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saini flyer

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Mar 12, 2010
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462
Location
Dallas, TX
  1. Avid, glastar,701, and kitfox are all welded fuselage cockpits.
  2. Avid, glastar,701, and kitfox are all STOL
  3. Avid, glastar,701, and kitfox are all very low stall speed designs
  4. Avid, glastar,701, and kitfox all have low cruise (80-140mph) Vs the RVs/lancairs. There is no "alternative physics" to deal with dissipating 1/2mv^2 yet!
Welded fuse+STOL+ low stall+ medium cruise.... sounds like a tried and tested winning formula.. 👍
Man, that glastar sportsman is just an awesome plane for a lot of money!!
 

Wanttaja

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Sep 15, 2013
Messages
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Location
Seattle, WA
My concern is for accidents with fatalities that are caused by secondary failures of equipment, not the primary failure to maintain flight.
So things like getting hit on the head by motors,
post crash fires,inability to escape a broken airframe.
And while I have no data,the getting hit on the head by 1, a severly flexing fuesalage frame
and 2, getting hit in the back of the head by a high
mounted pusher engine are both persistant anecdotes.
And again thank you for a demonstration of the power of statistics.
Your concern is in regarding crashworthiness, which is difficult to analyze based on the NTSB database. The accident reports will summarize the autopsies, but when they say, "The cause of death was blunt-force trauma," they don't say WHAT was the source of that blunt force.

So detailed information is difficult to come by. I've done some high-level analysis, on items such as wing positioning and the effect of fuel tank location on post-crash fires.

Here's a summary of my analysis of the effect of wing position. Note that it's plotted against the nominal cruise speed of the airplane...high or low wing, the harder it hits, the more likely someone's going to get seriously injured.
wing_pos2.JPG
You'll note the "Ultralight-Style Pushers" block on the left side, showing an elevated fatality rate vs. the cruise speed of the aircraft.

It's possible...but impossible to prove...that these fatalities were due to the engine coming free and striking the occupants. However, one thing in common with this aircraft is minimal structure around the occupants. In most of these airplanes, the first thing to hit the ground will be al ittle bit of fairing, a little bit of tubing, and the pilot's feet on the rudder pedals.

In my opinion, the crashworthiness advantage of a tractor-style airplane is due to the additional structure in front of the pilot required to support the heavy mass and gyroscopic effect of the engine and propeller. This has the happy side-effect of reducing the chance of the Continental co-habiting the cabin. But all that bracing the structure helps absorb the loads before it reaches the cabin.

Found this picture of the Searey structure:

You'll notice there is a cockpit floor attached to the fiberglass shell, and there's even a bulkhead near the front of the shell. This will give more protection than the classic ultralight-style where you can dangle your feet on the grass when you're on the ground. I suspect, as an amphibian, that the plane has a reinforced keel, as well. That, again, would help occupants survive. I would fully expect the Icon to be similar. To quote Monty Python: "Never kill a customer!"

As I've mentioned, the Searey has a fatality rate less than homebuilts in general, and probably typical for its speed range. There's another factor here, though.

A few months back, I looked at in-flight and post-accident fires in homebuilt aircraft (just published in the April 2020 issue of Kitplanes magazine). I realized that the Searey was unique among the homebuilts I looked at, in that it had suffered *no* post-crash fires.

Then I noticed that 70% of the Searey accidents occurred on water. Which, of course, greatly reduces the chance of a fire.

But then, if almost 3/4ths of the accidents occur on water, how does it affect the likelihood of occupant fatalities? Does it reduce the fatalities, since the water has more "give"? Or are fatalities higher, as badly-injured occupants drown before they can be extracted from the aircraft? This is something I probably could research for the Searey, but the "Fires" article gave me nightmares for a week.

I'm sure there are cases where the aft-mounted engine struck occupants on pusher aircraft. Remember, though, that if the FRONT-mounted engine ends up in the pilot's lap, folks do not assess this as a fault of the design. But if an aft-mounted engine hits the cabin, the opposite is true.

As folks may have picked up on, I am very data-driven. My primary data source is the NTSB downloadable datasets. The advantage here, is that *anybody* can download and analyze it. I feel confident making statistics-based statements, since anyone can do the same analysis and confirm or repute me.

Like most folks, I do speculate at times, but even then, like to have some information to back me up.

There are three axioms that my statistics analysis are based on:

"Statistics are like swimsuits. What they reveal is interesting. What they conceal is vital!” - Profession Aaron Levenstein

"The purpose of analysis is insight, not Bull****." -Tom Weston, one of my former bosses. (This was stitched on a sampler on the wall of his office. Bull**** was fully spelled out.)

