Fun With Parachute Mode

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Last week, I took a ride over to Ft. Lauderdale to visit with Premier Aircraft. The company's been having good success selling Diamond aircraft (and Mooneys) and they have a premium upgrade package for the DA40 that includes a composite prop and a luxury interior.

I've always liked the DA40. It's got a terrific combination of decent speed, cockpit visibility and, especially, benign handling. And that's not just idle journalistic blather; the DA40 has an accident record to prove it.

The first time I flew the DA40, Jeff Owen was the demo pilot at Diamond and now he works at Premier, so we flew again last week. One thing he delights in demonstrating is what Diamond (and others) call parachute mode. Basically, you trim the airplane full nose up, idle the power and take your hands off the controls. The airplane will maintain a stable phugoid mode at a descent rate of between 600 and 1200 FPM at an indicated airspeed of 48 knots or so. In selling the DA40 against the Cirrus, Diamond has pointed out that in parachute mode, the Star might descend slower than the Cirrus does under its BRS parachute, albeit with more forward speed. (BRS says the Cirrus descent rate is between 900 and 1680 feet per minute.)

Would the DA40 be survivable if taken to the ground in parachute mode? Over rough ground, trees or an unfriendly urban environment, I'd be more than willing to take my chances in it, if a conventional engine-out landing wouldn't work. As these things go, 48 knots and 1000 FPM is fairly low energy.

Noodling this a little further, I dove into the accident records for the DA40 to see what's actually happening with the airplanes. The reality is there are hardly enough accidents to draw any conclusions. Nearly 1600 DA40s are flying and splitting Diamond's low and high fleet hours estimates, the 15 or so accidents it has had give it an overall accident rate of .8/100,000 hours, just a fraction of the GA average of 6.8. Its fatal rate is about .16, a mere eighth of the overall GA average.

The real eye opener is that in all those hours, there's not a single stall accident of any kind. I don't think many, if any, other airplanes can make this claim. Given the number of high-profile stall accidents we've seen recently (Colgan and AF 447), this record is remarkable, in my view. While it may be true the DA40 is used as a trainer and its high-aspect, low wing loading make it less susceptible to stalls, it's also true things like this haven't kept pilots from unintentional stalls anyway. But evidently not in the DA40.

By the way, parachute mode works in other airplanes, too. But not necessarily as well, because the phugoid is less damped and the down-cycle airspeed builds to yield a higher descent rate. Next time you're out flying, try it. It could be a revealing exercise that might save your life.

Comments (56)

Paul, one stalled from 20 feet, or so, at our airport, a couple of years ago, while on final. My son was waiting to take off and saw it happen, right in front of hum. I was mid-field, saw it approaching slowly, and heard it hit, as a rise in the ground blocked my view of the hard landing. Several of us went over to help, as the plane ended up left of the runway, resting against some trees, 180 degrees to the runway. There was a power application associated with the impact on the runway, but it was too late to go-around. The DA-40 was "pretty torn up", mostly by the trees. The undercarriage was bent and apparently, by doing so, absorbed a lot of the vertical component of the splat. No one was hurt. The student-pilot owner stalled it and the instructor didn't correct in time (they were discussing this as they sat in the plane). Not sure if this one ever showed up in accident reports. Although damage was extensive (engine tear down- I hope, broken gear, perforated wing, by the limb), it probably wasn't totaled, as it was relatively new and pricey. The fact that no one was hurt and it hit relatively in a flat orientation probably supports your parachute mode article. I like theses planes, especially since they have sticks, rather than yokes. - Mark

Posted by: Mark Mayes | October 31, 2011 7:14 AM    Report this comment

It doesn't enter a spiral dive, given time?

