Cirrus safety vs Mooney safety

[Ken Ibold]

Made it up. I am more familiar with motor vehicle accident mechanisms of injury from my medical training including experience in the emergency department and rotations in trauma surgery. I do not see how airplane accidents would differ that much from a typical high speed MVA. The basic problem is that the car or airplane stops suddenly and the pilot and passengers keep going until they hit something in the aircraft. You might get crushed if the airplane flips over but I doubt that it is a common problem.

You are right on some of these issues, however, after more than a decade of intensive general aviation accident research, I have come to a different conclusion.

Yes, you have a percentage of accidents that involve car-like dynamics. Those would generally include runway overshoots, undershoots, loss of control, off field landings etc. However, there is that other group of accidents that involve loss of control in the air for whatever reason, and a more chaotic end. In this group I would also include airborne collisions with trees that involve uncontrolled tumbling after impact. The monocoque structure found in most "spam can" airplanes is not designed with impact in mind. The modern composite designs are somewhat more sophisticated. But in either case, the need to reduce structure weight takes it toll on impact survivability.

The dynamics of a Cirrus and of a Mooney differ considerably after impact. The Mooney has a continuous spar wing, and so a wing impact on one side can introduce an angular component that would be greater than in other airplanes. The Cirrus/fire issue has already been addressed. Another consideration is object penetration into the cabin after impact, particularly in trees. Obviously, you can't pick which kind of disaster you'll need to mitigate, so you really pay your money and take your chances.

In the final analysis, in my opinion, the most meaningful determinants are 1) make sure your aircraft has shoulder harnesses, and 2) fly into the crash as far possible. Remaining under control is the biggest determinant of survivability. Airplane structure is kind of lost in the noise.

 

[wabower]

Apparently, you really need to know what you are doing to fly a MU-2 safely.

And how is that different from flying a King Air safely? How much more does the pilot need to know? Is there some gap in fundamental training that pilots need to fill prior to mounting a Moo-too, or is it just another differences training exercise that requires more attention due to the differences between the rice rocket and conventional airplanes?

Stated differently, if all of the fleet were equipped with full-span spoilers and no ailerons, how much additional training would be required for the Mit?

 

[Gary F]

You are right on some of these issues, however, after more than a decade of intensive general aviation accident research, I have come to a different conclusion.

Yes, you have a percentage of accidents that involve car-like dynamics. Those would generally include runway overshoots, undershoots, loss of control, off field landings etc. However, there is that other group of accidents that involve loss of control in the air for whatever reason, and a more chaotic end. In this group I would also include airborne collisions with trees that involve uncontrolled tumbling after impact. The monocoque structure found in most "spam can" airplanes is not designed with impact in mind. The modern composite designs are somewhat more sophisticated. But in either case, the need to reduce structure weight takes it toll on impact survivability.

The dynamics of a Cirrus and of a Mooney differ considerably after impact. The Mooney has a continuous spar wing, and so a wing impact on one side can introduce an angular component that would be greater than in other airplanes. The Cirrus/fire issue has already been addressed. Another consideration is object penetration into the cabin after impact, particularly in trees. Obviously, you can't pick which kind of disaster you'll need to mitigate, so you really pay your money and take your chances.

In the final analysis, in my opinion, the most meaningful determinants are 1) make sure your aircraft has shoulder harnesses, and 2) fly into the crash as far possible. Remaining under control is the biggest determinant of survivability. Airplane structure is kind of lost in the noise.

I don't think our conclusions are really that different. An intact passenger compartment is a good thing since you do not want to be crushed or get trapped if a fire breaks out. You also need to remain conscious if escape from the wreckage is necessary. I believe that most potentially survivable aircraft accidents involve substantial forward deceleration so you need to survive this before you worry about being trapped or crushed.

 

[Ken Ibold]

And how is that different from flying a King Air safely? How much more does the pilot need to know? Is there some gap in fundamental training that pilots need to fill prior to mounting a Moo-too, or is it just another differences training exercise that requires more attention due to the differences between the rice rocket and conventional airplanes?

Stated differently, if all of the fleet were equipped with full-span spoilers and no ailerons, how much additional training would be required for the Mit?