And, finally,

"The plural of 'Anecdote' is 'Anecdotes,' not 'Data.'" - Anonymous.

Ron Wanttaja
 

dog

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Joined
Dec 29, 2019
Messages
299
Well Ron, hat off.
Thanks, your "speculation" is rather well informed.
My father flew in his youth and then reluctanly switched to medicine,where he worked among other things as phorensic pathologist and I became sensitized to the tradgedies that effected
him ,the phrase "otherwise survivable" has become a kind of catch all reminder to build well
research and design well, and ask the next question, and while we are destined to become
statistics, its the when and how that rankles.
I used anecdotes as as there is no other good source of info ,the data sets are small, and lumping of data "blunt force", leaves only autopsy
reports,
And my gut read of the parasol with pusher on a strut braced wing, is that it will crumple forward if it gets an asymetric hit, or twist.
I have heard (first hand)of them bieng droped realy hard on a too high flair over water and doing just fine.Still gona give em the stink eye.
And back to this thread, $75000 is exactly the same as the $250000 I dont have.
And the icon tops trees runs over embankments
and is still recognisable, wana try it in a sea ray?
Id say that there is another case where sea rays will sell icons.
Though it might be interesting if it turns out that the first thing people do with a safer aircraft is something dumber,just like with SUV's
And with a bit of "data" Ron can put the lid on this.
Cheers.
Dog
 

Wanttaja

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Messages
1,468
Location
Seattle, WA
Well, with only 11 fatal Searey accidents (1998-2018), let's take a look.

CHI03LA201 Stall/Spin after engine failure

No cause of death in autopsy. I tend to think this one did not involve engine displacement, because the report notes that the engine was able to be turned over afterwards and all the accessories were intact: "The airplane's engine could be rotated freely and compression was confirmed on each cylinder. The turbocharger was rotated freely. The carburetors, intake manifolds, and carburetor float chambers were dry and had no evidence of residual fuel. The diaphragm type fuel pressure regulator that supplies fuel to both carburetors was disassembled and did not contain residual fuel. Examination of the rubber diaphragm revealed a 1/4-inch tear near the center where the spring seats on the diaphragm."

ERA09LA325 Stalled while buzzing a boat
Cause of death "blunt force injuries of torso." No apparent displacement/damage to the engine: "The engine was drained of accumulated water, examined, and test run. During the test run the engine produced power and no mechanical anomalies were noted."

ERA14FA459B Midair
This doesn't really count; the fatalities were in the other aircraft, both Searey occupants survived.

NYC99FA096 Nose-low water landing
No displacement, "The engine, propeller, fuel lines, fuel tank, and engine controls were intact."

CHI05LA125 Ground collision for unknown reasons
No autopsy information, no mention of engine status. However, flight control continuity was verified.

NYC06LA187 Partial power loss for unknown reasons, followed by stall
Cause of death blunt force trauma. Aircraft was upside down, but report notes, "The engine, which remained attached to its normal above-wing location...."

ATL07LA089 Collision with power lines over a canal
The autopsy findings reported the cause of death as drowning, with contributory conditions as multiple blunt trauma. Unknown if the engine was in its design location...the plane was really thrashed. "...the wing center section partially separated and deformed. The fabric covering on both the left and right wings was ripped and torn away, exposing the internal structure of the wings. The left horizontal stabilizer sustained impact damage.

CEN10LA165 Loss of control for unknown reasons
The cause of death was determined to be multiple injuries as a result of an accident. Plane was on its back. No mention of status of engine, although the inspector noted that all three prop blades had been broken off.

ERA10LA391 Stall/Spin into Water
The cause of death was determined to be "blunt impact to head and torso." No mention of engine displacement, however, after the wreckage was removed from the water, they were able to re-start the engine.

ERA14LA423 Lost control during touch-and-go on the water
Cause of death was drowning; in fact, the pilot was "... located in the interior of the empenage. " Again, the engine was started after removal of the wreckage from the water, and I presume a displaced engine would not have knocked the pilot into the tail section....

WPR14FA209 Hit boat wake on takeoff and lost control
Cause of death was attributed to fresh water drowning, a significant finding was blunt force head trauma. No engine displacement here, "The engine appeared intact and in place on the engine pylon. Witnesses reported that the engine was still running as boats approached following the accident...."

Doesn't look like the engine coming forward is that common an occurrence....or, at least, is a survivable one.

Ron Wanttaja
 

Vigilant1

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If an anecdote is nearly worthless, what's the value of an untrue anecdote?
 

BBerson

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Port Townsend WA
It seems unlikely the engine could penetrate through the wing on either the Searay or Icon. ( in a "survivable crash")
 

12notes

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Louisville, KY
Well, with only 11 fatal Searey accidents (1998-2018), let's take a look.

