Advanced Driving Hub

Jonquirk wrote:As I understand it airbags don't deploy unless the vehicle has reached a minimum speed threshold, 18mph sticks in my mind but could be incorrect.

Good point. The impact sensor and safing sensor will both need to 'agree' that an impact has occurred.

Horse wrote:

Jonquirk wrote:As I understand it airbags don't deploy unless the vehicle has reached a minimum speed threshold, 18mph sticks in my mind but could be incorrect.

Good point. The impact sensor and safing sensor will both need to 'agree' that an impact has occurred.

AND the ignition switched on (see discussion on order of doing things)

GTR1400MAN wrote:

Horse wrote:

Jonquirk wrote:As I understand it airbags don't deploy unless the vehicle has reached a minimum speed threshold, 18mph sticks in my mind but could be incorrect.

Good point. The impact sensor and safing sensor will both need to 'agree' that an impact has occurred.

AND the ignition switched on (see discussion on order of doing things)

Nope.

That's why the fire service place restraints over the steering wheel before starting casualty extraction.

Horse wrote:Nope.

That's why the fire service place restraints over the steering wheel before starting casualty extraction.

Nope.

It's because they may set them off with their equipment (static charges released) or there is the possibility the ignition is not off due to crash damage or inability to turn the key. Big legal cases about this in America where faulty ignition switches were disabling safety aids, including air bags, even while the car was switched on. The control circuits need electricity. They are turned off when parked.

Don't forget residual charge in the vehicle's system

AFAIK, the only 'unexpected' deployment of an airbag was a 1990s Peugeot which had suffered a major fault with its wiring loom and the airbag deployed during recovery.

However, as Esther Rantzen used to say, if you know different then I'd like to hear about it

I did hear of a mechanic accidentally triggering all the airbags in a Volvo while working on the car. It happened in Keswick; I was delivering a new van to a BT workshop. The BT guy was talking to a parts delivery driver who had just witnessed this happen at another garage in the town while he was delivering there.

Horse wrote:

fungus wrote:And if some clown were to collide with your vehicle and you didn't have the seatbelt on when the airbag deploys... Ouch.

Nigel.

. . . Got some proof that it would be a problem? My understanding is that current airbag testing inudes 'out of position' occupants, using test dummies rested against the airbag.

I stand corrected. An airbag will deploy if the ignition is switched on and the car stationary. It will not deploy if the ignition is switched off.

Nigel.

fungus wrote:

Horse wrote:

fungus wrote:And if some clown were to collide with your vehicle and you didn't have the seatbelt on when the airbag deploys... Ouch.

Nigel.

. . . Got some proof that it would be a problem? My understanding is that current airbag testing inudes 'out of position' occupants, using test dummies rested against the airbag.

I stand corrected. An airbag will deploy if the ignition is switched on and the car stationary. It will not deploy if the ignition is switched off.

Nigel.

Apologies; I meant the 'ouch' comment. If you're sat in a normal driving position then an airbag deployment is unlikely to cause significant harm. Actually, it's highly unlikely full stop, so much so that it's not worth worrying about and so shouldn't be a consideration for cockpit drill - the rest of your drive will be more hazardous!

Jonquirk wrote:I did hear of a mechanic accidentally triggering all the airbags in a Volvo while working on the car. It happened in Keswick; I was delivering a new van to a BT workshop. The BT guy was talking to a parts delivery driver who had just witnessed this happen at another garage in the town while he was delivering there.

Blimey, that must have been noisy and spectacular! With the number of pyrotechnic devices which might be fitted, that's a lot happening!

How long ago did that happen?

It was either 1999 or 2000. Apparently the guy was temporarily deafened and looked like a ghost due to the cornstarch used to stop the folded airbags sticking to themselves.