I'm with Wayne here. Although the Mu-2 does have some ergonomic inefficiencies in the cockpit (at least compared to more modern standards), the accidents appear to be more the result of people trying to fly them like a Baron or an Aztec. By adopting a more "fly it like a jet" attitude, many of the issues disappear.

 

[Ted]

I'm with Wayne here. Although the Mu-2 does have some ergonomic inefficiencies in the cockpit (at least compared to more modern standards), the accidents appear to be more the result of people trying to fly them like a Baron or an Aztec. By adopting a more "fly it like a jet" attitude, many of the issues disappear.

+1. Fly it like what it is, not like what you want it to be.

 

[Gary F]

Apparently, you really need to know what you are doing to fly a MU-2 safely.

And how is that different from flying a King Air safely? How much more does the pilot need to know? Is there some gap in fundamental training that pilots need to fill prior to mounting a Moo-too, or is it just another differences training exercise that requires more attention due to the differences between the rice rocket and conventional airplanes?

Stated differently, if all of the fleet were equipped with full-span spoilers and no ailerons, how much additional training would be required for the Mit?

This is what the FAA thinks. I don't really know if it is justified.

ACTION: Final rule.
SUMMARY: This Special Federal Aviation Regulation (SFAR) creates new pilot training, experience, and operating requirements for persons operating the Mitsubishi MU-2B series airplane (MU-2. These requirements follow an increased accident and incident rate in the MU- 2B and are based on a Federal Aviation Administration safety evaluation of the MU-2B. This SFAR mandates additional training, experience, and operating requirements to improve the level of operational safety for the MU-2B.
http://rgl.faa.gov/Regulatory_and_G...1F451475446EEF12862574DA005851B7?OpenDocument

 

[Ted]

This is what the FAA thinks. I don't really know if it is justified.

ACTION: Final rule.
SUMMARY: This Special Federal Aviation Regulation (SFAR) creates new pilot training, experience, and operating requirements for persons operating the Mitsubishi MU-2B series airplane (MU-2. These requirements follow an increased accident and incident rate in the MU- 2B and are based on a Federal Aviation Administration safety evaluation of the MU-2B. This SFAR mandates additional training, experience, and operating requirements to improve the level of operational safety for the MU-2B.
http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgFinalRule.nsf/0/1F451475446EEF12862574DA005851B7?OpenDocument

That's because every other certified propeller aircraft from a 152 up to a King Air ends up flying somewhat the same. The MU-2's unique handling characteristics required knowledge of how to best use them, not that they made the plane inherently unsafe to fly.

If you've only ever ridden motorcycles and then go to a trike, the trike will have some interesting handling characteristics, and people flip them over because they ride them thinking they're motorcycles. Know your vehicle, and none of this will be an issue.

 

[wabower]

Did you read it?

This is what the FAA thinks. I don't really know if it is justified.

ACTION: Final rule.
SUMMARY: This Special Federal Aviation Regulation (SFAR) creates new pilot training, experience, and operating requirements for persons operating the Mitsubishi MU-2B series airplane (MU-2. These requirements follow an increased accident and incident rate in the MU- 2B and are based on a Federal Aviation Administration safety evaluation of the MU-2B. This SFAR mandates additional training, experience, and operating requirements to improve the level of operational safety for the MU-2B.
http://rgl.faa.gov/Regulatory_and_G...1F451475446EEF12862574DA005851B7?OpenDocument

 

[steingar]

Is anybody bashing Cirrus in this thread?

Asking if a Cirrus is as safe as airplane X is a bash. Implicit in the question is that Cirrus is unsafe.

Four place composite single.

Cirrus has had some issues with post crash fire. I reviewed the first of 7 pages of fatal Cirrus aircraft NTSB accident reports.
Results of the first 10 accidents listed: Four post impact fires documented. Two accidents could not be determined since they occurred overseas and report not available and one occurred in Gulf of Mexico therefore probably no fire.

Lots of airplanes have post crash fires. I know one that had a precrash fire. It would be interesting to note the instances of post crash fire of Cirrus vs. other wickedly fast single. Heck, tube and rag aircraft are plenty flammable, and no one is bashing them. Sorry, I had plenty of emergency training concerning airplane fires, and have been encouraged to keep a fire extinguisher handy in the aircraft. I doubt I would have received that training if there's never been an aircraft fire.