CHI03LA201 Stall/Spin after engine failure
No cause of death in autopsy. I tend to think this one did not involve engine displacement, because the report notes that the engine was able to be turned over afterwards and all the accessories were intact: "The airplane's engine could be rotated freely and compression was confirmed on each cylinder. The turbocharger was rotated freely. The carburetors, intake manifolds, and carburetor float chambers were dry and had no evidence of residual fuel. The diaphragm type fuel pressure regulator that supplies fuel to both carburetors was disassembled and did not contain residual fuel. Examination of the rubber diaphragm revealed a 1/4-inch tear near the center where the spring seats on the diaphragm."

ERA09LA325 Stalled while buzzing a boat
Cause of death "blunt force injuries of torso." No apparent displacement/damage to the engine: "The engine was drained of accumulated water, examined, and test run. During the test run the engine produced power and no mechanical anomalies were noted."

ERA14FA459B Midair
This doesn't really count; the fatalities were in the other aircraft, both Searey occupants survived.

NYC99FA096 Nose-low water landing
No displacement, "The engine, propeller, fuel lines, fuel tank, and engine controls were intact."

CHI05LA125 Ground collision for unknown reasons
No autopsy information, no mention of engine status. However, flight control continuity was verified.

NYC06LA187 Partial power loss for unknown reasons, followed by stall
Cause of death blunt force trauma. Aircraft was upside down, but report notes, "The engine, which remained attached to its normal above-wing location...."

ATL07LA089 Collision with power lines over a canal
The autopsy findings reported the cause of death as drowning, with contributory conditions as multiple blunt trauma. Unknown if the engine was in its design location...the plane was really thrashed. "...the wing center section partially separated and deformed. The fabric covering on both the left and right wings was ripped and torn away, exposing the internal structure of the wings. The left horizontal stabilizer sustained impact damage.

CEN10LA165 Loss of control for unknown reasons
The cause of death was determined to be multiple injuries as a result of an accident. Plane was on its back. No mention of status of engine, although the inspector noted that all three prop blades had been broken off.

ERA10LA391 Stall/Spin into Water
The cause of death was determined to be "blunt impact to head and torso." No mention of engine displacement, however, after the wreckage was removed from the water, they were able to re-start the engine.

ERA14LA423 Lost control during touch-and-go on the water
Cause of death was drowning; in fact, the pilot was "... located in the interior of the empenage. " Again, the engine was started after removal of the wreckage from the water, and I presume a displaced engine would not have knocked the pilot into the tail section....

WPR14FA209 Hit boat wake on takeoff and lost control
Cause of death was attributed to fresh water drowning, a significant finding was blunt force head trauma. No engine displacement here, "The engine appeared intact and in place on the engine pylon. Witnesses reported that the engine was still running as boats approached following the accident...."

Doesn't look like the engine coming forward is that common an occurrence....or, at least, is a survivable one.

Ron Wanttaja
Maybe the engine didn't come forward, but the human was shoved backwards towards the engine. After all, the lower crumple zones on a human aren't necessarily fatal when crushed, and the upper crumple zone can't do much damage to an engine.
 

Vigilant1

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I can only guess people are typing things without looking at the Searey.
 

dog

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Joined
Dec 29, 2019
Messages
299
Well, with only 11 fatal Searey accidents (1998-2018), let's take a look.

CHI03LA201 Stall/Spin after engine failure

No cause of death in autopsy. I tend to think this one did not involve engine displacement, because the report notes that the engine was able to be turned over afterwards and all the accessories were intact: "The airplane's engine could be rotated freely and compression was confirmed on each cylinder. The turbocharger was rotated freely. The carburetors, intake manifolds, and carburetor float chambers were dry and had no evidence of residual fuel. The diaphragm type fuel pressure regulator that supplies fuel to both carburetors was disassembled and did not contain residual fuel. Examination of the rubber diaphragm revealed a 1/4-inch tear near the center where the spring seats on the diaphragm."

ERA09LA325 Stalled while buzzing a boat
Cause of death "blunt force injuries of torso." No apparent displacement/damage to the engine: "The engine was drained of accumulated water, examined, and test run. During the test run the engine produced power and no mechanical anomalies were noted."

ERA14FA459B Midair
This doesn't really count; the fatalities were in the other aircraft, both Searey occupants survived.

NYC99FA096 Nose-low water landing
No displacement, "The engine, propeller, fuel lines, fuel tank, and engine controls were intact."

CHI05LA125 Ground collision for unknown reasons
No autopsy information, no mention of engine status. However, flight control continuity was verified.