Posted by: Thomas Boyle | October 31, 2011 7:32 AM    Report this comment

This trick only works up to a certain amount of weight and/or forward center of gravity. Don't try it with a 200 pound man in the back unless you are prepared for more traditional stall behavior. The other half of the safety equation is crash safety which Diamond likely has beat even Mooney on. I talked to the gentleman who walked away from the mid air at Georgetown, and needless to say, he is a fan. The airplane biz is full of cheats and liars, but what they say about the safety of Diamonds is not a fairy tale. I feel as safe in one as I do in my SUV.

Posted by: Eric Warren | October 31, 2011 8:46 AM    Report this comment

It will diverge into a turn, but not a true spiral dive because of the trim moment. You do have to keep the wings level with rudder or aileron.

Mark, I saw that accident report. It was at Leesburg, VA. There's another similar at Bardstown, so I guess it could be that one. NTSB lists it as loss of control, not a stall. Pilot said he drifted off the centerline and couldn't correct.

Posted by: Paul Bertorelli | October 31, 2011 9:27 AM    Report this comment

The PZL Koliber/Socata Rallye has similar safe-flight characteristics. With the stick full aft, and flaps out it would gracefully float down like a parachute. In addition, you could still control the aircraft left and right in this configuration, with a forward speed of under 35 kts.

For those who are interested, this airplane was on the cover of the book "Design for Safety" by David B. Thurston.

Posted by: DAVID COLEMAN | October 31, 2011 10:09 AM    Report this comment

Paul, I didn't see the Leesburg one. The one I saw was at Brandywine, KOQN. Here is the NTSB report. http://dms.ntsb.gov/aviation/AccidentReports/njkkpn45rt2ovd3oddkxmb451/H10312011120000.pdf It did hit on the centerline, as we had to pick up some of the broken off pieces before the runway could be used. The pieces were all on the runway. One of the loudest arrivals that I have ever heard. Definitely a stall. My son said that settled mostly vertically, with little forward momentum.

Posted by: Mark Mayes | October 31, 2011 10:15 AM    Report this comment

Ooops, the link didn't post so here's the NTSB number for it: ERA09CA34. - Mark

Posted by: Mark Mayes | October 31, 2011 10:17 AM    Report this comment

If the Leesburg, VA, accident referred to was July 6, 2002, it was a DA-20 two-seater and not a DA-40. I was flying loose in-trail formation as the pilot limped the aircraft back towards KJYO, then had a ring-side seat as he lost the engine again and stalled on his base-to-final turn into a somewhat tight emergency field. Pilot was a first officer on Boeing 777s and was, I believe, fairly new in the Diamond. His passenger survived the elevator ride down with just a broken ankle, perhaps because he was on the "high side" of the impact in this left-wing-down stall.

Posted by: Drew Steketee | October 31, 2011 11:02 AM    Report this comment

"If the Leesburg, VA, accident referred to was July 6, 2002, it was a DA-20 two-seater and not a DA-40"

Nope. Different accident. It was 4/16/2005.

Found the Brandywine accident, which came up under DA 40 not DA40. (Sigh). Looks like a drop in. We would normally code those as R-LOCs, runway loss of control, since the NTSB doesn't use the word "stall."

Looks like it was a stall, however.

Posted by: Paul Bertorelli | October 31, 2011 11:28 AM    Report this comment

What is the difference between "parachute mode" and a falling leaf stall (FLS)? When I was training for my PPL my instructor showed me the falling leaf stall in a 172. Going by the description of parachute mode, the FLS is flown at a flat attitude, not nose high, and in the 172 the pilot has to stay alert on the rudder peddles to keep a wing from dropping, but like parachute mode, forward speed was very low. I was flying in the Seattle area and put the FLS into my regularly practiced maneuvers as I thought it would be valuable should I lose the engine at night.

Posted by: RICHARD GIRARD | October 31, 2011 12:02 PM    Report this comment

I am not sure what you mean by falling leaf, but the diamonds don't lose aileron authority and the stall does not break. You simply mush down, or with power drag along.

Posted by: Eric Warren | October 31, 2011 12:25 PM    Report this comment

Rick - what was the vertical speed in the falling leaf?

