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-   -   BRS in a twin (https://www.pprune.org/private-flying/488541-brs-twin.html)

vjmehra 21st Jun 2012 00:06

BRS in a twin
 
Largely because I'm still up, I got thinking, is this likely to happen...

Would there be a market for this, after all surely this would then kill the debate, what would you rather have a BRS or an extra engine when flying over mountains or water?

Pilot DAR 21st Jun 2012 01:22

Well, having just spent a good part of the day flight testing a very nice twin with one engine shut down and feathered, I'm thinking the extra engine would be far superior!

As a matter of fact, I cannot imagine myself ever wanting a BRS on an aircraft I am to fly, as long as I am able to mitigate the associated safety factors!

I can imagine some non pilot "spouses" liking the BRS idea, and if that is the go/no go factor that keeps a couple flying happily together, then I do see the value in that if they do.... but not for me....

vjmehra 21st Jun 2012 01:31

Yep, that is largely the case with me, the parachute re-assures her!

Out of curiosity though why would you not want a BRS system?

I can understand why you may not wish to use one and would prefer more traditional methods of getting back to the ground, in the event of engine failiure's etc, but if its a free option, why would you not have one installed?

AdamFrisch 21st Jun 2012 02:22

You know what? A twin amphibian with BRS would suit me just fine. Then I'd launch over the Atlantic/Pacific without a second thought.

carlmeek 21st Jun 2012 06:55

I'd have a second engine any day, but they are to achieve different things. I don't think a pilot will pull a BRS unless the wings fall off (seen that vid?!)

For most BRS flying pilots I know the BRS lever is briefed to the passenger for pilot incapacitation.

Might be handy on a twin if the fuel runs dry or pilot collapses. I wonder if tecnam type light twins could have it?

Pace 21st Jun 2012 06:59

BRS in a twin?? There would be little benefit and more weight as the shute would have to be bigger.
More weight means less single engine climb performance so the only benefit would be single pilot incapacitation and maybe structural damage.
I believe the Cirrus uses the undercarriage as an inherent part of energy absorbing structure and landing on water with no forward motion can lead to broken backs.
So not sure I would use one with an engine failure over sea.

Pace

BackPacker 21st Jun 2012 07:37


I believe the Cirrus uses the undercarriage as an inherent part of energy absorbing structure
True. And guess what... A twin typically has a retractable undercarriage.

So it's not just a matter of adding the BRS (in itself quite a complex undertaking) but you also need to redesign the undercarriage so that it deploys automatically upon BRS deployment (and how do you do that in a dual engine failure with possibly no hydraulics available?), and that it can handle its part of the vertical impact load.

So in theory it may sound like a good idea but there are some construction details and weight penalties that will make it very hard to implement.

Ballywalter Flyer 21st Jun 2012 08:07

We are all trained that should the engine quit on us (single engine) to look for a suitable landing site. I know most pilots (me included) will keep an eye out for suitable sites as part of their en-route checks.

The only time I could see a BRS system being effective (apart from structural failure) would be in the even of an engine failure over mountainous terrain where no safe landing site would be available. Of course an extra engine would help to clear terrain.

Pace 21st Jun 2012 08:24

In the case of the SEP Cirrus the chute has saved lives over 25 now I believe.
A pilot taking his precious cargo ie his family on trips must worry about what would happen to them if anything happened to him.
Briefing them in the use of a chute must take a certain worry away.
Midairs? structural damage loss of control?

Then we get into areas where the chute probably creates the situation where the chute is deployed by adding overconfidence to press on in weather not suited to the pilot or aircraft.

Icing springs to mind as does flying into bad weather in IMC and loss of control!
Undertaking night trips which caution would normally stop you doing?
It would be interesting to have a breakdown of reasons for deploying the chute to know if the overconfidence in having the chute created the breeding ground for having to use it?

Pace

1800ed 21st Jun 2012 10:06

I believe that the seats in a Cirrus have some form of impact attenuation device within them too, so it's not all in the undercarriage.

vjmehra 21st Jun 2012 12:16

An interesting (but short article on Cirrus pulls here):

Cirrus Airframe Parachute System (CAPS) pull #32: Splashdown in the Bahamas - Golf Hotel Whiskey

Some interesting points made so far though, especially about undercarriage, although that got me thinking, isn't the Cabri G2 Helicopter supposodly one of the most 'crashworthy' cockpits around? Could this sort of design be used on fixed wing craft (I don't know the design details, so maybe the answer is no).

Also interesting point on Tecnams, this whole thread was started as I had the exact same thought, what if they fit a BRS to the P2006t...

