Lancair IV-P Down In San Diego

[N801BH]

...., I have yet to see a Lancair crash (other than an incident during taxi or rollout) with serious or fatal injury that did not involve one or all of the occupants being thrown out of the aircraft. .

.

This accident looks different...

The pic shows the fuselage intact from the spinner to the front of the tail section. Wings are splintered. The yellow canvas that is covering the windscreen is pulled back far enough possibly show the pilot and co pilot still sitting in ther seats... It really looks like a flat spin into the hillside to me..

 

[SteveinIndy]

The pic shows the fuselage intact from the spinner to the front of the tail section. Wings are splintered. The yellow canvas that is covering the windscreen is pulled back far enough possibly show the pilot and co pilot still sitting in ther seats...

I already have a call in to my contact with the county out there for the detailed information on this as it becomes available.. It does look like the seats are still in there although I couldn't tell if they were still where they started.

It really looks like a flat spin into the hillside to me..

I was wondering that too. You may well be correct.

 

[Ted]

Out of 19 fatal Lancair IVP accidents:

Private: 9
Commercial: 7
ATP: 2

Lowest number of total flight hours was 700. Median flight hours was 1900. Median for the Private Pilots was 1705. Time in type was not available in every case, but ranged from a low of 18 hours to a high of 1,000. Median time in type was 109 hours, but only about half the cases included a value.

Ron Wanttaja

My next question would then be how that compares to other aircraft. 1900 hours is a decent amount, but as we also know there's quality as well as quantity.

So in other words, someone who has 1900 hours flying typical certified singles and then hops in a IV-P might have a hard time with it. If that 1900-hour pilot has been flying more demanding aircraft and/or been flying in an environment that requires stricter discipline (corporate/135/121/military), that's a different matter.

Of course, there are the high-time pilots who go down and die. I think a lot of that is when an engine quits and the abysmal glide characteristics lead to an unpleasant landing.

The Moos were/are different in many ways, and lack of training led to the demise of pilots of all rank and odor. The fact that they were cheap and available to owners who probably shouldn't have been flying them obviously contributed to the accident rates. Many of the problems stemmed from the use of spoilers rather than ailerons, which resulted in the need for different control inputs during OEI ops. Once pilots were forced to understand the differences the airplane became just another turboprop.

I agree with your assessment, and nobody with any intelligence would ever call the IV-P "just another piston single."

That said, I think better training and discipline in the IV-P would make it significantly less deadly.

 

[wabower]

The difference is that the Moo's meet all the normal certification standards. When a pilot understands the systems, the need to be Sam Super-stick disappears. OTOH, nobody has lived long enough to know how much Yeager is required to survive in the Lawn Dart.

My next question would then be how that compares to other aircraft. 1900 hours is a decent amount, but as we also know there's quality as well as quantity.

So in other words, someone who has 1900 hours flying typical certified singles and then hops in a IV-P might have a hard time with it. If that 1900-hour pilot has been flying more demanding aircraft and/or been flying in an environment that requires stricter discipline (corporate/135/121/military), that's a different matter.

Of course, there are the high-time pilots who go down and die. I think a lot of that is when an engine quits and the abysmal glide characteristics lead to an unpleasant landing.



I agree with your assessment, and nobody with any intelligence would ever call the IV-P "just another piston single."

That said, I think better training and discipline in the IV-P would make it significantly less deadly.

 

[Ted]

The difference is that the Moo's meet all the normal certification standards. When a pilot understands the systems, the need to be Sam Super-stick disappears. OTOH, nobody has lived long enough to know how much Yeager is required to survive in the Lawn Dart.

Agreed.

 

[wanttaja]

My next question would then be how that compares to other aircraft. 1900 hours is a decent amount, but as we also know there's quality as well as quantity.

So in other words, someone who has 1900 hours flying typical certified singles and then hops in a IV-P might have a hard time with it. If that 1900-hour pilot has been flying more demanding aircraft and/or been flying in an environment that requires stricter discipline (corporate/135/121/military), that's a different matter.

An age-old issue...whether someone has flown 2000 hours, or one hour repeated 2000 times.