Posted by: THOMAS M CONNOR | October 31, 2011 12:25 PM    Report this comment

Paul, come on. Really. What's another 48 knots of forward speed compared to a real parachute? Well, how about you drive your car into a forest or a house at 48 knots to find out? That "parachute mode" is sales hogwash, pure and simple.

Posted by: Thomass Borchert | October 31, 2011 12:38 PM    Report this comment

R

Posted by: Eric Warren | October 31, 2011 12:40 PM    Report this comment

It's only sales hogwash if you use it as such. I never heard anyone from Diamond do that. It is generally used as a counter to the parachute as savior mentality to show the better handling and as an entree to a pitch about the comparative safety records which Diamond wins hands down.

Posted by: Eric Warren | October 31, 2011 12:57 PM    Report this comment

Thomass

The question is, which is more survivable, a forward or a vertical instantaneous G-load on impact? I was taught that a properly secured human in good physical condition can tolerate about 50Gs on the forward plane but only about 9 Gs on the vertical plane. The spine just isn't very tolerant of abuse.

The USAF has data on spinal injuries caused by the first generation of ejection seats, which were rather brutal contraptions that maimed as many pilots as they saved. The modern variants still cause injuries if the pilot isn't positioned properly during an ejection. Having the seat pan accelerate into one's backside is no different than one's backside decelerate on a rock.

When considering only the horizontal plane, The NTSB has papers that look at survival using two, three and four point restraints with or without airbags in passenger cars. Here's one: nrd*nhtsa*dot*gov/pubs/811206.pdf According to that paper, adding airbags to properly worn restraints doesn't add much survivability in a forward crash. But airbags were always aimed at the knucklehead who sits on the seat belt.

Posted by: THOMAS M CONNOR | October 31, 2011 1:39 PM    Report this comment

I've found that most 100 and 200 series Cessnas find their best glide speed rather nicely when trimmed full nose up, power off and one bottom in a front seat. Two bottoms up front makes it speed a little, and adding a 3rd in the rear makes it just right. It's a way of complying with the first rule of aviation while diagnosing an engine failure, and more elegant than pulling the rip-cord and letting the insurance company deal with the consequences.

Posted by: THOMAS M CONNOR | October 31, 2011 1:39 PM    Report this comment

Benign spiral mode is taught as recovery technique from accidental entry into IMC in gliders. The normal technique is trim full nose up (or nearly so), extend full spoilers / divebrakes and don't touch the controls. It is not a stable mode for all aircraft and CG positions.

Posted by: DAN MICHAEL | October 31, 2011 1:43 PM    Report this comment

"That "parachute mode" is sales hogwash, pure and simple."

Maybe. But then again, on pure safety, Diamond walks the walk and the reason for that is that its claim of passive safety bakes into the airplane design and embodied in the benign handling has resulted in a vastly better safety record than any other airplane. That's the point to be understand, not parachute mode itself.

Cirrus, which also hypes the parachute as a safety feature has a fatal rate eight times the Diamond. I doubt if this is just luck. If you normalize the accidents for like operations--that is, flown by owners not flightschools, the record appears even better.

Posted by: Paul Bertorelli | October 31, 2011 2:09 PM    Report this comment

Yep, my instructor taught me this during ab initio in a Piper PA-28-161 Warrior. The plane just bobs along nicely at a really slow rate of descent. I'm not sure how it compared against best glide speed, but if you're busy and have altitude it allows you to stop sweating the numbers while you work on another problem - say - extinguishing a cabin fire.

Rick Girard - this manoeuvre is a completely different concept to the 'falling leaf'. That's a stall with alternating left and right wing drop induced by the pilot working the rudder pedals. In this 'parachute mode' the aircraft gently pitches up due to the trim, and as the angle of attack increases past a point, lift is reduced and the nose gently pitches down. The wing never fully stalls.

