Is the Cirrus a Coffin Maker? [Archive]

IO540

12th Oct 2006, 10:00

This subject has been done to death in probably every pilot forum in the USA and everywhere else, and as far as I know nobody has demonstrated any statistical significance in this.

Cirrus have sold a lot of planes, and sold them very fast. They attract a lot of attention, for various reasons, some reasonable (the first company to break the Cessna/Piper mould; a nice looking well equipped and very capable plane) and others IMHO less reasonable (product bought by affluent young people which creates envy in the owner-pilot scene which tends to be dominated by rather older people; product advertised in mens' lifestyle mags i.e. to new pilots as a means of executive travel across the USA without spelling out that you need to be a very skilled IR pilot to use it in that way; BRS chute not liked by traditionalists who believe it offers a way out of poor planning and flying; etc). Anybody doubting the "less reasonable" reasons for getting attention needs to only read some of the trash written on the BRS chute... Why not just put a pneumatically operated 3ft spike in the instrument panel which impales the pilot if he makes a mistake? That would cut down the accidents very effectively.

It's probably true that since the plane is a) well equipped and b) has been bought by a lot of less experienced pilots, and c) a lot of them are limited to VFR (IMHO much more than would be the case with that level of mission capability in Europe, where they tend to be bought by IR pilots) the type of accident is different. The cockpit workload on autopilot should be much lower, so different mistakes will be made. Just as the mistakes made by airline pilots are different to those made by C152 pilots.

I think some of the mistakes reported were pretty stupid (like collecting a ton of ice, apparently doing nothing about it, and then pulling the chute when control is lost) and it is certainly true (with hindsight) that most if not all of the BRS activations were not necessary, but people do really stupid and easily avoidable things in ordinary spamcans all the time (like running out of fuel, getting lost, taking off massively overweight and going off the runway, busting controlled airspace etc etc etc) and it doesn't get any special press.

As I said, I have never seen data showing that the accident rate per mile, per hour, or whatever, is any worse than any other piston SE GA type.

soay

12th Oct 2006, 15:21

A member of AOPA US wrote in their forum an interesting analysis of the Cirrus accident statistics, which debunked a lot of myths. For those who are not members, it is quoted verbatim, about half way down this (http://forums.flyer.co.uk/viewtopic.php?t=26267&postdays=0&postorder=asc&start=15) thread.

scooter boy

12th Oct 2006, 15:34

Good points:

Angelina Jolie has one and if she is reading this I think she has great taste in aircraft and would be free to come flying with her anytime.:E

Bad points:(Miss Jolie you can stop reading now and feel free to PM me)

Fixed gear hanging down into the slipstream (even the most aerodynamic gear fairings are still worse than doing what the birds do and tucking the gear away). I just hate the aesthetics and the idea of that wasted avgas.(same goes for the Lancair Columbia)

Bits have fallen off - the cirrus chief test pilot was killed a few years ago after an aileron departed the airframe - tragically the aircraft he was in did not have a BRS fitted. There have been one or two other 'bits falling off' scenarios that scared me out of buying one.

Composite - I still don't trust it when there is any chance of lightning around - would much rather be in a metal airframe - remember than glider accident when the 2 guys ended up minus the wings sitting in a canopy-less fuselage with the wind whislting up their trouser legs after a lightning strike in a composite glider. (I write this having 500+ hours in composite aircraft myself)

De-icing - actually anti-icing AFAIK - not certified for known ice. So in other words not tested as rigorously as in known ice certified A/C. Hence iceblock scenario.

I really also hate all the "we just saved another life with our BRS" nonsense. C'mon guys - you can strap a 'chute to your back if you like but how many accidents are caused by the aircraft becoming unflyable?

Basically it's a plane for people who want their plane to be like a car with a get-out handle.

I am now going to hide as I know how popular they are.

Seriously though, Miss Jolie, Brad does not fly and you could have a lot more fun flying with me - I might even get into your cirrus if you promised to hold my stick.:E

SB

waldopepper42

13th Oct 2006, 14:01

Nope, the Cirrus SR20/SR22 is most certainly NOT a coffin maker!

Might be a coffin FILLER, though...:E :E :E :ok:

Cirrus-Pilot

13th Oct 2006, 14:41

I fly a Cirrus and have to say that when presented with the option of flying 20 year, and older, GA planes that populate the skies of the UK or flying a new modern Cirrus with all the latest technology there is no contest. I have come to the conclusion that most of what is being said is "Sour Grapes" from people who cannot afford to fly one. Planes such as the Cirrus will keep GA alive.

robin

13th Oct 2006, 16:23

..... I have come to the conclusion that most of what is being said is "Sour Grapes" from people who cannot afford to fly one. Planes such as the Cirrus will keep GA alive.

Not at those prices they won't

Confabulous

13th Oct 2006, 16:28

soay

13th Oct 2006, 16:55

If they keep pulling the chute in stupid situations it's going to get a repuation as dangerous, even if it's not. Take for instance the guy that pulled if after having a partial stroke. When he woke up it was going downhill above Vne. The chute held, but the descent rate was such that he broke his back, mainly because he landed on water, with no landing gear to absorb all those forces.
Are you suggesting that he was stupid to pull the chute in that circumstance? Seems like a good idea to me.

FYI, his "broken back" was a crushed vertebra, which was minor compared with the loss of function he suffered after the brain surgery for the tumour. The full story can be read here (http://www.ilanreich.com/Pics/Crash/Index.htm).

MNBluestater

13th Oct 2006, 17:33

Are there comparative figures to support the statement

Is this in respect of incidents/number of aircraft built or incident numbers comapred to other makes?

