prefer to fix that than run without the airbags.

While talking on this subject,, have you ever had one go off when removed from the car,, I know there was a case where this guy sent one through the post and it went off

 

[DansSlk]

While talking on this subject,, have you ever had one go off when removed from the car,, I know there was a case where this guy sent one through the post and it went off

No mate.

I've never had an airbag (even older ones) deploy while it was being removed or while it was in storage and MB say to ship as removed only requirements are a padded and well marked box so they don't seem to think these things will go pop because they are bored either.

Same applies for the belts with pretensioners.

 

[Rory]

Get an impact in the wing area like a glancing blow or a hit to the side and its very nasty, guess it helps if you have a wider car but its still one of the most dangerous places to get hit.

That sounds like what happened in the original post and I can well imagine that a car being spun would cause potentially fatal neck injuries.

My sister-in-law was in a car when a truck reversed into the side of her car, but it little more than touched it. However it jolted her neck sideways and she's had severe pain ever since (this was maybe 10 years ago) and has really never been properly well since the accident.

 

[DansSlk]

That sounds like what happened in the original post and I can well imagine that a car being spun would cause potentially fatal neck injuries.

Yes it can be very nasty indeed, just not enough space for sufficient dampening and once your spinning its a real bad day.

 

[wemorgan]

Surprisingly car width varies a relatively small amount compared to length and height. In side impact car ride height and sill section size are the significant safety factors. In a small car to car side impact the front bumper beam will ride over the sill section and directly into the B-pillar and side impact beam. Whereas in a small car side impacting a 4x4 the small car front bumper beam will load into the sill section initially, absorbing a lot of the energy before intruding into the door and occupant zone. Either way, side impacts are very nasty things to ever have.

 

[CiaranMcKeown]

I dont mean to hijack this thread but i am almost 100% sure that there is some sort of G force measurement that has to be triggerd to set off an airbag aswell when in a collision.
As well as the sensors that must be somewhere, although i just renently removed the front bumper on my car and it came into my head while doing it, where would the sensors for such a thing be located?

I also have a question, in my c200 w203 there is a thing in the centre of the dash that says "airbag off". Now i sometimes put my 3moth old child in the frong seat especially when its only me and him in the car so that i can see him at all times and put the dummy back in his mouth that seems to trigger the loudest cry ever. The seat i have is compatable with both rear and forward facing positions, but i do not know hwo to manually turn this passanger front airbag off. Come to think of it, im never risking putting him in the front again because of this.

I have heard that official mercedes baby/car seats have an electronic code that turns this aribag off when positioned in the car but i dont know of any truth in this matter. But it would be a severe pain as anyone with children will know, to take a sleeping baby out of a car seat to put in another or a seperate buggy/pram is not possible. My car seat just clips into the buggy and were off.

 

[wemorgan]

Yes airbag sensors are accelerometers and there is usualy one in the tunnel, though I'm not sure where all the others might be. The front bumper's roll is mostly in low speed impacts upto 10mph. So that in a low speed shunt your bumper can be unbolted and a new one replaced cheaply. This test is assessed by Thatcham and partly makes up your car insurance rating.

You're right to never put a child seat in the front without turning off the passenger airbag. The airbag fully deploys in less than 0.1s. So with a child seat so close to the airbag on deployment it would be like a boxer punching the back of the child seat. I appreciate why parents what their child on the front seat, but the rear seats are much safer.