Unfortunately, its applicability to aircraft accidents is impossible to answer without individual research on each accident well beyond what's available in the NTSB records. It's an attractive hypothesis, but impossible to prove or disprove.

However, I'd presume someone with a Commercial or higher ticket would probably have a broader experience base than someone with a Sport or Private ticket. On that basis:

Fatal Accidents vs. Pilot Rating
None/Student/Sport:
All: 6.6%
Lancair IV/IVP: 0
Vans RV-6/6A: 0

Private:
All: 61.3%
Lancair IV/IVP: 43.4%
Vans RV-6/6A: 76.6%

CFI/Commercial:
All: 26.3%
Lancair IV/IVP: 52.2%
Vans RV-6/6A: 21.3%

ATP:
All: 5.8%
Lancair IV/IVP: 4.3% [One accident]
Vans RV-6/6A: 2.1% [Also just one accident]

Median Flight Hours (fatal accidents)/Median Time in Type:
All: 1074/48
Lancair IV/IVP: 1908/90
Vans RV-6/6A: 1154/127

Of course, there are the high-time pilots who go down and die. I think a lot of that is when an engine quits and the abysmal glide characteristics lead to an unpleasant landing.

Well, THAT at least I can help answer. From the fatal accidents, here are the top twenty on the basis of pilot total time. The four cases that involved engine failure were all in what we might consider unforgiving aircraft:

LAX00FA093A Questair Venture ATP 20000 hours Probable Cause: The pilots' inadequate visual lookout in visual conditions and class 'E' airspace. Contributing to the accident were the initial position report location and the approach speed of the Questair.

CEN10LA184 Vans RV-6 COMM 20000 The pilot's failure to maintain clearance from the lake while maneuvering at low altitude.

LAX98FA112 Christen Eagle II ATP 20200 The pilot-in-command's failure to maintain control of the aircraft. Contributing to the accident was the improper altitude.

CHI98LA129 Velocity COMM 21000 improper planning/decision by the pilot, by using the airplane in an illegal activity and allowing the fuel to be exhausted before landing. Factors relating to this accident were: the pilot being under pressure to reach his destination with his illegal cargo, and trees in the forced landing area.

ERA12FA006 Arion LI COMM 21811. Preliminary only, investigation not completed. Preliminary says, "...shortly after takeoff, approximately 15 feet above ground level; the airplane pitched up to a 45 to 60 degree nose up attitude and then appeared to have stalled just prior to impacting the house."

CHI01FA235 Giles G-202 ATP 21936 The pilot failed to maintain aircraft control which resulted in an inadvertant stall. Factors with the accident were the pilot misjudged the approach and the pilot's lack of total experience in the Giles G-202.

DFW07LA160 Vans RV-6 COMM 24000 The pilot's loss of control for undetermined reasons.

ATL01LA046 Steen Skybolt CFI 25000 The pilot's failure to maintain control of the airplane during climb out that resulted in the in-flight collision with the ground. A factor was the physical impairment.

CHI01FA077 Steen Skybolt FE 25678 The pilot not maintaining altitude/clearance from terrain during the low altitude maneuver. Factors were the wind gusts and the low altitude maneuver the pilot performed.

DEN00FA005 Christen Eagle ATP 27000 The pilot's inability to maintain aircraft control due to an unknown physical impairment.

ANC09FA062 Zenair CH-701 ATP 27200 The pilot's failure to maintain sufficient airspeed to avoid an aerodynamic stall during takeoff and his decision to fly the airplane over its allowable gross weight. Contributing to the accident was the airplane's excessive gross weight.

LAX06LA041 Special COMM 28000 The pilot's excessive use of power during takeoff, which resulted in an inadvertent torque roll shortly after lift off. Also causal was the pilot's failure to abort the takeoff when directional control could not be maintained during the takeoff roll.

WPR10LA258 Pietenpol AIR CAMPER CFI 28000 The pilot's loss of airplane control for undetermined reasons while on final approach to land.

CHI98FA353 Revolution MINI 500 COMM 28000 A loss of engine power due to cold seizure of the power-takeoff cylinder. A factor contributing to the accident was the power lines.

