I remember as a kid watching in Bishop Ca, a contract pilot showing off in a Turbine Aero Commander make a high speed run down the runway then pulling up hard. The mechanic the next day noticed fuel leaking out of the left wing. Measuring the wing tips, the left wing was 9 inches higher off the ground and the top of the wing was wrinkled. He was no longer a contract pilot.
@dutchtuba
Жыл бұрын
The only Pilot that knew how to fly an Aero Commander with amazing feats was Bob Hoover. RIP. His plane now sits in the Smithsonian. What an awesome pilot.
@dependablepaul
Жыл бұрын
@@dutchtubahe was definitely a smooth operator.
@dethray1000
Жыл бұрын
At Bishop i saw a Lear type private jet that was ruined when the pilots were screwing around came over the sierras crest and got caught up in the sierra wave(140 mph jet stream winds)--it bent the jet and they were able to emergency land at Bishop--i heard the jet was totaled
@marka7831
Жыл бұрын
he had a future in the fast food industry
@rtbrtb_dutchy4183
Жыл бұрын
@@dethray1000LOL. Of all the things that never happened, this never happened the most. 😂
@mdbryan9525
Жыл бұрын
Retired ag pilot here. I started out in a Pawnee 260 C model. It would carry the 150 gallons, I doubt that the 235 version could. That being said, I didn’t notice you saying anything about the hopper being well forward of the CG. I’ve dumped many times. There’s always a violent pitch up if you’re not trimmed in advance for it. If he also pulled back at the same time, then that would certainly overstress the aircraft. As previously mentioned, corrosion was probably involved.
@mdbryan9525
Жыл бұрын
One other thing. Water weighs 8.33 pounds per gallon. Assuming 150 gallons, that’s an additional almost 50 pounds.
@nowjustanother
Жыл бұрын
Looking at the pitch up, it’s entirely possible that the sudden change in the moment arm at the release of the load caused it as well.
@mdbryan9525
Жыл бұрын
Yup.
@mdbryan9525
Жыл бұрын
@@bryanrackard9268 Elvis, you captain now?
@BrainWearmouth
Жыл бұрын
Thanks I was wondering how the CG was affected.
@raven6245
Жыл бұрын
I began my ag flying career flying the Pawnee and I never flew with more than 100 gallons. Never filled the hopper with liquid but we used the large hopper for dry fertilizer. I was trained at Ayers Corp. in Albany Georgia, where they make the thrush aircraft. You had to do a demonstration flight to get certified FAR 137 and part of the flight was a emergency dump. You had to learn to push the stick forward hard to keep the aircraft level cause dumping that much weight the aircraft wanted to climb like all get out.
@tedmoss
Жыл бұрын
That will tend to keep you out of trouble.
@PaleoWithFries
Жыл бұрын
The tank looks so far from the CoG, i’m curious now what the training manual looks like for an emergency drop.
@Tavdog
Жыл бұрын
I agree. Looks to me like a rapid change in CG pitched the nose up.@@PaleoWithFries
@jimmydulin928
Жыл бұрын
The Pawnee pitch trim system was simple but not comfortable. A large spring on one end of a lever in the back of the fuselage attaches to a cable that attaches to the stick just above the pivot point. Moving the trim handle aft pulls, through another cable, the spring lever to tighten the spring and provide pull on the stick. Forward on the trim handle will slacken the tension on the spring and allow the nose to go down. Taking off with 150 gallons, usually the load is less for DA, will require a strong pull on the stick which the trim spring will help with. Emergency dumping with full aft trim will result in a significant pitch up unless the pilot pushes forward on the stick. The dump gate in the bottom of the hopper, also used to release dry material through a slim crack, allows slow release of liquid material as well. Liquid goes to the pump on a spray rig through a hose. The pilot may have been startled by the rapid pitch up of a full dump lever travel, fully open gate, dump. Or he may have been going for a spectacular pitch up. Or both. I personally know of two practice emergency dump fatalities.
@bj8342
Жыл бұрын
@@gomertube I understand your comment - but a Crop Duster doesn't dump his whole load in one shot, it's sprayed in a fine mist. Which means that he's not experiencing a massive change in wing loading and Center of Gravity displacement.
@iugey
Жыл бұрын
I had to rewatch the part about why maneuvering speed decreases with weight... I don't know if I'm the only one who got a little lost, but I could still use a deeper dive into the physics. I appreciated that you explained it multiple ways, but for some reason it's still not clicking for me. Thank you for diving into these tragic events so that we can all learn to be better and safer pilots.
@kingsizedmidget7294
Жыл бұрын
If Juan is reading this I agree. I do not refute anything in the video, but clarification on the physics of why this happens would be good. There is a detailed comment above this one that goes into how lower weight makes the airplane more nimble, and therefore able to apply more stress to the airframe. This feels right intuitively, but hearing it from a pilot would be cool.
@KapiChris
Жыл бұрын
Yeah I feel the same. The reason why it is not “clicking” is because he didn't explained it at all.
@Orzorn
Жыл бұрын
@@kingsizedmidget7294 I was doing some reading just now and while there's a lot of talk about critical angles of attack, weight, etc, I think distilling it down to the nature of flight helped me understand it better: Flight is overcoming gravity. At straight and level flight, you are always pulling 1G. You are in balance with gravity because you are producing 1G of upward lift to counteract Earth's 1G of downward pull. When you start to climb, you pull more than 1G, because you're overcoming gravity. To generate 1G of lift in a heavy plane, you need a higher angle of attack from your wing than if you were lighter. If you suddenly dump a lot of weight, your lift is going to go up at any given angle of attack (in the same way that taking off in a heavy plane will have a more sluggish climb, taking off in a light one will have a much faster climb). So when a plane dumps a lot of water in the air while pulling some number of Gs, it will now generate more lift at that same angle of attack, which means more Gs. So what was a 4G maneuver becomes, say, a 6G or an 8G maneuver, then your wings rip off.
@scottmoore598
Жыл бұрын
The way I heard it put is a heavy load will stall. A lighter load can generate more lift before the stall and thereby more stress on the frame. Think of the Va stall as a safety valve that dumps excess lift. The wings will eventually create the extra lift, but the frame can’t spread the lift. Even if the struts and spar distribute the force to the frame, now the engine mount is overstressed with its heavy load.
@wyleb2
Жыл бұрын
It’s because he’s looking at a case where the wing attachment failed, but then explains how the wing loading actually goes down. At 6:39 he briefly explains it’s not the wings that are overstressed by this issue, but the same wing loading applies higher Gs which can break other things. It’s just a bad example for the issue being explained.
@ue4770
Жыл бұрын
Juan, let me add some details from my experience working as a aircraft structures certification engineer: It is true that the maneuvering speed vA is defined by vS times the square rout of the design load factor. However, it is not a limit up to which the pilot cannot damage the airplane. vS is a calculated stalling speed (FAR/CS 23.335(c)), as estimated early in the design process. vA is a defined airspeed limitation to be used mainly for control surface and control system structural sizing. FAA AC 23-19A explains: "VA should not be interpreted as a speed that would permit the pilot unrestricted flight-control movement without exceeding airplane structural limits, nor should it be interpreted as a gust penetration speed." The TCDS you present in this video is of a restricted category aircraft. Although limit maneuvering load factors seem not to be mentioned in this TCDS, in the restricted category certain limitations can be lowered below the FAR-/CS-23 minimum requirements, including limit load factors and structural safety margins. That is especially used for cropdusters to allow higher take off masses. As far as wing structural loading is concerned: it does actually not change when you empty the hopper tank. Given, that speed and angle of attack stay the same. Why is that? The aerodynamic forces on the wing are unchanged as long as airspeed, angle of attack and it's configuration (flaps, ailerons) don't change. So the lift force doesn't change. The same lift force acting on a lighter fuselage lighter than before means the vertical acceleration increased, as Newton claims in his second law. To maintain level flight, i.e. maintain 1g, the pilot needs to reduce the angle of attack during release of the payload, as you explain. It seems that the unlucky pilot in the video did the opposite and increased the angle of attack, leading to increased lift forces, which resulted in structural failure of the wing.
@FourthWayRanch
Жыл бұрын
speed can safely max deflection of a control surface
@anthonydevellis6708
Жыл бұрын
I found this very informative, thank you. Would suggest pinning it
@1KDave
Жыл бұрын
I was a structural tech for a while and completely agree with this comment. Pilots need to stick to talking about flying. They also have a bad habit of blaming pilots only. This is not the first time wings have failed in Mexico… Mexico is known for ignoring maintenance and inspections. I’m fairly confident a properly maintained aircraft would have survived that. I see those duster fly really hard in the states all the time and no issues.
@Thundersnowy
Жыл бұрын
@@1KDave Did you just say 'pilots need to stick to talking about flying.' Did I read that right?
