On Sun, 23 Jan 2011 12:18:03 -0600, Jim Logajan
wrote:


A PowerFLARM costs ~US$1800 per plane and can prevent only midair collision
accidents - but presumably only if a large proportion of other aircraft
invest the same amount. How much does one's safety improve for that
investment?

A BRS costs ~US$3100 to ~US$4500 per plane and can can prevent injury or
death after midair collision accidents and in other situations. No other
aircraft need to invest in it to make it work for your aircraft. What
fraction of fatal accidents would a BRS have turned into non-fatal
accidents? How much does one's safety improve for that investment?

Close to NIL.

- A BRS can NOT be retrofitted to any existing gliders apart from the
few that were designed for it (which are, at the moment, only special
versions of Ventus 2 and Discus 2).

- Why let the accident (=collison) happen in the first place? FLARM
lowers the probability of a collision a lot, a BRS doesn't.

- A BRS is NOT going to save you from a low-level stall, nor a CFIT.

- NO BRS has ever been tested in an extreme situation (one wing or
tailplane gon, violent spin, high positive or negative g-loads).

- Read the limitations on current BRS systems (especially, read the
limitations for the Cirrus). Prepare to be amazed.


What is the scenario where a BRS is a reliable help?
At the moment, straight and level flight below Vne. Usually such a
condition means a controllable glider.
Ask yourself if you would deploy a BRS in such a situation.



A better solution than a BRS?
Soteira by Akaflieg Darmstadt - a rocket that pulles the pilot and his
parachute out of the glider. No speed limits, no g-load limits, low
probability to get tangled in a spinning glider. Zero-zero capability.



Cheers
Andreas