LAX04LA110 Wittman Tailwind W8 ATP 29000 The pilot's incapacitation during descent, which resulted in a loss of control and an in-flight collision with water.

MIA99FA159 Classic Aircraft Corp. S-51D ATP 29000 A complete loss of engine power caused by the malfunctioning landing gear, which blocked the radiator scoop, leading to increased fuel temperature and the subsequent vapor lock condition and fuel blockage. A secondary cause was the pilot's failure to maintain flying speed resulting in the subsequent stall/mush

SEA07LA060 Pitts S1 CFI 30000 The airplane collided with a frozen lake for undetermined reasons. Contributing to the accident was the pilot's intentional operation of the airplane while impaired by alcohol and the FAA's failure to obtain additional information about the pilot's self-

LAX01FA212 LANCAIR 4P CFI 31000 the builder's failure to install a fuel compartment vent in the right wing, affecting the total available fuel capacity, and resulting in the loss of engine power due to fuel starvation. A contributing factor was the pilot's intentional flight with a known inoperative fuel gauging system.

ATL98LA032 Aerocomp CA-6 ATP 34700 The loss of engine power for undetermined reasons. A factor was the trees in the emergency landing area.

ATL02LA009 Monnett Moni ATP 36500 The pilot's failure to maintain airspeed during a low-altitude aerobatic maneuver, which resulted in an inadvertent stall/spin and subsequent uncontrolled descent into terrain.

You could probably knock one or even two zeros off the total times on the above, and the accidents would still make about the same amount of sense. "Fate is the Hunter," as Ernie Gann said, whether you've got 30 hours or 30,000.

That said, I think better training and discipline in the IV-P would make it significantly less deadly.

Same thing I tell the Fly Baby guys...

Ron Wanttaja

 

[N801BH]

Boy that N number has a VERY interesting past ...

N5M

http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=5M

 

[wanttaja]

Interesting...I was massaging the data a bit more, and found an interesting result:

Lancair IV/IVP Accidents vs. year
Year Total Accidents
1998 3
1999 2
2000 3
2001 4
2002 3
2003 4
2004 4
2005 0
2006 7
2007 4
2008 8
2009 2
2010 2
2011 2

Really spiked in 2006/2008, but has been quite a bit lower since. Looks like 2012 is going to be ~4 total, of which at least two are turbine.

Ron Wanttaja

 

[N801BH]

Interesting...I was massaging the data a bit more, and found an interesting result:

Lancair IV/IVP Accidents vs. year
Year Total Accidents
1998 3
1999 2
2000 3
2001 4
2002 3
2003 4
2004 4
2005 0
2006 7
2007 4
2008 8
2009 2
2010 2
2011 2

Really spiked in 2006/2008, but has been quite a bit lower since. Looks like 2012 is going to be ~4 total, of which at least two are turbine.

Ron Wanttaja

I am guessing that since the economy was really cooking in the 06 -07 -08 time frame. There were people with more money then sense buying the IV-P's amd promptly crashing them... I remember one that landed here in 05 or so.. His first flight in it, the next day he went to leave and hot started it and toasted the motor.. Plane had a 80,000 dollar custom paint job on it... I helped them load it on a trailer so they could take it someplace to repair... I remember the guy joking.." what's another 300,000 grand to get another motor"..

 

[MSPAviator]

So what is the stall speed on a Lancair IV-P?

I don't think I've flown a plane anywhere close as unforgiving as what the Lancair supposedly is, what makes it unforgiving, is it the high wing loading and small vertical tail surfaces?

 

[wanttaja]

I am guessing that since the economy was really cooking in the 06 -07 -08 time frame. There were people with more money then sense buying the IV-P's amd promptly crashing them...

I have a process to guess whether a plane in an accident was owned by the original builder. I compare the manufacturer name to the owner's name, and look at the pilot time-in-type vs. the aircraft total time. It's certainly not a perfect process, but it's probably OK for a rough estimation.

In 2006, there were seven Lancair IV/IVP crashes. Two were probably owned by the original builder, two were probably purchasers, and there was no good evidence either way on the other three. (Often, Lancairs are owned by Delaware corporations.... They're ALSO prime candidates for "Hired Guns," so the ownership/manufacturer comparison is probably even muddier.)