@darkarima
Жыл бұрын
If you go to 8:12 and change the setting to 0.25 playback speed, there's a moment right around 8:14 where you see the wing fold back diagonally. At least intuitively, it seems to me that this supports what you're saying. It's reminiscent of the silly game we'd play as kids, sticking our hand out of a high speed car and "surfing" - once the angle goes a tiny bit too high, the effect snowballs as the wing flips up and back.
@m.lozano9970
Жыл бұрын
Juan with a PHD level lecture. No distractions no opinions no judgments, stayed on topic with serious attitude, as it deserves. Operating an aircraft or any other vehicle that may hurt or kill someone deserves to be taken with the most high responsibility.
@Brotha00
Жыл бұрын
I’m not a pilot, but I watch these for precisely that reason. These people have a responsibility to themselves, especially to their passengers, and to the rest of us on the ground to analyze these events and learn the lessons. Juan hosts an excellent channel.
@moleisrich1
Жыл бұрын
Unlike that other KZitemr…. You know the one…. Named Dan…. Lol jk love them both!
@stuartadamsrailfanningvideos
Жыл бұрын
@m.lozano9970 @Brotha00 Former railroad conductor here. I totally agree. When I was a railroad conductor, I took safety really seriously! The safety of my train crew and train passengers was my first concern. I don't like seeing preventable accidents like this. If something like this happened on the railroad, there would definitely be a rulebook violation. Someone would get fired. If you don't follow the rules and don't safely operate heavy equipment, things go wrong! That's why I followed the rulebook every trip, every time. I decided to switch jobs from being a railroad conductor. It was enjoyable, but highly stressful. I'm glad I pulled the pin when I did. It takes a toll on a person. I wanted a slower pace of life. I'm now a farmhand on a 7 generation family farm in Oregon.
@simongchadwick
Жыл бұрын
I have much respect for Juan and his factual reporting combined with real experience analysis. It's really sad that this pilot lost his/her life during yet another stupid "baby gender reveal" party. RIP pilot, and sincere condolences to your family and friends.
@joesterling4299
Жыл бұрын
The title of the video almost made me skip it entirely. Then I saw it was Blancolirio. Oh! Not the crap I was expecting. Glad I caught on quickly. Great coverage from Juan as usual.
@Hooknspktr
Жыл бұрын
Many years ago ('94-'95), as a young A&P, we had a Pawnee with Hutch metal wings that were just full of cracks. We pulled the wings to repair them and found the fuselage wing attach points badly rusted internally. They looked great with nice paint on the outside, but just ugly inside with much material missing. It left on a truck to an aerospace welding facility for replacement. Scary stuff considering how they get yanked and banked in a highly corrosive environment.
@shable1436
Жыл бұрын
Like old houses near the sea, paint layers is only thing holding them together. I think Popeye the sailor man had a song about that
@JTV84
Жыл бұрын
@@shable1436 we had a water tank like that at work. you knew the metal had gone through when you saw the bubble in the paint. then we used to just drill it out and stick a nut and bolt in with a rubber washer.
@cameltube-vk7el
Жыл бұрын
the glory[& FAILS] always shines on the OPERATORS/pilots but, the MECHANICS and all that attached to support their mission[s] really is so important......maybe more so [idk4sure] OPERATORS are the ones also in the line of weather a vehicle or equipment is safe too operate. So it maybe would[have] passed PILOT pre-flight inspection but really it is a TEAM that creates the missions capability to be a success as in returning. The total success ends with safe return. Thanks Juan,great report w\insights Semper Prorsum ~ Godspeed
@InThisStyleGMinor
Жыл бұрын
It's fineeeee
@thefrener794
8 ай бұрын
You save money by replacing maintenance with paint.
@MikeSowsun
Жыл бұрын
I used to fly PBY water bombers and we called it “checking forward” as we dropped the load. With practice, you could time it just right, so you wouldn’t even feel the load being dropped.
@juliogonzo2718
Жыл бұрын
My grandfather flew PBYs in WWII. I was about 10 when he passed away, I wish I could remember his stories. I remember one where they ended up damaging a wing dropping depth charges
@ianwalton284
Жыл бұрын
I watched that maneuver from the ground as a firefighter in So. California. The large plane was almost vertical before it passed over a ridge, dump his phoscheck and dropped straight down the 3000 foot mountain. He missed the ridge by about 50 feet. Most of the pilots back in the 80's were ex-military guys.
@ccpperrett7522
Жыл бұрын
@juliogonzo2718 gathering of the eagles web page has some stories. Major Jack Randolph Cram (USMC), was the personal pilot of Marine Gen. Roy Geiger's PBY-5A, the "Blue Goose." On 15 Oct 1942, he won the Navy Cross and permanent nickname " Mad Jack" in operations at Guadalcanal. There's a great story of Cram rigging that PBY with torpedoes and dive bombing Japanese ships. J R Cram was my grandfather's cousin. I met him when I was eleven years old in 1967. I believe he was working in DC at the time. He had a large great Dane named Ace that my sisters and I got to play with.❤
@SoloRenegade
Жыл бұрын
until the day you misjudge it.....and C-130 rips its wings off.
@hugh9park
Жыл бұрын
That’s really cool. Where did you fly? I would really like to know more about pby water bombers. The old Martin mars often flew over my home as a child.
@benzracer
Жыл бұрын
I don’t know why this was recommended by the algorithm but you did a great job explaining and teaching. Thank you.
@oscarguerrero178
Жыл бұрын
Probably for me is because I’m subscribed to a channel that does mini documentaries on plane crashes and I watched one of the videos last night.
@tickmagnet
6 ай бұрын
I think the video title: "PA25-235 Sinaloa MX Gender Reveal Party Structural Failure" broke the algorithm.
@schecter6l6
Жыл бұрын
So the person filming the accident follows the plane up until the wing breaks and the plane disappears from line of sight then turns the camera back on the couple hugging and keeps it there like nothing ever happend? RIP to pilot.
@Goliver98
Жыл бұрын
Coming from a third generation ag pilot, great break down of this accident a lot of people misunderstand accidents in the ag world. Although mistakes were made, I am also leaning to the fact there was probably corrosion involved. Great job Juan keep up the good work.
@danielgoodson703
Жыл бұрын
Agreed. I’m imagining crumbling white spalling at the attachment. Decades of hard work, likely living outside, previous over stress and possible neglect. Condolences to the family(s).
@davidfrench5407
Жыл бұрын
Even with potential corrosion, it likely wouldn't have been an issue if the pilot hadn't pulled up so hard put so much load on the wings.
@JoshJones-xd5mw
Жыл бұрын
@@davidfrench5407he probably didn’t pull up. He just didn’t nose down while he was dumping. Most of the time you’d never pull the dump handle coming out of a dive and at high speed. You wouldn’t shed weight in an emergency under those circumstances in very many situations. I started my ag flying career in an O-320 150 hp Pawnee before I moved to an O-470 Ag Wagon and later an O-520 Ag Wagon.
@MeppyMan
Жыл бұрын
@@JoshJones-xd5mw from that angle he would have at least been conscious that he was heading toward a tree line. Tragic regardless of the exact cause, hopefully others can learn from this.
@JoshJones-xd5mw
Жыл бұрын
@@moretrash4you no, the nose came up. Did you watch the video? Juan explains it quite succinctly
@Kincentc
Жыл бұрын
Gender reveal parties have long been over the top. Now it just seems like it's out of control.
@ross4
Жыл бұрын
They wanted to hire a stunt plane for their party. I don’t have an issue with that. At the end of the day the pilot needs to make the choices for safety of their aircraft. Blaming the couple for this is just silly.
@donmoore7785
Жыл бұрын
Totally irrelevant to the poor technique of the pilot who made a tragic mistake and died.
@Kincentc
Жыл бұрын
Nice job, both of you. I didn't lay fault to the couple.
@Brommear
Жыл бұрын
And they only have two colors!
@andyfpt
Жыл бұрын
Because people want to make a big deal and post it on social media. Narcissistic behavior while people die, houses burn, forests burn and people get maimed for these stupid stunts. Boy or girl who cares!!!
@andrewjackson5127
Жыл бұрын
I miss the good old days when the cigar ring had the blue or pink on it. A simpler time.
@RockandRollWoman
Жыл бұрын
Yup. If you wanted to get fancy, you bought a pack of announcements at the Hallmark store and mailed them.
@Xxxxxx19-p1c
8 ай бұрын
Or the pink and blue bubblegum cigars!
@uscdwua
Жыл бұрын
Wow, what an educational video. That explains why there are several videos floating around the web showing structural failure AFTER dumping the load. Never made sense to me, but now I understand. I am a commercial pilot, helicopter, multi-engine, instrument rated, as well as A&P mechanic (all in the past, I am 80 years old). I was always keenly interested in areodynamics, and so am really grateful for your explanation of maneuvering speed dependence upon wing loading. As an A&P, I have performed the wing spar attach AD you talk about. I always liked the Pawnee 235, a very smooth and capable airplane, and a shame to see one lost. Thanks again.