Just interested.

http://www.flyingmag.com/article.asp...print_pag e=y (http://www.flyingmag.com/article.asp?section_id=13&article_id=510&print_page=y) tells about the aircraft and record at the time the article was written

MNBluestater

13th Oct 2006, 17:39

Good points:

Angelina Jolie has one and if she is reading this I think she has great taste in aircraft and would be free to come flying with her anytime.

Seriously though, Miss Jolie, Brad does not fly and you could have a lot more fun flying with me - I might even get into your cirrus if you promised to hold my stick.:E

SB

Would you get into her Cirrus if she promised to look after your nacelles as well ?...

englishal

13th Oct 2006, 17:51

Prehaps we should ban thunderstorms as well. Seems to have been a number of IFR deaths recently attributed to thunderstorms in America. Prehaps, having a ballistic chute may just save your life when the wings depart the airframe when you accidentally enter a cell.

Anyway, Miss Jolie has a very nice aeroplane, I had a little nose around one day. We used to fly the same aeroplane don't you know......;)

Morgo

13th Oct 2006, 17:54

Not at those prices they won't

Well, if anyone is interested, I'm in the process of setting up a group based around a near new Cirrus SR22 G2. Depending on actual aircraft purchased, share price approx £20K with monthly of £70 and dry rate of £20/hr.

http://www.pprune.org/forums/showthread.php?t=242395&highlight=cirrus

being in a group makes flying a Cirrus far more affordable!

shortstripper

13th Oct 2006, 17:57

I have to admit, if I ever needed encouragement to get into any aeroplane (I'm easy generally :p ) Angelina Jolie would have no problem .... PLEASE PLEASE! :}

SS

Confabulous

13th Oct 2006, 21:55

Prehaps, having a ballistic chute may just save your life when the wings depart the airframe when you accidentally enter a cell.

Perhaps, but I'm fairly certain that a CB strong enough to cause structural failure would also suck you up to 35,000 feet or more. If a Cirrus wing fails at around 9G, it could turn the chute into hankies.

As for the chute pull over Vne, I'm not sure. It seems like pulling the handle converts the pilot to a passenger, and it may or may not be the lesser of two evils. We know a BRS is not a panacea. It's a great idea on low weight/speed aircraft, that's for sure. And there's no doubt that the 135kt max-deploy speed is a tad conservative. But I get the impression, which could easily be wrong, that in some cases it was deployed because the pilot left himself with no way out. I'd guess it was designed for these situations:

1. Inadvertant spins
2. Structural failure

That's it. As far as I'm aware, Cirrus and Columbia both wanted aircraft that were either spin-proof or spin resistant. Cirrus convinced the FAA that the BRS counted as spin-proof, while Columbia went with being aerodynamically spin resistant. No point in going over the old Cirrus spin debate. It wasn't designed to get you out of jail free. It's been used for all sorts since, beyond its intended design brief. But that's not the aircraft's fault - it's a stunning design, fast, powerful and efficient.

However, claiming 'sour grapes' is not such a good idea - many simply don't need or want a Cirrus. Depending on the Cirrus, cruise is between 140 - 180kts depending on power setting. GA pilots in general rarely fly with more than one passenger, more often solo. And if you have the money to buy one, that's fine too, and I applaud you for it. But realise this: there are PFA aircraft out there that will almost match the Cirrus for speed and range, and do it at the price that makes the Cirrus look a tad silly. What's 10kts here and there?

If I had £200k to play with, a Cirrus would not be a priority - an Escapade and a Pitts S1S, with fuel, maintenance, insurance and hangarage (not to mention training) for 5 years would. Or maybe an MCR-01 with expenses for 10 years. I know a millionaire who'd go for the latter without a second's thought.

Like I said, don't bother trying to claim sour grapes ;)

EnglishAl: Did you hear that she gave her instructor a present of her bra when she passed her PPL test?

wileydog3

13th Oct 2006, 21:58

Hi there,
Guys - anyone have any ideas on this - the Cirrus SR20/SR22 seems to have an awful safety record. Another one is down - the Manhattan crash. Why does everyone keep crashing the damn things??
I personally think you should be type rated on it like a jet.
VT

More people are injured and killed in the US on ladders than in gen-av airplanes.
LETS BAN LADDERS!!!! or require a 5 day school on ladders and their use.

Fuji Abound

13th Oct 2006, 22:07

If I had £200k to play with, a Cirrus would not be a priority - an Escapade and a Pitts S1S, with fuel, maintenance, insurance and hangarage (not to mention training) for 5 years would. Or maybe an MCR-01 with expenses for 10 years. I know a millionaire who'd go for the latter without a second's thought.

I agree with much of your comment. Whilst clearly the above paragraph is a personal view, I think it is also important to understand the reasons for the success of aircraft like the Cirrus. The comparison with home builds or Escapade is not valid any more than comparing a Caterham with a Porsche. Both might offer similar performance but that is the extent of the comparison. Cirrus offer an "executive" cabin for pilot and passengers, a "solid" aircraft with many other safety features (aside from the BP), and a sophistication of avionics, to name but a few of the features not offered elsewhere. Its the whole package that makes the product attractive to some, in the same way that there are those that prefer Porsches to Caterhams.

Horses for .. .. ..

IO540

13th Oct 2006, 22:21

1. Inadvertant spins
2. Structural failure

3. Engine failure above mountainous terrain or dense forest

a CB strong enough to cause structural failure would also suck you up to 35,000 feet or more. If a Cirrus wing fails at around 9G, it could turn the chute into hankies

Within one CB, you get multiple columns of air, each going up and down. Each can be a few miles across, so you go up one minute and down the next. The structural failure risk is not from the vertical speed itself; it's from the vertical acceleration resulting from flying too fast through the boundaries between these.

