Sad day in Jackson Hole
- Thread starter N801BH
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Geico266
Touchdown! Greaser!
Amazing forces at work there.
Good work Ben, thanks again for all of the caring and humanity you have selflessly displayed during this tragic accident.
Good work Ben, thanks again for all of the caring and humanity you have selflessly displayed during this tragic accident.
guardrail
Pre-takeoff checklist
tru.dat
I'll buy her a coffee!Ben, you make me proud to be a fellow pilot, I hope if a time comes for me to step up I can do it half as well as you sir.
rwhenderson
Filing Flight Plan
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56s
Have you talked to NTSB? As a witness I would encourage you to do so if you haven't. Only because I was a witness to a crash several years back, one of many witnesses but several of them (who did talk to NTSB) had a better view of the incident than I did so I didn't think I'd have anything more to contribute. Comes the finding and some of the basic facts were so completely wrong I was amazed. I spoke to two guys who had talked to NTSB and they concurred with my recollection of the event. In the end I don't think it makes any difference since both versions essentially came down to "maneuvering flight" but still, it's bothered me ever since to think that the NTSB report is out there with such glaring errors (and likely others as well.)
Skylane81E
Final Approach
He worked closely with the NTSB
Jim Logajan
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He has indeed talked to them - I assume the number of posts to this thread obscured that fact.
Oh - and welcome to PoA! I assume by your display name of 56s that you fly out of Seaside Oregon? I fly out of Creswell Oregon.
During the investigation of the RV-7 crash ( N820RV) this gal impressed me with her thirst for details....
She is the lead investigator for the Lancair IV crash that killed the CEO of Micron a year earlier and her report on that is now final..... It is a LONG read but she didn't leave ANY stone unturned..
..
...http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=20120203X23028&ntsbno=WPR12FA089&akey=1..
It will be interesting to read her summary on the Jackson Hole crash.. Especially since the wreckage was left in my yard for a month while the Insurance company delayed picking it up......
Ps... I reconstructed it and found out EXACTLY what broke to cause the pilot to get distracted and stall it....
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LoneAspen
Line Up and Wait
Ps... I reconstructed it and found out EXACTLY what broke to cause the pilot to get distracted and stall it....
I read through the report, and although granted most of it is Greek to me, I didn't read anything that definitely pointed out "what caused it."
Did I miss something buried in there? What did you find that broke?
Jim Logajan
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Likely some confusion over what Ben is referring to. At the risk of adding to the confusion:
Ben is saying he believes he knows what caused the RV-7 crash that he witnessed; but the NTSB report he linked to is for a different crash - a Lancair. The only reason he linked to that report was to showcase the thoroughness of the investigator who wrote it because she was also assigned to the RV-7 crash investigation.
RV10flyer
Pattern Altitude
I wish all investigations involving fatalities were that thorough.
On the RV-7...most of us are probably thinking "that alternative engine". But it is probably more simple than that. Keep us posted Ben.
On the RV-7...most of us are probably thinking "that alternative engine". But it is probably more simple than that. Keep us posted Ben.
I was a supercharged Lycoming clone... Altho it probably makes it " alternative"..
..Attachments
LoneAspen
Line Up and Wait
Gotcha - I thought the report was for the incident he was mentioning, but I was mistaken.
Agreed on the thoroughness of that report. That was impressive.
Badger
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Badger
...
Ps... I reconstructed it and found out EXACTLY what broke to cause the pilot to get distracted and stall it....
are you thinking bird strike?
Nope....
.....Ps.... The pic in post 91 shows the path of the pilots upper half leaving the plane, not a bird entering it....
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sferguson524
Pattern Altitude
The words "My God" barely scratch the surface of this one
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Mantis Toboggan, MD
MAKG1
Touchdown! Greaser!
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MAKG
What the hell is the secret?
Someone died here. It's not a guessing game.
Someone died here. It's not a guessing game.
Cpt_Kirk
En-Route
Stiff drinks help.
