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Any Idea what caused the accident?
On May 5, 8:35*pm, JULIETT-DELTA wrote: Nelson Funston experienced a takeoff incident at Ephrata, WA on Sunday May 5; with substantial damage to JN. *Nelson is currently in a Seattle hospital with back injuries. Per Jan, he may be released sometime this week, though anticipating the usual long period of back healing. She says he is looking forward to being back on his feet, and he will much welcome hearing from his fellow soaring pilots during his recuperation. Here is the mailing address: Nelson Funston PO Box 979 Mercer Island, WA *98040 |
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On May 8, 7:38 am, wrote:
Any Idea what caused the accident? There are lots of ideas - but blind rumor and speculation at this point don't help anything. The best thing to do is take this as a reminder to ALWAYS be safety- conscious when involved with a glider operation. Take care, --Noel |
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On May 8, 7:59*am, "noel.wade" wrote:
On May 8, 7:38 am, wrote: Any Idea what caused the accident? There are lots of ideas - but blind rumor and speculation at this point don't help anything. The best thing to do is take this as a reminder to ALWAYS be safety- conscious when involved with a glider operation. Take care, --Noel Now this will help us all avoid the same mistakes... Aviation is full of unexplained fatal accidents which we can only speculate, but at least we can hope to learn from those who survived. I hope we don't need to wait for the NTSB report, we all know what they worth. Or Thelen's accident reports in Soaring Magazine, which from some reason he can never get the details from those involved, and have to speculate. I wish Nelson speedy recovery. Ramy |
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FAA initial report:
IDENTIFICATION Regis#: 747JN Make/Model: 4M Description: SCHEMP-HIRTH NIMBUS-4M Date: 05/04/2008 Time: 2122 Event Type: Accident Highest Injury: Minor Mid Air: N Missing: N Damage: Substantial LOCATION City: EPHRATA State: WA Country: US DESCRIPTION AIRCRAFT ON TAKEOFF ROLL, WING STRUCK THE PAVEMENT AND THE AIRCRAFT CARTWHEELED, EPHRATA, WA In somewhat of a contradiction to the FAA report, newspaper and eyewitness accounts state that the glider was on initial climb after takeoff and was at 40 or 50 feet when it experienced an uncontrolled roll. Extreme deflection of the wings on impact reportedly reduced the damage and injuries. Mike |
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On May 8, 6:34 pm, Mike the Strike wrote:
FAA initial report: IDENTIFICATION Regis#: 747JN Make/Model: 4M Description: SCHEMP-HIRTH NIMBUS-4M Date: 05/04/2008 Time: 2122 Event Type: Accident Highest Injury: Minor Mid Air: N Missing: N Damage: Substantial LOCATION City: EPHRATA State: WA Country: US DESCRIPTION AIRCRAFT ON TAKEOFF ROLL, WING STRUCK THE PAVEMENT AND THE AIRCRAFT CARTWHEELED, EPHRATA, WA In somewhat of a contradiction to the FAA report, newspaper and eyewitness accounts state that the glider was on initial climb after takeoff and was at 40 or 50 feet when it experienced an uncontrolled roll. Extreme deflection of the wings on impact reportedly reduced the damage and injuries. I think that "uncommanded" roll might be more precise than "uncontrolled", for technical reasons. The newspaper account said, "He noted the airport changed its operational procedure and added obstacles on the ramp. While not the cause, Funston said, 'It was certainly a complicating factor'." For mental exercise, let's forget about this particular accident for a moment and review the possiblities based on these 2 scraps of information: uncommanded roll and new obstacles. Let's think about the range of possibilities: First, we can assume that it's an accident, hence something unpredicted happened. Therefore, what caused the upset was either unpredictable or considered unlikely. A: Causes of aircraft flight accidents fall into just 3 categories: 1: Something about the a/c "broke" (in the broadest sense, including linkages not sufficiently connected) 2: Something about the pilot "broke" (again, in the broadest sense, including natural failures of perception, which we call 'illusion.') 3: Something about the air was "broken" (again, broadly, especially including vortices = turbulence). There is one component of this situation that is invisible: the air. Its motions become apparent only when dust or smoke are swept along. Then we're aware of remarkable turbulence, which must occur when it's windy. Any time there is a strong wind, complex vortices are shed by obstacles, which persist for a long distance downwind relative to the height of the obstacle. I was years ago taught a rule of thumb that amounts to a 1:60 ratio of height to persistence. By this rule, a 15- foot obstacle would cause turbulence that persisists 300 yards downwind along a plateau. Now, anytime the wings of an aircraft experience different winds, a roll moment will be induced. This does not require either wing to be stalled! For example, a friend rolled his helicopter up into a ball a few years ago. He was crop-dusting in nearly -still air, and flew head on into a dust devil. His airfoils obviously experienced dramatic differences in airflow, and a dramatic uncommanded roll occurred, and in a second, he was surrounded by wreckage, forturnately unhurt. For another example, a man was flying a single-engine a/c to landing in a 20-kt crosswind last November. The instructor pilot watching on the ground said that the airplane was level at 40 ft, when it abruptly rolled almost to vertical, struck a tip, cartwheeled, crashed inverted an burned. All 4 occupants died. For another example, a friend, a commercial pilot, was landing his SEL in gusty winds last year, and as he prepared to flare, it suddenly felt as though his left wing had suddenly lost lift. He managed to avoid a tip-strike and accident. Why do our wings rock when we fly through gusty winds? because the wings experience rapid local changes in airspeed and AOA in dimensions smaller than the wingspan. Might sometimes this be sufficient to cause a snap roll? Why not? I write this not to analyze Mr. Funston's accident, but because the concepts of "uncommanded roll" and "new obstacle" inspire me to remind fellow soaring pilots that windy conditions are always accompanied by significant turbulence close to the ground, exacerbated by nearby obstacles. This turbulence is invisible, and can indeed roll our aircraft enough to cause a tip strike or loss of control. Dan Johnson Menomonie, WI |
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Others have noted...