I am sure it would take a lot to break the wings off a Cirrus, or a TB20 for that matter. Probably flying into a nasty CB at close to Vne. But once a wing breaks off, the thing is just going to plummet; around 10,000fpm (100kt vertical speed) according to some NTSB reports. No CB will suck a 1000kg+ lump upwards, IMHO. The chute should work.

Re Permit planes, they can't go IFR and that severely limits mission capability. One can do a lot going "ostensibly VFR" especially if bending every rule enroute but you still end up scrapping some 90% of preplanned flights because you would never get back down.

While it is very possible that VFR-only 140kt composite planes costing under £70k will (over the next 20 years) suck the £250k+ European IFR aircraft market dry, there will always be a demand for planes that can carry 3-4 people and stuff across Europe. The flow of new models will be assured by the US market which has a large IFR contingent (accessible IR, etc).

aztruck

14th Oct 2006, 04:06

flew one in LA with an FAA safety counsellor as the check out pilot. He had a very sceptical view of the whole Cirrus manual/philosophy/parachute etc
The good news is that the plane is just fine, handles perfectly well, and after about an hour and a half of circuits plus sim engine failures and an IFR flight back to Santa Monica revealed no unpleasant traits at all. Any competent pilot could fly it.
But..........
It only has one engine, so...night or actual IFR ...over populated areas/mountains/sea etc is still as unwise with achute as without.
Also the glass cockpit encourages VFR pilots to fly like pretend IFR pilots, and a lot of customers are seduced by the false security provided by all the shiny technology, rather than stick their head out of the window and use natures horizon.
Almost lastly, my chum went to cirrus "approved" training and asked about their unusual attitude recovery technique. The instructor's response was that Cirrus recommend immediate engagement of the autopilot to correct unusual attitudes!! Cue pilot rolling inverted and engaging autopilot.....
Is this true?
Finally, just get a Twinstar and have done with it, thats how I'd spend my money, I'll take the extra engine over the parachute.

IO540

14th Oct 2006, 07:25

The instructor's response was that Cirrus recommend immediate engagement of the autopilot to correct unusual attitudes!! Cue pilot rolling inverted and engaging autopilot.....

Sounds totally unreal. An AP will auto disconnect if the pitch or roll exceed certain values, and it doesn't take much.

stickandrudderman

15th Oct 2006, 15:29

I met Angelina Jolie at Denham once. The big screen doesn't do her justice! When i cracked a joke and she smiled at me I damn near had an accident there and then!:O :O :O :O

Say again s l o w l y

15th Oct 2006, 21:42

Since the vast majority of accidents are caused by poor decision making, low currency and a lack of training/familiarity with a machine.
The thought of most PPL's I have met (I hasten to add that hopefully the folks I've had a hand in training don't fall into this category) jumping into something like a Cirrus with a minimum of training fills me with dread.

A Cirrus is fast, complex and very different from your average spamcan and requires differences training and maybe even a type rating. I hope we don't wait until there are accidents before this becomes reality.

The thought that you recover from an unusual attitude by switching on the autopilot fills me with horror.
Aztruck, I hope that isn't the case! If so, it shows a startling lack of understanding by the manufacturer of what happens in a cockpit when someone panics after everything goes wrong unexpectedly. That would be the first time I would totally ignore something in a POH!

ChrisVJ

15th Oct 2006, 22:21

I suspect that, if it was not said tongue in cheek, what the chap meant was that if you were to become dis-oriented then you should switch on the autopilot and so allow the aircraft to avoid extreme attitudes.

Having said that there are planes, granted they are bigger ones, in which the auto pilot, or at least the aircraft's computer controls are far more effiecient at returning the aircraft to normal flight after an upset than pilots are. Do not some modern passenger aircraft fly so on the edge of control in some circumstances that it is almost impossible for a pilot to stabilise oscillations without the help of the computers or is that just fiction?

Say again s l o w l y

15th Oct 2006, 22:57

No, I think you are thinking about the current crop of military fast jets. They rely on computer control (fly by wire) as they are designed to be unstable so that they respond faster.
Snapping into a 9G turn is not something we require our passenger a/c to do. There would be a few G&T's spilt, not to mention the trifling issue of the airframe being ripped apart!

Airbus use fly by wire for other reasons other than purely for stability control. Basically because we pilots like to do things the engineers would rather we didn't and the FBW helps stop that. (i.e flying into the ground and taking no corrective action. If the system can detect it, then it'll do something even if you don't.)

Sunfish

15th Oct 2006, 23:28

I'm a relatively low time PPL and it's been suggested more than once that I should get a Cirrus endorsement as there are a few around here for hire.

I've just last week done an endorsement on Piper Lance - my first six cylinder/six seat aircraft, and that is quite enough to keep me very busy for the forseeable future. I'm current in C172, Warriors, Arrow etc.

My current opinion is that I'm quite busy learning to handle a Lance competently and getting used to planning ahead in a 140/160 knot aircraft. A Cirrus (178 knots?) seems to me to be a bit too much of a handful just now.

Then of course there is the glass cockpit to train on. I note that the Cirrus POH seems to be about three inches thick as well.

My gut feel is as follows: While its a lovely aircraft, I'm a tad concerned about its marketing and who is buying it. I can't see myself in one for at least another year, and to use it propelry I would really like to have an IFR rating.

I'm also concerned about the possibility of "risk shifting" regarding the chute. It is possible that people may be taking more risks on the basis that they believe the BRS will get them out of trouble.

IO540

16th Oct 2006, 07:06

Autopilot operation is indeed mandatory on some bizjets, above a certain altitude, because it flies too close to mach 1 and can become very hard to control (for a human pilot) in pitch.