Posted by: Michael Gordon | October 31, 2011 2:45 PM    Report this comment

I own a 1996 DA-20-A1 Katana along with a partial share of a DA-40 XLS. They are wonderful airplanes. Diamond's safety record is no accident - high G seats in the -40 along with welded aluminum fuel tanks in the wings. These two items have contributed greatly to the safety record. The big wing and low stall speeds help, as well. I don't understand why the USAF has gone to Cirrus (now Chinese owned) for their Flight Screening Program - when they already have a fleet of Canadian-made Diamonds. I'm not convinced about the safety of the BRS parachute - especially when so many Cirrus owners have failed to use it.

Posted by: Keith Ellis | October 31, 2011 2:50 PM    Report this comment

"on pure safety, Diamond walks the walk and the reason for that is that its claim of passive safety bakes into the airplane design and embodied in the benign handling has resulted in a vastly better safety record than any other airplane." ....

Or, it could be as simple as benign pilots are drawn to benign aircraft. Risk-adverse pilots fly Diamonds just like risk-adverse drivers buy Volvos. Te safety record has as much to do with the pilot's attitude as it does with the airframe design.

Posted by: Mark Fraser | October 31, 2011 3:01 PM    Report this comment

Great topic, Paul. I also own a Diamond DA20-A1 Katana. Our stall speed is about 10 knots slower than the '40. I'm going to investigate this technique. It could be a very useful strategy if I get into trouble flying in southern California at night.

Posted by: David White | October 31, 2011 4:44 PM    Report this comment

Re: I've found that most 100 and 200 series Cessnas find their best glide speed rather nicely when trimmed full nose up: It is no acident that the airplane will trim up nice in the glide. part 23 (and its predecesor regs require that the airplane be trimmable to glide power off at 1.3 Vso. See FAR 23.161 you will have to read a little to put it all toghether, and read another section or two, but that is what it works out to be.

The Short field approach speed for most 100 series Cessna's is quite low and is based on 1.3 Vso.

Posted by: THOMAS INGLIMA | October 31, 2011 7:34 PM    Report this comment

Of course this only works with an airplane with fully functioning controls (including trim).

I understand that Dale Klapmeier was driven to put the parachute in the Cirrus primarily as a way to survive midair collisions.I don't think "Parachute Mode" would to do much good following midair...

How much of the Cirrus safety statistics are do to the type of owner/operators? I noticed that Brad and Angelina don’t fly Diamonds…

Posted by: KRIS LARSON | November 1, 2011 6:03 PM    Report this comment

The whole safer pilot story is a bit suspect. It's also a bit insulting (but not as insulting as the direct attack on Ms. Jolie's judgement for no apparent reason). So, nutbags choose Cirrus? Why? The diamond is a much better choice for aerial hoonage.

Posted by: Eric Warren | November 1, 2011 7:36 PM    Report this comment

I think what this shows, contrary to what Cirrus would like us all to believe, that the BRS is the be-all-end-all of safety. As to the Cirrus accident rate, it is possible that people who are more bold buy the Cirrus, and then fly it into situations they can't handle because they have the false notion that the chute will save them from themselves. They are proving yet again that the pilot is the most important factor. Regardless, "parachute mode" seems as good a safety feature to me as the BRS. So don't knock it.

Posted by: STEPHEN EGOLF | November 2, 2011 7:29 AM    Report this comment

To Tom Connor, I'm sorry but I don't remember the vertical speed during a falling leaf stall. Michael Gordon, Hmmm, perhaps the maneuver was taught to me wrong. As my instructor showed me, the idea was to hold the yoke full back and use the rudder to keep the aircraft in a level, flat attitude. I can't comment about aileron effectiveness during the maneuver. As taught, they weren't to be used.

Posted by: RICHARD GIRARD | November 2, 2011 8:42 AM    Report this comment

One advantage of the parachute mode is that the plane is still controllable, whereas once you pop a chute, the pilot is pretty much a spectator. Regardless, it sems to me the safest plane is the one with the most favorable flight hours to crash/fatality ratio. At present it seems the Diamond is the winner.