NYC06LA187 Partial power loss for unknown reasons, followed by stall
Cause of death blunt force trauma. Aircraft was upside down, but report notes, "The engine, which remained attached to its normal above-wing location...."

ATL07LA089 Collision with power lines over a canal
The autopsy findings reported the cause of death as drowning, with contributory conditions as multiple blunt trauma. Unknown if the engine was in its design location...the plane was really thrashed. "...the wing center section partially separated and deformed. The fabric covering on both the left and right wings was ripped and torn away, exposing the internal structure of the wings. The left horizontal stabilizer sustained impact damage.

CEN10LA165 Loss of control for unknown reasons
The cause of death was determined to be multiple injuries as a result of an accident. Plane was on its back. No mention of status of engine, although the inspector noted that all three prop blades had been broken off.

ERA10LA391 Stall/Spin into Water
The cause of death was determined to be "blunt impact to head and torso." No mention of engine displacement, however, after the wreckage was removed from the water, they were able to re-start the engine.

ERA14LA423 Lost control during touch-and-go on the water
Cause of death was drowning; in fact, the pilot was "... located in the interior of the empenage. " Again, the engine was started after removal of the wreckage from the water, and I presume a displaced engine would not have knocked the pilot into the tail section....

WPR14FA209 Hit boat wake on takeoff and lost control
Cause of death was attributed to fresh water drowning, a significant finding was blunt force head trauma. No engine displacement here, "The engine appeared intact and in place on the engine pylon. Witnesses reported that the engine was still running as boats approached following the accident...."

Doesn't look like the engine coming forward is that common an occurrence....or, at least, is a survivable one.

Ron Wanttaja
Understood.Acepted.And going to maintain my irrational stink eye perception of sea rays,but now
feel compelled to ask a few more questions about
the local fatality in a sea ray.
There is a question I have about post crash engine
testing.How is it done? In the as crashed airframe?Removed and bench tested as crashed?
or with some level of preperation?Club prop?, new fuel?
Dog
 

Wanttaja

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Messages
1,468
Location
Seattle, WA
There is a question I have about post crash engine
testing.How is it done? In the as crashed airframe?Removed and bench tested as crashed?
or with some level of preperation?Club prop?, new fuel?
It varies, probably depending on the degree of suspicion that the engine was involved, the amount of damage, and the inspector's own preferences/available budget. Homebuilt accident investigation is not a priority at the NTSB, so less may be done on E/AB aircraft. I think in most cases the inspections are done with the engine in place on the aircraft, but there are occasional references to removing the engine for inspection or test run. Sometimes, there are references to supplying fuel from a different source.

Here's some samples from NTSB reports...

"The airplane's engine could be rotated freely and compression was confirmed on each cylinder. The turbocharger was rotated freely. The carburetors, intake manifolds, and carburetor float chambers were dry and had no evidence of residual fuel. The diaphragm type fuel pressure regulator that supplies fuel to both carburetors was disassembled and did not contain residual fuel. Examination of the rubber diaphragm revealed a 1/4-inch tear near the center where the spring seats on the diaphragm."

"The engine was drained of accumulated water, examined, and test run. During the test run the engine produced power and no mechanical anomalies were noted."

"Ten hours after the airplane was recovered from the water, each cylinder was drained by removing the bottom sparkplugs. Then the sparkplugs were reinstalled, and the propeller was rotated by hand. After several attempts, the engine fired and the propeller rotated approximately 10 time."

"After draining the oil from the block, the lower spark plugs were removed and the cylinders were drained of water. With the spark plugs removed the engine was rotated by hand by turning the propeller. Compression and suction was obtained on all cylinders and water was ejected from the cylinders with force. Continuity of the crankshaft was confirmed to the rear accessory gears and to the valve train. Oil was inserted into each cylinder for preservation of the engine. The sparkplugs were reinstalled to prevent loss or further contamination. The visual examination revealed no anomalies that prevented the engine from being removed for a test run. The engine was removed and transported to an authorized repair center for an engine run on August 17, 2010."

Ron Wanttaja
 

Daleandee

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dragon2knight

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Bronx, NY
Here's Paul's take on the accident:

While Paul does say that the company did indeed pitch these all wrong....he kinda glossed over the fact that most all would be buyers thought this plane was something that it really wasn't. The all wrong hype the company generated attracted folks like Halladay's type, reckless and undisciplined. They brought all of this on themselves and deserve the backlash.
 

BBerson

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Port Townsend WA
I think Halliday was doing low level modified hammerheads or stall turns and didn't understand the required radius of recovery altitude. See Stick and Rudder book for explanation.
 
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