How fast in feet per minute does the BRS float a CTSW down?

[Acensor]

In another topic Roger Lee wrote...

"I ask BRS directly that question about opening speed. It will open just fine well past our published Vne speed and carry more weight than 1320. "

 

 

That brings up some questions:

 

If you pull the BRS and all works as advertised what vertical speed component do you hit the ground at ?

 

I realize there are some situations in which it would be black and white clear to pull or not pull, but easy to imagine some gray ones in which choosing between trying for a very questionable emergency landing spot and pulling deploying the BRS.

 

In my present Skyranger ELSA practicing power off stalls I have determined that I can do a full flat out power off stall with level wings and it will simply sink well behaved at 500 feet per minute vertically (which is 5.7 mph) drifting forward at about 25 knots airspeed with still some directional controllability. That seems like a very survivable pancake crash landing in some of the nastiest pieces of ground...So could be a better option than say a deployed BRS dropping you down at the same of close to same vertical speed but with NO control about exactly where or facing what direction I'd impact.

 

So for any aircraft in that situation we never plan to find ourselves in I'd like to know both (A) the vertical speed of descent under BRS and ( the vertical descent speed and forward speed in a full pancaked stall just above impact.

 

Anyone know either A or B for the CTSW?

 

Nice to have a really solid take on that comparison in case ever have to chose between deploy or shoot for a really ugly crash landing spot??

 

Bet most if you have practiced repeatedly full power off stalls and noted forward IAS... Maybe didn't look at vertical descent rate if holding plane at edge of stall?

 

Alex

[Roger Lee]

30 ft. per second. about 19-20 mph at 1700 lbs. Forward speed depends on winds.

[FlyingMonkey]

 

Bet most if you have practiced repeatedly full power off stalls and noted forward IAS... Maybe didn't look at vertical descent rate if holding plane at edge of stall?

 

 

My 2007 CTSW stalls about 45 knots at 0° flaps. There is a slight nose drop, then it just mushes. If I hold the stick full back in the stall it keeps mushing straight ahead and sinks in a 700-800fpm descent rate in a pretty much level attitude. It is very gentle. When I first did it with my non-pilot wife aboard she said: "That's it? why are people so scared of stalls?"

[Acensor]

 

 

My 2007 CTSW stalls about 45 knots at 0° flaps. There is a slight nose drop, then it just mushes. If I hold the stick full back in the stall it keeps mushing straight ahead and sinks in a 700-800fpm descent rate in a pretty much level attitude. It is very gentle. When I first did it with my non-pilot wife aboard she said: "That's it? why are people so scared of stalls?"

 

So that on the face of it would be a nasty 8 to 9mph vertical ground impact in Andy's hypothetical controlled flat-mush stall crash landing vs. a really really nasty 20mph vertical hit at 20 mph.

(The kinetic energy that has to be dissipated at impact is proportional to the square if the velocity. Did some calcs at a nice online dedicated calculator. Energy of impact at 20 mph is a bit more than four times of 9 mph. Can be difference between serious back injury or not.)

 

 

Of course both the BRS and full stall mush-descent will vary a with how heavily the plane is loaded, so since I'm sure Andy's mush-stall tests were at lower weight than the 1700 pounds Roger reports for the BSR dropping us at 20 MPH vertical ..... need to make an adjustment in favor of the BSR for comparing.

I have no engineering way of making that adjustment even if I knew exactly what weight Andy's SW was at during his test. I just spent 8 minutes on the phone with a nice guy at BRSparachutes kicking this around trying to get a number for vertical descent for and SW deployed at say 1300 pounds and all he could say is it would be slower but not be simply proportional to weight.

Anyway using proportional best rough guess for now ...until I can corner one of their actual engineers... works out to 12mph vertical descent under the chute if lightly loaded too 1000 pounds and to 15mph if loaded to 1300 pounds.

