Holy shit. Full fuel and three big ass adults in a 172 is never a GO. Pull that CFIs license now. She could have killed all three of them and I think it was more dumb luck than skill that she didn’t. That thing was teetering on a stall spin the whole climb out and the landing was total shit, granted she probably came in hot on purpose after riding the stall horn so hard earlier. Great breakdown and loving the channel!!!
I'll freely admit I did this once many years ago. Difference is that as soon as the mains lifted, it felt so mushy, weird, and uncontrollable in ground effect that I pulled power and immediately landed. We did not go flying that day. The book said the numbers were barely passable, but it felt like it was going to kill me that day. I've flown with the W&B in similar places in the envelope fine before, too.
@@mikepatterson4528 An N model with a 180hp conversion has a far better useful load than an S model with 180hp. It has a much lower empty weight. 180hp converted pre-R models are my favorite Skyhawks to fly... they're homesick angels in the climb! We had an N-model with a 180hp conversion that had a useful load better than most Skylanes.
@mkosmo Yeah, I thought maybe I was missing something when I read this comment. I don't know much about the "newer" Cessnas, but mine was like you said, basically a Skylane.
I took an introductiry flight for my 14th burthday. To this day, i specifically remember doing a WB check in the 150 with the instructor, i even remember he had me calculate how much fuel we would need, 9 gallons for an hour flight and a half-hour of reserve @ 6 / hr. That flight completed my formal training, but things that were stressed as important, i still clearly remember 25 years later. It shocks me when i see these type of videos that such egregious errors are routinely made.
C172SP guy here… Landed in Monterey, California to pick up one kid with total 4POB for return flight home, 3 of us went down to get the 1. Two adults, two kids. Had 30gal of fuel at start of trip (56/53). 40m flight each way. After arriving in Monterey for the pick up, went to town briefly, TOOK NO FUEL, for this exact reason. Even with two kids (total 150lbs) in the back, no luggage, why take the extra weight at all? Wasn’t a hot day for me. 256’ FE She climbed, no horn. But in the climb/angle of attack I definitely felt the extra weight as I normally fly by myself or with only one other passenger.
That’s great. I’m only on RUclips lol. But he’s been putting out daily content which is really the best thing to do if you want to grow fast. But it’s a grind. I appreciate him taking the time.
Here's the thing. Aviation is incredibly unforgiving of such "minor" errors. But these days we have tools like Foreflight which allow you to quickly and easily get a complete briefing, do flight planning and even W&B. In a minute or two! There is no excuse not to do these things now.
Absolutely. The S model is an especially heavy variant of the plane to begin with. Full fuel and more than 2 people is almost never feasible in my experience
I've taken 4 adults in a 172. Had to fly 2 hours before that flight to burn gas. Did the W&B and takeoff / landing data once on my own, once with foreflight, and once with the FBO excel sheet. It was within 50 lbs of MTOW and all of us were thin adults, not your average Americans. Bad call by this CFI
I can only imagine the shock the pilot felt when adjusting to the new flight characteristics. my first flight with a loaded 172 felt like i was flying with 30 less HP
@@garou5682 it's not a big deal if you've trained that way, or if you're at gross, but not over. AOA will be higher for the same airspeed, but you'll adapt. If you're over max gross, on the other hand, things are very different. You can't use your POH V-speeds anymore, you'll stall at airspeeds you would never normally even be close to stall at.
I used to do tailoring and got good at eyeballing measurements and weights. The CFI is no less than 200 lbs by herself at her height, guy walking with her is about 270 (about 70 of it in his midsection), and the guy in the back looks to be about 290 by himself, plus the bags. I think the actual weight and balance was quite a bit further outside the envelope than even your estimate was.
Us pilots must never forget that all V-speeds are proportional to gross weight. For smaller aircraft POH typically gives the value at max gross due to that being the highest speed, and therefore the worst case scenario. That means that if you're over max gross and you're looking at your airspeed indicator and see a number that should give you stall protection, but the stall warning horn is blaring - you are about to die. On top of not doing W&B the reason that CFI must be immediately grounded is because she didn't lower the nose when she heard the stall horn. I bet she thought the airspeed was fine, so nothing to worry about. You can't stall at 70 knots wings level in a 172, can you - she though. They almost died.
I work as a FI and me and my students always leave our heavy bagage on the ground and take only essential equipment such as headphones and maps and documentation. Any extra pound (even within the envelope) can be dangerous during emergency landings etc...
I fly a C182. With full fuel and 3 grown adults, it does okay, but I’m doing careful math on the weight and balance. Switch me to a 172 and I’m thinking either no-go period, or, we’re going to be on the boundaries so proceed with care. What are these 3 thinking? This needs to be called out by other pilots, as you are. You could be saving lives by getting the message across.
OK so couple things I notice here. First, I thought rather than side-loaded it sounded like they bounced a couple times. There's a moment just a few seconds before they touch down where you can see the Airspeed indicator and he came in fast (almost 90 knots). Second, is it normal to get a vacuum system annunciator at low idle on these 172S models? I've never flown one but I notice the light come on when they were taxiing at low idle and it came on again when he started to flare and stayed on after they landed. (Personally I do think your weight estimates were pretty solid and do agree there's no way those three people + full tanks were within max gross on that plane)
@@AlyssaM_InfoSec that light is likely the “volts” light. In my 172S when I come to idle sometimes that light will come on. That may have been what happened here. But yes I agree with you, I think they could have bounced and pretty hard too.
Assuming weight & position but your star is well within the CG envelope if you extrapolate it to the actual weight. Yes over weight, 5%. Flown plenty of various aircraft commercially that had upgross kits installed, normally in the 5-10% range, one was almost 15%. Same wing, same HP and they all narrowed the CG envelope from the front. AFT CG limit stayed the same. The FWD limit moves back as gross weight increases. Reason is that you need more down force on the elevator the farther FWD your CG is. More down force is more AOA to hold up the same weight (actually more when you factor in the down force required). If anything being overweight and we draw the FWD CG line at the same angle they were closer to FWD CG than AFT.
@@jingle1161 Well, I’m a private pilot (Airplane Single Engine Land), and I’ve never heard of the idea in all of my training, that rear passengers should move forward in such an event during takeoff. It’s an interesting idea, but it comes with its own risks. A sudden change in the CG during takeoff could mess up what the pilot is doing.
@@xlhits Well it’s a 50/50 kind of thing. If a passenger unbuckles and moves forward, and the plane still crashes, they’d be much worse off than if they had stayed with their seatbelts and harnesses fastened. On the other hand, if it helps break the stall, then it worked.
I’m a 172 pilot, and while it is technically a four seater, even with two larger adults, it can easily come close to the weight limit. Not doing a weight and balance, especially when flying with multiple people is very dangerous. While people may sometimes get away with flying an overweight airplane, even though it’s risky, and not allowed, an aft CG is especially dangerous, because the plane would be difficult to control.
I once did a flight with 3 adult passengers and full fuel in 172M. I'm average size, but all three passengers were so tiny one of them couldn't tighten the seatbelt around her waist, the other one had to use a cushion to see over the nose... Those are the kinds of people you need to fill all 4 seats in a 172... safely. You definitely don't load up three overweight adults and take full fuel. By the way, I had no idea 172S had such huge tanks. A moron will always find a way to use the aircraft's features to kill themselves.
@ Yes, it is very rare that one can actually fly a 172 with four people. I fly the 172N for the most part, many of which have a maximum takeoff weight of 2300 lbs. Flying with even three people is often out of the question. To not bother doing a weight and balance is extremely reckless, and totally unacceptable.