On my first day at my current job, I watched a piece of auger roll off a flatbead and on top of a guy standing next to it. It severed 90% of his left leg just below the hip. I had to hold a rag on the wound to stop the bleeding until the paramedics got there. He's alive now, but he barely made it.
You want to pretend it didn't happen, but you know to go run and help in any way you can, regardless of how it looks.
On my first day at my current job, I watched a piece of auger roll off a flatbead and on top of a guy standing next to it. It severed 90% of his left leg just below the hip. I had to hold a rag on the wound to stop the bleeding until the paramedics got there. He's alive now, but he barely made it.
You want to pretend it didn't happen, but you know to go run and help in any way you can, regardless of how it looks.
Two humans died here... Not one....
..There is NO secret.. I am waiting for the NTSB to release their final / Factual report and then I will explain my findings of the wreckage.....
sferguson524
Pattern Altitude
You sir, are a class act
. Many years ago, i witnessed 2 marines, drunk as hell roll their car across all 4 lanes of I-5 in N. San Diego county. One was bleeding profusely from a rather large cut on his arm, my sweater and belt were sacrificed to stop the bleeding, his buddy, was hanging unconscious from his seatbelt in the upside down truck, my friend and I had to pull him out, and all he could say when he regained consciousness was "don't tell my wife i was driving drunk." It's true what you say about running to help.
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Mantis Toboggan, MD
There is no secret. The NTSB has not released a final report.
Nauga,
full circle
Were you working for the NTSB in some official capacity?
Nauga,
full circle
Matthew
Touchdown! Greaser!
Two humans died here... Not one....
There is NO secret.. I am waiting for the NTSB to release their final / Factual report and then I will explain my findings of the wreckage.....
Probably something simple, too.
A buddy of mine lost his mom about 10 years ago in an RV. Her husband was the pilot, got distracted when the canopy popped open during takeoff, stalled it and pancaked it from about 20'.
Katamarino
Pattern Altitude
Report is out: http://www.ntsb.gov/_layouts/ntsb.a...-8c4c-4651-af12-f2b8933a8706&pgno=1&pgsize=50
The report states that no reason could be found for the malfunction. This seems at odds with what Ben states?
The report states that no reason could be found for the malfunction. This seems at odds with what Ben states?
JOhnH
Ejection Handle Pulled
I skimmed back a few posts and couldn't find where Ben inidcated a cause. He said he would withhold his findings until after the NTSB report.
So, now we await Ben's findings. He won't be constrained by internal policies.
So, now we await Ben's findings. He won't be constrained by internal policies.
Katamarino
Pattern Altitude
Yeah, that was what I meant. Ben seems to state that he found a clear cause; the NTSB apparently did not want to share, if so!
Fearless Tower
Touchdown! Greaser!
I think this is the post others are referring to:
During the investigation of the RV-7 crash ( N820RV) this gal impressed me with her thirst for details....
Ps... I reconstructed it and found out EXACTLY what broke to cause the pilot to get distracted and stall it....
Seems to indicate that Ben thought he identified a cause not mentioned in the final report.
Zoe has most of the details correct.... The observation from the construction worker and my hangar mate ( who built and flies a RV-6) both heard the plane engine sound as loud but normal, they both heard the motor rev up for a split second and then go to idle. Zoe was pretty sure the prop governer failed and had me remove it from the motor along with the fuel pump.. She took those with her back to Boise along with the prop itself.. Since she drove a Prius I had to use a sawzall and cut off both blades so the prop hub would fit in her car. She also took the Garmin 496 to send to the lab in DC so they could extract data from it..
I tried to explain to her the function and dynamics of a supercharger ( especially one that was modified) but she apparently didn't grasp the finer details..
I still give her a atta boy for looking at every part of that planes airframe to see if there were any issues.... My old compuer got hit with the crypto virus and I lost all my data, but I assumed this crash might generate a lawsuit or two so I burned a CD of all the pictures. As soon as I can transfer them to this new computer I will create a detailed report of what I found when I reconstructed the wreckage. motor, supercharger and fuel injection system....