Speaking as someone who went from a C150/PA28 straight to a TB20, I had about 10 hrs' diff training and that was plenty for VFR flight. Then I did the IMC Rating in it (no point in flying something like that VFR-only); another 20-30hrs. No problem.

Training how to do flight/weather planning for the sort of missions one is going to want to do is something else altogether. There simply isn't anybody in the UK who knows how to do that; VFR or IFR. To this day I have not met an instructor who has even 1/10 of a clue how to do European touring flight planning combined with this level of (limited) mission capability.

I don't think it is flying a nice 150kt plane that is going to get somebody killed. 150kt v. 100kt just means you have to think 1.5 times faster but that's no big deal; it comes with doing a bit of regular flying anyway (which is a fair point; you can fly a C150 at 6.1 hours a year and stay alive, and many do just that, but you can't fly a decent plane at that level). The "slippery" bit means you have to plan ahead a bit but if you get that wrong you just end up overhead the target airfield, still at 5000ft and doing 149kt, so you end up looking like a d*ck, but it won't do any harm. It also means it can go into a spiral dive faster, but that's a pretty basic sort of inattention, IMHO.

What will get you will be stuff like flying into a mountain, or collecting six inches of ice and plummetting.

Chimbu chuckles

16th Oct 2006, 07:38

The fact that the Cirrus is viewed as such a potential handfull is more a example of how truly pathetic the modern standard of pilot training has become than anything else.

The BRS has been fitted, in my opinion, to minimise the exposure of the manufacturers to the US penchant for product liability law suits. If fewer people die in their product there will be fewer law suites from the family...and the few there are can be defended with.."But we fited a parachute that could have saved them and they didn't use it..or they didn't use it until it was too late..etc"

As far as modern civvy jet handling at high mach numbers is concerned?

They handle beautifully...on the B767 I currently fly we cruise at Barber Pole...exceeding barber pole (MMO) occassions a beeper alert and nothing else...the handling is so benign they don't even have Mach trim.

I took a falcon corporate jet to M0.90 once on a test flight...the normal limit (MMO) being M0.865...slight buffet and had to push bloody hard against the mach trim but that was it.

Modern passenger jets don't have the levels of automation they have because the aircraft are hard to handfly, they are easy to hand fly. Busy, crowded airspace, complex SIDs and STARs and allowing for the lowest common denominator airline pilot is the driver behind ever more clever airliner automagics.

Rod1

16th Oct 2006, 09:33

scooter boy

16th Oct 2006, 13:44

scooter boy

“Fixed gear hanging down into the slipstream (even the most aerodynamic gear fairings are still worse than doing what the birds do and tucking the gear away).”

Most of the modern studies would disagree. By the time you have added in the extra weight and the compromised wing design you break even on performance but lose out on useful load. You also have increased maintenance and insurance costs.

“Composite - I still don't trust it when there is any chance of lightning”

A modern carbon fiber aircraft designed for IFR is likely to survive a lightning strike much better than a 1950’s metal machine.

I find it hard to understand how you can compare a 1950;’d design with a modern aircraft, it is just a shame that it does not use a modern engine.

Rod1

Dear Rod,
I chose a Mooney over the Cirrus, lancair columbia and twinstar for many reasons - The best way of summing up my reasoning is "Product Integrity".

Product integrity IMHO is proven over time and the long body Mooney airframe has had a pretty long shakedown in my opinion. Accident statistics will confirm that when a Mooney crashes (usually) all of the bits are usually found in the same spot - meaning bits do not fall off (unlike cirrus where ailerons have left the airframe on 2 reported occasions in the short life of this airframe without it even having been subjected to a lightning strike).
Yes, the shape of the Mooney is not new but the aerodynamic principles hold true, as does the structural integrity of the very overengineered airframe - (I have visited the factory and seen the Mooney wing structure during assembly - it truly is something to behold. I have also flown with the Mooney chief test pilot and been demonstrated the aircraft and shown that it performs exactly as published in the book - 192KTAS in the cruise - how many other manufacturers can say the same (twinstar owners case in point in particular - you max out 40 ktas slower than you guys were led to believe!).
In addition to this a friend of mine is a retired Air France 747-400 training captain (now flying instructor).
He instructs on the cirrus SR-22 and tells me that it requires far more grunt (power and fuel) to cover the same distance as even a 1970s Mooney (like his own).
If you have any doubts about composite and lightning I would recommend reading the AAIB report into the glider which was struck a year or 2 ago. Remember the Top Gear test when Hamster Hammond was put in a golf and electrocuted? Metal shields the occupants from a perm (or worse).

Sorry, but IMHO age of design is unimportant - you really want to know it won't fall apart on you and that you are not just another "test pilot" for the manufacturer - my advive is give any new design 5-10 years to be shaken down. Look at the Mooney Acclaim (237KTAS) vs anything else (except the columbia which is almost as fast).

As for the undercarriage I just hate the way fixed gear looks - call it subjective but it is just plain ugly IMHO ruining the lines of what would otherwise be stunning looking aircraft (bit like a ferrari with stabilisers or towing a caravan) - sorry but I hate the look.

What I love though is the feeling of acceleration I get when my mooney gear doors completely seal in my gear and we get underway.

SB

englishal

16th Oct 2006, 15:22

Did you hear that she gave her instructor a present of her bra when she passed her PPL test?
Wonder what she gave him (or her) when she got the CPL and IR :ooh:

The fact is that chutes, Glass cockpits and FADEC are here and will be here to stay whether anyone likes it or not. Might as well get to grips with it now. Parachutes will become commonplace on all new aeroplanes I am sure.