I think this might be too far into speculation. Without RPM, I don't think you can assess the situation accurately. I think you're probably over estimating the weight in the back by about 50lbs which would have put them if not on, then damn near the max weight limit. From my read, they're well inside the rear CG limits. The only thing that caught my eye as curious is that if you hear a stall horn, why are you cranking for 500 FPM? I've had heavy hot days before and I'll do sub 200 FPM until airspeed improves (or not...) but I wouldn't be pushing for 500 with 3 people and a stall horn going off. Either way, always appreciate your perspective and insights.
Yeah there is no real way to tell their way so I just had to use my best judgment. Either way, even if I’m a few pounds off they are still outside of the CG envelope as annotated by the star. But yes I don’t know why they were climbing steeply. At least it seemed like they were. I appreciate your input. This is a good discussion to have.
@@kanjo167👆🏼 This right here. You don’t HAVE to climb unless you’re trying to clear an obstacle. And even then, only have to clear the obstacle enough not to hit it.
@@VictoryAviation I’m pretty sure she was just flying her normal airspeeds and ignoring the stall horn. Obvious lack of knowledge of how anything works.
Non pilot question. When I take my car on the track I can feel the difference between me alone in the car and driving with a passenger/instructor. Can't you just feel that a plane feels sluggish and slow when it is heavy? Not even overweight but just full of people and fuel?
Still a student pilot but you can definitely feel this. Took off once with 2 other people: my instructor, and a prospective instructor in the back. The plane climbed out way slower. Also, outside air temperature has a definite impact: warm weather means the engine will perform less. Which is true for cars as well, but probably not as noticeable unless you're drag racing :)
Yes, most definitively. My first solo I was surprised how I had to keep my nose quite higher than normal to keep the target climb airspeed and the vertical speed felt like a rocket (a lame rocket, but as lame as with the instructor on board).
A plane on the ground is like a car. It will roll and turn overweight and out of CG. If you don’t do the calcs, what you don’t know until you take off is where the CG is. Forward or Aft. And as he states, aft CG is so dangerous and if you are too far out you may not have enough elevator authority to pitch the nose down and the plane will pitch up until it stalls. Crazy to take this chance in a 172.
@@mikecournoyer ... To be fair, fwd CG limit is typically based on elevator-up authority, but aft limit is based on static longitudinal stability margins and sometimes spin recovery. The plane would become unstable way before you are out of nose-down elevator. I know of several incidents and accidents where the pilots were not able to lower the nose, but all of them were related with problems in the controls themselves (elevator or trim) and none of them was due a CG that was too aft. Even a couple where the CG was beyond the aft limit, the plane would have been controllable if not for the the elevator or trim issue. Of course that having the CG beyond the aft limit didn't help, but it was not the cause.
@ ok but I also have known and read about a lot of accidents where a load slips to the back causing so much aft cg that the plane stalled. Happened to a guy here where I live. Had a load of flooring in a Cherokee 6 and the load broke free and slid all the way back. Caused nose up until the stall. He didn’t make it. Spun it off the end of the runway.
That person should not be a CFI, that was reckless and is also teaching other students to be reckless. They are extremely lucky that 172 was a 180 horsepower model, if they did that in a 160 HP I am sure that would be their last flight.
Boy if the local FSDO sees this that Cert could/should see a suspension. Even a 709 ride. I agree with your analysis. That was very dangerous. Anybody get a glance of the RPMs in climb? Is the 172S run the IO-360? Or the O-360?
Gonna guess it it is a fixed pitch prop so may not apply. I own a constant speed with IO-360 and max rpm is 2700. 2680 on the roll. Idk about fixed pitch though. Probably lower.
I have 200+ hours of 172 model S time and 800+ hours of total 172 time. They were no doubt overweight. I pulled out an airport diagram and it looks like you are correct about this being at Long Beach. At 3:04 you can see 08L. The crossing runway would be 12. Everything else I can see in that frame lines up with the diagram. That being said, they would have been departing runway 26R and drifted off the centerline to the right. Runway 26R is a 6192 ft runway. Why would they have been up against the stall horn on a runway of that length? They could have just leveled off in ground effect and accelerated to a suitable climb speed. If I were to guess, I would say it was a practice short field takeoff. The flaps appear to be in the 10 degree position and that would be the appropriate setting for a short field takeoff. In the 172S I fly, the stall horn starts to chirp very early and increases in pitch and volume as you get closer to the stall. It will start the low pitch low volume chirp right around Vx, just as we heard in the video. Was it ever mentioned in the video they were returning to the field due to an issue? If not, I would suspect they are just flying the pattern with a crappy student landing. I also don't think this is a discovery flight. The student has a backpack on and a headset in his hand, he was also doing the flying on departure and I suspect on landing, although I couldn't tell for sure. Most people show up for a discovery flight with nothing, and wouldn't be doing the takeoff. Probably just a flight lesson and the student wanted to take his buddy. I think the overloading is a terrible example for the student and shows an anti authority attitude, but I honestly don't think they were ever in danger of stalling the airplane. Just my opinion, so take it as such.
There was another accident recently which occurred for the very reason you spoke of also on an intro right. I can't recall if it was on your channel or not, but it might be good to link to it.
I agree for sure that they were out of the envelope, 100% overweight especially with full fuel and thoes bags. However, their arm was not aft of limits. They still had a good 2 inch margin before they would be aft of limits. Although I do recognize that it would be further aft than a normal training flight. They should have just postponed the flight till another day, and let someone else burn off some of that fuel. I think its also important to highlight all of the characteristics of an aft CG. Decreased longitudinal stability as you said. But also a lower stall speed because of the reduced tail downforce required. My question is, how prominent are these characteristics with their CG still being 2 inches within limits? (If they had less fuel of course). Because I would have thought that the CG being at 45 inches would be beneficial.
Hey! Watch that Boomer talk, kid. There might be some of us watching. And what's wrong with The Facialbook, Tik Tok boy? But yeah, I do weight and balance when it's just me with no luggage. It's a good habit so I don't forget when I need it. Cuz, you know, my memory ain't so good anymore, being a Boomer and all.
This was likely a short field demo. 10° flaps, riding stall speed in the climb out. Stupid decisions nonetheless. But that’s the only credit I can give the situation.
I understand how aft CG reduces pitch stability but I’m going to have to mentally work through the rest of what’s going on here. Simply being over loaded means the engine power is going to lift not airspeed at a high AOA. This is a good reminder that while the 172 can put up with a lot, it still does have very real limits.
it's very simple - if you use POH V-speeds - you may stall. You need to use higher V-speeds, and you don't know which ones. AOA is much higher for the same airspeed.
It’s been a hot minute since I’ve done W&B for a Cessna, but the position of the TOW datum as you’ve drawn it looks comfortably within CG limits? Overweight, which is a no-no of course, but only slightly aft of mid-range as I look at it. I’ve flown all the main Cessna models: 152, 172, 182, 206 and 210. The latter three in particular I have flown in commercial operations on or near the aft CG limit, and although you definitely have to be a little more careful, it’s still perfectly flyable. Assuming I haven’t misunderstood the way you’ve drawn your W&B plot, I think a possible explanation for the stall horn is that they were overweight. With a lower power excess to climb at Vy, perhaps the student was over-pitching to achieve the kind of performance they were used to seeing and thereby increasing the AoA closer to the critical angle.