 

[Ted]

Lots of airplanes have post crash fires. I know one that had a precrash fire. It would be interesting to note the instances of post crash fire of Cirrus vs. other wickedly fast single. Heck, tube and rag aircraft are plenty flammable, and no one is bashing them. Sorry, I had plenty of emergency training concerning airplane fires, and have been encouraged to keep a fire extinguisher handy in the aircraft. I doubt I would have received that training if there's never been an aircraft fire.

And what experience did the people training you actually have with the fires? While the training can still have value, it's similar to the CFII with 0 actual IMC time.

But as has been stated already, the best idea is just to avoid crashing in the first place.

 

[Gary F]

That's because every other certified propeller aircraft from a 152 up to a King Air ends up flying somewhat the same. The MU-2's unique handling characteristics required knowledge of how to best use them, not that they made the plane inherently unsafe to fly.

If you've only ever ridden motorcycles and then go to a trike, the trike will have some interesting handling characteristics, and people flip them over because they ride them thinking they're motorcycles. Know your vehicle, and none of this will be an issue.

That's what I said, that you really need to know what you are doing to fly a MU-2 safely.

 

[wabower]

You missed the point of the comparison. How many other airplanes in the fleet are equipped with a chute?

Asking if a Cirrus is as safe as airplane X is a bash. Implicit in the question is that Cirrus is unsafe.



Four place composite single.




Lots of airplanes have post crash fires. I know one that had a precrash fire. It would be interesting to note the instances of post crash fire of Cirrus vs. other wickedly fast single. Heck, tube and rag aircraft are plenty flammable, and no one is bashing them. Sorry, I had plenty of emergency training concerning airplane fires, and have been encouraged to keep a fire extinguisher handy in the aircraft. I doubt I would have received that training if there's never been an aircraft fire.

 

[Gary F]

Asking if a Cirrus is as safe as airplane X is a bash. Implicit in the question is that Cirrus is unsafe.

I don't know what you mean by unsafe. You can get killed in any aircraft that can fly higher than about 20 feet. I don't think we should ignore the fact that some airplanes require greater skill and training to fly safely. I think these things should be discussed.

Four place composite single.

The comparison ends there? The SR22 is a much higher performance airplane than the DA40, the SR20 is a better comparison although it has a slight performance advantage. I put in a few hours in a SR20 before I bought a DA40. It fits my needs better. I don't have anything against Cirrus aircraft.

Lots of airplanes have post crash fires. I know one that had a precrash fire. It would be interesting to note the instances of post crash fire of Cirrus vs. other wickedly fast single. Heck, tube and rag aircraft are plenty flammable, and no one is bashing them. Sorry, I had plenty of emergency training concerning airplane fires, and have been encouraged to keep a fire extinguisher handy in the aircraft. I doubt I would have received that training if there's never been an aircraft fire.

I am not convinced that it is not higher for the Cirrus than the average of GA aircraft. It certainly is higher than Diamond since there have been no reports of a post crash fire in any Diamond anywhere that I am aware of. (A DA40 crashed last week and I am still waiting for the NTSB report to come out.) We could use a rigorous statistical analysis of this subject.

 

[Ken Ibold]

I believe that most potentially survivable aircraft accidents involve substantial forward deceleration so you need to survive this before you worry about being trapped or crushed.

I think they involve substantial forward deceleration relative to the direction of flight, but I think you are underestimating the amount of rolling, flipping, cartwheeling and tumbling that occur. The deceleration relative to the person inside is by and large chaotic for anything other than a relatively benign landing accident.

 

[Everskyward]

I think there are a number of questions here. Is the Cirrus structure unsafe? Does the chute make it more unsafe? What if Mooneys had chutes? Would that make them safer? I think chutes would generally make most small airplanes somewhat safer because they would mitigate some types of accidents. However the question is whether or not the expense and design problems outweigh the benefits.

 

[Ken Ibold]

However the question is whether or not the expense and design problems outweigh the benefits.

Bingo. An aircraft accident can involve any combination of forces. Pick your poison. You COULD mitigate them all, but the penalty in terms of weight and cost would have you flying 4 seat, 12,000 pound, $4 million machines.