A lot of this "new plane" FITS training is based around the autopilot, which lets face it, is a bloody good pilot aid. For serious "go places" flight, why bother with hand flying when the auto pilot can do it? You can then spend more time concentrating on other things, like the routing, aeroplane systems etc....

On the subject of spins and the Cirrus, some people would like to believe that the spin characteristics of the aeroplane may be the cause of a number of accidents. As a comparison there is not one twin out there certified for spins, the reason being that if you put one into a spin, it won't be coming out unless you are very very lucky. So whats the problem? At least the Cirrus has a way out, you pop the chute.

It probably won't be long before we see light aeroplanes with built in protocols to prevent pilot induced unusual attitudes or stressing the aeroplane beyond limits. The G1000 is half way there, you pull up beyond about 30° or roll beyond a certain limit and a series of red arrow appear on the screen showing you which way to push or pull to correct the UA.

IO540

16th Oct 2006, 16:26

“Fixed gear hanging down into the slipstream (even the most aerodynamic gear fairings are still worse than doing what the birds do and tucking the gear away).”
Most of the modern studies would disagree. By the time you have added in the extra weight and the compromised wing design you break even on performance but lose out on useful load. You also have increased maintenance and insurance costs.

This one is regurgitated over and over, by fixed gear proponents or fixed gear aircraft owners.

I don't actually believe it myself. It is admittedly hard to test one way or the other, because there are so few planes which are available in an identical form but with and without fixed gear, but there are some. There is the TB10 and the TB20, fairly similar, and if you compare fuel flow rates (I don't have the data handy but remember doing it a while ago) you find that about 20-25% of engine power must be lost on the wheels. That is with wheels in generous PA28-type cowlings suitable for European-type grass airfields.

Cirrus's cowlings are more slippery than the TB10s but by compromising the tyre-cowling clearance, so you risk fouling with grass or mud, and the grass catching fire from hot brakes.

Lancair have gone nearly all the way to making the thing unusable on grass, with very tight cowlings. But their main market by far is the USA; same with Cirrus. In the USA, fixed gear is a key marketing point.

A Cirrus doesn't go any faster than a TB20, for the same fuel flow rate. Presumably the Cirrus is more slippery to start with, before they chuck it all away on the fixed gear.

For Lancair I have no data because all the fuel flow figures I have seen are for close to full bore flight, and they are understandably very high. I'd like to know what the flow rate is for 140k IAS... should be better than say a TB20 but by how much?

As to the often quoted maintenance issues: let's say you fly 150hrs/year. That will cost you about £8000/year. 20% of that is £1600/year. if you put that towards maintenance, you can have a brand new undercarriage every few years :)

And you will have a much better looking plane in the meantime ;)

Rod1

16th Oct 2006, 16:47

"If you have any doubts about composite and lightning I would recommend reading the AAIB report into the glider which was struck a year or 2 ago. Remember the Top Gear test when Hamster Hammond was put in a golf and electrocuted? Metal shields the occupants from a perm (or worse)."

I know about the accident, I am an ex gilder pilot and have built a composite PFA aircraft. WHY do you think metal is better than Carbon?

Rod1

scooter boy

16th Oct 2006, 16:59

Rod,

I think (and I may well be wrong) that metal acts as a conductor and carbon fibre acts as a capacitor - so carbon fibre is more likely to overheat and blow when a large discharge takes place across it than metal which shields the contents and passes the charge on to another point. The entry and exit points in the glider wreck mentioned previously were the aileron push/pull as far as I remember and the wings just vapourised leaving the metal bits behind - a perfect time to reach for the Cirrus parachute handle.

Any materials scientists out there?:8

I'm sure Stephen Hawking could help with this one.

Alternatively we could go to Top Gear again - perhaps Jeremy Clarkson (as Hammond is out of action for now but hopefully making a speedy recovery) might volunteer to sit in a Sinclair C5 (composite car) and repeat the Hammond lightning experiment - it certainly might improve his hairstyle!

Actually a reliant Robin (another plastic car) would be a fairer choice as it is not a convertible and would not expose the Clarkson perm to the megawattage so directly.

:hmm:
SB

Rod1

16th Oct 2006, 18:05

Now we are getting some ware. Carbon fibre is an excellent conductor, fibreglass is not. Composite is a very wide range of materials, which is why I mentioned carbon. A Carbon structure is capable of handing lightning strikes, and the modern tests are to a higher standard than the old metal airframes were tested to. Metal aircraft sometimes survive a strike with their controls welded solid …..

Rod1

IO540

16th Oct 2006, 18:57

Glass fibre + resin is an insulator, and if lightning hits it will break down the insulation, turn it into a partial conductor, and fry the material.

Carbon fibre is a relatively poor conductor, and if lightning hits then the current flow will raise the temperature of the stuff and fry it.

Metal is a good conductor.

AIUI.

That's why composite IFR planes have metal mesh embedded within the insulated sections, to conduct the current away so it cannot ionise (and destroy) the nonconductive material.

Rod1

16th Oct 2006, 19:14

Think about it. You have a carbon webb , all interconnected with resin running around the web. The Jel coat is an insulator, but is very thin and about as relevant as the non conducting paint on a metal aircraft.

During the construction of my MCR fus I touched a 1.5 v bulb to the skin at one end, a battery at the other and a wire to complete the circuit, it lit as it would if it had been two wires. The resistance was very low indeed at any point on the fus. This would be just as capable of forming a faraday cage as a metal structure. Carbon fibre is strands of carbon woven together and conducts just fine. Glass fibre, Dealin or Kevlar are all good insulators, (and composite materials along with carbon)

Rod1

soay

16th Oct 2006, 19:48

Interestingly, there have been reports on the Cirrus owners' forum about p-static issues, causing heavy static interference on the radios and electrostatic discharges. Given that those aircraft don't have any static wicks, I wonder how conductive the surfaces of its wings are. In comparison, both Columbia 300/400's and Diamond DA4x's do have wicks.