@@CFIIMunden thanks for clarifying. At 11:15, the graph shows a forward CG limit of 35 and an aft CG limit of 47.3 or so along the X axis, while the star is positioned at a CG of ~44 as you mentioned. The position of the star looks to me like it’s within fore/aft limits (but biased aft-of-midrange) for the normal category envelope, overweight by about 200lbs as you calculated? That would make sense as the circle appears within limits, and adding fuel in a Cessna single shifts the CG forward. In any case, as you said you were being conservative with the calculations, so perhaps the CG was even further aft than you calculated. I would have put the camera guy at around 280-300, and who knows how much weight was actually in the baggage area. It’s academic as the aircraft was likely overweight and should never have taken off on that basis alone. A lot of sub-optimal things were doing on in that video. I don’t know how you keep finding all these great examples but please keep it coming, really enjoy your breakdowns and the service you’re offering to the GA community.
@@CFIIMunden yeah gotta agree with JM87Fly here, i dont know why you kept saying aft CoG when both the star and circle are within the limits of an aft CoG and the star is more forward than the circle, Sure the star indicates overweight which is not good but really only affects performance not stability
eh that's only 4% overweight, and well within the aft CG limit. when the camera pans out the side, we can see they've gained 200ft by the intersection of the crossing runway... with 10° flaps extended... I personally don't think the performance impact necessitates riding the stall horn like that...
Could you make a walk through video about this exact weight & balance calculation? This is a fantastic example where it’s critically important and we do have accurate numbers to work with. Just a suggestion ;)
@@CFIIMunden I'm sure you did it correcly. It was about how to calculate it for a 172S. This is a great example, as life literally depnds on it. It seems simple to you, but honestly I don't know how to do it....
Maybe is just me, but that engine doesn’t sound to me to be at full power or hear the acceleration to takeoff power, maybe editing had something to do with it. Again it could be just me.
Engine sounded fine to me, you see instructor reach to controls, I think see was trying to lean engine for more power but they had all that was available.
You would be surprised, many tall women who are somewhat curvy can be 300lbs and you would never guess. Because they’re not fat, they’re just very tall and large. My girlfriend is shorter than this guy and she’s 200lbs and definitely is fat, but I’ve met women who are much taller, and weigh more, but don’t visibly appear as chubby.
@@CFIIMunden the VSI showed 500fpm which seemed to somewhat correspond to their altitude gain when the camera pointed out the window. I don't see any reason to be honking the horn.
The performance charts don't have margin built in them. Rather the opposite. They are based on test data obtained on impeccable new plane with top-notch maintenance by the manufacturer themselves and flown by an expert test pilot. If anything, real-life performance will be worse than the charts, which is why there is a rule of thumb to add 20% to 50% margins. The stall warning does have a margin of 5 to 10 kts over the actual stall at max weight, CG at the aft limit and 1G. And for the wind on take-off and landing performance they have to take 50% of the headwind and 200% of the tailwind components. But other than those, there are no margins.
@toml.6884 Not in the Cessna POH performance chart for take off distance. There is only a column for pressure altitude and it doesn't tell you to calculate density altitude.
@ when you look at the top of the performance chart it shows columns with different temperatures to choose from, that and picking a pressure altitude equates to a density altitude corrected performance result.
At least from your estimates the CG was well within limits, so unless some unaccounted for uranium ore made its way to the baggage compartment, CG was likely an insignificant factor. Aircraft certified by the FAA must have positive static longitudinal stability at all allowed CG locations, and they do account for the forward movement of the CL as the AOA increases, so flying at CLmax (maximum coefficient of lift, or right on the edge before stalling) won't make the plane unstable or even neutrally stable. Also according to your estimates, the overloading was only 4% over MTOW. From what I could hear, the engine was fine and it sounded like it was turning at a reasonable RPM. I would argue that the greatest danger was the student pilot trying to get a higher climb rate by pitching up excessively and the CFI doing nothing about it (although we can't hear the cockpit audio to tell for sure). It should go without saying that the CFI should have checked the W&B before flying an aircraft at a different loading.
I think you followed the evidence where it led. How much do you really feel the pitch stability/twitchiness with the change of CoG position in a 172? I've only had 5 hours on a 172 and it feels like it's on rails (2 POB and full fuel)
Don't understand why you say that the CG was aft. According to your estimation, they were a bit overweight with the CG some 3+ inches ahead of the aft limit. By the way, an aft CG, while it makes your plane less stable, it reduces your stall speed (i.e. increases your stall margin) and improves your climb performance a little bit, because you have less force pulling down on the tail that the wing would have to compensate.
The CG is more aft than it is forward which is made worse by being overweight. And yes you're correct that an aft CG reduces your stall speed. That's why I wanted to show that bold method simulator because it's so good.
@@CFIIMunden .... So now my confusion shifted. I totally see how being overweight is a bad thing that made this situation worse. But now I don't understand why you consider the CG to be a factor in this incident. Being more aft that forward is being in range, and even if it was at the aft limit (which it wasn't) the plane still has plenty of positive longitudinal stability. CG at the aft limit is perfectly safe and acceptable. Being overweight is not.
@@adb012 If you look at the POH for the 172S 35 is the forward limit while 47.3 is the aft. We assume the CG is 44 which would put it more aft, not forward. As I said, we can only assume because we don't know their actual weights. The problem becomes when the CG is both fft and overweight. Really bad combination. We are both right in saying this is not a good situation to be in.
@@CFIIMunden ... Believe me I am not trying to disagree with you, just trying to understand what, if any, is the issue with the CG. If 47.3 is the aft limit, then a CG of 44 is forward of the aft limit, hence in tolerance. The aft limit is defined in general based on static margin which is independent of the mass, that's why it is a vertical line (same aft limit for any weight) while the fwd limit is in general based on elevator authority (which is why it slopes back as weight increases). A plane with a CG of 44, when the aft limit is 47.3, should be perfectly ok from a stability point of view no matter the weight. I don't see how a CG of 44 could have made this situation worse compared with, say it being at 40. Being overweight, on and by itself, is probably the reason why they were at around the onset of the stall warning while climbing at some 60 knots with 10 degrees of flaps (remember that the stall warning will sound, at 1G, about 5 to 10 knots above the actual stall). I also observe how each stall warning occasion seems to be correlated with an updraft (by the way the camera moves each time). In any case, if there is ONE thing that they did mostly good is not to let the stall warning sounding continuously. Most of the stall warnings were brief and I think that only once the second (high pitched) stall waring sounded, which scared the soul out of me. They had a relatively healthy climb rate, I don't understand why they didn't temporarily reduce the climb speed 100 or 200 fpm (it would have still been well in the positive side) to gain some speed. What kind of instructor would allow that? I also observe that they were overspeeding the flaps during final. Again, which kind of instructor would allow that? Overweight, stall and overspeed all in the same flight. But I don't find the CG concerning or problematic in any shape or form.
@@CFIIMundenI see what you are saying: CG limits are no longer accurate when gross weight is exceeded. For example, an airplane at the forward CG limit but over gross may be too nose heavy for the tail to provide sufficient nose-up pitch at low speeds. There may also be a dangerous effect at the rear CG limit when over gross. However, in this case they were nowhere near the front or rear CG limits and we're not even sure they were over gross. They did not seem to have any noticeable pitch control problems. So the CG being a bit aft but still well within limits is not the issue.