@JohnDoeDoeJohn69
11 ай бұрын
I’m a chemistry guy with no aviation knowledge, but this was so easy to follow while still diving into the technical. Excellent
@transmaster
Жыл бұрын
These crop dusters are loaded to cover several fields before they need to be reloaded. The emergency dump is used if you have a in flight emergency and have to take weight off of the air frame for an emergency landing.
@Dan-gg8fk
Жыл бұрын
As a private pilot this was never mentioned to me and I was unaware that at minimal weight this could be a factor. I guess that's why they call it a license to learn. Great video.
@owisagrom
Жыл бұрын
It's troubling that your training did not cover this. If you got your license in the US, please re-read chapter 5 of the PHAK (Aerodynamics of Flight), specifically the section on "Load Factors", which includes everything mentioned in this video, including the V-G diagram.
@oisiaa
Жыл бұрын
@@owisagrom I'm a commercial, multi-engine pilot and I was never taught that Va changes with weight. I always assumed it was for the worst condition.
@owisagrom
Жыл бұрын
@@oisiaa The POH of the PA28 and C172 that I'm familiar with both publish a VA at multiple weights, showing a lower speed for lower weights. I have an extra step in my preflight planning that determines my VA based on my weight by interpolation. This is always my personal Vne
@oisiaa
Жыл бұрын
@@owisagrom I fly big jets where Va isn't really a thing. "Maneuver speed" speed for us is the speed at which we can fly a 30 degree turn with stall margin. We have a hard g limit, not Va.
@aaronbrown6266
Жыл бұрын
There's a reason why no markings for Va are on the AI. It is directly affected by weight. @@oisiaa
@johnhinkey5336
Жыл бұрын
Excellent video as usual! As a sometimes-getting-paid-for-it aerodynamics by training Ph.D. I view this through the basic physics lens. The force on the wings is proportional to the AoA and square of the airspeed (hence the exponentially rising limit curve vs. air speed). For a given speed, at heavy weight when you pull back on the stick the airplane cannot increase it's angle of attack quickly due to the airframe/load inertia and thus the rise in force on the wings is slow. At low weight when you pull back on the stick the AoA can rapidly increase because of the lower inertia/weight and quickly get to the point of generating a huge amount of force that's trying to yank the rest of the plane upward. Ever put your hand out the car window like an airplane wing and tilt it upward a little too much too quickly and your hand snaps upwards. If your hand was made of lead it would snap upward far more slowly than your water-ish made hand. That and the heavy plane/hand was already at a higher angle of attack to counter the aircraft weight/hand weight to keep it in the air. Ever see a light paper/balsa wood airplane suddenly get too much lift it pitches up very quickly whereas a heavier paper airplane does not pitch up nearly as fast. Excellent video as usual.
@colinjohnson5515
Жыл бұрын
Ok that makes sense. I was about to rewatch the video. I was also wondering if destructive oscillation could be a factor as the wing load drops quickly as the water is dumped then loaded quickly when the pilot pulled up?
@neuropilot7310
Жыл бұрын
Thank you for confirming the reason for the "low weight" limits on maneuvering speed. This is the same reason why some friends who work as maintenance/defense contractors warn pilots to be extremely careful when flying aircraft on short ferry flights. Minimal fuel, no pax or cargo (or wing ordinance!) the jet will respond very differently than it normally does, and this is especially noticeable on takeoff as the jet will accelerate quickly, and overspeed the gear and flaps, etc. and a sudden pitch up, is at high risk of exceeding limits. Another risk for inexperienced pilots is scraping the tail on the runway.
@57Jimmy
Жыл бұрын
So…as I understand it…Don’t treat an aircraft like some video game!
@johnhinkey5336
Жыл бұрын
Or a high performance jet fighter!@@57Jimmy
@elmoreglidingclub3030
Жыл бұрын
Excellent explanation. Thank you, from one PhD (in an entirely different field) to another. I’m a student of aerodynamics as a hobby, especially low-speed aerodynamics for soaring and the use of negative flaps (“drag buckets”) for increasing L/D at various speeds. So this nice summary really resonated with me. Thanks again.
@TheFrenchPug
Жыл бұрын
Amazing how everyone saw the wings fold and the plane start spinning but didnt miss a beat with their task on the reveal or miss the shot.
@worldwideflyby
Жыл бұрын
Right, was wondering why no one else had pointed this out! A guy plumetting to his death... Pan back to the choreographed reveal hug. Lost a little more faith in humanity...
@cameltube-vk7el
Жыл бұрын
THis has @@worldwideflyby prompted much reaction. BUT I highly doubt they really seen what we did in a post flight event w\video review...think about it PERSPECTIVE → point of view[actual] then also add in SPEED & flight altitude & then window of visual [time] before out of. SemperProrsum~Godspeed
@michaelbrown2470
Жыл бұрын
Aero Engineer here with a lot of ag design/testing/certification testing..... When you emergency drop, the effluent drops down entraining air which increases the angle of attack at the horizontal tail which increases the down force at the horizontal tail. This tends to pitch the aircraft nose up without any input from the pilot. A number of AT-802's have been lost because of this phenomenon, but in this case the horizontal tail stalls and the aircraft bunts (uncontrollable nose down).
@robertalan4717
9 ай бұрын
I think you have the answer sir. After watching the video frame by frame it appears the tail got sucked down by the water down wash coupled with sudden wing unloading. Maneuvering speed has to do with full control deflection limits, as I recall from ground school.
@gilbertocastroarenas460
Жыл бұрын
Once again you did an outstanding job gathering all this info and putting it all together so we can all understand and learn from these horrible accidents.
@alayneperrott9693
Жыл бұрын
Yes indeed. Very upsetting for the family who presumably hired this guy.
@militaryav8r
Жыл бұрын
0:17 I love how whoever is operating the camera paid enough attention to the plane to stay with it as the wings fold, but then just pans back to the soon-to-be parents as if they didn't just see what we all saw. "Screw that guy... it's a girl!" 🤔🤨
@joeyvanostrand3655
Жыл бұрын
It probably didn't even register in their mind what just happened. That plane was literally flying by. 100+ mph. They just swung the camera back behind them and then right back to the over-spending, braggadocios couple.
@jamieknight326
Жыл бұрын
Aye, I suspect they didn’t process what was happening and just swung back to the couple on instinct.
@joesterling4299
Жыл бұрын
I doubt very seriously that anyone was aware of the tragedy that just happened. I would love to see video of the next 5-10 minutes. My guess is that the mood changed drastically once reality sank in.
@thardyryll
Жыл бұрын
The first clue that the person making the vid has no idea what they’re doing is the vertically held phone. It goes downhill from there.
@gnoLeDwerdnA
Жыл бұрын
They were watch the video of it right when the wing bends there is a terrified high pitched scream followed by a glimpse of people running away towards it, people were absolutely aware of what happened the second it happened and the cameraman had a perfect view so put two and two together
@57appel
Жыл бұрын
Your chart explains why I’m not an Engineer. All I knew was the weight changed and he stressed the plane’s limits. Thank you for the explanations.
@jnavonoD
Жыл бұрын
I had a very similar response. I also realised yet again why I am not a pilot (though I am a keen armchair aviator).
@Jleed989
Жыл бұрын
Even that’s too much information for most of us.
@Relkond
Жыл бұрын
If I follow (which I my not), by halving the planes mass and not changing it’s profile in the air, it’s accelearation from aerodynamic forces double - which if you’re pulling a 1-g nose up maneuver as you do that, you go from 1g to 2g of force on the fuselage. The wings may be fine taking those forces, but it’s going to maneuver more nimbly, and it’s going to mean 2g of force on the engine mounting in the nose.
@Kalimerakis
Жыл бұрын
@@Relkond thanks, thats what I needed to finally understand it. Reducing the weight suddenly doesn't change the lift the wings are creating, but it does increase the G's the airplane is pulling.
@rtbrtb_dutchy4183
Жыл бұрын
@@Koi-Koi-Koiwasn’t paper. Was colored water. And the palms didn’t have anything to do with this.
@ralfsingmann6580
Жыл бұрын
This is again a sad story where pilots are pushed towards being a “flying circus” with a bad outcome. I will file this video for all my aerobatic, UPRT or instructor students, when I’m desperately try to explain a flight envelope. Thank you Juan for doing it for me! I like the visualisation with different colours. 👍🏻
@bunglejoy3645
8 ай бұрын
They proberly often did flying g displays that was ptoberly their job what was this one sny different
@--SPQR--
5 ай бұрын
They're the captains of their aircraft. No one is forcing anyone to do anything. If you're not comfortable with a request, don't do it. That simple.