 

[bbchien]

I think most of this Cirrus-bashing is BS.....

It's not bashing. Corvalis has tanks. Tank you.

 

[wabower]

You have just described the the King Air 200 that is (and has been since 1974) the most popular turboprop in the market. It holds more than four and can be bought (used) for a fraction of your stated price, but provides a level of safety and comfort that people seem to like.

Bingo. An aircraft accident can involve any combination of forces. Pick your poison. You COULD mitigate them all, but the penalty in terms of weight and cost would have you flying 4 seat, 12,000 pound, $4 million machines.

 

[steingar]

It's not bashing. Corvalis has tanks. Tank you.

I liked the Corvalis back when it was Lanceair, and suspect I would like it now that its Corvalis if I could afford it. I doubt they're any more or less safe than a Cirrus, and gas tanks can be ruptured (and lots of other aircraft have wet wings). Between the Cirrus and the Corvalis I'd take the Corvalis, only because I've heard repacking the chute is expensive. Lanceair/Columbia/Corvalis have had fewer crashes, but there are fewer of them. I honestly don't know how their safety relates to Cirrus. Any difference is likely due to the kind of pilots who wind up flying them, though. They're all wonderful aircraft, and I would fly them if I could. I can't, so it is a pokey Cherokee for me.

I do agree that any safety problems likely reside with the guy (or gal) in the front left seat.

 

[bbchien]

The Mooney has wet wings, but has no reputation for breaching tanks on runway loss of control. The Pipers PS28 line have tanks, but they are also part of the surface structure, and similarly have no no reputation for breaching tanks/burning.

 

[steingar]

The Mooney has wet wings, but has no reputation for breaching tanks on runway loss of control. The Pipers PS28 line have tanks, but they are also part of the surface structure, and similarly have no no reputation for breaching tanks/burning.

While the Pipers have no reputation, they have caught fire in numerous crashes over the years. While the rate at which they do so is lower than the Cirri, their speeds are also considerably lower, reducing the energy available to break tanks and ignite avgas. The rate of post crash fires in Mooney versus Cirrus is of interest in this, since Mooneys are also very fast airplanes with wet wings, so the comparison has teeth.

Of course, all this is academic if you don't crash the airplane. Given that most of the crashes in Mooneys and Cirri are due to stupid pilot tricks, it doesn't seem unreasonable to ask that they be kept in one piece.

 

[Gary F]

I think they involve substantial forward deceleration relative to the direction of flight, but I think you are underestimating the amount of rolling, flipping, cartwheeling and tumbling that occur. The deceleration relative to the person inside is by and large chaotic for anything other than a relatively benign landing accident.

Possibly. Do you mean something like this?

http://www.youtube.com/watch?v=gOaAZ1i2gNA&feature=fvw

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20070910X01354&key=1

Would the two passengers who perished in this crash been saved if the cockpit remained intact? I don't know. They were in the aft facing passenger seats.

I believe that absent an in-flight breakup (not survivable without ballistic chute) most initial impacts occur in the forward direction. I also suspect that a substantial amount of the kinetic energy is dissipated in that direction. I also surmise that you suffer more injury being tossed around inside a rolling aircraft than from the structure collapsing in on you. There are so many different accident scenarios that I'm not sure if it is practical to try to strengthen the cockpit.

 

[flyersfan31]

Mooney's aluminum structure will deform, absorbing crash forces. Shed the rest of the plane, you sit nice and snug in your roll cage, with shoulder harnesses securely fastened, you'll be in pretty good shape.

I guess I like my chances of controlling the crash in the horizontal plane better than relying on the chute, landing gear, 26g seat, and my spine in the vertical plane.

I'm not against the Cirrus. Beautiful planes. They just seem to be occupied by dolts more frequently than other planes. If the Cirrus wasn't around, those dolts would find something else to crash (VTail Bo maybe?).

 

[geneseib]

I know this is a bit of an apples to oranges comparison, but which of these 2 safety systems do you think is most likely to save your life? a roll cage or a parachute??

Depends if it's real life or a video game.

 

[Gary F]

Mooney's aluminum structure will deform, absorbing crash forces. Shed the rest of the plane, you sit nice and snug in your roll cage, with shoulder harnesses securely fastened, you'll be in pretty good shape.