They were too slow when still in ground effect and heavy with aft cg, as you found. They were climbing in ground effect and then the stall horn comes on and stays on when they climb out of ground effect. Good lesson on figuring weight and balance. What I try to get across to young instructors is how default level in low ground effect takeoff, total energy management, will prevent us less organized pilots and instructors from stabbing straight through the last couple of holes in the Swiss cheese. Had they done a soft field, very similar to level in low ground effect but unfortunately not continued to Vcc, they at least would have had some zoom reserve airspeed. I am continuing to work with local instructors to come up with ways to workaround the possible DPE expectation of pitch to Vy rather than Vcc when still in ground effect. And just normal takeoff at Vy and especially short field at Vx scares any old crop duster (no zoom reserve airspeed over the wires.). The best we have come up with is to add the +5 knots allowed on takeoff and subtract the -5 knots allowed on landing. Why don't Wolfgang's experienced pilots get to actually know about the law of the roller coaster and how to actually fly get a break on the flight test? The outcome of the maneuver is never in doubt. Other than being a bit slow and overloaded, this one in the video would pass the test just based on the numbers mathematicians, not experienced pilots, came up with. Yes, Vy will get you up fastest...if you don't stall coming out of ground effect.
@igclapp Read "Holding It Down:" on page 85 of Stick and Rudder by Wolfgang Langewiesche. "If the take-off is from a small field surrounded by tall obstructions, the working of the roller-coaster effect can be quite dramatic--if an experienced pilot is at the controls. The inexperienced pilot has a strong tendency to point the nose up steeply and simply hope that the airplane will climb out. But it is easy to overdo this and, by trying to get too much altitude too quickly, to kill one's speed and stall, perhaps 50 feet off the ground. The experienced pilot will therefore point his nose up only as high as absolutely necessary to clear obstructions. In fact, if the take-off is from a very tight field, he will often point the ship's nose actually at the obstructions --maybe a half height of the trees. This does not help the airplane gain height, but it does help it gain speed. And the experienced pilot does not worry because he knows (without even thinking about it) that speed and height are two forms of the same thing, and for various reasons he prefers to have that thing in the form of speed. And he knows that he can always at the last moment convert speed into height by pulling the nose up, the airplane will then 'zoom' and clear the obstructions."
@@igclapp Are you Wolfgang's experienced pilot? I have operated this way since 1963, but I learned before PTS, which predated ACS. I have found, over 61 years, that the energy management principles to be superior to PTS or ACS.
@@igclapp In the interest of safety, we need to examine which techniques are more energy efficient and therefore safer. The manuals indeed have extensive fudge factor to cover the less effective techniques. That would make them safer, one might think, than the better total energy management. But since the book numbers err in reference to the extensive data derived from the experience of Wolfgang's experienced pilot (crop dusters, bush pilots, even heavily loaded helicopter pilots), they don't use the book. The state of Alaska codified it in FARs that allow them 15% greater legal gross weight. Like every other crop duster I knew, I loaded based on the maximum I was able to put in the hopper last time with the same conditions. This, using total energy management techniques, worked well.
@@jimmydulin928 RUclips won't let me post links, but search for "Backcountrypilot ground effect or Vx with tall trees". I think we've discussed this before and were looking for a real-world comparison of the two techniques. In this article, the pilot noted that the Vx technique put him higher over the trees on takeoff. With all due respect, I see some problems with the zoom technique: 1. you don't have any book figures to calculate distance over a 50' obstacle; 2. by flying at greater than Vy you are incurring higher parasitic drag (which increases with the square of airspeed); and 3. a zoom climb will induce some g-loading and increase stall speed.
Not nearly fatal. Definitely embarrassing. This problem began in the terminal with poor pre-flight planning, hazardous attitudes, and probably an experience-limiting school SOP including ritualization of "fifty-five, rotate" mantra. The 6 ounces of smartphone in the backseat pushed it into the RUclips folklore envelope. I'm amazed how many PPL students pass a checkride without safely learning how their school's planes fly outside the school SOP envelope. If you haven't loaded the plane up at all edges of the envelope (with an instructor) to learn how the plane performs you're missing out.
Well I’m not going to disagree with you here. It’s also common for flight schools to top off fuel. I’ve seen it pouring out of the vents taxiing and on take off. I think the fundamental take away here is simple. Do your weight and balance or know your plane well enough to look at a situation and say this is too close let me do a weight and balance we might be out of limit. I’m a low time student and I could tell you just by looking at those 3, with that guy in the back and full fuel in a 172 is probably not ok.
Bro love ur vids BUT they’re way too long. This video doesn’t need to be 15 mins. Been a sub since you had less than 100 subs. You talk way too much about stuff unrelated to the video. I and most people won’t click a 15 mins video unless it’s pilot debrief, and no hate ur quality is not pilot debrief. But that’s okay we like ur setup. But these vids really shouldn’t be more than 4-5 mins long. Just analyze the video. Love the channel but I think these long videos are hurting you
Thanks the comment and thanks for being here! I’m unedited, unscripted and off the cuff. I don’t even look at how long my videos are before I up upload them. I just speak until I feel as though I don’t have to anymore. Maybe one day I will make them shorter but as for now I see little need.
@ sounds good bro ur killing it. I learn more from you than any other RUclipsr, so keep it up please. It just bums me out when I see you release another 15+ min video cuz I know I can’t watch it all. You’ll find your groove tho. Btw this is definitely Long Beach, I fly out of there, you can see signal hill in the distance so mad props for figuring that out. Also you should make CFIIMunden shirts I would totally buy one. Merry Christmas
Thanks so much man and I definitely took your comment into consideration for future videos. I actually want to fly out of that airport when I go back to California because I used to work near Long Beach.
Consider that it actually takes a lot of time to edit a video and make it shorter. I think it was Ben Franklin who said "I didn't have time to send you a short letter, so I sent you a long one".
@ yeah I like his videos but I’m just worried most people won’t want to click on a 15 min video especially when they know most of it is talking. That’s why I’m saying a video like this could be 4-5 mins and still get across the points. He don’t even need to edit one take style is better imo anyway
It looks real hot. But anyway, sea level climb with the horn blaring?.... jeez. oh and its time to start talking about peoples weight.. the airlines are having a hard time too.
There is nothing like taking off with the stall warning horn on and then deciding to add some turns into the mix.
my 1st thought! I literally shouted wtf is he maneuvering for?! as I waited for a wing to drop lol
Holy shit. Full fuel and three big ass adults in a 172 is never a GO. Pull that CFIs license now. She could have killed all three of them and I think it was more dumb luck than skill that she didn’t. That thing was teetering on a stall spin the whole climb out and the landing was total shit, granted she probably came in hot on purpose after riding the stall horn so hard earlier. Great breakdown and loving the channel!!!
I'll freely admit I did this once many years ago. Difference is that as soon as the mains lifted, it felt so mushy, weird, and uncontrollable in ground effect that I pulled power and immediately landed. We did not go flying that day. The book said the numbers were barely passable, but it felt like it was going to kill me that day. I've flown with the W&B in similar places in the envelope fine before, too.
Huh? It is on a 180hp 172. I owned a 172N with a Pen Yan 180 and I could take 4 adults and full fuel and be well within useful load.
@@mikepatterson4528 An N model with a 180hp conversion has a far better useful load than an S model with 180hp. It has a much lower empty weight. 180hp converted pre-R models are my favorite Skyhawks to fly... they're homesick angels in the climb!
We had an N-model with a 180hp conversion that had a useful load better than most Skylanes.
@mkosmo Yeah, I thought maybe I was missing something when I read this comment. I don't know much about the "newer" Cessnas, but mine was like you said, basically a Skylane.
I took an introductiry flight for my 14th burthday. To this day, i specifically remember doing a WB check in the 150 with the instructor, i even remember he had me calculate how much fuel we would need, 9 gallons for an hour flight and a half-hour of reserve @ 6 / hr. That flight completed my formal training, but things that were stressed as important, i still clearly remember 25 years later. It shocks me when i see these type of videos that such egregious errors are routinely made.
If I was in the back seat...I would be terrified
C172SP guy here…
Landed in Monterey, California to pick up one kid with total 4POB for return flight home, 3 of us went down to get the 1. Two adults, two kids.