@yamatowolfgang7960
Жыл бұрын
Great video Juan! If I understand correctly, because the mass of the load being dumped is about 80% of the empty weight of the plane, after release, the instanenous g-load is increased to 180% of the value before dumping. Thus if the plane is already pulling 2 Gs at the moment of dumping, it is now pulling 3.6 Gs the moment after dumping. No wonder things snap.
@dbaider9467
Жыл бұрын
This is a great analysis. Really sorry for the pilot and family. RIP. Corrosion will be a factor, no doubt. It's always somewhere isn't it.
@IrishmanAC
Жыл бұрын
Maybe, but the manoeuvre itself was pretty crazy too, I'm not an expert by any means but I would wonder how much of a difference that might make when the pilot put the plane under such forces in the first place. The wing might have snapped regardless of any wear and tear. If it is a factor, I'd expect it to be a footnote rather than anything that significantly contributed to this outcome.
@enginerdy
Жыл бұрын
These are old planes. It’s not unheard of to find cracks in the tube structure after decades of rough service
@BamaRailfan
Жыл бұрын
@IrishmanAC many Ag pilots pull off these maneuvers several times on a daily basis. I have witnessed iy many times here in Ohio. I feel this pilot miscalculated his load and attempted a maneuver he was used to. A miscalculated load, and a potentially structurally weakened aircraft lead to this.
@pennhiker5117
Жыл бұрын
@@BamaRailfan AD 95-12-01 addresses In-flight separation of wing from airplane.
@BamaRailfan
Жыл бұрын
@@pennhiker5117 yes, it does. Unfortunately there are those owner/pilots out there that think it'll be ok unless they get caught. Sad but true. It happens a lot in the private aviation field and really is scary.. that said, I don't mean to accuse the pilot in the video.
@bullthrush
Жыл бұрын
Dumping the hopper causes an extreme nose up trim, it will take you by surprise if your not ready for it. A massive push on the stick is required during the dump. I am guessing he was a banner or glider tow pilot, not an ag pilot.
@frontagulus
Жыл бұрын
Not in a Fletcher - the hopper is right over the wing - relatively neutral compared to forward hopper planes like Pawnees and AgWagons when dumped
@DrAHorn
Жыл бұрын
Thanks, that fits much better to what the accident video shows than Juan's explanation. Reducing weight (e.g. by dumping cargo) while in a turn with a constant wing-loading will increase the g-force on the aircraft, which can cause structural failure. But in that case it wouldn't be the wings that fail, those are at a constant load as we said. What would fail are the "fixed weight components", i.e. the high gees would rip the engine off its mountings or so. What happened in the accident video was that the aircraft pitched up massively as the hopper was dumped. As Juan explained, at lower air-speed that would have led to a stall instead of a structural failure, but I don't believe the pilot intended to put the aircraft into a stall so close to the ground. So an unexpected change in trim that caused the nose to pitch up is a more likely explanation.
@josephoberlander
Жыл бұрын
@@DrAHorn The final picture in the video is stopped at exactly where the wing failed. You can clearly see it twisting as the attachment point failed. So the wing was fine. Just it decided to go one direction and the body another. With a poor couple of bolts left somewhere in the middle.
@DrAHorn
Жыл бұрын
@@josephoberlander Well, O.K. it may technically not be the wing. But it's still part of the structure that is engineered to support the full force that the wings can carry.
@josephoberlander
Жыл бұрын
@@DrAHorn True. It does look like it failed a bit earlier than it should have, but such are old machines. A little deformation, a loose bolt, a bit of rust and it could be still up to spec but just barely/needing replacement soon. It will get interesting to see what the reports say about the condition of it and the maintainence recrords.
@dirkhoekstra727
Жыл бұрын
And they didn't even see the aircraft breaking and crashing and just continue celebrating! 😡
@markkussusa
Жыл бұрын
Was looking for this comment. Though it seems that one person actually did and ran towards the crash site.
@vernicethompson4825
Жыл бұрын
I'm sure they didn't celebrate for much longer, after realizing the plane had crashed.
@flightsimguides
Жыл бұрын
It was in the video, someone should have noticed. Or heard.
@robertrosanelli444
Жыл бұрын
I could not believe that no one, or almost no one, noticed the airplane come apart and crash.
@wolfy6631
Жыл бұрын
@@flightsimguides The cameraman noticed and didn't give a shit
@donosticopter9225
Жыл бұрын
While it is true that low weight does increase max Gs for the same control input at any given speed, the lift of the wings and so the couple at the wings roots is the same, so I don't see how low weight can be to blame for this kind of structural failure. Other parts of the airframe indeed are more stressed with more Gs, but not the wings because of this low weight situation. Thanks for your response, it meens a lot for us GA pilots your videos. Congrats.
@scottmoore598
Жыл бұрын
Lightly loaded, the wings can produce more lift before stalling because it has more available angle of attack. The way I heard it put is a heavy load will stall. A lighter load can generate more lift before the stall and thereby more stress on the frame. Think of the Va stall as a safety valve that dumps excess lift. The wings will eventually create the extra lift, but the frame can’t spread the lift. Even if the struts and spar distribute the force to the frame, now the engine mount is overstressed with its heavy load.
@paulis7319
Жыл бұрын
I've got around 7000 hours in the PA-25 235 as an aerial advertising pilot (banner towing). Our operating manual had the maneuvering speed listed (yes it is 120 MPH). I'm glad you started by mentioning the variable maneuvering speed as the weight changes. Our planes were STC'd with 75 gallon tanks where the hopper used to be (3 gallons unusable) so we had to be aware of the maneuvering speed vs weight difference as we flew cross-countries to different locations. It's a very fun and rugged airplane when used correctly. I usually called it the flying pickup truck.
@ronjones1077
Жыл бұрын
Thank you for explaining this. The old C130 that lost both wings is an example as well.
@jessicav2031
Жыл бұрын
It looks like the left wing bent backwards, causing a runaway pitch-up moment until it snapped off. That is, in the first frame where the wing flexes it looks like the wingtip flexes first, rather than at the root. You can even see the wing crease just outboard of the root.
@jessicav2031
Жыл бұрын
@@michaelbigelow3255 Electrical engineer. I've never flown anything but a 172. Aircraft are mostly cool for the engineering 😄
@duncandmcgrath6290
Жыл бұрын
A wing is the pitch axis , it cannot affect pitch .
@robertalan4717
9 ай бұрын
Yes like a forward swept wing. I can see that. I just came across this tragic video btw.
@kennetheavey8921
Жыл бұрын
I wonder how the child will feel about this when she grows up.
@jeanetteshawredden5643
Жыл бұрын
I'm sure the child will never know.
@CLEAREDDIRECT
Жыл бұрын
Flying fighters, we use a version of the V/G diagram to show 2 important features of performance-corner velocity (smallest turn radius which happens to match Vm) and best turn rate airspeed (faster and G-limited). If you lay two competing [Em] diagrams on top of each other, you can find your maneuvering advantage. As always, fantastic video Juan.
@heeder777
Жыл бұрын
Maneuvering speed was an area one of my instructors drilled into me. (I had three total and lost each one as they moved up into the airlines) I’ve never seen that chart before but I can say that its a great tool, especially if you want to explain why less weight will decrease maneuvering speed. I assume the same logic would apply when 12 skydivers exit an aircraft. Great teaching moment. I enjoyed the entire presentation.
@lolbots
Жыл бұрын
very counterintuitive
@scottmoore598
Жыл бұрын
The way I heard it put is a heavy load will stall. A lighter load can generate more lift before the stall and thereby more stress on the frame. Think of the Va stall as a safety valve that dumps excess lift. The wings will eventually create the extra lift, but the frame can’t spread the lift. Even if the struts and spar distribute the force to the frame, now the engine mount is overstressed with its heavy load.
@macroglossumstellatarum3068
Жыл бұрын
@@scottmoore598best way I’ve heard it so far for me I think
@terke1230
Жыл бұрын
Great video Juan, as always. One detail: if you step through the video you’ll see the spar attach did not fail but the struts collapsed. First the rear (the wing twists in torsion first) then the front strut, and whole wing rotates around the fuselage about the spar attach pin.
@bardmadsen6956
Жыл бұрын
I had seen personally three of that aircraft in the early 70's where the tubing next to the tail wheel was corroding apart from the chemicals, speaking of such, why would anyone, especially pregnant, want pesticides and defoliant tank water to be dropped on them???
@MattyEngland
Жыл бұрын
Anyone who wants this kind of nonsense for a 'gender reveal' probably has a IQ so low that they struggle with any concept above 'Whoo pink pretty stuff'
@windwatcher11
Жыл бұрын
I thought the same thing.
@kentuckybowl-o-sticks
Жыл бұрын
Probably cartel members... not exactly geniuses.