For the two probably purchased cases, the pilots had 30 and 120 hours time in type. Both were private pilots with about 2,000 hours. Both aircraft were powered by Walther turbine engines.

And in neither case was anyone seriously hurt.

For the two that were probably owned by the builders, one was a Private with 1200 total time and 700 hours Lancair IV time. The 0ther was a Commercial pilot with 23,000 hours total time (no listing for time-in type, but the airplane had only 85). The one flown by the Commercial pilot had a Garrett turbine.

And in neither of THESE case was anyone seriously hurt, too.

In 2008, with eight Lancair IV/IVP crashes, two were builder-owned, three had been purchased. One of the purchased ones, the pilot (Commercial) had 20 hours in type (196 for the other, and the time isn't supplied for the third). All three cases resulted in fatalities. Two had recips, the engine for the third isn't supplied.

Ron Wanttaja

 

[Ted]

However, I'd presume someone with a Commercial or higher ticket would probably have a broader experience base than someone with a Sport or Private ticket. On that basis:

I'd agree. Thanks for the good information, Ron.

So what is the stall speed on a Lancair IV-P?

I don't think I've flown a plane anywhere close as unforgiving as what the Lancair supposedly is, what makes it unforgiving, is it the high wing loading and small vertical tail surfaces?

According to Lancair, the stall speed is 75 mph. So while it's really not all that fast (certainly within similar range of a number of twins), the issue is the unforgiving stall nature.

What causes its unforgiving nature is better answered by someone who knows more about aerodynamics. But the wing loading at about 36 lb/sq ft (32 with winglets) is higher than the twins I've spent much time flying (those are typically in the ~25 range). So I'd expect that to be part of it.

Of course, it's worth noting that the 310 and Aztec are both extremely forgiving in stalls, so there is more to it than just that.

 

[N801BH]

I have a process to guess whether a plane in an accident was owned by the original builder. I compare the manufacturer name to the owner's name,.........

.....In 2008, with eight Lancair IV/IVP crashes, two were builder-owned, three had been purchased. One of the purchased ones, the pilot (Commercial) had 20 hours in type (196 for the other, and the time isn't supplied for the third). All three cases resulted in fatalities. Two had recips, the engine for the third isn't supplied.

Ron Wanttaja

..

I commend you sir on outstanding research, spending the time to compile the stats and using common sense to arrive at logical conclusions...

One thing I might add to the discussion is the time frame we are looking at is right in the middle of most abused period of time by kit owners who farmed out their kits to professional build centers and private A&P's.. Once the FAA was able to digest the extent of the massive problem they were years behind the issue... and ALOT of professional built experimentals got into the air.

The spirit of the FAA rules of " for recreational and /or educational purposes" was laughed at by people who had more money then sense and there were PLENTY of companies out there ready to take that cash and allow the kit owner to engrave their name on the data tag....

This led to numerous owners who claimed they "built it" but had no sweat equity in the plane at all.... other then the sweat they got opening their wallet. I agree, the ones who actually built the plane most probably are/ were more careful in flying it as they had "skin"in the game and didn't want to crash their pride and joy..

Personally I have witnessed the illegal, less then honest way business was done in the 2003-2008 timeframe as my motor program was still in development and I refused to sell the engine package until it is perfected.. I would guess in that time frame I was contacted by a dozen, or more IV builders, as my motor was a great fit for that airframe, size and horsepower considered... All but one of those people who contacted me wanted the motor shipped to a "completion "center. Just one guy was building the plane himself , at home...... and wanted to install it himself... Just ONE... Because the people who died or were hurt in the crash, and their name was on the data plate does not represent the fact they actually built it..

Draw your own conclusions to that.....

Once again Ron..... Your write ups are GREAT....:wink2:

Ben Haas

 

[JimNtexas]

Interesting...I was massaging the data a bit more, and found an interesting result:

Lancair IV/IVP Accidents vs. year
Year Total Accidents
....
Really spiked in 2006/2008, but has been quite a bit lower since. Looks like 2012 is going to be ~4 total, of which at least two are turbine.

