AmSafe news

[Piloto]

2 hours ago, DanM20C said:

Proper four point harness would be preferable to the shoulder harness,  But I don't think that is an option in our Mooneys. 

The faulty Takatat airbag system is a real concern.  The problem, as I understand it, is when the propellant aged sometimes it would "explode" (chemical reaction faster than designed) when activated.  That caused bits of metal and plastic to become shrapnel when the airbag deploys.  That is what killed people, not random airbag deployments.  Much will be learned from this and airbags will be even safer.  When an AmSafe deploys the energy is 180 from the traditional car airbag, if anything is ejected from the airbag system it will be moving away from the occupant. Even if the propellant "explodes" it will likely not be fatal.

I can see premature deployment a real concern, especially in aircraft.  Has there been any?  There are a lot of AmSafes flying around in GA for the last decade. 

Cheers,

Dan

Thanks for your comments. My concern for unexpected deployment in-flight is while in turbulence particularly in wind shear events. Some of these events can have wind shift speeds of 40kts with high decelerations. These events are survivable by small planes. I was involved in the development and testing of predictive wind shear radar in a CV580 turboprop N580AS and can tell you that these events can feel like crashing multiple times at less than 500ft AGL. Here in Florida there is a lot turbulence activity and a high g activated balloon is not my preference to have.  

José

[jetdriven]

I wonder if there has ever been an unintended deployment of an Amsafe seatbelt airbag. Airliners even have these systems too and I’ve never heard of one going off outside of a crash. 

Even with the faulty Takata airbags and malfunctioning Tesla auto pilots killing people, they still save a great many more lives than they take. 

[aviatoreb]

29 minutes ago, jetdriven said:

I wonder if there has ever been an unintended deployment of an Amsafe seatbelt airbag. Airliners even have these systems too and I’ve never heard of one going off outside of a crash. 

Even with the faulty Takata airbags and malfunctioning Tesla auto pilots killing people, they still save a great many more lives than they take. 

I remember reading a few years ago of a company pilot for Mooney who had to crash land an Acclaim that then stopped at when it hit a fence.  He got out without any injuries and said it was an abrupt stop but not brutal and the airbag did not deploy.  So I took this as evidence that it takes quite a lot of force to cause it to deploy (when functioning properly) just like a car airbag is not supposed to deploy unless it is quite a bad crash.

That does not mean that it is impossible to have them deploy when faulty.  But I have never heard of that.  Come to think of it, I have never heard of a car bag deploying spontaneously - but I bet the have somewhere in the world at some point. Still would a false alert spontaneous amsafe airbag deployment necessarily cause a crash?  I would guess more likely it would be a nonissue other than an expensive annoyance.

[aviatoreb]

1 hour ago, Piloto said:

Thanks for your comments. My concern for unexpected deployment in-flight is while in turbulence particularly in wind shear events. Some of these events can have wind shift speeds of 40kts with high decelerations. These events are survivable by small planes. I was involved in the development and testing of predictive wind shear radar in a CV580 turboprop N580AS and can tell you that these events can feel like crashing multiple times at less than 500ft AGL. Here in Florida there is a lot turbulence activity and a high g activated balloon is not my preference to have.  

José

I read somewhere (take it as unverified) that it takes 20-30g's to cause the car airbags to deploy when functioning properly.  If that kind of force is coming from wind shear, then surely you have bigger things to worry about - the wings would fall off.

What is the true acceleration threshold - in g's, that car airbags are designed for?  How about amsafe airplane belt bags?

[jetdriven]

It must be several G’s. The switch is low tech but works, takes only forward force to make the magnet overcome the spring and fire the bag. 

They say there’s never been an inadvertent deployment. Even if so, would it injure, kill, or cause you to lose control of the plane? I don’t think so. 

[Piloto]

47 minutes ago, aviatoreb said:

I read somewhere (take it as unverified) that it takes 20-30g's to cause the car airbags to deploy when functioning properly.  If that kind of force is coming from wind shear, then surely you have bigger things to worry about - the wings would fall off.