Posted by: Richard Montague | November 2, 2011 8:45 AM    Report this comment

Well just a comment: Consider the feared IMC loss of control diving spiral. If the pilot could put the aircraft into parachute mode, it wouldn't be needed. That pilot could activate the BRS. However I mean no disrespect for the "parachute mode" as a somewhat similar "benign spiral" is a characteristic of many gliders and a useful tool if stuck on top with no suitable instrumentation.

Posted by: JAMIE ALEXANDER | November 2, 2011 10:47 AM    Report this comment

I agree that Cirrus & Diamond attract different groups of buyers. The 214kn SR22T is a high performance airplane, compared to the DA-40's 150kn max speed. There's also the Cirrus' side stick, which I think (personal opinion here) provides less direct feedback than the Diamond's center stick. It's obvious that Diamond has chosen safety & maneuverability over speed & interior finish. Hopefully they can carry this philosophy to the D-Jet.

Posted by: Nick Prudent | November 2, 2011 10:53 AM    Report this comment

Total Sales Hogwash! And that paul makes a story from it I think is Quite lame! Many Types of honest old Airplanes had that feature and Nobody ever made any fuss about it: In the East the AN2 can do that with 25knots forward speed and its listed in its POH as a procedure. Wilga and Yak12 do it too, Morane Rally, number of German planes, Even My B7GCBC will come down harmlessly at 40mph (stall 38) with full flaps&trim, stable! And with its steel tube fuselage I recon I would have better chances in a crash, too! What GA needs is Better training and more Proficient pilots, not "Safer" airplanes that are un-affordable anyway!

Posted by: Lars Gleitsmann | November 2, 2011 11:48 AM    Report this comment

It is my opinion and experience (after training 1300 pilots) that the Cirrus BRS system attracts over-ambitious but under-skilled pilots whose spouses are placated by the BRS myth making the Cirrus the "doctor killer" of the current era. Of all of the pilots whom I respect the only time they would consider the BRS a useful tool is when they have lost a control surface. Otherwise, and virtually without exception, they would rather control their own destiny. I am very uncomfortable when the published spin-recovery technique on the Cirrus is "pull the chute" (BRS) and the BRS documentation is quite clear on the potential outcomes: injury or death. There has never been a post crash fire in any Diamond airplane. On the other hand, I have seen too many videos of flaming Cirrus aircraft hanging below their chutes. The Cirrus is an attractive high performance aircraft; too much so for most of its pilots. The passive safety components of Diamond aircraft are fair trade for slightly reduced performance and are, IMHO, the better, safer choice!!

Posted by: Michael Gillespie | November 2, 2011 12:02 PM    Report this comment

I recall the falling leaf as a maneuver that teaches rudder finesse to prevent yaw.

Posted by: THOMAS M CONNOR | November 2, 2011 10:19 PM    Report this comment

Let's clarify a couple of things:

"I have seen too many videos of flaming Cirrus aircraft hanging below their chutes. "

Only one of these that I know of. The Boulder crash of 2/10/10, a midair. It does appear true that the incidence of post-impact fire is high in the Cirrus, definitely higher than in Diamonds.

There have been two incidents of post crash fire in Diamond airplanes, neither involving fatalities. One hit a powerline and grounded the high voltage, causing the airplane to burn. The other was a DA20 that had a minor fuel leak that caught fire after the impact, but the airplane wasn't consumed.

