Vfrpilotpb,
The training helos are all older designs, and meet the previous versions of FAR, where the crashworthiness was much less.
In 1965, the aircraft and the non-energy absorbant seats are designed to:
i) Upward--1.5g.
(ii) Forward--4.0g.
(iii) Sideward--2.0g.
(iv) Downward--4.0g
In 1989 it was increased to:
(i) Upward--4g.
(ii) Forward--16g.
(iii) Sideward--8g.
(iv) Downward--20g, after the intended displacement of the seat device.
and they included crash absorbant seats:
(b) Each seat type design or other seating device approved for crew or passenger occupancy during takeoff and landing must successfully complete dynamic tests......(basically a 30 G stroking seat).
In 1994 they added:
[(v) Rearward--1.5g.]
Recall all that wonderful argument about the certification of the EC 225 grandfathering this stuff? This is the same thing, and creates a compelling case to look to new helos instead of older ones. The problem is I don't know of any newly certified training helos! Anyone out there know?
Here is a web site that gives the evolution of the FAR. Paragraph 27.561 is the crash g's and .562 is the seat stroking (the even number is because it was inserted later, where no previous paragraph existed). Just chose Historical FAR from the left column. Look too at .571 flaw tolerance, and perhaps others, all of whch upgraded the safety.
http://www.airweb.faa.gov/Regulatory...e?OpenFrameSet