Closer to the hypothetical pancake mush-stall crash landings vertical descent speed but still a nastier and more dangerous vertical bump under the BRS.

And, unless there's ~40 knots ground wind, a slower horizontal speed with less rusk of a nasty horizontal impact injury under a BRS impact.

 

So All I can say reasonably confidently if forced to be quickly choosing between deploying in a gray decision scenario is unless no visibility I'd likely have much more control on exactly where and what direction I'd impact opting to pancake in a undesirable spot, less spine crushing impact, but if risk of horizontal impact at ~40 knots....such as too many solid tree or objects ....better to deploy.

 

Maybe waste of time to play with hypotheticals...expect it never need to know. But wouldn't want to have to be looking at the ipad and exploring these factors while descending power off over questionable terrain. ;-)

 

Other thoughts?

 

Alex

[FlyingMonkey]

Every person I have heard discussing the let down under a BRS describes it as a teeth-rattling impact. It's no joke, and it is definitely possible to get a serious injury from the "landing".

 

I just read an article on impact survival in Aviation Safety magazine. They said that the human body is very good at surviving front-to-back impacts, but really sucks at up and down impacts. Our skeleton is designed to resist gravity constantly vertically, and so the bones and joints are more rigid and easily broken in that direction. The article concluded that impacts up to 65-70 knots are survivable in the longitudinal axis of the airplane, but only about 30 knots is easily survivable in the vertical axis. Above those speeds survivability goes WAY down, to near zero above 80 knots longitudinally and 40 knots vertically. This is part of the reason spins are really deadly even at low speeds; the impact is almost always largely vertical against an immovable object (the Earth).

 

Our BRS sets us down right on the vertical axis, so even a 20mph impact is severe. The gear and seats collapsing eats up some of the impact energy, but it's still enough to have to worry about spinal compression injuries. I think you are better off landing with some forward speed and dispersing the energy longitudinally if you have even a marginal landing spot you can get to. I'd save the BRS for midair collisions, stall/spin at low altitude, engine out over really hostile terrain, or other events where the chance of injury or death is much higher than the BRS deployment is going to give you.

[Tom Baker]

30fps is 3x a gear crushing impact. if true, then don't expect much airplane left after one of these events.

 

Just pulling the chute causes major damage.

[Anticept]

BRS isn't designed to save the plane. The first things to hit will be the prop, front gear, and engine compartment. They will collapse and bend. Then the plane will roll back, collapsing the main gear, and slapping the tail down. It should come to rest in this position. This design sets up multiple "crumple zones" so that the plane will fall apart around you, instead of transferring the impact straight through your spine.

[FlyingMonkey]

BRS isn't designed to save the plane. The first things to hit will be the prop, front gear, and engine compartment. They will collapse and bend. Then the plane will roll back, collapsing the main gear, and slapping the tail down. It should come to rest in this position. This design sets up multiple "crumple zones" so that the plane will fall apart around you, instead of transferring the impact straight through your spine.

 

I got in the habit from my instructor of calling the BRS handle the "ownership transfer handle", since pulling it basically transfers ownership of the airplane from you to the insurance company.

[FlyingMonkey]

Nice to know the expected sequence hitting the ground. The seat is designed to absorb most of the spinal impact. Notice the seat is suspended a bit off the floor with straps. this is supposed to tear loose on impact absorbing most of the g force. The 'egg' is supposed to provide protection from the ground.

 

I agree , but stuff happens. If you land on a stone wall the gear might miss it and not absorb squat, etc. Just pointing out that pulling the BRS is definitely a high risk maneuver.

[Jim]

And, unless there's ~40 knots ground wind, a slower horizontal speed with less rusk of a nasty horizontal impact injury under a BRS impact.

 

If there's ~40 knots ground wind and you pull the chute, Mr. Toad's Wild Ride will really start after you hit the ground.

[FlyingMonkey]

If there's ~40 knots ground wind and you pull the chute, Mr. Toad's Wild Ride will really start after you hit the ground.