Posted by: Paul Bertorelli | November 3, 2011 7:21 AM    Report this comment

One flaming Cirrus does not make a flaming fleet. The safety aspects of the Cirrus chute have been tested and proven true. Those who have pulled the chute within the operating envelope have all walked away. Given an engine out or incapacitated pilot over mountainous terrain or at night, a chute pull is a logical choice. The argument made by COPA is that pilots choose NOT to pull the chute and impact terrain/ground at high forward speed causing far more fatalities. As for the spouse comment I would totally agree and even more reason to get a plane with an 'out' for the passengers. I feel 100% comfortable IFR at night ALONE, but stick my whole family in the airplane and I get a whole lot more jumpy. My current airplane is a Mooney. I will note that I am in the market for a Cirrus.

Posted by: Michael Penman | November 3, 2011 7:37 AM    Report this comment

I have heard of this technique for C172's as a way to survivably descend at night or in IFR given a power loss. I tried it in my M20C (wisely) at 9,000 ft and got into a spin - and I was trying to keep wings level (hands on). Based on the above comments, I am now wondering if my error was technique or aircraft.

Posted by: ROBERT YEAGER | November 3, 2011 9:18 AM    Report this comment

Michael, that is false. COPA members like to say that, but there were several cases of the chute apparently failing to launch. It's believed Cirrus fixed the problem though, IIRC, they still deny there was one. Also, how do you prove after impact a pilot chose not to use the chute? If I have the numbers correct, you are safer in a Mooney unless your fear is RLOC or something specific not shown by stats. Mooney never had an airframe fail except on engine modified planes where it's suspected the extra HP caused the failure. Overall, mooney has better stats than Cirrus. OTOH, you feel what you feel, and if BRS gives you comfort, then thats adequate reason to buy one.

Posted by: Eric Warren | November 3, 2011 9:23 AM    Report this comment

Even the original "doctor killer" Bonanza will do this. Gear down, flaps 20, power off, trim to 70 knots and keep the wings level with your feet. Would prefer not to ride it all the way to the ground but inadvertent IFR, engine failure at night, etc. the technique works, BUT you must NOT loose control of the airplane first. But then that applies to the BRS system in the Cirrus too doesn't it?

Posted by: Barton Robinett | November 3, 2011 10:34 AM    Report this comment

Is it not the case that Cirrus added the BRS as a way to avoid the changes required for FAA spin resistance test/requirement? It was then marketed as a way to save oneself from LOC or engine out over unfavroable terrain.

Posted by: Brian Hutchinson | November 3, 2011 11:33 AM    Report this comment

Other way around, according to early press reports. Alan Klapmeier had been in a midair and thought there ought to be a way to survive that and that the full-airplane parachute was the answer. The spin solution came later, but it was never reported as the primary motivation for having BRS.

Posted by: Paul Bertorelli | November 3, 2011 12:14 PM    Report this comment

I've done this in C172, C152, and Aeronca 7AC. To Robert Yeager above, I suspect you tried to keep the wings level with ailerons, which in most a/c will lead to a stall/spin. Keep the wings level with the rudder, my instructor had me practice this in the 152 not by watching the attitude indicator but simply by maintaining my heading on the heading indicator - works great and I'd feel good about riding down through clouds in an emergency this way, so long as I broke out somewhere before hitting the ground. I've also done the "falling leaf" in both the 152 and 7AC, it's much more like a leaf in the Champ as you really have to dance on the rudder to keep the wings level and not drop into a spin. It's been a while but I think the descent rate in both was right around 300 fpm. The falling leaf would be less useful in IMC or on a dark night as I don't think I could execute it well without outside visual references. For those unfamiliar, to execute the falling leaf pull the a/c into a slow stall (power at idle), and when it breaks, keep holding the yoke/stick back and maintain level with the rudder alone - just pull the yoke/stick into your gut and freeze it. I don't really like stalls, but it's the nose dropping that bothers me, I kind of like this exercise as it results in a benign level attitude, and a kind of quiet, peaceful flight, just don't let a wing drop unless you enjoy spins.

Posted by: Mark Consigny | November 3, 2011 1:46 PM    Report this comment

Thanks Mark - maybe it is time to try it again. I did in fact keep the wings level with ailerons so I'll try the rudder.