007helicopter 21st Jun 2012 19:11

As a Cirrus owner and pilot I would generally use the CAPS in virtually all situations that required an off airport landing due to engine failure or loss of control etc.

This was not my original opinion when I first purchased a Cirrus and it took several years to change my opinion from what I was originally trained to do and often practiced (ie a PFL)

Having read more or less all the Cirrus Fatality reports and also all the CAPS reports my opinion now for me is that I have tried to re programme myself to accept what is likely to be the safest outcome for me and any Pax.

I fully understand the arguments for and against and if anyone has time or inclination this one hour presentation sums up the arguments for in a way I never could and I try and watch it a few times a year to remind myself.

http://www.cirruspilots.org/media/p/593875.aspx

In a twin I accept it is a different argument but I see plenty of fatalities in twins where one engine failed, they seem like a real handful.

007helicopter 21st Jun 2012 19:20


It would be interesting to have a breakdown of reasons for deploying the chute to know if the overconfidence in having the chute created the breeding ground for having to use it?
Pace I do not disagree the Chute in some cases must create in some Pilots to accept a higher degree of risk and yes I must confess to being one of them.

For example I like flying in Mountain areas, would I do it in a SEP without a chute, maybe, but I do now feel a lot more comfortable with a Chute and therefore do it more. But do not see anything wrong with this.

Cobalt 21st Jun 2012 19:43

The second engine only helps in the case of a single engine failure. The parachute helps in case of
  • mid-air collision (well, most of them)
  • loss of control (if not too extreme / too low)
  • structural failure
  • dual engine failure (e.g. fuel starvation, fuel icing) and no landable terrain
  • severe icing encounters (boots have given up, freezing level on the deck)
  • engine failure over mountains with mountain tops above SE ceiling
The Cirrus has the parachute primarily because the co-founder of Cirrus, Alan Klapmeier, had a mid-air collision where the other aircraft crashed and the pilot died; he himself barely made it to the ground with 3ft of his wing missing.

The case for a parachute in a light twin is almost as strong as in a light single - but the market will be much smaller.

007helicopter 21st Jun 2012 19:59


So not sure I would use one with an engine failure over sea.
I would 100%, no other decision personally.

The Damage your back theory is not factual and a bit of an OWT

Benefits:

Time to prepare
Unlikely to flip over
Not hitting a wave at 60+ knots
Gives notice to boats (loud bang)
Gives visual to search and rescue, ie large orange parachute.

There may be disadvantages but I am not sure of them.

Relative to the thread in a twin of course you could carry on with single engine failure which would be a massive advantage.

I do quite regular sea crossings and remind myself each time this is what I will do.

Cobalt 21st Jun 2012 21:12

007helicopter, BRS over water is also what the POH says. It also recommends using the BRS over un-landable terrain, at night etc, but recommends a forced landing for engine failure over hospitable terrain.

You also write you would use it in case of engine failure over green pastures - do I understand you correctly? Why is that? Now if you decide on the way down the approach to the field is not going well, fine, but if you glide nicely, why not land?

peterh337 21st Jun 2012 21:22

I am sure the "rep" from the Cirrus owners group (USA) will be along in a moment....

007helicopter 21st Jun 2012 22:48


You also write you would use it in case of engine failure over green pastures - do I understand you correctly? Why is that? Now if you decide on the way down the approach to the field is not going well, fine, but if you glide nicely, why not land?
because imho what looks nice field at 1000ft can be a different story when inspected from the ground and the dangers of coming up short, hitting wires, tree stumps, ditches, gradients, water logged, rocks etc.

The Cirrus would be a worse aircraft to land in a field compared to say a Robin, due to its smaller wheels and relatively higher stall speed, 60 knots or so is a lot of energy to hit something or cart wheel.

Many people have successfully forced landed Cirrus just like any other aircraft but a reasonable percentage have failed with fatal consequences and they had a perfectly good chute that for ever reason they chose not to pull.

I appreciate this view may differ from 95% + of other readers and each to their own.

As I said my view has changed from thinking I would only use in the event of mid air or catastrophic failure etc to a serious consideration in the event of an off airfiled landing for whatever reason.

This thinking does take a certain change of attitude.

flybymike 21st Jun 2012 23:04


You also write you would use it in case of engine failure over green pastures - do I understand you correctly? Why is that? Now if you decide on the way down the approach to the field is not going well, fine, but if you glide nicely, why not land?
Because you will almost certainly be at too low a level to deploy the chute by the time you have decided you need it.

abgd 21st Jun 2012 23:37

The other difference over the sea is that your aircraft is likely to be a write-off whether you fly or go down by 'chute, whereas at least if you're overhead a green field you may be able to keep the aircraft intact.


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