Had 30gal of fuel at start of trip (56/53). 40m flight each way.
After arriving in Monterey for the pick up, went to town briefly, TOOK NO FUEL, for this exact reason.
Even with two kids (total 150lbs) in the back, no luggage, why take the extra weight at all?
Wasn’t a hot day for me.
256’ FE
She climbed, no horn. But in the climb/angle of attack I definitely felt the extra weight as I normally fly by myself or with only one other passenger.
Starting to see your videos everywhere now!
That’s great. I’m only on RUclips lol. But he’s been putting out daily content which is really the best thing to do if you want to grow fast. But it’s a grind. I appreciate him taking the time.
Everyone, lean forward
LMAO......😊
Here's the thing. Aviation is incredibly unforgiving of such "minor" errors. But these days we have tools like Foreflight which allow you to quickly and easily get a complete briefing, do flight planning and even W&B. In a minute or two! There is no excuse not to do these things now.
Absolutely. The S model is an especially heavy variant of the plane to begin with. Full fuel and more than 2 people is almost never feasible in my experience
I've taken 4 adults in a 172. Had to fly 2 hours before that flight to burn gas. Did the W&B and takeoff / landing data once on my own, once with foreflight, and once with the FBO excel sheet. It was within 50 lbs of MTOW and all of us were thin adults, not your average Americans.
Bad call by this CFI
I can only imagine the shock the pilot felt when adjusting to the new flight characteristics. my first flight with a loaded 172 felt like i was flying with 30 less HP
@@garou5682 it's not a big deal if you've trained that way, or if you're at gross, but not over. AOA will be higher for the same airspeed, but you'll adapt. If you're over max gross, on the other hand, things are very different. You can't use your POH V-speeds anymore, you'll stall at airspeeds you would never normally even be close to stall at.
Weight and Balance is so important, and you should always be conservative in your calculations!
I used to do tailoring and got good at eyeballing measurements and weights. The CFI is no less than 200 lbs by herself at her height, guy walking with her is about 270 (about 70 of it in his midsection), and the guy in the back looks to be about 290 by himself, plus the bags. I think the actual weight and balance was quite a bit further outside the envelope than even your estimate was.
Us pilots must never forget that all V-speeds are proportional to gross weight. For smaller aircraft POH typically gives the value at max gross due to that being the highest speed, and therefore the worst case scenario. That means that if you're over max gross and you're looking at your airspeed indicator and see a number that should give you stall protection, but the stall warning horn is blaring - you are about to die. On top of not doing W&B the reason that CFI must be immediately grounded is because she didn't lower the nose when she heard the stall horn. I bet she thought the airspeed was fine, so nothing to worry about. You can't stall at 70 knots wings level in a 172, can you - she though. They almost died.
V speeds are not proportional to weight. If anything, they are proportional to the square root of weight.
@@igclapp well yeah it's the load factor, but it won't matter for you in flight...
I work as a FI and me and my students always leave our heavy bagage on the ground and take only essential equipment such as headphones and maps and documentation. Any extra pound (even within the envelope) can be dangerous during emergency landings etc...
I fly a C182. With full fuel and 3 grown adults, it does okay, but I’m doing careful math on the weight and balance. Switch me to a 172 and I’m thinking either no-go period, or, we’re going to be on the boundaries so proceed with care. What are these 3 thinking? This needs to be called out by other pilots, as you are. You could be saving lives by getting the message across.
Talk about "playing a tune" with the stall horn.
OK so couple things I notice here. First, I thought rather than side-loaded it sounded like they bounced a couple times. There's a moment just a few seconds before they touch down where you can see the Airspeed indicator and he came in fast (almost 90 knots). Second, is it normal to get a vacuum system annunciator at low idle on these 172S models? I've never flown one but I notice the light come on when they were taxiing at low idle and it came on again when he started to flare and stayed on after they landed. (Personally I do think your weight estimates were pretty solid and do agree there's no way those three people + full tanks were within max gross on that plane)
@@AlyssaM_InfoSec that light is likely the “volts” light. In my 172S when I come to idle sometimes that light will come on. That may have been what happened here. But yes I agree with you, I think they could have bounced and pretty hard too.
Assuming weight & position but your star is well within the CG envelope if you extrapolate it to the actual weight. Yes over weight, 5%. Flown plenty of various aircraft commercially that had upgross kits installed, normally in the 5-10% range, one was almost 15%. Same wing, same HP and they all narrowed the CG envelope from the front. AFT CG limit stayed the same. The FWD limit moves back as gross weight increases. Reason is that you need more down force on the elevator the farther FWD your CG is. More down force is more AOA to hold up the same weight (actually more when you factor in the down force required). If anything being overweight and we draw the FWD CG line at the same angle they were closer to FWD CG than AFT.
If you ever experience this as rear passenger, unbuckle immediately and crawl to front seats as much as possible :-)
If you unbuckle, and the plane crashes, that would be extremely dangerous.
@@videogameplayer0552 If you stay buckled and stall spin, your life is over.
@@jingle1161 Well, I’m a private pilot (Airplane Single Engine Land), and I’ve never heard of the idea in all of my training, that rear passengers should move forward in such an event during takeoff. It’s an interesting idea, but it comes with its own risks. A sudden change in the CG during takeoff could mess up what the pilot is doing.
@@videogameplayer0552. I’ve heard it before. Shifting the weight in an emergency should and has been done
@@xlhits Well it’s a 50/50 kind of thing. If a passenger unbuckles and moves forward, and the plane still crashes, they’d be much worse off than if they had stayed with their seatbelts and harnesses fastened. On the other hand, if it helps break the stall, then it worked.
They also oversped the flaps in approach / landing.
I’m a 172 pilot, and while it is technically a four seater, even with two larger adults, it can easily come close to the weight limit. Not doing a weight and balance, especially when flying with multiple people is very dangerous. While people may sometimes get away with flying an overweight airplane, even though it’s risky, and not allowed, an aft CG is especially dangerous, because the plane would be difficult to control.
I once did a flight with 3 adult passengers and full fuel in 172M. I'm average size, but all three passengers were so tiny one of them couldn't tighten the seatbelt around her waist, the other one had to use a cushion to see over the nose... Those are the kinds of people you need to fill all 4 seats in a 172... safely. You definitely don't load up three overweight adults and take full fuel. By the way, I had no idea 172S had such huge tanks. A moron will always find a way to use the aircraft's features to kill themselves.
@ Yes, it is very rare that one can actually fly a 172 with four people. I fly the 172N for the most part, many of which have a maximum takeoff weight of 2300 lbs. Flying with even three people is often out of the question. To not bother doing a weight and balance is extremely reckless, and totally unacceptable.
I think this might be too far into speculation. Without RPM, I don't think you can assess the situation accurately. I think you're probably over estimating the weight in the back by about 50lbs which would have put them if not on, then damn near the max weight limit. From my read, they're well inside the rear CG limits. The only thing that caught my eye as curious is that if you hear a stall horn, why are you cranking for 500 FPM? I've had heavy hot days before and I'll do sub 200 FPM until airspeed improves (or not...) but I wouldn't be pushing for 500 with 3 people and a stall horn going off. Either way, always appreciate your perspective and insights.
Yeah there is no real way to tell their way so I just had to use my best judgment. Either way, even if I’m a few pounds off they are still outside of the CG envelope as annotated by the star. But yes I don’t know why they were climbing steeply. At least it seemed like they were. I appreciate your input. This is a good discussion to have.
facts. put that nose down
@@kanjo167👆🏼 This right here. You don’t HAVE to climb unless you’re trying to clear an obstacle. And even then, only have to clear the obstacle enough not to hit it.