How many Lancair IV/IVP airplanes are there? That sure seems like a lot of accidents for what must surely be a fairly small fleet!

 

[N801BH]

How many Lancair IV/IVP airplanes are there? That sure seems like a lot of accidents for what must surely be a fairly small fleet!

Actually... There are NONE left... They all crashed..:wink2:....

Well... there are few left,, but they are still in the building stage and have not made their first flight yet....

 

[LearDriver]

Just because you can write the check for it, doesn't mean you should buy it and try to fly it.

 

[N801BH]

Just because you can write the check for it, doesn't mean you should buy it and try to fly it.

We have all seen that movie before...

 

[gismo]

So what is the stall speed on a Lancair IV-P?

I don't think I've flown a plane anywhere close as unforgiving as what the Lancair supposedly is, what makes it unforgiving, is it the high wing loading and small vertical tail surfaces?

I'd say it's a combination of high stall speed (clean and dirty), abrupt and asymmetrical stall characteristics, high wing loading (aka high stall speed), and a super critical wing.

I've flown a IV and a turbo 360 a tiny bit. Both had similar flying characteristics and both owners were reluctant to let me stall their plane. Personally I probably wouldn't own an airplane I was afraid to stall at altitude.

As near as I can tell the most significant issue with these planes is that if you nibble at a stall below 1000-2000 AGL you probably won't survive.

 

[wanttaja]

How many Lancair IV/IVP airplanes are there? That sure seems like a lot of accidents for what must surely be a fairly small fleet!

I just downloaded the newest FAA registration database, but haven't had a chance to analyze it yet. My previous copy (30 Dec 2011) says 317 aircraft. I look for Lancairs, and then any combination including 4, IV, Four, or Prop (e.g., Propjet).

As I previously posted, there were two Lancair IV crashes in 2011...which would give Lancair IV a "Fleet Accident Rate" of 0.63%. This is similar to the overall GA rate, and lower than the overall homebuilt rate (which is about 0.8%). However, 2012 did have four accidents, and I doubt the fleet got that much bigger last year.

The fleet rates are going to take a hit once the deregistration process is finally tallied in. Right now, I'm just basing the numbers on the N-number database.

Ron Wanttaja

 

[N801BH]

I'd say it's a combination of high stall speed (clean and dirty), abrupt and asymmetrical stall characteristics, high wing loading (aka high stall speed), and a super critical wing.

......

That is exactly why they are so darn fast....

Now we are back to the razor edged toys again.. They produce a clean shave.. And they will cut your throat just as fast... Ya just gotta know how to use the razor correctly..that's all...:wink2:

 

[Ted]

I've flown a IV and a turbo 360 a tiny bit. Both had similar flying characteristics and both owners were reluctant to let me stall their plane. Personally I probably wouldn't own an airplane I was afraid to stall at altitude.

I liked the way the former U-2 pilot/IV-P owner handled it of installing an AoA indicator and just saying "I don't do it anymore."

Of course, I do agree with your assessment that it is good to own a plane that you aren't afraid to stall, and aren't afraid to let others stall. I'd have no qualms letting you stall the 310.

 

[wabower]

Unfortunately, the styptic pencil that solves most sharp-razor problems isn't available for the aero-toys.

That is exactly why they are so darn fast....

Now we are back to the razor edged toys again.. They produce a clean shave.. And they will cut your throat just as fast... Ya just gotta know how to use the razor correctly..that's all...:wink2:

 

[Everskyward]

Of course, I do agree with your assessment that it is good to own a plane that you aren't afraid to stall, and aren't afraid to let others stall. I'd have no qualms letting you stall the 310.

You probably want to stay away from that Lear 24 I've heard you talk about then.

We hire a test pilot if one of the 35s needs to have a stall test done such as when the leading edge has been removed. The pilots who have gone along with the test pilot have said that it is a wild ride.

 

[SteveinIndy]

The pic shows the fuselage intact from the spinner to the front of the tail section. Wings are splintered. The yellow canvas that is covering the windscreen is pulled back far enough possibly show the pilot and co pilot still sitting in ther seats... It really looks like a flat spin into the hillside to me..