Posted by: ROBERT YEAGER | November 3, 2011 4:08 PM    Report this comment

One factor to consider with the Cirrus's descent under it's parachute is its seat supports are designed to absorb much of the landing impact. Other airplanes' seats are likely to be more rigid.

Posted by: David White | November 3, 2011 4:33 PM    Report this comment

I completely agree with Lars Gleitsmann. What's a safe airplane? One with a skilled pilot in flight operations corresponding to his ratings and currency. Without my instrument rating (or instrument currency), I would simply give up flying.

Posted by: JAN MELKEBEEK | November 3, 2011 4:35 PM    Report this comment

The problem with taking the " it's all about the pilot" approach is that it's wrong, leads to bad decisions, and has been helping to destroy GA for decades. The pilot is a big part of the equation, but ignoring design and equipment is just as wrong headed as ignoring pilot quality. Furthermore, the argument that other planes can stall the same as the diamonds do, and therefore the whole thing is just sales hype leaves out the most important thing - the Diamonds have proven to be safer planes.

Posted by: Eric Warren | November 3, 2011 5:02 PM    Report this comment

Diamonds may have the statistics to support that they are safer, but the cause of the safety record may not be design alone. Remember that correlation is different than causation. Diamonds are newer planes and therefore more expensive. Those that can afford newer planes may be able to fly more and are, as a population, more current. I don't have the data to back up this relationship, but there isn't enough data to confirm that Diamonds are inherently safer *by design*.

My safety pick would be a skilled / current pilot with good judgement in the average plane over the average pilot in a Diamond any day of the week.

Maybe Diamond pilots are better than average? ;)

Posted by: ROBERT YEAGER | November 3, 2011 7:03 PM    Report this comment

@Robert Yeager,

Looking at the accident database, you can see that Cirrus & Diamond are generally build in the same time period (late 90's to now). So, at least for Diamond & Cirrus, the age of the airplanes is not a factor.

Also, generally Cirrus planes are more expensive. The base DA-40 is $350K compared to $530K for an SR-22. BTW, the very accident-proned Lancair Evolution kit plane can go for $700K. So higher prices are unrelated to increased safety.

The statistics are the result of people who value safety over performance choosing Diamond vs Cirrus or Lancair. Even the 180kn Diamond DA-42 twin uses its second engine for redundancy rather than performance. Diamond's safety record is not a fluke: it was designed in.

Posted by: Nick Prudent | November 3, 2011 10:19 PM    Report this comment

I don't have the data to back up this relationship, but there isn't enough data to confirm that Diamonds are inherently safer *by design*.

You might wish to rethink this statement a little because the facts don't support it. First of all, the fuel. In the Diamond, it lives well-protected in aluminum cells between to massive spar structures, with armored lines leading to the engine and pump components. In the Cirrus airplanes, the fuel is much more exposed, ahead of the spar in the SR22.

Second, basic handling. Because of its high aspect ratio wings, the DA20/40 series have benign slow speed and stall characteristics, so much so that it's difficult to stall with a break. That's what this blog is about. The Cirrus has the split leading edge wing to maintain aileron effectiveness through the stall and it works as claimed. Nonetheless, it will stall and a number of fatal accidents have been caused by stalls.

Last, occupant protection. Diamond said it built in "crash space" around each occupant to prevent secondary impact injuries. Cirrus has the same thing, by the way. It appears to be effective, as are the 26G seats.

When Diamond first claimed this stuff 11 years ago, which is when I first reported on it, I thought it to be utter BS. I opined at the time that the airplane would have an accident record no better than anything else. I also predicted the hinged canopy and rear pax hatch would be just too weird for buyers. I was wrong on all counts.

Posted by: Paul Bertorelli | November 4, 2011 5:14 AM    Report this comment

It's fair, I think, to attribute some of Diamond's safety success to the type of buyers and pilots it attracts. But it's not credible to attribute it all to the human factor. The airplane has demonstrated it deserves a lot of the credit.