@@VictoryAviation I’m pretty sure she was just flying her normal airspeeds and ignoring the stall horn. Obvious lack of knowledge of how anything works.
@@alk672 I think that's exactly right. "Don't know what happened, I did everything like I always do."
Non pilot question. When I take my car on the track I can feel the difference between me alone in the car and driving with a passenger/instructor. Can't you just feel that a plane feels sluggish and slow when it is heavy? Not even overweight but just full of people and fuel?
Still a student pilot but you can definitely feel this. Took off once with 2 other people: my instructor, and a prospective instructor in the back. The plane climbed out way slower.
Also, outside air temperature has a definite impact: warm weather means the engine will perform less. Which is true for cars as well, but probably not as noticeable unless you're drag racing :)
Yes, most definitively. My first solo I was surprised how I had to keep my nose quite higher than normal to keep the target climb airspeed and the vertical speed felt like a rocket (a lame rocket, but as lame as with the instructor on board).
A plane on the ground is like a car. It will roll and turn overweight and out of CG. If you don’t do the calcs, what you don’t know until you take off is where the CG is. Forward or Aft. And as he states, aft CG is so dangerous and if you are too far out you may not have enough elevator authority to pitch the nose down and the plane will pitch up until it stalls. Crazy to take this chance in a 172.
@@mikecournoyer ... To be fair, fwd CG limit is typically based on elevator-up authority, but aft limit is based on static longitudinal stability margins and sometimes spin recovery. The plane would become unstable way before you are out of nose-down elevator. I know of several incidents and accidents where the pilots were not able to lower the nose, but all of them were related with problems in the controls themselves (elevator or trim) and none of them was due a CG that was too aft. Even a couple where the CG was beyond the aft limit, the plane would have been controllable if not for the the elevator or trim issue. Of course that having the CG beyond the aft limit didn't help, but it was not the cause.
@ ok but I also have known and read about a lot of accidents where a load slips to the back causing so much aft cg that the plane stalled. Happened to a guy here where I live. Had a load of flooring in a Cherokee 6 and the load broke free and slid all the way back. Caused nose up until the stall. He didn’t make it. Spun it off the end of the runway.
That person should not be a CFI, that was reckless and is also teaching other students to be reckless.
They are extremely lucky that 172 was a 180 horsepower model, if they did that in a 160 HP I am sure that would be their last flight.
Boy if the local FSDO sees this that Cert could/should see a suspension. Even a 709 ride. I agree with your analysis. That was very dangerous.
Anybody get a glance of the RPMs in climb? Is the 172S run the IO-360? Or the O-360?
It's an IO-360. I found it's data on FlightAware.
Gonna guess it it is a fixed pitch prop so may not apply. I own a constant speed with IO-360 and max rpm is 2700. 2680 on the roll. Idk about fixed pitch though. Probably lower.
I have 200+ hours of 172 model S time and 800+ hours of total 172 time. They were no doubt overweight. I pulled out an airport diagram and it looks like you are correct about this being at Long Beach. At 3:04 you can see 08L. The crossing runway would be 12. Everything else I can see in that frame lines up with the diagram. That being said, they would have been departing runway 26R and drifted off the centerline to the right. Runway 26R is a 6192 ft runway. Why would they have been up against the stall horn on a runway of that length? They could have just leveled off in ground effect and accelerated to a suitable climb speed. If I were to guess, I would say it was a practice short field takeoff. The flaps appear to be in the 10 degree position and that would be the appropriate setting for a short field takeoff. In the 172S I fly, the stall horn starts to chirp very early and increases in pitch and volume as you get closer to the stall. It will start the low pitch low volume chirp right around Vx, just as we heard in the video. Was it ever mentioned in the video they were returning to the field due to an issue? If not, I would suspect they are just flying the pattern with a crappy student landing. I also don't think this is a discovery flight. The student has a backpack on and a headset in his hand, he was also doing the flying on departure and I suspect on landing, although I couldn't tell for sure. Most people show up for a discovery flight with nothing, and wouldn't be doing the takeoff. Probably just a flight lesson and the student wanted to take his buddy. I think the overloading is a terrible example for the student and shows an anti authority attitude, but I honestly don't think they were ever in danger of stalling the airplane. Just my opinion, so take it as such.
There was another accident recently which occurred for the very reason you spoke of also on an intro right. I can't recall if it was on your channel or not, but it might be good to link to it.
This Video is Great! Again I can’t thank you enough for disseminating this information to Fellow Aviators.
I agree for sure that they were out of the envelope, 100% overweight especially with full fuel and thoes bags.
However, their arm was not aft of limits. They still had a good 2 inch margin before they would be aft of limits. Although I do recognize that it would be further aft than a normal training flight.
They should have just postponed the flight till another day, and let someone else burn off some of that fuel.
I think its also important to highlight all of the characteristics of an aft CG. Decreased longitudinal stability as you said. But also a lower stall speed because of the reduced tail downforce required. My question is, how prominent are these characteristics with their CG still being 2 inches within limits? (If they had less fuel of course). Because I would have thought that the CG being at 45 inches would be beneficial.
Hey! Watch that Boomer talk, kid. There might be some of us watching. And what's wrong with The Facialbook, Tik Tok boy? But yeah, I do weight and balance when it's just me with no luggage. It's a good habit so I don't forget when I need it. Cuz, you know, my memory ain't so good anymore, being a Boomer and all.
This was likely a short field demo. 10° flaps, riding stall speed in the climb out. Stupid decisions nonetheless. But that’s the only credit I can give the situation.
Just by my ear the RPMs don’t *sound* like full throttle but that’s speculation.
I understand how aft CG reduces pitch stability but I’m going to have to mentally work through the rest of what’s going on here. Simply being over loaded means the engine power is going to lift not airspeed at a high AOA. This is a good reminder that while the 172 can put up with a lot, it still does have very real limits.
it's very simple - if you use POH V-speeds - you may stall. You need to use higher V-speeds, and you don't know which ones. AOA is much higher for the same airspeed.
do a tutorial on when how to use rudder(s)/rudder pedal.
Calling her and him 400# is very generous. She’s at least 180 and he’s 275+ depending on his height.
It’s been a hot minute since I’ve done W&B for a Cessna, but the position of the TOW datum as you’ve drawn it looks comfortably within CG limits? Overweight, which is a no-no of course, but only slightly aft of mid-range as I look at it.
I’ve flown all the main Cessna models: 152, 172, 182, 206 and 210. The latter three in particular I have flown in commercial operations on or near the aft CG limit, and although you definitely have to be a little more careful, it’s still perfectly flyable.
Assuming I haven’t misunderstood the way you’ve drawn your W&B plot, I think a possible explanation for the stall horn is that they were overweight. With a lower power excess to climb at Vy, perhaps the student was over-pitching to achieve the kind of performance they were used to seeing and thereby increasing the AoA closer to the critical angle.
And what does the POH say about stalling and exceeding the critical AOA? Why on earth would you risk it?
If you look above the circle there is a star which is where the CG could be. It’s outside of the envelope and aft.
@@CFIIMunden thanks for clarifying. At 11:15, the graph shows a forward CG limit of 35 and an aft CG limit of 47.3 or so along the X axis, while the star is positioned at a CG of ~44 as you mentioned. The position of the star looks to me like it’s within fore/aft limits (but biased aft-of-midrange) for the normal category envelope, overweight by about 200lbs as you calculated? That would make sense as the circle appears within limits, and adding fuel in a Cessna single shifts the CG forward.