Confabulous

16th Oct 2006, 20:19

No CB will suck a 1000kg+ lump upwards, IMHO.

With the greatest of respect, that's not correct.

Firstly it's not a lump, it's an aerodynamic object. With a chute that simply means that if the descent rate is matched by a similar updraft, the the object will neither climb nor descend. If it's stronger, it will go up. Without a chute makes very little difference - once again if the updraft exceeds the descent rate you will climb. That's the basis of gliding, and it works for heavier aircraft. There have been multiple instances of jet aircraft simply not having the power to climb in a microburst, and consequently the aircraft crashed. The opposite is also true. No pilot can risk assuming he will be able to descend (or climb) in a CB.

How fast can a TB20 safely descend? 4000fpm? A CB can easily exceed a 5000fpm updraft. What was it the man said? 'Rule books are paper - they will not cushion a sudden meeting of stone and metal.'

dublinpilot

16th Oct 2006, 20:52

Con,

I think you need to read IO540's reply again.

I am sure it would take a lot to break the wings off a Cirrus, or a TB20 for that matter. Probably flying into a nasty CB at close to Vne. But once a wing breaks off, the thing is just going to plummet; around 10,000fpm (100kt vertical speed) according to some NTSB reports. No CB will suck a 1000kg+ lump upwards, IMHO. The chute should work.

There is little doubt that a CB could suck a fully intack aircraft upwards. But IO540 was saying that if the CB caused the wings to break off, then it's not going upwards.

Without a chute no CB is going to suck a 1000kg lump of metal without wings upwards. It's no longer designed to fly. With the chute deployed, perhaps in an extreme situation it might be possible, but I doubt it.

I think you are talking at cross purposes. You are talking about an aircraft with wings getting sucked up, and IO540 is talking about an aircraft with it's wings broken off.

dp

IO540

16th Oct 2006, 21:19

I accept that a Cirrus with a wing(s) broken off could float upwards if the chute was deployed and it was inside a CB, because the descent speed with the chute is supposed to be no more than about 1000-2000fpm (10-20kt).

But it's only a matter of time before it will come down again. The CB will dissipate anyway in 10-20 mins.

The occupants might get a bit of hypoxia in the meantime :)

Back to the conductivity of materials, I think most people have got it wrong. Fibreglass doesn't conduct at all, and becomes partly conductive only when carbonised by the breakdown of its insulating properties. Carbon fibre is a pretty poor conductor but good enough to conduct the lightning, getting extremely hot in the process (and probably delaminating) through resistive heating. Metal is fine if thick enough, and all the airframe parts are well joined electrically. That is why IFR certified planes which are nonmetal have metal mesh buried within them. I have no idea if the SR20/22 has but it probably should have. Gliders have had their controls disabled after being hit by lightning which (obviously) preferred the control cables over the composite, and melted them.

scooter boy

16th Oct 2006, 21:54

On the subject of lightning strikes I ran into Geoff Boot (of Flyer) at Sun 'n Fun a few years ago and he told a story about his twin cessna taking a lightning strike while he was ferrying it back to the UK after he first bought it in South America. The electrics took the brunt of the strike but the aircraft flew on just fine til he could make a precautionary landing. Took some time to get the fried wiring out and iron out the problems but he eventually got it sorted.

I also understand that airliners are expected to be able to soak the odd lightning bolt up and take it in their stride. I would be interested in how the new composite boeing gets over the problem of conductivity.

Carbon fibre/composite (I recognise that there are differences Rod1 but basically non-metal) is undoubtedly stronger, fatigues better and is less maintenance intensive than metal - however I would like to see what a cirrus does in the Top Gear lightning simulator. I had heard of the metallic conducting mesh, I wonder what circumstances it has been tested in?

Anyway, surely if the Cirrus were a perm maker :confused: (static problems) Angelina's hair would be curly? Perhaps she flies with straightening tongs permanently plugged in?

SB

NeedaJet

23rd Oct 2006, 09:24

The Cirrus...like any aeroplane is a potential coffin filler....it just depends on the capability of the cr*p stuck between the seat and the rudder pedals! ;)

PCentR

26th Oct 2006, 14:34

http://www.allheadlinenews.com/articles/7005305332

SR22 down in icing

Gugnunc

26th Oct 2006, 16:33

Having been recently "cut up" by a Cirrus in the circuit (well, my student was flying a circuit and the Cirrus just joined on finals!), and then reflecting on the incident with another instructor -

We pondered that the Cirrus may earn the same accolade as the V tail Bonanza in the sixties, ie "The Twin Tailed Doctor Killer". Just idle chat, and it will probably annoy someone out there.

ps - on having a "chat" with the Cirrus pilot about his circuits, he was terribly apologetic and extremely polite. What a nice man. He may have had lots of money, and I may be jealous as hell 'cos I'm in a 152, but we still managed to discuss things in a civil manner. As always happens on pprune......:)

IO540

26th Oct 2006, 18:33

Did the Cirrus pilot actually do something wrong and, if so, what was it?

Or was it just that a C152 can fly the circuit at 65kt, whereas the only way an SR22 could go that slow is either way back on the curve (and not doing the engine much good, due to poor airflow) or with the parachute deployed :)

I have the same problem flying a TB20 (very similar performance) into some non-ATC airfields. Some places are a total free for all. You get cut on from the left, from the right. Most of the people that think they can fly a tighter circuit usually get it wrong and they force the faster plane to go around.