What is the true acceleration threshold - in g's, that car airbags are designed for?  How about amsafe airplane belt bags?

At a 28g's crash your eyeballs will come out and for sure a broken neck or decapitated. But no need to worry because the airbag deployed.

[jetdriven]

I know the FAR 23 airplanes such as Cirrus seats are designed to a 26G standard. Interestingly the restart 172 has them too, some even have the airbags as well. 

Humans can survive high G events for a short timeframe, remember Colonel Stapp’s rocket sled.  46G with an onset of 500G per second. Perhaps Jose can learn from this page  http://www.ejectionsite.com/stapp.htm

An Airplane or car hits something solid such as a tree, the initial G of the event can be 100G but that’s the car slowing down. The occupants are still moving forward until the belts arrest their motion or they begin to hit the instrument panel or the survivable space becomes too small. The airbag sensors detect this and deploy the airbag to spread the deceleration over a little longer timeframe. 

 

Edited January 30, 2018 by jetdriven

[aviatoreb]

7 minutes ago, Piloto said:

At a 28g's crash your eyeballs will come out and for sure a broken neck or decapitated. But no need to worry because the airbag deployed.

Yeah - that sounds right - my memory is bad....

But there is an actual number - what is the number?  My guess is the number for airbag deployment is significantly higher than vne stress and probably in the metal-crunch range.

[aviatoreb]

10 minutes ago, Piloto said:

At a 28g's crash your eyeballs will come out and for sure a broken neck or decapitated. But no need to worry because the airbag deployed.

The human body is better at surviving g-forces that are perpendicular to the spine. In general when the acceleration is forwards (subject essentially lying on their back, colloquially known as "eyeballs in"^[13]) a much higher tolerance is shown than when the acceleration is backwards (lying on their front, "eyeballs out") since blood vessels in the retina appear more sensitive in the latter direction^{[citation needed]}.

Early experiments showed that untrained humans were able to tolerate a range of accelerations depending on the time of exposure. This ranged from as much as 20 g for less than 10 seconds, to 10 g for 1 minute, and 6 g for 10 minutes for both eyeballs in and out.^[14] These forces were endured with cognitive facilities intact, as subjects were able to perform simple physical and communication tasks. The tests were determined to not cause long or short term harm although tolerance was quite subjective, with only the most motivated non-pilots capable of completing tests.^[15] The record for peak experimental horizontal g-force tolerance is held by acceleration pioneer John Stapp, in a series of rocket sled deceleration experiments culminating in a late 1954 test in which he was clocked in a little over a second from a land speed of Mach 0.9. He survived a peak "eyeballs-out" acceleration of 46.2 times the acceleration of gravity, and more than 25 g for 1.1 seconds, proving that the human body is capable of this. Stapp lived another 45 years to age 89^[16] without any ill effects.^[17]

The highest recorded G-force experienced by a human who survived was during the 2003 IndyCar Series finale at Texas Motor Speedway in the 2003 Chevy 500 when the car driven by Kenny Bräck made wheel-to-wheel contact with Tomas Scheckter's car. This immediately resulted in Kenny's car impacting the catch fence that would record a peak of 214 G-force. ^[18][19]

https://en.wikipedia.org/wiki/G-force

 

[aviatoreb]

11 minutes ago, Piloto said:

At a 28g's crash your eyeballs will come out and for sure a broken neck or decapitated. But no need to worry because the airbag deployed.

https://en.wikipedia.org/wiki/G-force#/media/File:Human_linear_acceleration_tolerance.svg

[Piloto]

The average human head weights 11 pounds. The average man weight is 200 pounds. When a man is hanged it is the equivalent of imposing 18 g's on his neck in a crash. A 214 G-force will flatten your skeleton.

[Piloto]

2 hours ago, jetdriven said:

I wonder if there has ever been an unintended deployment of an Amsafe seatbelt airbag. Airliners even have these systems too and I’ve never heard of one going off outside of a crash. 