 

LOL, you are right, but if I'm flying where there's a 40kt surface wind, my mistake happened long before I had to pull the handle!

 

You more experienced rockstar pilots may disagree.

[CT2kflyer]

Personally, I'm using the BRS when I have little or no control over the aspect of the impact to the ground, or whenever the ground isn't pretty flat. Another words, if my aircraft is pretty much out of control, I'm pulling the handle. From experience, I do know that when an emergency happens, we tend to get tunnel vision and brain-freeze. We're not going to do any in-depth thinking about the situation when our survival instincts kick-in. Which finally brings me to my point: I believe we need to pre-think our reactions to emergency situations, internalize those reactions, and try as much as possible to instinctively apply those reactions when the emergency happens;

 

1. Engine out on take-off......... land straight ahead or pull the chute.... no messing around with trying to make the magical turn.

 

2. incipient spin-stall on landing - instant chute (although you probably won't make it.)

 

3. In-flight fire - no chute if at all possible, and if necessary 2,000 ft and below.

 

4. Engine out over water - chute before water entry.

 

5. Engine out over rocky terrain - chute

 

6. Mid-Air - chute

 

7. IMC - chute (VFR pilots don't do well in IMC - a statistical fact.)

 

Bottom line, is that in an emergency I'm not as smart as I like to think I am, and I'll take every possible advantage I can gain to get the outcome I need. That's what 24 years in the Navy taught me...... practice your emergency procedures, so when the crap hit's the fan, your not required to find the users manual to figure out what to do.

 

Seconds do count.

[Jim]

 

 

Personally, I'm using the BRS when I have little or no control over the aspect of the impact to the ground, or whenever the ground isn't pretty flat. Another words, if my aircraft is pretty much out of control, I'm pulling the handle. From experience, I do know that when an emergency happens, we tend to get tunnel vision and brain-freeze. We're not going to do any in-depth thinking about the situation when our survival instincts kick-in. Which finally brings me to my point: I believe we need to pre-think our reactions to emergency situations, internalize those reactions, and try as much as possible to instinctively apply those reactions when the emergency happens;

1. Engine out on take-off......... land straight ahead or pull the chute.... no messing around with trying to make the magical turn.

2. incipient spin-stall on landing - instant chute (although you probably won't make it.)

3. In-flight fire - no chute if at all possible, and if necessary 2,000 ft and below.

4. Engine out over water - chute before water entry.

5. Engine out over rocky terrain - chute

6. Mid-Air - chute

7. IMC - chute (VFR pilots don't do well in IMC - a statistical fact.)

Bottom line, is that in an emergency I'm not as smart as I like to think I am, and I'll take every possible advantage I can gain to get the outcome I need. That's what 24 years in the Navy taught me...... practice your emergency procedures, so when the crap hit's the fan, your not required to find the users manual to figure out what to do.

Seconds do count.

1. Training. Learn what your airplane can do. With the engine pulled to idle at 500', a CT is trivial to return to the runway. Nose down, 60 knots, 45 degree turns. I can consistently get back over the numbers with 200' of altitude. I'm not going to damage or destroy a perfectly good aircraft if I have the skills to turn the problem into a non-event.

7. Depends on equipment and training. I have an HSI and several hours of hood time. I will not pull the chute until I run out of talent and options..

[FastEddieB]

Just pointing out that pulling the BRS is definitely a high risk maneuver.

 

The data coming in so far from the Cirrus world does not support that.

 

Did you ever have a chance to view that Rick Beach video I've linked to before? If not, it may just change your mind.

[FastEddieB]

 

3. In-flight fire - no chute if at all possible, and if necessary 2,000 ft and below.

 

Guys smarter than me over on the Cirrus Owner's site have done the math, and you actually get on the ground faster under canopy than gliding in, even at high speed - which could fan the flames in addition.