Anyway, I don't want to start another thread on joining procedures. If a field is a real free for all, and is busy, there isn't a perfect way to do it. Every join has a risk, especially the overhead one...

The Cirrus incident may not have been anything to do with airframe icing. Just because a pilot reported ice doesn't mean that he plummeted as a result of ice. He may have flown into a CB at Vne, or whatever, and that will take a wing off anything except, maybe, an F16. He should have pulled the chute, of course; structural failure or loss of control is one of its principal uses. At this stage nobody can tell the cause, and quite likely (as is the case with most GA fatal accidents) nobody ever will know the whole story.

Gugnunc

26th Oct 2006, 19:13

Joining overhead, and repeating that he was no.3 to two in the circuit, he was in the wrong to fly outside the two on downwind and then carve in onto finals.

On discussion, he said he didn't see either of us. However, as the day before a microlight did the same thing (on the inside) and the day after a C2K again carved a student up I am now thinking that we operate a Stealth 152 which is invisible to the mk1 eyeball. I can't say anymore as the MOD are now interested in the technology..............:)

IO540

26th Oct 2006, 20:17

It is a closely guarded secret in aviation that most planes are invisible to the Mk1 eyeball. The closer they are to hitting you the less visible they are, and those on a perfect collision course are not visible at all.

But don't tell anybody; I don't want all the retired RAF navigators in the CAA getting a court order on pprune admin to divulge my IP :)

In the overhead, on average half the planes will be invisible, because they are somewhere behind you. That's why it is such a stupid way of joining. But I've said too much already ...........

NorthUp

29th Oct 2006, 00:24

Gugnunc,
I was the Cirrus pilot involved in this incident. First let me clarify for the record that I am not a doctor nor am I particularly rich! I don’t own the aircraft but am fortunate enough to get to fly it regularly.
Let me explain a little more clearly what happened from my point of view. As you say, I carried out a full overhead join for a right-hand circuit, as mandated in Pooley’s, giving all the standard circuit calls. I was indeed aware that there were two other aircraft in the circuit but on turning downwind could not see anything ahead of me. At this point I asked the A/G operator to confirm the position of the other circuit traffic. The next call I heard was from an aircraft reporting on crosswind. My downwind leg was about 1nm out from the runway which is the way I was taught. One small error I did make was to turn base a little later than usual. This was a result of momentarily losing sight of the runway, a consequence of looking out for the still invisible traffic. I estimate my base leg was flown just over 1nm out from the threshold. Not a massive error but further out than I would normally aim for. I imagine the conflict occurred when you turned base closer into the field and saw that I was already on final. I don’t believe that relative speed was an issue as I had the Cirrus down to just over 100kts before joining the circuit. It seems to me that this incident was just simply the result of the two of us flying different size circuits; yours a fairly tight one close in to the field and mine rather wider with an slightly extended downwind leg. I expect you caught up with me due to your shorter flight path rather than the speed difference. The real concern is that neither of us was fully aware of the other’s position which is obviously worrying. I remember being slightly higher than 1000ft AGL when downwind so the classic low-wing v high-wing mismatch would have worked against us. I can only apologise again most sincerely for the inconvenience. I accept that as a visiting pilot it is my responsibility to fit into the circuit pattern without getting in the way of others. I failed on this occasion. Thanks again for speaking to me after the incident in such a civil manner, I was expecting a stern dressing down!
This is really a subject for another thread but I find that there is quite a spread of opinion on the subject of what size circuit to fly. Some aerodromes are very prescriptive with clear published instructions but others give practically no information at all. Visiting pilots could be in for a nasty surprise at places with unpublished ‘variable’ training circuits. A few such places spring to mind in the south of England. I’m beginning to wonder if there is any such thing as a standard circuit or standard overhead join. It’s obviously more difficult to spot other traffic if it’s not where you expect it to be, especially at an unfamiliar airfield.
Returning to the main subject of this thread, I have to say that I don’t think there is anything specific about the design of the Cirrus that qualifies it as a ‘coffin maker’. Our incident had nothing to do with aircraft type; the same problem could have arisen if I’d been in a club PA28. As you say; a C2K also managed to get in the wrong place after my visit. The Cirrus actually has surprisingly benign flying characteristics, even when pushed to the limits. In practice, its not really any more difficult to handle than something like a PA28 provided it’s operated in a safe and responsible manner. The extra speed and performance is something that you get used to very quickly. Having said that, a thorough type conversion training programme is essential due to the large number of differences compared with more traditional light singles. Pilot training is of course an issue that Cirrus as a company takes very seriously.
My final thoughts go to your student. Please pass on my best wishes for his PPL and an obvious personal tip if he hasn’t learnt already – look out at all times in the circuit!

IO540

29th Oct 2006, 18:21

I may be misreading it but I don't see what you have done wrong, NorthUp.

Yes you are supposed to fit in behind other traffic but equally traffic that ends up (for whatever reason) behind you is supposed to fit in behind you, and follow you all the way round. If they think you fly a big circuit, they are still supposed to fit in behind you, and follow you all the way round.

That procedure is clear. A lot of people don't like it and cut you up.

Equally, some people may not see you and turn base before you, but if you made the right calls in the right places.... these things can't be done perfectly.

411A

29th Oct 2006, 19:41

I dunno much about these aeroplanes, but when talking to one owner yesterday, who parks his Cirrus 22 next to my booted twin Cessna, he mentioned that...."Ice is absolutely no problem for me, as I have TKS fitted, I can fly in all icing conditions."

This got me to thinking...if this is the way many of these Cirrus owners think, look for many smokin' holes in the ground this coming winter, in the USA.