Worth noting is that when it began promoting the BRS system, Cirrus was honest about the parachute not being a panacea and that riding it down would likely yield a survivable crash, but with injuries. The actual deployment performance has been better than claimed. Very few injuries.

Posted by: Paul Bertorelli | November 4, 2011 5:18 AM    Report this comment

I have the opportunity to install an Amsafe airbag system in my plane at reduced cost, so I've been Googling the topic and read research papers until I cannot maintain consciousness. A general overview of GA accident risks are summarized here:

doctorgrayson*com/Aircraft*pdf

Probably the most definitive is this NTSB study that uses real crash data from aircraft with airbags:

ntsb*gov/doclib/reports/2011/SS1101*pdf

The reason I submit it to this blog is the effectiveness of airbags in a crash: They might add survivability in addition to seatbelts plus three and four point shoulder harnesses if the impact is on the longitudinal axis. There is less to no benefit if there are large vertical or side loads. Thus, it seems that if the pilot of any plane equipped with airbags just lets the plane maintain a parachute glide to impact he maximizes their benefit.

Posted by: THOMAS M CONNOR | November 4, 2011 2:55 PM    Report this comment

Apparently Diamond does not offer airbags but they can be had with an STC. Cirrus installs both the Amsafe airbags and the CAPS parachute, perhaps on the theory that they compliment each other in different scenarios. Where the plane is still under control it seems that trimming a Cirrus for best glide and riding it into the crash maximizes the airbag's usefulness. It might also protect the occupants against side and inward deformation of the cockpit. From some of the pictures in the above report it's also tempting to conclude that when a Cirrus hits with a side load they come apart in a rather spectacular fashion.

The impression I get is that one needs to arrive at the scene of the accident both mobile and conscious. Head injuries account for about 20% of GA deaths, and preventing them seems to be where a shoulder harness with or without airbags seem to excel, and the shoulder harness is definitive with the airbag sometimes filling in if the plane inverts or disintegrates. I'm beginning to wonder if some sort helmet - perhaps as simple as a ski or bicycle helmet would be adequate? That and a Mach-1 in-ear headset and it would be a cheap, fast and good way to prevent head injury. Also noted in the report are ankle injuries from the rudder pedals. Friends who crashed twin Cessnas and Beech also broke ankles, making egress from a burning aircraft a problem. It's a detail worth considering.

Posted by: THOMAS M CONNOR | November 4, 2011 2:55 PM    Report this comment

Just because a safety feature does not work every time does not mean there isn't a legitimate reason to have it available.

It may also be the case (I don't know) that when the chute did not work, the aircraft was already outside the design envelope for its deployment.

Even with my low time, I know what a near miss looks like and understand how quickly the "big sky" can become the "little fishbowl." If I ever have a midair, it may kill me instantly. If it doesn't, I intend not to spend my last few seconds wishing I had a BRS handle to pull.

Most of the pilots I know think it's a waste of 35 lbs. I disagree. YMMV.

Posted by: Patrick Underwood | November 4, 2011 6:42 PM    Report this comment

"Just because a safety feature does not work every time does not mean there isn't a legitimate reason to have it available." ........

It simply means that it costs way too much.

Posted by: Mark Fraser | November 4, 2011 9:15 PM    Report this comment

Most military bombers, fighters and CAS aircraft have an ejection seat and nobody makes fun of that, why make fun of a GA plane with a parachute? If the owner is willing to pay for it's care and feeding what's the problem? It's all part of a free market.

Posted by: THOMAS M CONNOR | November 4, 2011 10:18 PM    Report this comment

"why make fun of a GA plane with a parachute?"

Same reason you can laugh at someone building a non-amphibious seaplane in Arizona just in case it ever floods. The cost/benefit is just not there.

Posted by: Mark Fraser | November 7, 2011 12:41 PM    Report this comment

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