I think that you might be surprised how poorly a seat-belt and shoulder harness restrain the head and upper body in a crash. The head can really flail around and there is usually very little clearance between the head and the airplane even if the cockpit remains intact.

http://www.youtube.com/watch?v=CS6wof_d1_8&feature=related
http://www.amsafe.com/news/videos/detail.php?id=236

 

[Dan Thomas]

The 'chute has a ten-year replacement requirement. Something to do with repacking to make sure the fabric is OK, and the rocket gets replaced; pyrotechnics age. This replacement has to take place at the factory, since the chute is pretty much sealed into the tailcone, and it costs a quoted $40,000. That's $4K per year just for the 'chute.

The SR20 we have here has been 'chuted once. The 'chute tears a harness out from under the fuselage skin (and this one also took the pilot's door off), the rocket blows a great hole in the tailcone, and the landing didn't damage it too much further. Still, the insurance company paid $140K to get it rebuilt, and that's what the airplane is worth today. The system should be seen as saving the occupants, not the airplane.

I sometimes wonder how easy it would be to "grab handle with both hands and pull firmly" when the airplane is gyrating around out of control (after some structural failure, say, or a spin induced by fuel imbalance) and grabbing anything would be difficult while being thrown about.

Dan

 

[steingar]

Easier to "grab handle and pull" than hold onto yolk or stick and try and fly all the way to the crash.

 

[Ken Ibold]

Easier to "grab handle and pull" than hold onto yolk or stick and try and fly all the way to the crash.

I find the yolk tends to run through the tines of my fork. But I'm able to hold onto a yoke fairly consistently.

 

[steingar]

I find the yolk tends to run through the tines of my fork. But I'm able to hold onto a yoke fairly consistently.

picky picky

 

[Clark1961]

I find the yolk tends to run through the tines of my fork. But I'm able to hold onto a yoke fairly consistently.

Go for the dry scramble and that yolk won't be a problem. Then again, there is always the toast to use in mop up operations...

 

[Capt.Crash'n'Burn]

Go for the dry scramble and that yolk won't be a problem. Then again, there is always the toast to use in mop up operations...

 

[flyingcheesehead]

I don't own a Cirrus but I have 300+ hours flying the SR22. There is no way to prove or disprove the case for "false sense of security". Stupid people will always do stupid things. The absolutely LAST thing I want to do is put myself into a situation where I have to fire off the chute. I think it would take an incredible dumbo to fly into a situation on purpose where he could pull the chute and destroy a $400K+ airplane.

The problem is not that they "fly into a situation on purpose," but that they use the chute as a potential out. "Well, I don't think I'm going to hit ice, BUT..." etc.

 

[flyingcheesehead]

I own a DA40.
From the AMM: The DA 40 has a fuel tank in each wing. Each wing tank is made of two chambers: the inboard fuel chamber and the outboard fuel chamber. The inboard fuel chamber and the outboard fuel chamber are interconnected. Aluminum makes the fuel chambers. Baffles in the chambers prevent the fuel from moving quickly from one end of the tank to the other during flight.

Tim,

Gary's right. It is most definitely an aluminum tank - Burn at least 5 gallons off from one side and you can see the bottom without any fuel in the way. It is most certainly a metal tank!

Gary, welcome to PoA!

There have been several reports of post crash fires involving Cirrus aircraft. The CAPS rocket has been known to fire on impact if it was not already deployed. There is speculation that this serves as an ignition source.

I thought it was the other way around - Fire starts in the fuel, causing the rocket to cook off?

 

[flyingcheesehead]

Nobody bashes the Diamond Star either, despite the fact that for all intensive purposes it is a Cirrus-light. Slower speeds, smaller engine, etc...

Except it's not. The DA40 is very comparable to the SR20. Both are fixed-gear, 4-place, technically advanced, composite singles. The SR20 has 20hp and about 5-10 knots on the DA40.

Searching the NTSB database, there have been 30 accidents in the SR20, 13 of them fatal. There are 15 accidents listed for the DA40, with only 3 fatal. (As Gary mentioned, there has been another fatal - Just happened a week or two ago - But there's presumably some SR20 accidents that haven't made the database yet as well, so I'll stick to what the database has.)

