BRS Question

Is there any mechanical reason the BRS system could not be designed to allow
the chute to deploy, stabilize/slow the plane and, optionally, allow the
pilot to disconnect the chute to land normally?

I'm thinking about floating down in a $400K Cirrus with chute deployed in a
spin in IMC, then breaking out at 1500 feet looking at a suitable landing
place and cursing the imminent destruction of the plane.

Michael

In article e9bjc.41664$IW1.1992513@attbi_s52,
Michael 182 wrote:
I'm thinking about floating down in a $400K Cirrus with chute deployed in a
spin in IMC, then breaking out at 1500 feet looking at a suitable landing
place and cursing the imminent destruction of the plane.

I thought the parachute attachment cables ripping out of seams in the
composite airframe is what totalled it.

Deploying the chute isn't that bad from an insurance perspective. The
avionics, engine and probably many other parts will have significant
salvage value.

--
Ben Jackson

http://www.ben.com/

No, that's fixable. The first successful BRS deployment
landed in some small trees which softened the landing.
The airframe was (so I read) repaired. That part
is just cosmetic. It's the 1500 fpm touchdown that drives
the gear through the wings, breaks the engine mounts
and so on.

John

"Ben Jackson" wrote in message
news:S9cjc.36611$GR.4993942@attbi_s01...
In article e9bjc.41664$IW1.1992513@attbi_s52,
Michael 182 wrote:
I'm thinking about floating down in a $400K Cirrus with chute deployed in
a
spin in IMC, then breaking out at 1500 feet looking at a suitable landing
place and cursing the imminent destruction of the plane.

I thought the parachute attachment cables ripping out of seams in the
composite airframe is what totalled it.

Deploying the chute isn't that bad from an insurance perspective. The
avionics, engine and probably many other parts will have significant
salvage value.

--
Ben Jackson

http://www.ben.com/

"Michael 182" writes:

Is there any mechanical reason the BRS system could not be designed to allow
the chute to deploy, stabilize/slow the plane and, optionally, allow the
pilot to disconnect the chute to land normally?

Weight, complexity, reliability, and practicality. The venerable SR20
s/n 1 used for flight testing of the parachute was rigged to be cut
away (they couldn't afford to trash a dozen airframes) and I was told
by the test pilot that the cutaway system was problematic, though
presumably if it were meant to be a production device they'd refine
the design a bit more.

The test pilot also told me that the cutaway was very disconcerting,
as the nose dropped abruptly past the vertical, which isn't surprising
given that the plane is starting at 0 airspeed.

The number of scenarios in which this would be useful seems very
small. I imagine that it takes quite a bit more than 1500 feet to
recover from the "steep nose-down attitude" (as the NTSB would put
it.)

I'm thinking about floating down in a $400K Cirrus with chute deployed in a
spin in IMC, then breaking out at 1500 feet looking at a suitable landing
place and cursing the imminent destruction of the plane.

It's all a matter of perspective. I'd be much happier floating down to
the imminent destruction of the plane than I'd be to briefly glimpse the
suitable landing space just before ending up in a smoking crater.

Plus, when in an emergency, always remember that the plane belongs to the
insurance company. Or as a pilot friend of mine puts it, "f**k the airplane,
save the seats!" ;-)

(Ben Jackson) writes:

I thought the parachute attachment cables ripping out of seams in the
composite airframe is what totalled it.

Nah, that's just some bondo. The straps lie in channels in the airframe,
and there is a thin layer of composite glued over the top of it.

Deploying the chute isn't that bad from an insurance perspective. The
avionics, engine and probably many other parts will have significant
salvage value.

There's an additional wrinkle to this that I hadn't considered, but
was pointed out by a Cirrus-savvy insurance broker: the straps make
off-airport recovery of the aircraft much easier because you can hook
them to a crane or heavy-lift helicopter and lift the airplane out,
instead of having to chop it into pieces and drag it. Recovery costs
are not insignificant...

Michael 182 wrote:

I'm thinking about floating down in a $400K Cirrus with chute deployed in a
spin in IMC, then breaking out at 1500 feet looking at a suitable landing
place and cursing the imminent destruction of the plane.

