Now I would guess that most of you have seen the recent gender reveal video of the Pawnee making a pass and pulling up when the wing folded and a fatal crash was the end result. As the Pawnee revealed the gender with a load of colored water half of thecrown cheered and half of the crowd was screaming, OH S***.
Next time you annual your Pawnee make sure all the strut assembly is in order. OBTP
On Tuesday, September 5, 2023 at 6:02:02 PM UTC-4, youngbl...@gmail.com wrote:the crown cheered and half of the crowd was screaming, OH S***.
Now I would guess that most of you have seen the recent gender reveal video of the Pawnee making a pass and pulling up when the wing folded and a fatal crash was the end result. As the Pawnee revealed the gender with a load of colored water half of
Next time you annual your Pawnee make sure all the strut assembly is in order. OBTPYep. I had a failure at the end of the strut. Fortunately it docked on the wing fitting and the airplane was marginally controllable. Pure luck that I'm alive.
Clearly there was an over stress here but I would not rule out strut failure leading to folding the wing.
UH
On Wednesday, September 6, 2023 at 8:18:35 AM UTC-4, Hank Nixon wrote:the crown cheered and half of the crowd was screaming, OH S***.
On Tuesday, September 5, 2023 at 6:02:02 PM UTC-4, youngbl...@gmail.com wrote:
Now I would guess that most of you have seen the recent gender reveal video of the Pawnee making a pass and pulling up when the wing folded and a fatal crash was the end result. As the Pawnee revealed the gender with a load of colored water half of
just the daily wear and tear from towing has to take a toll on the airframe in general. There is much that cannot be seen and inspected in a walk around, one must depend on the A&P who does the required inspections and not everyone of them isDon't know if this bird was ever a tow plane or if it was still being used in ag flying but either way the Pawnee gets lot of abuse, ESPECIALLY the tow plane Pawnee. The stress from poor student flying, boxing the wake poorly, slack rope recovery andNext time you annual your Pawnee make sure all the strut assembly is in order. OBTPYep. I had a failure at the end of the strut. Fortunately it docked on the wing fitting and the airplane was marginally controllable. Pure luck that I'm alive.
Clearly there was an over stress here but I would not rule out strut failure leading to folding the wing.
UH
Walt ConnellyA Pawnee used for towing is operating well below it's maximum weight. Shouldn't that make life relatively easy for it?
Former Tow Plane Pilot
https://www.youtube.com/watch?v=wp19ch40t0c&t=6sThis video has important lessons and brings important questions:
Juan Browne presents a good tutorial here.
Nick
T
On Wednesday, September 6, 2023 at 6:21:31 AM UTC-7, Nicholas Kennedy wrote:should be reduced below that. Modern gliders which can carry ballast are flown at about 30% below max gross when empty, so based on the information I read maneuvering speed is reduced by about 15% which brings the ASG29 VA speed from 113 knots down to 96
https://www.youtube.com/watch?v=wp19ch40t0c&t=6s
Juan Browne presents a good tutorial here.
NickThis video has important lessons and brings important questions:
T
According to the video and other articles on the subject, maneuvering/rough air speed is calculated at max gross weight and is reduced with weight. I checked my ASG 29 manual and nowhere is it mentioned that the VA speed is at max gross weight and
Another lesson relevant to gliders is NOT to pull G when releasing load, which is exactly what we do when releasing ballast during low pass, although the G force is probably only 2-3G and the dump rate is relatively low, so probably not a significantfactor.
The biggest question is what is the correct VA for our gliders and does it indeed change with weight, and if so, how come this is not mentioned in the manual and I don’t recall ever hearing about this before.One of the things that comes to mind in this accident is the fact that the CG was well forward prior to the dump being opened. Once the dump was opened the cg went from forward to more rear and the increased angle of attack increased the g load. If you
Ramy
On Wednesday, September 6, 2023 at 3:45:03 PM UTC-4, Ramy wrote:should be reduced below that. Modern gliders which can carry ballast are flown at about 30% below max gross when empty, so based on the information I read maneuvering speed is reduced by about 15% which brings the ASG29 VA speed from 113 knots down to 96
On Wednesday, September 6, 2023 at 6:21:31 AM UTC-7, Nicholas Kennedy wrote:
https://www.youtube.com/watch?v=wp19ch40t0c&t=6s
Juan Browne presents a good tutorial here.