FAA initial report: IDENTIFICATION Regis#: 747JN Make/Model: 4M Description: SCHEMP-HIRTH NIMBUS-4M Date: 05/04/2008 Time: 2122 Event Type: Accident Highest Injury: Minor Mid Air: N Missing: N Damage: Substantial LOCATION City: EPHRATA State: WA Country: US DESCRIPTION AIRCRAFT ON TAKEOFF ROLL, WING STRUCK THE PAVEMENT AND THE AIRCRAFT CARTWHEELED, EPHRATA, WA In somewhat of a contradiction to the FAA report, newspaper and eyewitness accounts state that the glider was on initial climb after takeoff and was at 40 or 50 feet when it experienced an uncontrolled roll. Extreme deflection of the wings on impact reportedly reduced the damage and injuries. I think that "uncommanded" roll might be more precise than "uncontrolled", for technical reasons. The newspaper account said, "He noted the airport changed its operational procedure and added obstacles on the ramp. While not the cause, Funston said, 'It was certainly a complicating factor'." For mental exercise, let's forget about this particular accident for a moment and review the possiblities based on these 2 scraps of information: uncommanded roll and new obstacles. Good, thoughtful stuff snipped... Where this thread has gone is - to me - an excellent example of how *thoughtful* speculation (perhaps it is better described as "imagination") may wisely be used to enhance one's own safety when soaring. No need to wait for the (too often, hopelessly homogenized) NTSB reports... Respectfully, Bob - no fan of off-the-wall speculation -W. |
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On May 13, 12:44*pm, Bob Whelan
wrote: DESCRIPTION * AIRCRAFT ON TAKEOFF ROLL, WING STRUCK THE PAVEMENT AND THE AIRCRAFT CARTWHEELED, EPHRATA, WA In somewhat of a contradiction to the FAA report, newspaper and eyewitness accounts state that snipped I think that "uncommanded" roll might be more precise than "uncontrolled", for technical reasons. Good, thoughtful stuff snipped... Where this thread has gone is - to me - an excellent example of how *thoughtful* speculation (perhaps it is better described as "imagination") may wisely be used to enhance one's own safety when soaring. *No need to wait for the (too often, hopelessly homogenized) NTSB reports... Respectfully, Bob - no fan of off-the-wall speculation -W.- What a nice thread in response to a sad situation. Sorry Nelson was hurt, hope he recovers well. I am very glad to see the shift from "let's not talk 'til a report is written" toward a "let's consider possibilities and see how I could avoid similar scenarios." That is the most productive view to take following any breakage, human, airframe or atmospherically. That was also the total gist of my presentation at the ABQ Convention, titled "What the NTSB will Never Say About 2007 Fatalities." Keep after this concept folks. It helps build mental flexibility which I believe is vastly undertrained in glider cockpits. Cindy B Another fan of constructive speculation for personal-use accident- analysis www.caracolesoaring.com |
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danlj wrote:
I write this not to analyze Mr. Funston's accident, but because the concepts of "uncommanded roll" and "new obstacle" inspire me to remind fellow soaring pilots that windy conditions are always accompanied by significant turbulence close to the ground, exacerbated by nearby obstacles. This turbulence is invisible, and can indeed roll our aircraft enough to cause a tip strike or loss of control. While this does not invalidate what Dan says, pilots may be interested to know the "obstacle" was basically flags marking changes in the runway, and would not affect the wind on the runway. They did add some distraction for the pilot, however, as it was his first launch since the new runway was marked on a portion of the ramp. Previously, the entire width of the ramp was "available". My guess is the distraction was a much bigger factor than the wind. -- Eric Greenwell - Washington State, USA * Change "netto" to "net" to email me directly * Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4 * New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more * "A Guide to Self-launching Sailplane Operation" at www.motorglider.org |
#9
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![]() A: Causes of aircraft flight accidents fall into just 3 categories: 1: Something about the a/c "broke" (in the broadest sense, including linkages not sufficiently connected) 2: Something about the pilot "broke" (again, in the broadest sense, including natural failures of perception, which we call 'illusion.') 3: Something about the air was "broken" (again, broadly, especially including vortices = turbulence). I stick with my use of the term "uncontrolled" and since it appears that neither the pilot nor the air were broken I choose 1) above as most likely. Mike |
#10
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On May 8, 12:22*pm, Ramy wrote:
On May 8, 7:59*am, "noel.wade" wrote: On May 8, 7:38 am, wrote: Any Idea what caused the accident? There are lots of ideas - but blind rumor and speculation at this point don't help anything. The best thing to do is take this as a reminder to ALWAYS be safety- conscious when involved with a glider operation. Take care, --Noel Now this will help us all avoid the same mistakes... Aviation is full of unexplained fatal accidents which we can only speculate, but at least we can hope to learn from those who survived. I hope we don't need to wait for the NTSB report, we all know what they worth. Or Thelen's accident reports in Soaring Magazine, which from some reason he can never get the details from those involved, and have to speculate. I wish Nelson speedy recovery. Ramy No need to speculate anymore. According to the NTSB report it was disconnected aileron http://www.ntsb.gov/NTSB/brief2.asp?...CA122& akey=1 I hope Nelson is recovering fine. Ramy (who wonders why we had to wait for the NTSB report to learn this) |
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