In any case, as you said you were being conservative with the calculations, so perhaps the CG was even further aft than you calculated. I would have put the camera guy at around 280-300, and who knows how much weight was actually in the baggage area.
It’s academic as the aircraft was likely overweight and should never have taken off on that basis alone. A lot of sub-optimal things were doing on in that video. I don’t know how you keep finding all these great examples but please keep it coming, really enjoy your breakdowns and the service you’re offering to the GA community.
@@CFIIMunden yeah gotta agree with JM87Fly here, i dont know why you kept saying aft CoG when both the star and circle are within the limits of an aft CoG and the star is more forward than the circle, Sure the star indicates overweight which is not good but really only affects performance not stability
@ because the CG was more possibly aft than it was forward.
eh
that's only 4% overweight, and well within the aft CG limit.
when the camera pans out the side, we can see they've gained 200ft by the intersection of the crossing runway... with 10° flaps extended... I personally don't think the performance impact necessitates riding the stall horn like that...
Could you make a walk through video about this exact weight & balance calculation? This is a fantastic example where it’s critically important and we do have accurate numbers to work with.
Just a suggestion ;)
Are you asking how to do a W and B or are you asking if I did it correctly? You can pause the video on my W and B and double check my math.
@@CFIIMunden I'm sure you did it correcly. It was about how to calculate it for a 172S. This is a great example, as life literally depnds on it.
It seems simple to you, but honestly I don't know how to do it....
Again - just a suggestion - if this does not match you channel - ignore my comment :)
@@extremegf ok cool! Just wanted to clarify. I have a video on my channel on how to do a W&B.
Yeah thats KLGB 26R
Maybe is just me, but that engine doesn’t sound to me to be at full power or hear the acceleration to takeoff power, maybe editing had something to do with it. Again it could be just me.
Engine sounded fine to me, you see instructor reach to controls, I think see was trying to lean engine for more power but they had all that was available.
At least they didn't try to turn! Or panic and make a abrupt control movement.
@@libertine5606 I was thinking the same thing.
You would be surprised, many tall women who are somewhat curvy can be 300lbs and you would never guess.
Because they’re not fat, they’re just very tall and large.
My girlfriend is shorter than this guy and she’s 200lbs and definitely is fat, but I’ve met women who are much taller, and weigh more, but don’t visibly appear as chubby.
It doesn't seem like that engine was producing full power. It was close on the WB envelope. All the performance charts have a safety margin built in.
Mostly though, just looks like poor technique, flying behind the power curve for no reason.
Yeah, hard to tell if it was at pull power or not. Couldn't get a read on the RPMs.
@@CFIIMundenif you look closely, it seems as though the CFI is pushing the throttle, so maybe…
@@CFIIMunden the VSI showed 500fpm which seemed to somewhat correspond to their altitude gain when the camera pointed out the window. I don't see any reason to be honking the horn.
The performance charts don't have margin built in them. Rather the opposite. They are based on test data obtained on impeccable new plane with top-notch maintenance by the manufacturer themselves and flown by an expert test pilot. If anything, real-life performance will be worse than the charts, which is why there is a rule of thumb to add 20% to 50% margins. The stall warning does have a margin of 5 to 10 kts over the actual stall at max weight, CG at the aft limit and 1G. And for the wind on take-off and landing performance they have to take 50% of the headwind and 200% of the tailwind components. But other than those, there are no margins.
The poh doesn't use density altitude it uses pressure altitude
no, it uses pressure altitude on the left side and then you choose your temperature column, effectively making it a density altitude calculation
@toml.6884 Not in the Cessna POH performance chart for take off distance. There is only a column for pressure altitude and it doesn't tell you to calculate density altitude.
@ when you look at the top of the performance chart it shows columns with different temperatures to choose from, that and picking a pressure altitude equates to a density altitude corrected performance result.
@@toml.6884 thanks for the explanation I've been scratching my head over that one!
At least from your estimates the CG was well within limits, so unless some unaccounted for uranium ore made its way to the baggage compartment, CG was likely an insignificant factor. Aircraft certified by the FAA must have positive static longitudinal stability at all allowed CG locations, and they do account for the forward movement of the CL as the AOA increases, so flying at CLmax (maximum coefficient of lift, or right on the edge before stalling) won't make the plane unstable or even neutrally stable. Also according to your estimates, the overloading was only 4% over MTOW. From what I could hear, the engine was fine and it sounded like it was turning at a reasonable RPM. I would argue that the greatest danger was the student pilot trying to get a higher climb rate by pitching up excessively and the CFI doing nothing about it (although we can't hear the cockpit audio to tell for sure). It should go without saying that the CFI should have checked the W&B before flying an aircraft at a different loading.
@@quentagonthornton49 if you look at my calculations the star indicates the CG position which was outside of the allowable envelope.
@CFIIMunden true it's outside the envelope but isn't it due to weight not CG?
@@riggitydoo5116 The arrangement of the weight is what causes the CG or to forward or aft.
I think you followed the evidence where it led.
How much do you really feel the pitch stability/twitchiness with the change of CoG position in a 172? I've only had 5 hours on a 172 and it feels like it's on rails (2 POB and full fuel)
Just me or did it look like he had some flaps in 3:02
Don't understand why you say that the CG was aft. According to your estimation, they were a bit overweight with the CG some 3+ inches ahead of the aft limit. By the way, an aft CG, while it makes your plane less stable, it reduces your stall speed (i.e. increases your stall margin) and improves your climb performance a little bit, because you have less force pulling down on the tail that the wing would have to compensate.
The CG is more aft than it is forward which is made worse by being overweight. And yes you're correct that an aft CG reduces your stall speed. That's why I wanted to show that bold method simulator because it's so good.
@@CFIIMunden .... So now my confusion shifted. I totally see how being overweight is a bad thing that made this situation worse. But now I don't understand why you consider the CG to be a factor in this incident. Being more aft that forward is being in range, and even if it was at the aft limit (which it wasn't) the plane still has plenty of positive longitudinal stability. CG at the aft limit is perfectly safe and acceptable. Being overweight is not.
@@adb012 If you look at the POH for the 172S 35 is the forward limit while 47.3 is the aft. We assume the CG is 44 which would put it more aft, not forward. As I said, we can only assume because we don't know their actual weights. The problem becomes when the CG is both fft and overweight. Really bad combination. We are both right in saying this is not a good situation to be in.
@@CFIIMunden ... Believe me I am not trying to disagree with you, just trying to understand what, if any, is the issue with the CG. If 47.3 is the aft limit, then a CG of 44 is forward of the aft limit, hence in tolerance.
The aft limit is defined in general based on static margin which is independent of the mass, that's why it is a vertical line (same aft limit for any weight) while the fwd limit is in general based on elevator authority (which is why it slopes back as weight increases). A plane with a CG of 44, when the aft limit is 47.3, should be perfectly ok from a stability point of view no matter the weight. I don't see how a CG of 44 could have made this situation worse compared with, say it being at 40. Being overweight, on and by itself, is probably the reason why they were at around the onset of the stall warning while climbing at some 60 knots with 10 degrees of flaps (remember that the stall warning will sound, at 1G, about 5 to 10 knots above the actual stall). I also observe how each stall warning occasion seems to be correlated with an updraft (by the way the camera moves each time). In any case, if there is ONE thing that they did mostly good is not to let the stall warning sounding continuously. Most of the stall warnings were brief and I think that only once the second (high pitched) stall waring sounded, which scared the soul out of me. They had a relatively healthy climb rate, I don't understand why they didn't temporarily reduce the climb speed 100 or 200 fpm (it would have still been well in the positive side) to gain some speed. What kind of instructor would allow that? I also observe that they were overspeeding the flaps during final. Again, which kind of instructor would allow that? Overweight, stall and overspeed all in the same flight. But I don't find the CG concerning or problematic in any shape or form.
