Transponders won't protect you from most VFR traffic, but they will protect
you from IFR traffic, thanks to not only TCAS, but also the ability of ATC
to see you and keep the traffic away from you.

Mike Schumann

"Terry" wrote in message
ups.com...

Mike the Strike wrote:
Reminds me of an old instructor who told me that instruments that were
not working were as useful as runway behind you!

So if the glider had its transponder turned on, the TCAS on the jet
would likely have alerted the Hawker pilots in time to avoid the
collision?

Mike
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Has it been established that the Hawker had TCAS? and if it did, what
type configuration?

I have flown airliners with a scalable display which shows all targets
up to 40 NM around the aircraft. Other airliners have a much more
modest display. Given the smaller panel space in a bizjet, the modest
display would be the best to hope for. If you know how TCAS works, then
I appologize if I offend:

TCAS II has a two level threat warning area. The first area, which is
largest forward of the airplane will generate an audible "TRAFFIC,
TRAFFIC" at this time, the display I am familiar with would should the
target as an amber where previous it was a white on black diamond with
relative altitude displayed. If the target's and the unit's flight path
are projected to enter the inner threat area, a resolution advisory
(RA) is given to the pilots. At the RA level, the vertical speed
indicator will have red arcs for rate of climb/descent to not do and
green arcs to fly towards. The announciation will say: "CLIMB, CLIMB,"
or "CLIMB NOW" for added urgency. Insert "DESCEND" for alternate
scenarios. At completion of the confict, the TCAS will announce:
"MONITOR VERTICAL SPEED" and "CLEAR OF CONFLICT."

Pilots are free to deviate from ATC clearance when an RA is received.
Had the transponder been operating on the glider with correct mode C
indications and the bizjet had TCAS II installed and operating, the
bizjet pilot would have heard the "TRAFFIC, TRAFFIC" and likely
"MONITOR VERTICAL SPEED" with some change required in their descent
rate.

Would the transponder have prevented this? Yes, if the glider had a
correctly functioning mode C transponder and the bizjet had a TCAS
system selected on and the bizjet pilots promptly followed any RA. A
lot of ifs there.

I don't beleive that transponders are the magic sheild that some do.
There are far too many airplanes that do not have this installed.