Helmets - Should you? and Which?

[flyingmedic]

It wont be hard to guess what profession I am in from my user name. I am fortunate enough to fly in a helicopter AND ride a motorbike for a living. Whilst flying I use an Alpha Eagle helmet and whilst riding I use a Shoei Multitech. The reason I have two different helmets is because although they are both designed to protect your head, they do it in different ways, and for different type of impacts. Trust me if my employer could get away with not buying two helmets, it would.
The vast majority of motorbike accidents involve a single impact, followed by a long slide. The longer this slide is the better, as it means that there are less deceleration forces absorbed by the poor victim and therefore fewer and less serious injuries, so a bike helmet is designed to slide so deceleration is at a minimum and it therefore has good abrasion resistance. The noise reduction methods used in motorbike helmets is primarily done to reduce the noise created BY the helmet, wind noise being the greatest form of noise pollution with motorbikes. Venting on motorbike helmets is designed to work in a flow of air, not whilst static. The pressure differences around the helmet cause airflow through it, but that is something you guys will understand far better than I. Any biker stuck in traffic will tell you how hot it gets inside that gear when there is no airflow around you.
It seems to me that aviation helmets are designed differently. I would think that an aviation helmet would have to withstand multiple impacts as your head is thrown around inside an aircraft and lose objects strike you. As noise is created by the aircraft and not the helmet, the way in which an aviation helmet deals with noise also has to be different. Aviation is a far safer industry than road transport, you don't see the same level of investigation or recommendations after a road accident, I don't think Ford would redesign a car because a driver lost control.
In short I cant see why anyone would wear a motorbike helmet in a helicopter. Yes aviation helmets are expensive, and I'm not going to try and justify that, I'm sure most things aviation could be done a lot cheaper if the manufacturers Vs demand ratios were different. But I would say that each helmet is fit for ITS purpose, each helmet has to reduce the risk that IT will be exposed to and do so without increasing any other risks. Can you honestly say that a motorbike helmet will do this in an aviation environment.
Happy flying guys, and take care.