@davidmotter5140
19 күн бұрын
Mexicans dont care we should let all if them into our country NOT
@kurtkaster5666
Жыл бұрын
Grandma killed by shrapnel, massive wildfire and now a dead pilot. How about just saying "it's a boy".
@XRP747E
Жыл бұрын
I used to fly the Pawnee (later the Canso) spraying in Africa, in the 70s. It is now a nostalgic chapter of my life and I found this video both illuminating and sad. Thanks Juan, you ALWAYS produce such high value information. Pilots would do well to follow EVERY ONE of your videos. Thank you.
@EmesiS
Жыл бұрын
Juan, as always a spot on analysis of a tragic event. I have great respect for your aviation knowledge! I'm not sure if you know, but when a KZitem video is paused you can use the greater than less than keys to move one frame at a time. I find it useful on many videos when trying to see something important. Of course the quality of the freeze frame depend on the quality of the video. Cheers!
@StevenBruce-s1o
Жыл бұрын
@EmesiS - Thank you! This reminds me to search for an instructional video for using KZitem. And if you use the period and comma keys, the increments are much shorter.
@EmesiS
Жыл бұрын
@@StevenBruce-s1o Lol...well that's basically what I meant. Same keys, I just always say greater and lesser instead of comma and period. I didnt even think about the difference when I posted....duh. if you do hit shift, that changes the speed and not the frame increments. Anyway you figured it out....cheers!
@StevenBruce-s1o
Жыл бұрын
@@EmesiS Oh, thanks! I'll try that out!
@Species1571
Жыл бұрын
Dying fighting fires or some other practical function is bad enough, but dying for something so utterly ridiculous and pointless is even worse.
@bobwilson758
Жыл бұрын
$$$
@tedmoss
Жыл бұрын
So dying is worse than dying.
@buhnux
Жыл бұрын
Really great breakdown, as soon as I saw the crash video a few days ago, I thought "I hope Juan makes a breakdown video on this crash".
@Squidbillies1000
Жыл бұрын
Unfortunately, I could not wait for today's class. Once again you did a stellar job. Sir, you save lives with your channel. Sorry for the pilot and his family. RIP young man.
@DrDisconnect666
Жыл бұрын
No he doesn’t tell me how he saves lives the NTSB saves lives not this clown
@ibluap
Жыл бұрын
This is why I'm your patreon! You are able to explain short and clearly, whatever may be intrincate and hard to pick up from harsh or sad events like this!
@blancolirio
Жыл бұрын
Thanks for your support!
@FlyingSylo
Ай бұрын
Currently working on my Bachelor Thesis about fatigue damage in aerial firefighting. This video including the comment section is great! Thank you all :)
@islandmonusvi
Жыл бұрын
As I recall… during the low level skip-bombing assault on the Ruhr Valley Dams during WWII, 5 of the 8 attempts resulted in loss of aircraft to both defensive gunnery and catastrophic structural failures.
@bwyseymail
Жыл бұрын
One of my favorite movies as a kid was "The Dam Busters".
@ROBIN_SAGE
Жыл бұрын
I have a small 2x2” piece of “AJE” , a Lancaster lost on the dambusters mission, AKA “operation chastise” … flown by Flt. Lt. Norman Barlow and his crew, lost to ground fire at 23:50 hrs May 16-17 1943… Godspeed boys…..
@MainSequence1
Жыл бұрын
Nice reference!
@chriss.4147
Жыл бұрын
Only one aircraft was lost over the dams, that happened at the Mohne dam. It pulled up but one wing was on fire and it broke up and crashed. The Eeder dam did not have defences. The aircraft that had to attack that dam all pulled up very steeply but none broke up.
@worldcomicsreview354
Жыл бұрын
@@chriss.4147 He could be talking about training / testing too. There's film of a least one where the bomb bounced into the tail and the aircraft went straight into the sea.
@mikepriceup
Жыл бұрын
It's amazing to me the lengths ppl will go to reveal a gender of a baby. Pilot killed, wild fire started and so on so on. Call or text your friends it a boy or girl. Ppl died because of this nonsense, enough all ready
@kentuckybowl-o-sticks
Жыл бұрын
Monkey see, monkey do... it's rampant.
@theflyingfool
Жыл бұрын
That was the best explanation of the danger of exceeding normal or lower Vp I've read or heard. Thanks Juan!
@atatton9892
Жыл бұрын
Hey Blanco, when the water is dropped rapidly, remember the wings were making 3,000 lbs of lift but the aircraft now weighs only 1,600 lbs. The airplane climbs violently, sometimes exceeding the available down elevator.
@TheHuesSciTech
Жыл бұрын
I'm no expert, but this doesn't sound right to me. The wings are placed at, or even slightly behind, the center of mass of the plane; so even with the large discrepancy between lift and weight, it doesn't have a significant moment arm to operate around, and if anything, with the wings behind the centre of mass, that would create a slight nose-down torque upon release -- but regardless, the tail fin is there to keep the plane flying generally straight. So I think you're confusing linear forces with torques. I mean, the plane can fly straight and level when full, and can fly straight and level when empty. It's just a angle of attack change to move towards those two regimes.
@cooperised
Жыл бұрын
@@TheHuesSciTechThe tank in that Piper looked to be forward of the natural CoG, mounted in front of the pilot like that. The dump probably moved the CoG backwards a bit, and did so suddenly. Given the likely strong nose-up trim required at maximum weight, even a small movement of the CoG could induce a strong pitch moment if the pilot wasn't ready to counteract it.
@atatton9892
Жыл бұрын
@@TheHuesSciTech it has nothing to do with CG. Presuming everything is in equilibrium, trim is set, the horizontal stab is neutral or pulling down slightly and the wings are making 3100 lbs of lift to carry the 3,000 lb gross weight straight and level. Now dump the 1,500 lb load in about 3 seconds. The airplane will pitch up violently, not because of any change in cg, but because the wings are still making 3100 lbs of lift but you only weigh 1500 now. Try it sometime...ag pilots are accustomed to taking 20 or 30 minutes to empty their hoppers, not 2 or 3 seconds. Best of luck, and be ready with ALL the forward stick!
@jayallen5177
Жыл бұрын
Great reminder to all of us sir!! Some aircraft are more susceptible than others. I loved the way you went back to the basic chart to reiterate how dangerous exceeding design limits can be!!! Thanks again Juan!!!👍
@scofab
Жыл бұрын
In the first clip it seems the party attendees didn't notice the crash...? Sad indeed and well done Juan.
@kekke2000
Жыл бұрын
The most eerie thing in my opinion is that the person filming definately noticed but filmed back to the couple as if it didn't happen. Like they didn't want the plane crash to ruin the day.
@kekke2000
Жыл бұрын
@@TELE6220 definitively
@saleplains
Жыл бұрын
its a somewhat common response to some types of traumatic events. almost as if the brain just overwrites that portion of memory to avoid dealing with it. always creepy to see though. people dying and everyone just going about acting like its not happening
@iitzfizz
Жыл бұрын
Like "Oh the plane just had a huge structural failure and the wings ripped off...it's a girl, yayayy!!" :/
@alexanderSydneyOz
Жыл бұрын
@@kekke2000 "he person filming definately noticed " The phone follows the plane past the point where the wing broke, but that does not mean the person holding the phone was looking at the phone or the plane.
@challenger2ultralightadventure
Жыл бұрын
What a tragic event, that was supposed to be full of joy. My deepest sympathies go out to the family and friends of the pilot.
@Skank_and_Gutterboy
Жыл бұрын
I just can't relate to people who do stuff like this. I guess trying to do something cool and memorable trumps good sense. A flyby with a plane is cool and I've seen things like this done with skydivers and it makes no sense. It's cool if it all goes well but look at the penalty for failure!
@jlo7770
Жыл бұрын
It looks like they were still celebrating even though they literally watched the plane break up directly over head. Maybe they thought the wrong falling off was part of the show?
@tonyc223
Жыл бұрын
@@Skank_and_Gutterboy Everything has to be on Facebook even the morning bowl movement.
@ginvr
Жыл бұрын
Thank you for covering this tragic loss. You have given me a good understanding of what went wrong
@walterthorne4819
Жыл бұрын
I didn’t recall the issue of how changing the A/C load effects maneuvering speed. Thanks Captain.
@superandy89
Жыл бұрын
That “ahah” before the Argentinian reveal was peak dad joke reveal. Love you Juan. Keep the content coming!
@scottstewart5784
Жыл бұрын
Suggestion - attach smoke canisters, approach with white smoke, switch to pink overhead, fly tomorrow.
@Parkhill57
Жыл бұрын
Ride a motorcycle with training wheels.
@Maggie-tr2kd
Жыл бұрын
A life is worth so much more than the fleeting momentary thrill of seeing colored water drop from a plane for a gender reveal. I'm so sorry for the pilot and his loved ones.