NickThis video has important lessons and brings important questions:
T
According to the video and other articles on the subject, maneuvering/rough air speed is calculated at max gross weight and is reduced with weight. I checked my ASG 29 manual and nowhere is it mentioned that the VA speed is at max gross weight and
factor.Another lesson relevant to gliders is NOT to pull G when releasing load, which is exactly what we do when releasing ballast during low pass, although the G force is probably only 2-3G and the dump rate is relatively low, so probably not a significant
look at that video it was a pretty hard pull that the pilot did with an increased angle of attack.The biggest question is what is the correct VA for our gliders and does it indeed change with weight, and if so, how come this is not mentioned in the manual and I don’t recall ever hearing about this before.
RamyOne of the things that comes to mind in this accident is the fact that the CG was well forward prior to the dump being opened. Once the dump was opened the cg went from forward to more rear and the increased angle of attack increased the g load. If you
On the other hand it was in Mexico, how was this Pawnee maintained??? Eric asked the question about the Pawnee being used for tow was somewhat subjected to a life of less stress or abuse. Well, not exactly, Walt made a great statement about the abuse aPawnee takes during tow, these beautiful birds take a beating from the teaching and extreme application during towing.
I have done things in a Pawnee that would make most of you shake your heads and say, NUTS! OBTP
On Wednesday, September 6, 2023 at 4:48:50 PM UTC-4, youngbl...@gmail.com wrote:should be reduced below that. Modern gliders which can carry ballast are flown at about 30% below max gross when empty, so based on the information I read maneuvering speed is reduced by about 15% which brings the ASG29 VA speed from 113 knots down to 96
On Wednesday, September 6, 2023 at 3:45:03 PM UTC-4, Ramy wrote:
On Wednesday, September 6, 2023 at 6:21:31 AM UTC-7, Nicholas Kennedy wrote:
https://www.youtube.com/watch?v=wp19ch40t0c&t=6s
Juan Browne presents a good tutorial here.
NickThis video has important lessons and brings important questions: According to the video and other articles on the subject, maneuvering/rough air speed is calculated at max gross weight and is reduced with weight. I checked my ASG 29 manual and nowhere is it mentioned that the VA speed is at max gross weight and
T
significant factor.Another lesson relevant to gliders is NOT to pull G when releasing load, which is exactly what we do when releasing ballast during low pass, although the G force is probably only 2-3G and the dump rate is relatively low, so probably not a
you look at that video it was a pretty hard pull that the pilot did with an increased angle of attack.The biggest question is what is the correct VA for our gliders and does it indeed change with weight, and if so, how come this is not mentioned in the manual and I don’t recall ever hearing about this before.
RamyOne of the things that comes to mind in this accident is the fact that the CG was well forward prior to the dump being opened. Once the dump was opened the cg went from forward to more rear and the increased angle of attack increased the g load. If
a Pawnee takes during tow, these beautiful birds take a beating from the teaching and extreme application during towing.On the other hand it was in Mexico, how was this Pawnee maintained??? Eric asked the question about the Pawnee being used for tow was somewhat subjected to a life of less stress or abuse. Well, not exactly, Walt made a great statement about the abuse
under similar circumstances. OBTP makes a good point about being in Mexico, I'm betting their investigation will not be as comprehensive as it would be by the NTSB and FAA.I have done things in a Pawnee that would make most of you shake your heads and say, NUTS! OBTPJuan. Browne does a great job as usual. I am still surprised that the wing would depart so suddenly under such circumstances but it appears that the pull up was substantial. There is another case of the wings folding on an ag plane south of the border
Walt ConnellyFor years the NTSB budget has not allowed them to perform at the same level as they did in decades past. Had this happened in the US I doubt they'd even have showed up.
On Wednesday, September 6, 2023 at 6:21:31 AM UTC-7, Nicholas Kennedy wrote:should be reduced below that. Modern gliders which can carry ballast are flown at about 30% below max gross when empty, so based on the information I read maneuvering speed is reduced by about 15% which brings the ASG29 VA speed from 113 knots down to 96
https://www.youtube.com/watch?v=wp19ch40t0c&t=6s
Juan Browne presents a good tutorial here.
NickThis video has important lessons and brings important questions:
T
According to the video and other articles on the subject, maneuvering/rough air speed is calculated at max gross weight and is reduced with weight. I checked my ASG 29 manual and nowhere is it mentioned that the VA speed is at max gross weight and
Another lesson relevant to gliders is NOT to pull G when releasing load, which is exactly what we do when releasing ballast during low pass, although the G force is probably only 2-3G and the dump rate is relatively low, so probably not a significantfactor.
