Inflatable restraints are the air-bags of the aircraft world. We conducted a
lot
of R&D in the 90's using car technology (FMVSS, NCAP etc test data) we then
set up some simulations using nifty finite element codes. The result from this
work (and the work of others) is a commercially available inflatable air-bag
system used in Cessnas and other products. Unlike most cars the air-bags are
fitted within the seat belts themselves (this makes periodic
inspection/replacement
easier and also makes them potentially retro-fitable). The positioning
of accelerometers and sensors is still subject to optimisation within a
particular
aircraft - that is why qualification has to be done on a type rating basis.
For the Europa pilot the correlation of the 4 point harness and helicopter
seating
and restraint systems is more relevant. The approved systems for Cessna etc
are all 3 point (car-type) restraints. Four-point systems have inherent
advantages
in terms of overall levels of safety (read that as occupant protection).
In a typical nose down, high rate vertical 'arrival' the major concern with
Europas
(and all other VLA/LSA) is the high levels of intrusion into the occupant
space. Clarification - intrusion by airframe parts and/or powerplant/systems.
Air-bag restraints and similar systems would not necessarily help with reduction
in overall levels of occupant injury.
In summary, airbag restraints form an effective and desirable means of
potentially
limiting occupant injury during typical GA type arrivals. Especially so if
integrated properly. However, of more relevance to Europa (read VLA/LSA) is
the requirement to have a high level of crashworthiness in the primary
structure.
Typically this will require a optimally deformable seat base, 4 or 5 point
restraint system (to control occupant kinematics), roll-over protection.
Tomorrow's GA designs will have more focus on these key safety issues. They
will
have adaptive ainflatable restraints (possibly mandated). This is especially
the case as electric powerplants and energy storage systems (batteries to you
and me) have high local inertias/mass and require effective restraint or
controlled
kinematics during 'arrivals'.
Sorry to bore anyone with this - hopefully this answers the original question.
Happy landings.
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http://forums.matronics.com/viewtopic.php?p=331992#331992
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