The problem that brought down the flight was a modification to the supercharger bypass valve... Her explanation is incorrect in this statement "
The airplane was equipped with an experimental Lycoming IOX-360-A41N engine, s/n 407040. The engine was outfitted with a G3i forced induction supercharger kit. The supercharger was mounted to the engine's vertical draft sump. The supercharger system was driven from the flywheel, through the alternator via a serpentine belt. The compressor was a mechanical, belt driven system that utilized a pair of four-lobe, high-helix rotors. In an effort to maximize efficiency during cruise power settings, the supercharger has an integrated bypass valve that is vacuum controlled. This vacuum operated system was designed to allow air to bypass the supercharger and the rotors to spin freely under lower manifold pressure requirements."
Fearless Tower
Touchdown! Greaser!
Ben, are you saying the bypass valve failed open during takeoff robbing the supercharger of air?
JOhnH
Ejection Handle Pulled
You're right.
I didn't scroll back far enough to find that and I either missed it before or just forgot.
Sounds to me like this story isn't finished yet.
I have never seen such a bypass system exist on a mechanical drive supercharger except in movies, and it wasn't working there.
Matthew
Touchdown! Greaser!
Is this a comment about the valve?
"The supercharger was disassembled by applying heat to the outside casing and removing the rotors. The butterfly valve was frozen in a partially open position. The inside casing was dyed dark blue consistent with extended exposure to 100LL Avgas. The bearings rotated freely and no anomalies were noted."
"The supercharger was disassembled by applying heat to the outside casing and removing the rotors. The butterfly valve was frozen in a partially open position. The inside casing was dyed dark blue consistent with extended exposure to 100LL Avgas. The bearings rotated freely and no anomalies were noted."
Yes and No...
Once you see the pics it will be crystal clear to motor savvy people...
The Readers Digest version is..
He removed the vacuum actuated device and installed a push pull cable to turn a auto system into a manual system.... The mechanism failed when the drive belt broke, hit the lever and bent it... and all the incoming air had to squeeze by the rotors/ housing, which have a .003" clearance between them... The motor will idle,, but that is all... And it was idling all the way to the ground...
I was hopeful the lab would have been able to extract the data from the 496 as that would have provided data to confirm which belt broke..
If the serpentine belt from the flywheel to the alternator broke, the ship voltage would have dropped to battery voltage for the last 32 seconds of flight... if the belt from the rear of the alternator to the supercharger broke then the voltage would remain normal until impact...
One of those two belts broke, I am 100% sure of that... That series of serpentine belts are used to drive alternators, AC compressors and water pumps on most cars today.. The problem is those accessories use 1-4 HP... This set up had the alternator driving a positive displacement supercharger at 3.20 - 1 overdrive.. So when the motor is turning 2800 rpm on take off, the supercharger is turning just under 9000 rpms... My calculations show that HP requirement is 26-28 horsepower, just to drive the supercharger...
... so the belt was really working hard,, most probably too hard.The thing that make me real sure of myself is a few days after the crash, I got a call out of the blue by a CFI from down in Colorado... Just a few weeks before, the deceased pilot was doing a BFR in that plane and it did that exact same thing and quoting the CFI " WE barely made it back to the airport with the motor not wanting to do anything but idle"...
The CFI told me he called Zoe and left a message on her voicemail explaining that episode... I would have told her that story myself but she has not returned my emails or calls.... Probably because the NTSB NEVER paid my modest bill for recovering the wreckage, spending several days assisting her in cutting the plane apart to look at everything... In fact the National Park service never paid me for cleaning up the crash site..... The insurance company did send me a check for a couple of hundred bucks for my efforts though... BFD.....
And to cap it off.... about 6 months later I get a call from a 202 area code.. Turns out is was some resource enforcement officer from the Dept Of The Interior in DC wanting to fine me 2000 dollars.... 500 for each little 16" tall PVC cross I erected where the bodies ended up for not getting a memorial permit and 500 dollars each for not doing an enviromental study where the 1/2" PVC crosses where stuck in the ground...