@DaveG-qd6ug
Жыл бұрын
the party goers se3med to have a different take on things
@edgarmuller6652
Жыл бұрын
Great class for all pilots. Usually, there is more than one link broken for an accident to happen, this may well be the case. Thanks Juan. Poor guy didn’t know what he was getting into. RIP.
@billtisdale6122
Жыл бұрын
Thanks! There are numerous Airworthiness Directives on the struts, the one you showed for the main spar attachment and another for the aft spar attach. It does not look like either of those failed. As you mentioned, it does appear that the left wing failed at the outboard strut attach point. I’ve not done crop dusting with these birds, but I do have over 600hrs in Pawnees on glider tow duty. We are about 1200# below MaxGW. You are hard pressed to get over 120mph in a dive without that extra weight.
@MustangsTrainsMowers
Жыл бұрын
I’m probably in the minority but I think that gender reveals are a stupid, look at me act. I remember a few years ago at least one of them started a forest fire that burned multiple houses to the ground. Why don’t people just wait until the child is born and announce its gender then?
@poneill65
Жыл бұрын
Wouldn't have even thought that dropping something (heavy) from an aircraft would be legal, outside of some exceptions like agricultural or fire fighting activities. Far better to release colored smoke or something like colored confetti/chaff
@BrainWasherAttendent
Жыл бұрын
Exactly!!! People don’t think, is everyone more idiotic by the day?
@tedmoss
Жыл бұрын
@@BrainWasherAttendent Yes.
@enginerdy
Жыл бұрын
It’s legal (in the US) as long as you make sure it won’t harm anything on the ground and you have landowner permission, etc But low altitude dropping over a crowd in the US would probably be a quick license pull
@mantolis33
Жыл бұрын
@@BrainWasherAttendent Yes they are.
@ElementofKindness
Жыл бұрын
It's been done before. But narcissistic parents always want to one-up their reveal parties.
@michaelbrodsky
Жыл бұрын
If I had nickel for every gender reveal disaster…
@DaveG-qd6ug
Жыл бұрын
and notice how the pilot plundering to his death was not enough stop the celebration.
@bradsanders407
Жыл бұрын
You'd have about 15 cents
@davidbiagini9048
Жыл бұрын
I wish I had a nickel for every flight disaster caused by poor flying and/or poor maintenance.
@lawnmowerdude
Жыл бұрын
@@bradsanders407 keep counting.
@danielmclaughlin9043
Жыл бұрын
That was crazy! Even the guy recording it!!@@DaveG-qd6ug
@leeross7896
Жыл бұрын
wow I never thought about it, counter intuitive and scary.. of course I never had the option to dump all my passengers out the bottom of the aircraft and yes I have had my mother-in-law in the back before :)
@wintercame
Жыл бұрын
😆I know the content was not funny but your comment is. Very.
@lesigh1749
Жыл бұрын
I'm horrified at the happy couple hugging and celebrating as that plane is going down. How deep in the moment do you have to be to not see that wing just came off the plane flying right over your head. The camera guy turning away from the crashing plane to film those two is astonishing too.
@user666mega
Жыл бұрын
Maybe he wanted to catch their shocked reactions....
@cameltube-vk7el
Жыл бұрын
Hey, review the clip again. Maybe their view was obstructed by a massive pink mist right between them and the pilot..............so there is that !!!
@cameltube-vk7el
Жыл бұрын
Had the wing came off [it did not, it folded] that could have been very bad & might have increased the souls lost count and damages/injury. Keep being horrified for nothing. Me I choose greatful for that being all that went wrong, good copy?
@lesigh1749
Жыл бұрын
@@cameltube-vk7el The wing is off, it has detatched from the body of the plane and is held in place only by the outer skin but its structural supports are completely detatched. it was instantly obvious to most people watching that this was the case, but apparantly not the people that were watching it at the scene where they had an even clearer view. I will keep being horrified at the emotional detachment of the happy couple and the camera guy, and will add disgust at you for trying to excuse it not just once, but with two seperate posts made just two minutes appart.
@cameltube-vk7el
Жыл бұрын
Bro @@lesigh1749 now I am horrified at your understanding of the term DE-ATTACHED / detached. I does not matter what held it on as it spirals forward FOLDED ontop of the cabin. It stayed with the craft As to your other limited situational understanding of the full environment and different perspectives i.e. MASSIVE PINK MIST supported by a second event of confetti & smoke & the "out of view" element ha ha ha ahhhh man come on. I really doubt they were fully if remedially aware of the FAIL, again SPIRAL OUT OF VIEW in tact i.e. one piece & OK HELD on by skin it was still with the craft body bro. So back to you, for more HORRIFUNG ineptness of situational awareness Just replay the vid man ha ha ha ahhhhh we are doomed as a species. Alwaysw FOrward ~ Godspeed
@AgentJayZ
Жыл бұрын
Counterintuitive... yes! I definitely learned something today. Your analysis videos and commentary on real world events are extremely useful and educational. Nobody better to comment on aircraft occurrences than an experienced pilot. Thanks again!
@jackoneil3933
Жыл бұрын
Indeed... Many unfortunate things revealed during such a tragic event. Thanks Juan.
@rrich8371
Жыл бұрын
I'm just wondering how much Ag spraying experience the pilot had... thinking not much.
@EvanAndersen-et9qy
Жыл бұрын
I don't think dumping the weight had a negative effect on the structural integrity of the wing spar. When the aircraft is flying, aerodynamic forces (primarily airspeed and AoA) dictate the force generated by the wing. That force is distributed to each component of the airframe through the structure. When weight is dumped, the total load on the wings doesn't change, because airspeed and AoA haven't changed. However, the load factor increases, such that the total force remains the same. What this DOES do is change how the loads are distributed through the airframe. However, since the fuselage is now a smaller share of the total aircraft weight, the force in the wing spar actually goes DOWN when the water is dumped. Of course, you can still get other failures, but that's not what's observed in the video. For example, when the water is dumped, the load on the wing spar is reduced, but the force on every component in the fuselage is increased. If we had seen a failure of the engine mounts, or the body itself, then the load dump would make more sense as a contributing factor. But, since it seems to only have been the wing spar, whose load DECREASES when the water is dumped, it leads me to believe it was the wing spar AD at play here.
@HE-162
Жыл бұрын
I’m not a physicist or a pilot but that was my thought as well. It seems to me that the shock of the weight(force?) suddenly reducing could have caused the compromised/corroded spar point to finally shear. Kind of like how extremely rusty metal or cracked wood will sometimes hold together when force is applied in one direction, but will fail quite easily as soon it’s pushed in the opposite direction. I could definitely see the spar holding, but when it got shocked with an A-typical force while already under load, it caused it to finally fail. Structural anything in general tends not to like rapid alternating/shifting forces, which surely the sudden drop would have caused?
@aeroegnr
Жыл бұрын
Load goes down suddenly->Back stick pressure to maintain level flight goes down. That's why he mentioned that you relieve the load traditionally by easing out on traditional firefighting planes. By yanking back hard, the pilot exaggerates the tendency for the plane to nose up. If he was above maneuvering speed, he could have easily overloaded the plane. The forces go up because the plane was accelerating upward. Or, in other words: If he pulled back (not an uncommanded control failure), he suddenly showed a lot of bottom wing to the airflow at very high angle of attack at high speed. That wants to bend the wings back and up. If it was too fast for it to take it, then there you have wing failure. Like entering the beginning of a loop by pulling back hard. It's high G because you are accelerating UP. The load on the wing spar isn't reduced then.
@EvanAndersen-et9qy
Жыл бұрын
@@aeroegnr Yes, because the tank is forward of CG, dumping the load causes a pitch up, which causes increased lift/spar load. However, the aircraft still needs to be above the Va for max-gross, not below, since emptying the tank reduces the spar load at max-lift for a given speed. So either the pilot was flying faster than the max-gross Va, and/or the spar was unsound due to the non-addressed AD.
@robertschlemmer5039
Жыл бұрын
What a food for thought treat from Dr. Juan. Dumping the load will cause a pitch up if uncompensated by forward stick. Uncompensated pitch up without a comenserate simultaneous change in velocity vector overstressed the wing connections. Pitch up induced huge parasitic drag. This suggests that fuselage structure could also be damaged at engine mounts and at wing connections. This how the explanation came across to me. Thanks.
@rtbrtb_dutchy4183
Жыл бұрын
@@EvanAndersen-et9qyno, you are missing the whole point. You don’t understand how Va works. If Va is 120 knots at max gross, when you drop say 1000 lbs, the VA would drop significantly. Likely to around 100 knots. So if he had flown at 110 knots and pulled back fully on the stick, without releasing the water, the airplane would’ve stalled at say 2.5 Gs and not damaged the wings. Had he flown at 110 knots with the water dumped and pulled fully back, the airplane could pull 4.5 Gs and still not stall. This would be above its limit.