Now, as for fleet size - There are 706 DA40's on the FAA registry, and 758 SR20's. So, less than a 10% difference, but with twice the total number of accidents and over 4 times the number of fatal accidents.

Now, you tell me which is the safer airplane. The DA40 is most certainly NOT a "Cirrus Light."

 

[flyersfan31]

I think that you might be surprised how poorly a seat-belt and shoulder harness restrain the head and upper body in a crash. The head can really flail around and there is usually very little clearance between the head and the airplane even if the cockpit remains intact.

http://www.youtube.com/watch?v=CS6wof_d1_8&feature=related
http://www.amsafe.com/news/videos/detail.php?id=236

No I wouldn't be surprised at all. I'm an F1 fan.

 

[Everskyward]

Now, you tell me which is the safer airplane. The DA40 is most certainly NOT a "Cirrus Light."

I think a big part of the reason the DA40 is "safer" is that for about the same wingspan it's 800 pounds lighter and stalls 10 knots slower. That's a lot less energy than a Cirrus. I also don't think its mission is quite the same. The Cirrus is much more of a traveling machine. It's 35 knots faster in cruise. I don't buy the theory that the airbag, oops I mean parachute, encourages risky flying to any great extent. Of course there are people who would think that way but they would probably come to grief in a conventional airplane too. I don't know enough about the tanks in the Cirrus to make a judgment one way or the other.

 

[SCCutler]

Except it's not. The DA40 is very comparable to the SR20. Both are fixed-gear, 4-place, technically advanced, composite singles. The SR20 has 20hp and about 5-10 knots on the DA40.

Searching the NTSB database, there have been 30 accidents in the SR20, 13 of them fatal. There are 15 accidents listed for the DA40, with only 3 fatal. (As Gary mentioned, there has been another fatal - Just happened a week or two ago - But there's presumably some SR20 accidents that haven't made the database yet as well, so I'll stick to what the database has.)

Now, as for fleet size - There are 706 DA40's on the FAA registry, and 758 SR20's. So, less than a 10% difference, but with twice the total number of accidents and over 4 times the number of fatal accidents.

Now, you tell me which is the safer airplane. The DA40 is most certainly NOT a "Cirrus Light."

Good analysis, Kent.

If only Apple made an airplane...

 

[Jim Logajan]

Searching the NTSB database, there have been 30 accidents in the SR20, 13 of them fatal. There are 15 accidents listed for the DA40, with only 3 fatal. (As Gary mentioned, there has been another fatal - Just happened a week or two ago - But there's presumably some SR20 accidents that haven't made the database yet as well, so I'll stick to what the database has.)

Now, as for fleet size - There are 706 DA40's on the FAA registry, and 758 SR20's. So, less than a 10% difference, but with twice the total number of accidents and over 4 times the number of fatal accidents.

Now, you tell me which is the safer airplane. The DA40 is most certainly NOT a "Cirrus Light."

Turns out that the SR20s are flown three times as often as DA40s, and so the per trip and per hour accident rate for SR20s is lower than the DA40s.

OK - I just made that "three times" part up. The point of the above being that accidents normalized to "fleet size" is a statistic only of value to insurers. Fleet size normalization would work for aircraft that are comparable in the missions flown, but the DA40 and SR20 seem different enough (to the pilots flying them) that the latter are likely to see a higher utilization factor. Twice as much? That would be consistent with "risk compensation" (http://en.wikipedia.org/wiki/Risk_compensation)

 

[Gary F]

The attached photo shows why a DA40 is much less likely to spill fuel after a crash. The aluminum fuel tank is well protected.

 

[bbchien]

Turns out that the SR20s are flown three times as often as DA40s, and so the per trip and per hour accident rate for SR20s is lower than the DA40s.

OK - I just made that "three times" part up. The point of the above being that accidents normalized to "fleet size" is a statistic only of value to insurers. Fleet size normalization would work for aircraft that are comparable in the missions flown, but the DA40 and SR20 seem different enough (to the pilots flying them) that the latter are likely to see a higher utilization factor. Twice as much? That would be consistent with "risk compensation" (http://en.wikipedia.org/wiki/Risk_compensation)

Ah. another Cirrus partisan. Facts not in evidence....debunking these partisans is a tankless job.....