Well, you're not traveling forward anymore, and you have less than a minute to cut
the chute loose and dive the plane enough to get enough forward speed to get flying
again. With no airflow over the control surfaces. Doesn't sound real feasible to me.

George Patterson
If you don't tell lies, you never have to remember what you said.

This is way more engineering than I can deal with, but it seems there could
be a way to gradually increase airspeed over the control surfaces before
cutting the chute loose, in the same way air is spilled from a chute to
control direction. Maybe a vent that opens in the chute - all theory,
anyway...

Michael



"G.R. Patterson III" wrote in message
...


Michael 182 wrote:

I'm thinking about floating down in a $400K Cirrus with chute deployed
in a
spin in IMC, then breaking out at 1500 feet looking at a suitable
landing
place and cursing the imminent destruction of the plane.

Well, you're not traveling forward anymore, and you have less than a
minute to cut
the chute loose and dive the plane enough to get enough forward speed to
get flying
again. With no airflow over the control surfaces. Doesn't sound real
feasible to me.

George Patterson
If you don't tell lies, you never have to remember what you said.

"Michael 182" wrote in message
news:f0hjc.43581$IW1.2174699@attbi_s52...
This is way more engineering than I can deal with, but it seems there
could
be a way to gradually increase airspeed over the control surfaces before
cutting the chute loose, in the same way air is spilled from a chute to
control direction. Maybe a vent that opens in the chute

The parachute used in the BRS isn't anything like the sport parachutes that
provide directional control and forward momentum. It's a basic round
parachute, designed to eliminate the airplane's forward momentum and then
allow it to descend vertically to a survivable landing. It would require a
complete redesign of the BRS, and would greatly add to the complexity.
Complexity is a bad thing in general (though is often unavoidable), and in
an emergency safety feature is to be avoided at all costs, IMHO.

Besides, even if you could theoretically design a parachute that provided
for a straight-down vertical descent, while at the same time being
convertible to something like a sport parachute, you'd be hard-pressed to
increase the forward speed to anything even close to the stall speed for the
airplane. Ten or twenty knots max, is my guess and then you'd still have
the same issue, with the airplane detaching from the parachute in a steep
nose-down configuration until it gained enough airspeed to actually glide.

The current system is nice and simple, giving the pilot no options once the
decision to pull the cord is made. The system you're proposing allows the
pilot to turn what should almost always be a survivable landing into a
potentially deadly situation, and significantly increases the overall
complexity of the system at the same time. I just can't see how that's a
good idea.

If you *really* want to be able to let go of the parachute, I'd say install
some sort of rocket canisters to the airframe. When you want to detach from
the parachute, you hit a button that ignites the rockets, and before the
pitch attitude gets dragged too high by the parachute dragging behind, the
system automatically detaches the parachute, leaving you in a
soon-to-be-unpowered rocket-propelled airplane.

But that solution, even if I think it's superior to the one you propose, is
still fraught with problems.

Pete

"Peter Duniho" wrote in message
...
"Michael 182" wrote in message
news:f0hjc.43581$IW1.2174699@attbi_s52...

If you *really* want to be able to let go of the parachute, I'd say
install
some sort of rocket canisters to the airframe. When you want to detach
from
the parachute, you hit a button that ignites the rockets, and before the
pitch attitude gets dragged too high by the parachute dragging behind, the
system automatically detaches the parachute, leaving you in a
soon-to-be-unpowered rocket-propelled airplane.

Hey, I like this idea. Always wanted a rocket powered 182...

Dave Katz wrote:
There's an additional wrinkle to this that I hadn't considered, but
was pointed out by a Cirrus-savvy insurance broker: the straps make
off-airport recovery of the aircraft much easier because you can hook
them to a crane or heavy-lift helicopter and lift the airplane out,
instead of having to chop it into pieces and drag it. Recovery costs
are not insignificant...


This can't be unique to the Cirrus. My aircraft's maintenance manual
includes a procedure for sling-lifting, and I would think that the same
technique could be applied to many other aircraft. I recall that the
Cherokee that landed piggyback on top of a 152 in Florida was lifted off
by crane and flew away home ;-)