The biggest question is what is the correct VA for our gliders and does it indeed change with weight, and if so, how come this is not mentioned in the manual and I don’t recall ever hearing about this before.
Ramy
I wasn't sold on Juan's logic either.The loads on the other parts of the fuse see higher loads. Since the Pawnee appears to fail at the wing and not with the seat, engine mounts, floorboard, etc. I think we're more likely to find that the reduction in weight due to the water dump is not a
I found this video and I think it makes more sense. It starts off down the path of Va reducing with aircraft weight, but when you run the math (which the presenter does point out later in the video) the loads on the wings are the same in the 2 cases.
https://www.aopa.org/news-and-media/all-news/2020/may/flight-training-magazine/ol-maneuvering-speedVa does decrease with weight. Can any of you Smart Keyboard warriors tell me why?
On Thursday, September 7, 2023 at 9:19:06 AM UTC-8, Mark Zivley wrote:The loads on the other parts of the fuse see higher loads. Since the Pawnee appears to fail at the wing and not with the seat, engine mounts, floorboard, etc. I think we're more likely to find that the reduction in weight due to the water dump is not a
I wasn't sold on Juan's logic either.
I found this video and I think it makes more sense. It starts off down the path of Va reducing with aircraft weight, but when you run the math (which the presenter does point out later in the video) the loads on the wings are the same in the 2 cases.
https://www.aopa.org/news-and-media/all-news/2020/may/flight-training-magazine/ol-maneuvering-speedVa does decrease with weight. Can any of you Smart Keyboard warriors tell me why?
Charlie
Va does decrease with weight. Can any of you Smart Keyboard warriors tell me why?
Charlie
From the video that I linked above, here is a short explanationsupports the seat. It's good at 4G (at maximum seat load), but at 5G, it's now over stressed.
Say the wing to fuse junction is designed to sustain 10,000 lbs at 4 Gs (rounded up from 3.8) for a 2,500 lb aircraft at max gross of 2,500.
If the plane now weighs 2,000 lbs then the wing can still pull 10,000 lbs, which is now equal to 5 G.
It's not the wing/fuse joint that is the issue, it's things like the motor mount which are designed to support the engine or pilot at 4 G... If that motor mount sees 5G then the failure occurs at the motor mount. Same thing for the bracket that
If the aircraft weight decreased to 1,000 lbs, the wing could support 10G and not fail, but then the motor mount is way over stressed, same for the seat bracket.
So, if the capability to create higher G's is possible with a lower weight, the way to protect against over stressing (with an abrupt aft stick input) is to reduce airspeed.
Va does decrease with weight. Can any of you Smart Keyboard warriors tell me why?
Charlie
On Thursday, September 7, 2023 at 3:08:12 PM UTC-4, Mark Zivley wrote:supports the seat. It's good at 4G (at maximum seat load), but at 5G, it's now over stressed.
From the video that I linked above, here is a short explanation
Say the wing to fuse junction is designed to sustain 10,000 lbs at 4 Gs (rounded up from 3.8) for a 2,500 lb aircraft at max gross of 2,500.
If the plane now weighs 2,000 lbs then the wing can still pull 10,000 lbs, which is now equal to 5 G.
It's not the wing/fuse joint that is the issue, it's things like the motor mount which are designed to support the engine or pilot at 4 G... If that motor mount sees 5G then the failure occurs at the motor mount. Same thing for the bracket that
There is no doubt that the left wing strut failed, I think that the failure was at the single attach point at the fuselage. As far as the original struts I have had original struts on all my Pawnee's, never had any doubt about their possibility ofIf the aircraft weight decreased to 1,000 lbs, the wing could support 10G and not fail, but then the motor mount is way over stressed, same for the seat bracket.
So, if the capability to create higher G's is possible with a lower weight, the way to protect against over stressing (with an abrupt aft stick input) is to reduce airspeed.
Va does decrease with weight. Can any of you Smart Keyboard warriors tell me why?
Another videoCharlie
https://twitter.com/aviationbrk/status/1698255432630796349
It looks to me like the left wing was twisting leading edge up just before the catastrophic failure. This is consistent with a failure of the front strut either at the outboard fitting, or buckling due failure of the jury strut.
G loads are high when it looks like you can see deflections.
Anybody still using original struts, even if they test "good" is being foolish in my opinion. Our struts looked fine with no corrosion and we had a failure.
FWIW
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