@marinrealestatephotography
Жыл бұрын
Thanks for the clear explanation, Juan. So glad no one on the ground was hurt. So sorry for the family of the pilot.
@Toy1er
Жыл бұрын
The fact that they still kissed and celebrated right after the plane crashed was the most insane part of the video.
@Aeronaut1975
Жыл бұрын
Gender reveal parties are cringe AF. RIP to the pilot who thought he was playing DCS and tried to do a cobra maneuvre in a Piper Cub.
@Charon58
Жыл бұрын
I used to Tow banners and gliders in a 260 hp Pawnee. Very rugged plane. Very easy and forgiving to fly. I’m guessing the pilot must have pulled very hard here to cause structural failure even accounting for the sudden weight change.
@tedmoss
Жыл бұрын
Hard enough to pull the wing off, investigation will tell if there was a corrosion problem.
@MrTruckerf
Жыл бұрын
I would be very surprised if corrosion wasn't the main cause. Fire-fighting planes dump a heavy load very quickly and sometimes have to do a steep climb to avoid terrain in mountainous areas.
@ohger1
Жыл бұрын
@@MrTruckerf Probably depends on the plane.. Looking at this chart, this particular plane wasn't all that stout even if there was no corrosion problem.
@ohger1
Жыл бұрын
Probably the pull-up combined with the sudden change of balance. If he kept the stick level, it might have pulled up by itself just on weight transfer of the emergency dump. Adding the pull just added to the maneuver.
@VTPSTTU
Жыл бұрын
Thanks for the video. I always thought that the point of a crop duster was to release chemicals in a very slow, controlled way. I understand that the fire suppression planes need to make a hard drop at once, but I thought crop dusters were made for a different kind of use.
@MattyEngland
Жыл бұрын
That's correct, this kind of drop was meant to be for emergencies only.
@guntherberger596
Жыл бұрын
Yes, normal operations of crop duster would release small amounts over time, however as explained in the video there is an emergency release which was used here.
@dasmith.4536
Жыл бұрын
I wonder if the pilot was qualified as a duster pilot. I would guess that this scenario would be covered in training.
@VTPSTTU
Жыл бұрын
@@guntherberger596 I remember him saying that there was an emergency release. I wonder whether the manufacturer established conditions under which the release should be used. For instance, if the engine fails and the plane is going to crash anyway, I can see value to releasing the chemicals so that a rescue doesn't have to deal with the chemicals. I wonder whether the "owner's manual" for the plane basically says that if one isn't crashing already then using the emergency release is likely to cause a crash.
@WyndiDae13
Жыл бұрын
As a pilot and someone who works on aircraft, Pipers aren’t structurally built as well as a Cessna. If you go through the boneyards you’ll find pipers fill these yards. Rarely will you find a Cessna with a broken wing spar. I’d bet had he been in a different aircraft the spar would have bent, but not broken. Great job explaining what could have gone wrong. Condolences to his friends and family.
@whamo1966
Жыл бұрын
One of the most ignorant comments so far. Cessnas are also subject to physics. The Pawnee has several AD’s relating to spar attachment. These are not design related but maintenance related. When these are exported south of the border AD compliance is often ignored. Decades of carrying very corrosive materials necessitates careful attention to maintenance, Cessna, Piper, or otherwise.
@guitarhillbilly1482
Жыл бұрын
AD 95-12-01 SUMMARY: This amendment supersedes Airworthiness Directive (AD) 93-21-12, which currently requires inspecting (one-time visual and dye penetrant) the wing forward spar fuselage attachment assembly for cracks or corrosion on certain Piper Aircraft Corporation (Piper) PA-25 series airplanes, and replacing or repairing any cracked or corroded part. This action requires repetitively inspecting (using ultrasonic and dye penetrant procedures) the wing forward spar fuselage attachment assembly for cracks or corrosion, replacing or repairing any cracked or corroded part, and reporting to the Federal Aviation Administration (FAA) the results of the inspections. This action is prompted by the FAA's lack of confidence in detecting internal corrosion in the wing forward spar fuselage attachment fittings while accomplishing the inspection methods required by AD 93-21-12. A report of a crack in the wing forward spar fuselage attachment assembly on an airplane where the inspection requirements of AD 93-21-12 were accomplished also prompted this action. The actions specified by this AD are intended to prevent possible in-flight separation of the wing from the airplane caused by a cracked or corroded wing forward spar fuselage attachment assembly. Just wonder with foreign registry if AD was even complied with. The early Pipers were built much stronger with welded steel Truss fuselage. This also includes the PA 25 Pawnee. Wing Failures with the PA 25 are long term maintenance issues and not Design issues. AG planes operate in a Highly CORROSIVE Chemical environment. The failures occur with the fuselage attach fittings and not the wing spar itself.
@desertshooter007
Жыл бұрын
@whamo1966 she's right tho...Piper has more wing spar issues than Cessna. There's no debate here sorry if this fact offends you...well not really lol
@guitarhillbilly1482
Жыл бұрын
@@desertshooter007 this video is about the PA25 PAWNEE. It's major wing issues are with the Fwd Spar FUSELAGE Attach Fittings. The PA 28 has major wing spar issues as does several other models .
@whamo1966
Жыл бұрын
@@desertshooter007 another ignorant statement void of actual facts. Thanks for your contribution…. Lol
@danielmiller2886
11 ай бұрын
I have always loved aircraft but I am not a pilot. This is an excellent reminder to me why I should never try to fly. The details that must be remembered around the weight, G-force, stall speed, etc... are not my strong suit. Would love to be a mechanic again, but you guys that are (good) pilots get all my respect.
@shenandoahhills7263
Жыл бұрын
No telling how many G's had been pulled on that aircraft during its life of dusting, particularly if the same Pilot had been flying it.
@maxtanicfilms
Жыл бұрын
Thanks for the insight Juan. It only takes one mistake to pay with your life. Simply put "small corrections" That's what my Dad would say when I was first learning to fly as a kid. I was a career pinch hitter with my Pops you could say. Every flight was a learning experience :)
@tedmoss
Жыл бұрын
I see you are still alive.
@maxtanicfilms
Жыл бұрын
@@tedmoss It worked out, only crashed once which was no fun.
@TootUncommon
Жыл бұрын
Thx for a complicated but clear explanation of this strange, unfortunate event.
@GyroBlain
Жыл бұрын
Juan, I love how can you be such an aviation nerd AND help us fellow aviators with your experience, research and insight at an understandable level. Keep 'em coming, and come visit us in Idaho again sometime!
@closewatermelon
Жыл бұрын
I’m about to find out the gender of my baby. I’m gonna use this thing called my my mouth and vocal chords to reveal the gender to my friends and family.
@tomm1968
Жыл бұрын
Great explanation. I've never even seen a V-G diagram before, so this was all new material for me. I wish you could have shown us a modified V-G diagram showing the unloaded state for comparison. My only complaint (albeit a minor one.)
@coriscotupi
Жыл бұрын
06:17 - Yes, but it's not the wing loading or "X" pounds of lift that break the wings - it's the g's. On the examples given the g's are fixed at 4. It takes an "X" amount of g's to break a wing, at whatever wing loading or lift force. At a lower wing loading the wing may not stall (which would unload the wing) before reaching its design g-load factor and may break, hence the lower maneuvering speed at lower weights.
@blancolirio
Жыл бұрын
Correct! You got it!
@vihai
Жыл бұрын
It's a bit more complicated. The limitations are given in "g"s because it is an easy to express limitation. However, when you change the masses configuration of an aircraft there are changes in the forces, some forces increase, some decrease. In this case, if you unload a fuselage-mounted tank, the wing attachment forces decrease while the fuselage structure (engine mounts in particular) experience greater forces for the same angle of attack. That's why manouvering speed often decrease with weight.
@russelltaylor535
Жыл бұрын
@@blancolirio I’m not sure he does have it correct. The lift the wings produce depends only on airspeed and angle of attack. In your example if the 16000 lb airplane pulling 4Gs suddenly releases 8000 lbs of weight it won’t be pulling 4Gs anymore it will be pulling 8Gs unless the pilot lowers the angle of attack to reduce the lift. An aircraft that drops weight at constant angle of attack is likewise going to accelerate upward and climb without any pitch input from the pilot. So that’s what likely happened in this mishap. The pilots 2-2.5 G pull-up became a 4+ G pull-up as the water was released overstressing the airframe in the process. This would have been exacerbated if the aircraft was above maneuvering speed.
@6StringPassion.
Жыл бұрын
My first thought was corrosion, but the information you presented makes it clear that the failure of the air frame was most likely the result of the pilot's actions while releasing the payload.