[coppercity]

The chute may not be the best option for every scenario but you should always make it a consideration in your emer procedures and continue to consider it one of your safest options to get down. The most important thing about your airplane is you and your passenger, if pulling the handle means your down with a few bruises and bumps vs an unknown outcome of say an off airport landing in a unknown field then the BRS is the way to go. Don't wait until you fight the aircraft to low to decide , wish you would have pulled the chute, and realize it's to late. Keep the option to pull available and brief your passengers in case your not there to do it.

[CT4ME]

I'd like to explore Alex's "stall it in" idea a bit more. I know that Diamond's official position is that you trim the airplane full nose-up, and it will descend slower than the rate of an SR22 under 'chute. Of course, there is still some forward motion to deal with...

tim

[FlyingMonkey]

 

 

The data coming in so far from the Cirrus world does not support that.

 

Did you ever have a chance to view that Rick Beach video I've linked to before? If not, it may just change your mind.

 

I would not say because most people walk away from it uninjured makes it low risk. I think it's a great safety aid, I just don't think it's a low risk option.

[Roger Lee]

Stalling it in may also have the nose break over at too low an altitude and kill you just as fast as a departure stall. The CT has limits for it's mushy stall and add a few variable factors like winds or pilot error and your just as dead. baring a fire and just a normal decent under a properly functioning chute everyone should walk away. The reason you pulled the cute was it was life or death regardless of the cause.

 

If you trust stalling it in then why not practice from 100'?

The answer of course is you have a high probability of screwing it up and dying. It's the variables and pilot error that will kill you. I think the chute offers a better chance of survival from a well proven practice.

[sandpiper]

I don't believe stalling it in is a good option. If it was, why isn't it in anyone's training manual.

 

Can you hold it in a stall all the way to the ground? Without dropping a wing?

 

Try this. From safe altitude do a power off stall. Keep the stick all the way back. Use rudder to keep the wings level. Can you do this for a thousand feet? If so, is this how you want to hit the ground?

 

Anyone wanna be a test pilot? If so, let us know how it works. With the invention of this new life saving maneuver you could become wealthy. Or dead.

[Doug G.]

Sound here your choice would often be landing on drifted snow (which would in nearly all cases out you upside down), or descending under the chute onto snow drifts.The this option would be a road with the attendant power lines, mailboxes and highway signs, plus possible traffic.

I practice engine idle approaches to roads, but, I know that at the point of commitment to that landing I will not know what I will be dealing with when I get there.

[Doug G.]

That should say, "Around here..."

[FastEddieB]

That should say, "Around here..."

 

Across the bottom of your post, there is an "Edit" button.

 

Lord knows, I have to use it all the time to hone my posts to purfection!

[Roger Lee]

We pull the chute as a last resort because all is lost and to save our hides not because the plane is still flyable. If it was flyable then land and the other scenario is over too rugged a terrain to land without getting killed.

Why would anyone with a sutible landing spot pull a chute on a flyable plane. If it is that controllable to stall it to the ground then it is flyable because that takes coordination.

[FastEddieB]

There's a very long list of dead Cirrus pilots who would be alive today had they pulled. Who may have considered their plane still "flyable", and then flew to the scene of a fatal crash.

 

Here's just one:

 

http://www.carolinalive.com/news/story.aspx?id=532072#.UuEU1n88KSM

 

I had flown with Manfred. He was a good pilot, with conservative procedures and very safety oriented. Active on COPA and a proponent of CAPS (the Cirrus acronym for BRS).

 

Yet when the chips were down and the adrenaline started flowing, he did what you suggested and tried to land it. Or something. We'll never know for sure, but the alternative history where he pulled the chute instead would have been better.

 

I will stipulate that a sub-40k stall speed will make a Light Sport crash more survivable than a 60k-stall-speed Cirrus. You may want to figure that in.

 

I will keep posting the link below. Please take the time to watch it, and reflect on the data presented. Then come to your own conclusions.