Some follow-up information as of last night from my contacts. While I am still waiting to see the final report (which should take a month or two), but at least two of the occupants were "found out of the normal spots in the aircraft". The way I read that is either they were thrown out of the seats or the seats broke loose. Given the history of the Lancair, the latter would be a way where you could have the occupants appear to still be in their seats in the picture but have them effectively unrestrained during the crash sequence.

 

[N801BH]

You probably want to stay away from that Lear 24 I've heard you talk about then.

.

Yup...... Waaaaaaay far away.......

 

[Ted]

You probably want to stay away from that Lear 24 I've heard you talk about then.

I think you know me well enough to know that the Lear 24 is a pipe dream for me for a number of reasons.

But I didn't say being afraid of stall characteristics would preclude me from buying an airplane per se, just that it's a consideration.

We hire a test pilot if one of the 35s needs to have a stall test done such as when the leading edge has been removed. The pilots who have gone along with the test pilot have said that it is a wild ride.

I'd believe that. I was thinking the point that most jet owners wouldn't let Lance (or anyone who's not very qualified) stall their jet. This illustrates the point.

 

[Everskyward]

I'd believe that. I was thinking the point that most jet owners wouldn't let Lance (or anyone who's not very qualified) stall their jet. This illustrates the point.

True. I think it also illustrates a point about the Lancair. I don't know much about the airplane but it seems that it has some nasty stall characteristics just like many jets. But even jets are certified to certain tolerances plus most have shakers and some have pushers. I think people may get into a Lancair and think it should handle much like any other small GA airplane when it doesn't.

 

[wabower]

You need to fire them on the spot. Nobody with good sense does that stuff and should not be trusted at the controls of an airplane.

You probably want to stay away from that Lear 24 I've heard you talk about then.

We hire a test pilot if one of the 35s needs to have a stall test done such as when the leading edge has been removed. The pilots who have gone along with the test pilot have said that it is a wild ride.

 

[Ted]

True. I think it also illustrates a point about the Lancair. I don't know much about the airplane but it seems that it has some nasty stall characteristics just like many jets. But even jets are certified to certain tolerances plus most have shakers and some have pushers. I think people may get into a Lancair and think it should handle much like any other small GA airplane when it doesn't.

Precisely.

 

[gismo]

I'd believe that. I was thinking the point that most jet owners wouldn't let Lance (or anyone who's not very qualified) stall their jet. This illustrates the point.

Lance probably wouldn't want to try.

 

[Ted]

Lance probably wouldn't want to try.

Nor would Ted.

But the offer stands on the 310 next time we meet.

 

[Everskyward]

Nor would Ted.

Nor would I, unless I had more training specifically do stall tests. That's what test pilots are for.

The 680 test pilot showed me a stall to the break which was really not that bad, but still more pronounced than any smaller airplane I have flown.

 

[wanttaja]

I commend you sir on outstanding research, spending the time to compile the stats and using common sense to arrive at logical conclusions...

Thank'ee kindly, Ben. In my appreciation, I'm going to disagree with something ELSE you said: :wink2:

The spirit of the FAA rules of " for recreational and /or educational purposes" was laughed at by people who had more money then sense and there were PLENTY of companies out there ready to take that cash and allow the kit owner to engrave their name on the data tag....

This led to numerous owners who claimed they "built it" but had no sweat equity in the plane at all.... other then the sweat they got opening their wallet. I agree, the ones who actually built the plane most probably are/ were more careful in flying it as they had "skin"in the game and didn't want to crash their pride and joy.

I'm sure that builders have more appreciation for the hardware and have a stronger desire to protect it. However, I don't think that has a strong effect on the builder vs. buyer accident rate.

What I think *does* happen is that the builder is immersed in the "Lancair World" for a long time. They talk to other builders, they're in touch with the company, they belong to various member's groups (such as the Lancair Owners and Builders Association, LOBO). I think the "get some training before your first flight" message has a LOT longer time to soak in. There'll be guys with flying aircraft offering to give them rides, and others (both overtly and subtly) pushing them to gain familiarity with the aircraft prior to first flight.