No good deed goes unpunished....
mtuomi
En-Route
What was the compression ratio of the engine? Its a design fault if a stuck-open bypass valve prevents the engine from working like a NA engine.
Edit: posted this while Ben was posting. What a stupid design - what a horrible price to pay for it
Just about any modern automotive supercharger application has a flap valve after the supercharger that fail safes to full external air if the air through the charger is blocked. It sounds like this would've saved their lives :/
Edit: posted this while Ben was posting. What a stupid design - what a horrible price to pay for it
Just about any modern automotive supercharger application has a flap valve after the supercharger that fail safes to full external air if the air through the charger is blocked. It sounds like this would've saved their lives :/
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Matthew
Touchdown! Greaser!
In spite of the mechanical aspect - there is another lesson to be learned: Maintain airspeed, don't be fooled by visual cues from groundspeed, on a downwind landing. The few times I've landed downwind have been very enlightening.
What was the compression ratio of the engine? Its a design fault if a stuck-open bypass valve prevents the engine from working like a NA engine.
Edit: posted this while Ben was posting. What a stupid design - what a horrible price to pay for it
It depends if you are just pushing air, or as is more normal, fuel and air, through the supercharger. If you run a 2 stage FI system that injects at the port as well as the SC inlet, and have the ability to independently meter both air flow sources, you can make a system like this work, but I never knew anyone to actually do it. Apparently these people did;
It's a Mad Max carry over. I never saw the point, if I want that ability, I'll use a turbo with a wastegate dump. Doing this with a mechanical supercharger is a poor application of a mechanical supercharger IMO. Where mechanical super chargers belong on GA planes is with Diesels to make them restart at altitude after the turbo spools down. There you want turbos feeding mechanical superchargers. Mechanical superchargers are for when you always want positive displacement from it.I imagine he went to mechanical control of the system because it's an inherently poor application to meter by vacuum. I doubt it worked as advertised.
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As soon as I can load all my pics into this puter I will explain in detail,,,
Here is a link to the supercharger company.. It was similar to this.. ALL thier units have a vacuum diaphram to open the bypass valve in case of belt or drive failure, it opens the valve automatically... You can see it on the side of the case..
http://www.magnacharger.com/p-121-magnuson-mp2300-6th-generation-supercharger.aspx
There are a few pics from the G3I site....
He had several pics of this exact plane but must have removed them since the crash.. They used N820RV as their demo / prototype / promotion platform.. I spoke to the owner for a few hours and he was VERY upset at loosing his close friend and customer.... The guy was totally honest with me during those calls.
http://www.g3ignition.com/Supercharging.html
If some of you want to view them, I have 76 pics stored on Flicker..... PM for my account and password as they are protected from public viewing...
Here is a link to the supercharger company.. It was similar to this.. ALL thier units have a vacuum diaphram to open the bypass valve in case of belt or drive failure, it opens the valve automatically... You can see it on the side of the case..
http://www.magnacharger.com/p-121-magnuson-mp2300-6th-generation-supercharger.aspx
There are a few pics from the G3I site....
He had several pics of this exact plane but must have removed them since the crash.. They used N820RV as their demo / prototype / promotion platform.. I spoke to the owner for a few hours and he was VERY upset at loosing his close friend and customer.... The guy was totally honest with me during those calls.
http://www.g3ignition.com/Supercharging.html
If some of you want to view them, I have 76 pics stored on Flicker..... PM for my account and password as they are protected from public viewing...
Wait, you're talking about the vacuum safety valve, that's not an operational valve for low power settings, that's an emergency valve for when the blower fails. Was he injecting at the ports or the supercharger, or both?
To me , it looks like it serves both functions... When there is vacuum in the intake manifold, it sends air straight from the throttle body fuel injection to below the rotors and into the motor, When it senses boost pressure, it shuts off that easy path to the motor and sends the air/ fuel mixture to the rotors to get compressed...
Interesting, how does it sense boost pressure when bypassing? How does it sense vacuum while producing boost?