@vortec4253
Жыл бұрын
Very well could have been both issues contributing to the failure. Without knowing the details of his speed, angle of attack, amount of weight dropped, etc, it's impossible to say for sure. He may very well have been within the design limits but with a corroded airframe. Like you, I tend to think he was not, but that's why they do investigations. Don't assume.
@6StringPassion.
Жыл бұрын
@@vortec4253 Good point.
@6StringPassion.
Жыл бұрын
@@Koi-Koi-Koi Do pilots do practice runs to help anticipate the issues that may arise during a drop? Maybe I am naive, but I would think that having obstructions that close to a drop point and flying into direct sunlight would necessitate a 'dress rehearsal' of sorts.
@6StringPassion.
Жыл бұрын
And I don't mean to be insensitive or sound like I am assigning blame. Just inquiring as to what would be considered 'best practice'.
@rtbrtb_dutchy4183
Жыл бұрын
@@Koi-Koi-Koiagain with your palm tree. This is silly now.
@LindysEpiphany
Жыл бұрын
Juan is the best at giving precise information in a language we can all understand!🙂
@todd2515
Жыл бұрын
Superb analytics so clearly explained Thanks so much Chris Cambridge UK
@georgekilleen629
Жыл бұрын
Early Pawnee ‘s had wooden wings which have broken. Most were updated to aluminum. We used them for banner towing as some companies still due. That could have happened here.
@FreshTillDeath56
Жыл бұрын
HOLY SHIT. How do you film that deadly plane crash where you literally witness the plane snapping in half, and just go back to a baby celebration? How are these people not mortified?
@RockandRollWoman
Жыл бұрын
No kidding. I would be distraught.
@NovaNinja_
Жыл бұрын
I was wondering the same thing
@j_taylor
Жыл бұрын
I imagine that the person with the camera didn't mentally process the scene immediately. It really is shocking to watch.
@FreshTillDeath56
Жыл бұрын
I had to wait like 10 minutes before I could watch Juan's analysis because I was so bewildered by the combination of events I just witnessed.
@militaryav8r
Жыл бұрын
@@j_taylor How could they not? I processed the bad unplanned thing as soon as I saw wings touching. Even people who have spent their entire lives riding the bus know that can't be what wings are supposed to do.
@steve-o5600
Жыл бұрын
This has happened before, a few years ago, at a wedding I think. A family member flying. Tragic. Can't remember where.
@kekke2000
Жыл бұрын
There are too many examples unfortunately. April 2021, 2 people died crashing into water after a gender reveal stunt in Cancun. November 2019, a pilot survived a crash after dropping pink water for a gender reveal in Texas.
@RockandRollWoman
Жыл бұрын
@kekke2000 Really unbelievable. And I must be really out of it - I had never heard of a gender reveal party. We used a cute mailed announcement. Or nothing. I'm sure mail changed to email. But a pink water dump? 🤷♀️
@christopherrobinson7541
Жыл бұрын
When flying the wing generates lift which causes the wings to bend upwards. The weight of the aircraft causes the wings to bend dowards. This is called G relief. The heavier the aircraft the greater the G relief. If the weight of the aircraft is suddenly reduced the amount of G relief is also reduced. This can be seen launching gliders by winch. As the glider climbs higher the force pulling the glider down increases as the angle of the cable gets steeper. During level flight the Vne of an ASK-21 is 151 kts the maximum winch speed is 81 kts. (All the other numbers in the VG graph will change pro rata). This effect is most noticeable when winch launching long winged gliders such as the ASH-25.
@dmoney2015
Жыл бұрын
Wow this was an awesome assessment and breakdown. I never knew the dangers that those fire planes are in when dumping a load. I couldn't image how difficult it would be to drive my car if I had to worry about speed, g-forces and weight to keep my tires on when going around a corner.
@StevenBruce-s1o
Жыл бұрын
I imagine you're doing that intuitively in your car but such lectures wouldn't hurt for drivers-ed classes.
@dmoney2015
Жыл бұрын
Not exactly. You couldn't tear the wheels off a car by turning sharply. You would either start to skid or roll. I am talking about operating something that is very fragile and you can destroy by fairly normal operation. @@StevenBruce-s1o
@m118lr
Жыл бұрын
I knew (or had a REALLY good idea) what it was the instant his wing separated. Could never explain it LIKE you Juan..the graph was everything in bringing the point ‘home’. Thanks Juan! Edited to ADD: The comment section has SO MANY worthwhile and meaningful, specific comments. Thanks to ALL who posted!
@fayelitzinger9824
Жыл бұрын
this and the helicopter crash earlier this week where the aircraft broke up mid air in like 2 seconds is visually so startling. they don't usually just fall apart like that. rip to everyone who passed in these two incidents
@Datamining101
Жыл бұрын
Is it possible that this emergency dump imposes a transient dramatic shift in the center of mass too, that contributes to that large nose-up rotation?
@omegawolf81
Жыл бұрын
My thoughts as well. He is essentially dumping over a half ton of weight from the nose of the aircraft in less then 2-3 seconds. Seems like that would cause a CG shift, that maybe he tried to counter too much?
@flyinbryanfpv
Жыл бұрын
I think the hopper is on the CG so shouldn't have a shift as it was dumped all at once
@jamesm568
Жыл бұрын
I'm leaning towards structural failure from either pass flights or an ongoing issue that was unnoticed. That plane should not have failed during a simple maneuver like that.
@omegawolf81
Жыл бұрын
@@flyinbryanfpv even if it was perfectly centered on the cg of the airframe that much weigh loss in that time frame would cause it to at least "balloon" up a bit. Which the pilot might have tried to counter with forward stick. Which would have been bad idea. I am not saying I know any of these things to be fact, just stating my own point of view from the video provided. It could have been coupled with a problem airframe as well. Just a bad way to go and for no good reason.
@flyinbryanfpv
Жыл бұрын
@omegawolf81 I agree with you. The part I was addressing was the possibility of cg shift being the cause. Its more likely the sudden loss of 1000+lbs of water and pilot input causing the catastrophic failure
@dsantos10
Жыл бұрын
I know nothing about planes and this was explained beautifully. I have no questions. thank you 👌🏼
@chedatomasz
Жыл бұрын
One thing doesn't track for me - yes, the g-load increases when dumping weight and keeping airspeed and angle constant, but g's don't break metal - Newtons do. And while we usually think in g's because the force comes from inertial loading, in this case the force exerted by the fuselage on the wings didn't increase - the only force trying to tear off the wings was still just the constant lift. (What could have changed was the distribution of forces inside the fuselage, and slightly in the wing itself). I am more inclined to believe that the CG moved aft abruptly and the aircraft pitched up, increasing lift force on wings and thus causing a break.
@kenclark9888
Жыл бұрын
You know with some of the wild videos originating out of Mexico it’s a wonder we don’t see more of these
@ziggelito
Жыл бұрын
So the airplane crashes and people continue celebrating?
@jordanhenshaw
11 ай бұрын
Yeah
@JPGtampa
Жыл бұрын
I love watching videos of someone telling me what I can read for myself
@joso5554
Жыл бұрын
Thanks a lot Glenn. An extremely clear lesson on structural limits. And the difference between an oooold crop dusting utility aircraft (turned into a light firefighter aircraft) and an aerobatic aircraft…
@chaspfrank
Жыл бұрын
OK Juan, this one has me confused! I’m not sure I understand how reducing the overall weight of the aircraft increases the strain on the air frame at a lower speed. Is it because you suddenly now have the ability to change direction more rapidly, therefore exceeding the stress levels of the air frame? It seems to defy logic, and I’m really not sure from a physics perspective how this happens. Would love a video on the physics of this.
@rtbrtb_dutchy4183
Жыл бұрын
In a sense, you are correct. I’ll try to explain and since I’m not sure how much you know about aviation lingo, I’ll try and keep it simple. When an airplane flies level, it flies slightly nose up. A heavier airplane has to fly more nose up than a lighter aircraft to create the same amount of lift. (Technically it’s the wing’s “nose up”, but for ease of explanation, I use the whole airplane) Wings will stop flying when the nose is up too high while in level flight. Small airplanes, this is around 18° degrees nose up. A heavy airplane will cruise at 6° nose up, while that same aircraft when light, will cruise at 2° nose up. If you were to yank back on the stick and create high G’s, the heavy airplane can only increase the angle from 6 to 18°, so 12° and the wings would stop flying. But the light aircraft, starts at 2°, so pulling the same G load, it’s only at 14° and the wing is still flying. So this light aircraft can still pull back harder and increase Gs before it hits 18°. These extra Gs might overstress the aircraft.
@thejackbox
Жыл бұрын
With higher weight, the aircraft stalls before it can exceed the maximum load factor (Gs) of the design of the aircraft.
Пікірлер: 2,2 М.