"Hired Gun" buyers...or buyers of used Lancairs...don't undergo this "conversion" process. They go from (maybe) Bonanza to Lancair IV in the time it takes to cut a check. If they've used a hired gun, they may even avoid the builder community since they won't be able to "walk the walk."

The issue is a fundamental one that people just don't understand: These are not certified airplanes.

"But of COURSE I know it's not certified!!!!"

The problem is, people don't understand the physical ramifications of that. All their flying lives, they've flown airplanes that handled in accordance to Part 23. My copy of Part 23 had 7-8 pages devoted to how the airplane should handle. Elevator force, behavior with flaps up and down, rate of roll, stability, stall characteristics, it's all there. This leads to a homogenization of control feel; because they're designed to the same standards, all airplanes certified to Part 23 tend to fly the same.

This means we're programmed to how we think planes should fly. Not a problem...until you get behind the stick of a plane that never had to comply with the regulations.

Years ago, I got a demo flight in an Avid Flyer-class homebuilt. The demo pilot took the takeoff, climbed to a safe altitude, and let me take the controls. I moved the stick to the left for a turn...and found the nose going right. The airplane had a ton of adverse yaw. I'd never flown a plane like that before. It was strange, making the turns with the rudder and a tad bit of stick to coordinate.

Had I been making a first-flight in such an aircraft, without the benefit of a prior flight? May not have ended well.

So someone writes a check and takes delivery of a brand new Hired-Gun Lancair IV. Checkout? "No need, I've been flying [210s][Bonanzas][Cirruses]." They just don't have the fundamental understanding that the airplane may react far differently from they are used to. Even if they're buying a previously-flown aircraft, they are, essentially test pilots.

But they don't have the mental attitude of a test pilot; they're not ready for anything that's beyond their certified-airplane flying experience.

I feel someone BUILDING the aircraft has several years time to hear other folks' impressions of how the airplane flies. The cautions from other folks may eventually stick, may ensure the builder gets some decent experience prior to their first flight.

Ron Wanttaja

 

[wanttaja]

Some follow-up information as of last night from my contacts. While I am still waiting to see the final report (which should take a month or two), but at least two of the occupants were "found out of the normal spots in the aircraft". The way I read that is either they were thrown out of the seats or the seats broke loose. Given the history of the Lancair, the latter would be a way where you could have the occupants appear to still be in their seats in the picture but have them effectively unrestrained during the crash sequence.

The trouble is, if they DID come out of position, all that proves is that the crash forces exceeded the capability to hold the occupants. You can't prove that Cessna 210 in an identical accident (hitting the ground at the higher rate the Lancair is capable of) wouldn't exhibit the same effect.

Real-world accidents make lousy lab tests. You need to set up fuselages in fixtures and test under controlled conditions.

Ron Wanttaja

 

[SteveinIndy]

The trouble is, if they DID come out of position, all that proves is that the crash forces exceeded the capability to hold the occupants. You can't prove that Cessna 210 in an identical accident (hitting the ground at the higher rate the Lancair is capable of) wouldn't exhibit the same effect.

Agreed, but it also indicates that the standards may be set artificially low. That was my point. If you have a person who can withstand 40+ G in a forward impact (which has been established since the days of Hugh de Haven and Hasbrook's original work in the 1940s and 1950s and the work of Stapp et al in the 1960s and 1970) but the seats are attached in ways where they will fail at 5, 10, 20 or 26 G then you have a design point that is a potential problem.

Real-world accidents make lousy lab tests. You need to set up fuselages in fixtures and test under controlled conditions.

Agreed. You actually need data from both. You need the real world data to determine the circumstances of crashes (angle, velocity, etc) and to delineate the injuries associated with differing scenarios as well as the real world benefits of changes in designs or other safety efforts. You need the controlled tests to elucidate the specific mechanisms, identify areas that need improvement before introducing a new design to service and to evaluate safety tests.

Very few of the controlled tests (the NASA Langley studies for example) conducted thus far has been directly applicable to real world crashes because of the limitations of the test rig in terms of velocity and the confirmation bias with regards to the supposed correlation of speed, angle and survivability that furthers the lower standards we have in the FAR and are utilized in the tests. This gives the impression that the human survivability threshold is lower than it is when where the demonstration is likely of the limits of the aircraft and not its occupants. However, the tests have demonstrated that most current design standards do not stand up to even marginal impact situations in a way conducive to survival.