@@CFIIMundenI see what you are saying: CG limits are no longer accurate when gross weight is exceeded. For example, an airplane at the forward CG limit but over gross may be too nose heavy for the tail to provide sufficient nose-up pitch at low speeds. There may also be a dangerous effect at the rear CG limit when over gross. However, in this case they were nowhere near the front or rear CG limits and we're not even sure they were over gross. They did not seem to have any noticeable pitch control problems. So the CG being a bit aft but still well within limits is not the issue.
That boldmethod page is cool, never seen that before!
They were too slow when still in ground effect and heavy with aft cg, as you found. They were climbing in ground effect and then the stall horn comes on and stays on when they climb out of ground effect. Good lesson on figuring weight and balance. What I try to get across to young instructors is how default level in low ground effect takeoff, total energy management, will prevent us less organized pilots and instructors from stabbing straight through the last couple of holes in the Swiss cheese. Had they done a soft field, very similar to level in low ground effect but unfortunately not continued to Vcc, they at least would have had some zoom reserve airspeed. I am continuing to work with local instructors to come up with ways to workaround the possible DPE expectation of pitch to Vy rather than Vcc when still in ground effect. And just normal takeoff at Vy and especially short field at Vx scares any old crop duster (no zoom reserve airspeed over the wires.). The best we have come up with is to add the +5 knots allowed on takeoff and subtract the -5 knots allowed on landing. Why don't Wolfgang's experienced pilots get to actually know about the law of the roller coaster and how to actually fly get a break on the flight test? The outcome of the maneuver is never in doubt. Other than being a bit slow and overloaded, this one in the video would pass the test just based on the numbers mathematicians, not experienced pilots, came up with. Yes, Vy will get you up fastest...if you don't stall coming out of ground effect.
I've never seen an airplane manual that recommends accelerating to Vcc instead of Vx or Vy in ground effect for a soft field takeoff.
@igclapp Read "Holding It Down:" on page 85 of Stick and Rudder by Wolfgang Langewiesche. "If the take-off is from a small field surrounded by tall obstructions, the working of the roller-coaster effect can be quite dramatic--if an experienced pilot is at the controls. The inexperienced pilot has a strong tendency to point the nose up steeply and simply hope that the airplane will climb out. But it is easy to overdo this and, by trying to get too much altitude too quickly, to kill one's speed and stall, perhaps 50 feet off the ground. The experienced pilot will therefore point his nose up only as high as absolutely necessary to clear obstructions. In fact, if the take-off is from a very tight field, he will often point the ship's nose actually at the obstructions --maybe a half height of the trees. This does not help the airplane gain height, but it does help it gain speed. And the experienced pilot does not worry because he knows (without even thinking about it) that speed and height are two forms of the same thing, and for various reasons he prefers to have that thing in the form of speed. And he knows that he can always at the last moment convert speed into height by pulling the nose up, the airplane will then 'zoom' and clear the obstructions."
@@igclapp Are you Wolfgang's experienced pilot? I have operated this way since 1963, but I learned before PTS, which predated ACS. I have found, over 61 years, that the energy management principles to be superior to PTS or ACS.
@@igclapp In the interest of safety, we need to examine which techniques are more energy efficient and therefore safer. The manuals indeed have extensive fudge factor to cover the less effective techniques. That would make them safer, one might think, than the better total energy management. But since the book numbers err in reference to the extensive data derived from the experience of Wolfgang's experienced pilot (crop dusters, bush pilots, even heavily loaded helicopter pilots), they don't use the book. The state of Alaska codified it in FARs that allow them 15% greater legal gross weight. Like every other crop duster I knew, I loaded based on the maximum I was able to put in the hopper last time with the same conditions. This, using total energy management techniques, worked well.
@@jimmydulin928 RUclips won't let me post links, but search for "Backcountrypilot ground effect or Vx with tall trees". I think we've discussed this before and were looking for a real-world comparison of the two techniques. In this article, the pilot noted that the Vx technique put him higher over the trees on takeoff. With all due respect, I see some problems with the zoom technique: 1. you don't have any book figures to calculate distance over a 50' obstacle; 2. by flying at greater than Vy you are incurring higher parasitic drag (which increases with the square of airspeed); and 3. a zoom climb will induce some g-loading and increase stall speed.
Too high DA maybe? They were also only getting about 500 fpm in the climb WITH one notch of flaps.
That's not so bad for a 172. They would have had a better rate of climb with flaps up.
On your own diagram it's in the middle of the range for the CG? Why do you keep saying it's "aft"?
That could have ended badly.
Sherlock Holmes probably would have approved.
Not nearly fatal. Definitely embarrassing. This problem began in the terminal with poor pre-flight planning, hazardous attitudes, and probably an experience-limiting school SOP including ritualization of "fifty-five, rotate" mantra. The 6 ounces of smartphone in the backseat pushed it into the RUclips folklore envelope. I'm amazed how many PPL students pass a checkride without safely learning how their school's planes fly outside the school SOP envelope. If you haven't loaded the plane up at all edges of the envelope (with an instructor) to learn how the plane performs you're missing out.
Well I’m not going to disagree with you here. It’s also common for flight schools to top off fuel. I’ve seen it pouring out of the vents taxiing and on take off.
I think the fundamental take away here is simple. Do your weight and balance or know your plane well enough to look at a situation and say this is too close let me do a weight and balance we might be out of limit.
I’m a low time student and I could tell you just by looking at those 3, with that guy in the back and full fuel in a 172 is probably not ok.
Vr in a light single engine piston is not set in stone. Fight me in the comments.😂
I’ll do u one better, Vr doesn’t exist in light singles. Never mentioned in the POH. Except for the Cirrus
Bro love ur vids BUT they’re way too long. This video doesn’t need to be 15 mins. Been a sub since you had less than 100 subs. You talk way too much about stuff unrelated to the video. I and most people won’t click a 15 mins video unless it’s pilot debrief, and no hate ur quality is not pilot debrief. But that’s okay we like ur setup. But these vids really shouldn’t be more than 4-5 mins long. Just analyze the video. Love the channel but I think these long videos are hurting you
Thanks the comment and thanks for being here! I’m unedited, unscripted and off the cuff. I don’t even look at how long my videos are before I up upload them. I just speak until I feel as though I don’t have to anymore. Maybe one day I will make them shorter but as for now I see little need.
@ sounds good bro ur killing it. I learn more from you than any other RUclipsr, so keep it up please. It just bums me out when I see you release another 15+ min video cuz I know I can’t watch it all. You’ll find your groove tho. Btw this is definitely Long Beach, I fly out of there, you can see signal hill in the distance so mad props for figuring that out. Also you should make CFIIMunden shirts I would totally buy one. Merry Christmas
Thanks so much man and I definitely took your comment into consideration for future videos. I actually want to fly out of that airport when I go back to California because I used to work near Long Beach.
Consider that it actually takes a lot of time to edit a video and make it shorter. I think it was Ben Franklin who said "I didn't have time to send you a short letter, so I sent you a long one".
@ yeah I like his videos but I’m just worried most people won’t want to click on a 15 min video especially when they know most of it is talking. That’s why I’m saying a video like this could be 4-5 mins and still get across the points. He don’t even need to edit one take style is better imo anyway
Maybe don't be a flight instructor if you're the female version of Shaquille O'Neal?
It looks real hot. But anyway, sea level climb with the horn blaring?.... jeez. oh and its time to start talking about peoples weight.. the airlines are having a hard time too.
TL:DW