Now, I have flown only one aeroplane fitted with TKS (Shorts Skyvan) and indeed it IS known ice approved, but sadly, the Cirrus is not.

Also, there have been three Cirrus fatal accidents just this week, one here in Arizona...in icing conditions.

Rather bad news.:uhoh:

IO540

29th Oct 2006, 21:09

Is there any relationship between TKS (KI) and TKS (not KI)?

A G-reg TB20 is approved for icing, an N-reg TB20 is not (full TKS case). Same plane, different stickers on the side.

So I don't think one can make these judgements.

How many Cessna/Piper fatals have you had this week?

411A

30th Oct 2006, 01:20

It all depends on the certification criteria, IO540.
On known ice TKS equipped aeroplanes on the FAA register, the following are certified....
Wings
Tail surfaces
Propellor
Windshield
Engine inlets (some acft)

...and in addition, the rest needs to be followed as well, such as, dual heated pitot, heated static sources, heated fuel vents, the list goes on and on.
The SkyVan complied, the Cirrus does not.
It really is that simple.
As the Cirrus has a rather clean laminar flow airfoil, icing and the accretion thereof can well be a major concern, something clearly lacking in the knowledge of many Cirrus owners, who truly believe the have ahhh....the safest single engine aeroplane in general aviation.

They are quite mistaken.

IO540

30th Oct 2006, 06:58

Was the Cirrus submitted for KI?

soay

30th Oct 2006, 11:09

Was the Cirrus submitted for KI?
No. I think the fixed undercarriage made it a non-starter.

Gugnunc

30th Oct 2006, 13:06

Circuit patterns are off thread, but where we are we don't use any particular land marks to define the pattern, more the ability to land with an engine failure from the downwind leg onwards. When joining crosswind, turning downwind is the classic "extended centre line passing by the tailplane" which also fits in nicely with the glide performance on our 152's.

Having flown the same pattern in a Tecnam P2002 - that just didn't want to come down - I can see how fitting into the "training" pattern could be difficult if your glide performance is considerably better than a 152.

Alluding that the Cirrus may become the V tail Bonanza of today really came from speculation about speedier types and everything happening so much faster. I wouldn't be happy climbing into our Arrow now, after a six month gap, and would probably want a bit of solo time just to get the feel again before I took up any GV's. Sigh, oh to be able to do 130kts again......:)

IO540

30th Oct 2006, 14:08

I think the fixed undercarriage made it a non-starter.

I am not disputing that fixed gear prevents FAA certification for flight in icing (I haven't read the regs, if indeed they are online, and have enough to do) but it totally amazes me.

Hard to believe that Cirrus and Lancair would have tied both hands behind their backs before they even started, making planes that are all-out long distance IFR machines, and IFR without collecting ice is a bit like letting your cat run around outside and expecting it to not poo in next door's garden.

To top it all, with a finger-up gesture to the American legalistic climate surrounding "known ice", they offer TKS. Of course, nobody will ever use the system... It's a bit like the CAA CofA inspector sticking an INOP sticker over my TKS prop on/off switch :)

Alluding that the Cirrus may become the V tail Bonanza of today really came from speculation about speedier types and everything happening so much faster

I don't think that's a problem really. The thing flies only 50% faster than a spamcan. Thinking 50% faster is the difference between a 20hr/year pilot and a 50hr/year pilot, perhaps. This isn't an SR71.

The problem is lack of training for flight planning for real IFR; nobody offers anything like that. Pilots have to pick it up as they go along.

Gugnunc

30th Oct 2006, 15:51

.

I don't think that's a problem really. The thing flies only 50% faster than a spamcan. Thinking 50% faster is the difference between a 20hr/year pilot and a 50hr/year pilot, perhaps. This isn't an SR71.

.

If going 50% faster isn't a problem, how come we teach slow flight? There will always be a situation where you'll want to just slow it all down, be it in the circuit or in bad weather. If you are flying something even 50% faster, then you may get nearer to VNE quicker, you may get nearer to Vs quicker, you might bust that zone quicker and your turning radius will increase if it all goes wrong and you need that 180.

IO540

30th Oct 2006, 16:08

Flying too slowly is far more dangerous than any other sort of flight; loads of people die from stalling/spinning. That's is probably why it is taught; to show how to fly on the back of the curve.

I don't think for a moment that slow flight is taught to give somebody more time to think. One is far better off flying at Vbg (=Vy) than very slowly; flying just above Vs overheats the engine and blocks your forward view.

Gugnunc

30th Oct 2006, 18:48

I don't think for a moment that slow flight is taught to give somebody more time to think.

Exercise 18(ii) Navigation at low level and poor visibility. I'll return to the field at a lower level as part of S&L (ii) to emphasise how everything slows down. Then, when we do it specifically in 18(ii) the stude should remember why we did it in S&L (ii).

IO540

30th Oct 2006, 20:00

Yes, I know it is in the CAA approved syllabus, but that doesn't mean it is smart for use in the context of giving the pilot more time to think.

Take a plane with Vs=50kt, Vy=70kt (a C152 perhaps?; years since I flew one).

Case 1. Flying at 55kt. Damn hard work, poor pitch control, poor forward vis, poor engine cooling. Not the sort of thing you would ever want to do in your own plane. 5kt above stall, 5kt above death if flying low.

Case 2. Flying at 70kt. Much easier and safer. Better control response etc etc.

The difference between the two, in terms of thinking time, is negligible, and I would suggest that Case 2 represents lower pilot workload and therefore more thinking time.

Slow flight is essential to teach as a part of the envelope which must be known, but to do it for giving the pilot more time to think... I don't think that's smart.