 

[Jaybird180]

Agreed, but it also indicates that the standards may be set artificially low. That was my point. If you have a person who can withstand 40+ G in a forward impact (which has been established since the days of Hugh de Haven and Hasbrook's original work in the 1940s and 1950s and the work of Stapp et al in the 1960s and 1970) but the seats are attached in ways where they will fail at 5, 10, 20 or 26 G then you have a design point that is a potential problem.



Agreed. You actually need data from both. You need the real world data to determine the circumstances of crashes (angle, velocity, etc) and to delineate the injuries associated with differing scenarios as well as the real world benefits of changes in designs or other safety efforts. You need the controlled tests to elucidate the specific mechanisms, identify areas that need improvement before introducing a new design to service and to evaluate safety tests.

Very few of the controlled tests (the NASA Langley studies for example) conducted thus far has been directly applicable to real world crashes because of the limitations of the test rig in terms of velocity and the confirmation bias with regards to the supposed correlation of speed, angle and survivability that furthers the lower standards we have in the FAR and are utilized in the tests. This gives the impression that the human survivability threshold is lower than it is when where the demonstration is likely of the limits of the aircraft and not its occupants. However, the tests have demonstrated that most current design standards do not stand up to even marginal impact situations in a way conducive to survival.

Very interesting. So in essense, Cirrus' marketing of seats that can withstand 26G is still inadequate to provide protection, while the human body can naturally take 40G before destruction? (...and no one else is advertising 26G seats to my knowledge.) Is that what you're saying?

 

[wabower]

I think Cirri seats are part of the cert reqs in lieu of slower VSO.

Very interesting. So in essense, Cirrus' marketing of seats that can withstand 26G is still inadequate to provide protection, while the human body can naturally take 40G before destruction? (...and no one else is advertising 26G seats to my knowledge.) Is that what you're saying?

 

[SteveinIndy]

Very interesting. So in essense, Cirrus' marketing of seats that can withstand 26G is still inadequate to provide protection, while the human body can naturally take 40G before destruction? (...and no one else is advertising 26G seats to my knowledge.) Is that what you're saying?

Yes and no. Yes, the structure is inadequate. No, the level of tolerance (with injury) to forward facing deceleration is probably closer to 60-70 G for the average person. One of the classic examples of the limits is de Haven's article on survival from extreme falls. This is a good example because of the lack of subject For a very fit person (such as race car drivers, etc), the limit in a crash is probably well in excess of 100 G. The actual level to destroy (fragment) the human body through simple impact is usually estimated to be over 300 G.

A lot of confusion stems from relying upon differing standards, namely "survival without injury" (which is effectively the standard the FAA and most designers rely upon) versus "survival with injury" which is the optimal and more realistic standard which should be utilized.

 

[N801BH]

Steve is pointing out the G limits and alot of people are grouping it in a general term... Key points are Forward G's...

Properly restrained a human can withstand the high limits, lets say 70 g's... and walk away... Race drivers do it on Sundays.. . Take that same 70 G's and convert that to downward G's like a human would be subjected to in a flat spin pancaking into the earth and the person would be crushed into a 3 foot tall corpse.. Not a snowballs change in hell of surviving..

 

[docmirror]

I hesitate to bring this up, but G loads also have a duration that is most critical to survivability. The pressure graph should be a pulse, much like a Std Dev line with 1G at each end, and the excursion measured in mS or seconds. No human can survive 26 or 40 Gs sustained more than a few hundred mS, no matter the direction.

Also, I'm not a mech engineer, just an ole EE but the surrounding structure needed to support a restraint system of 40Gs on a 200Lb person would be pretty beefy. It could surely be done, but it wouldn't be painless to aircraft design.

The first mod I put in my old flivver was a double shoulder restraint, including new lap belts and hardware. It's attached to a stringer and longeron brace and looks pretty solid. The weak part now is the seat hardware which is held to the spar with a 5/16 shank av-grade bolt on each side.