Even with the faulty Takata airbags and malfunctioning Tesla auto pilots killing people, they still save a great many more lives than they take. 

Unexpected airbag burst in a B777 killed a man on the ground.

https://www.stritmatter.com/cases/otto-v-boeing-company-transdigm-group-inc-amsafe-inc/

Edited January 30, 2018 by Piloto

[jetdriven]

29 minutes ago, Piloto said:

Unexpected airbag burst in a B777 killed a man on the ground.

https://www.stritmatter.com/cases/otto-v-boeing-company-transdigm-group-inc-amsafe-inc/

Faulty part that went off during maintenance. Does this have any bearing on the average GA pilot who walks out to his plane and goes flying? What’s your point?

[jetdriven]

49 minutes ago, Piloto said:

The average human head weights 11 pounds. The average man weight is 200 pounds. When a man is hanged it is the equivalent of imposing 18 g's on his neck in a crash. A 214 G-force will flatten your skeleton.

Ok well there’s a whole page where men routinely survive 38-40+ G-forces in forward deceleration so your statement above is bogus. 

[mike_elliott]

21 hours ago, DanM20C said:

The shoulder harness in my Mooney saved my life.  I would have loved to have the  AmSafe's, they probably would have saved me several years of dental work.  Well worth the $2500.  I will be in the front of the line also!

  Cheers,

Dan

I might not have had 14 broken ribs, a broken arm, orbital, nose, clavical, fingers, punctured lung and some other more severe injuries if the plane was equipped with Amsafe airbags. Who knows? Ill be at the front also

[Andy95W]

4 hours ago, jetdriven said:

I wonder if there has ever been an unintended deployment of an Amsafe seatbelt airbag. Airliners even have these systems too and I’ve never heard of one going off outside of a crash. 

I've probably come close a couple times...  

[Piloto]

3 hours ago, jetdriven said:

Ok well there’s a whole page where men routinely survive 38-40+ G-forces in forward deceleration so your statement above is bogus. 

Shall we try the rope on your neck. After all it will be less than 38G. 

[jetdriven]

Thanks for your thoughtful discussion backed up by factual data.  

Edited January 31, 2018 by jetdriven

[thinwing]

1 hour ago, Piloto said:

Shall we try the rope on your neck. After all it will be less than 38G. 

Hey Piloto?...you sounding like your relief tube ended up in the wrong orfice

[aviatoreb]

7 hours ago, Hyett6420 said:

From my understanding the airbag, crumple zones etc in cars are there to slow the deceleration.  The human body can cope with deceleration of quite high amounts as long as it is over a period.  For example if i fired you out of a chair  at 70 mph into a solid brick wall which you hit at 70mph then the impact and forces on your body are greater than if i fire you at a wall at 70mph which has an airbag that will depolymjist as you hit it, this bag has the effect of slowIng the deceleration.

Your physics is not stated correctly.  You are contrasting accelerations.  Acceleration is the issue.  Acceleration is the rate of change of velocity - so its the first derivative of velocity which is the first derivative of position, with respect to time and so acceleration is the 2nd derivative of position.

Anyway if you slow the velocity of something over a short period to a stop, that IS by definition a large acceleration. If you slow the same object to a stop over a longer period of time, that is a smaller acceleration.

In fact - this may be less intuitive - if you (case I) slow something going 1mph to a stop over 1 millisecond, then the (de)acceleration is larger than if (case II) you slow something going 100mph over a thousandth of a second.

But the damage on the body is not just acceleration - it is the acceleration integrated across time.  So if you experience the larger acceleration in case I but it is over a short time window you may experience less damage total than in case II where the acceleration is over a longer window( but still short time).  

 

Another take - Why do we get hurt?  Kinetic energy 1/2mv^2 is larger in the second case and in part goes to heat and in part goes to re-arranging structures - like changing the brick wall, and changing the structures (breaking bones and soft tissue) in your body.