Accelerated Stall FAIL - CFI Mock Checkride Pt 3 - TakingOff Ep 66

[@rex669]

I did my CFI 8 months ago. Just had 3 students pass private EOC and it feels great honestly.

[@aviatrix007]

Watching this is educational but it’s making me feel sick to my stomach (checkride jitters) as if I’m taking my checkride right now. I hate checkrides. 😅 Still, I’ve managed to pass them and have this one coming up. Breathe. 😂

[@TakingOff]

You got this.

[@ded1333]

Dan likes to argue. best of luck in your check ride! wishing you the best.

[@mckadeballance8408]

I love that Dan shares his mistakes with us, a lot of people would edit out their mistakes, but Dan shows them so we can learn from them. I really think that says a lot about the kind of person/pilot that he is.

[@bkey79]

This a great training video for cfis’ showcasing how to deal with students with a poor attitude. Good job Juan staying level headed and not falling for the students attempt at arguing in the cockpit!

[@SPI828]

Whew. Got my CFI check ride in a few days. Binge watching these like no one's business lol

[@TakingOff]

Thanks! And hope everything goes smooth for you! Let us know how it goes.

[@moxiepilot9209]

The steep spiral standard is actually to complete the maneuver above 1500' AGL.

[@barstadryan]

I didn't hear the engine clearing every 360 degrees or 1000ft

[@abbieamavi]

these and power off 180s are the only maneuvers I need to practice, otherwise feeling really ready for my commercial SEL checkride in a week! :D

[@michaelgarrow3239]

How did it go?

[@flybobbie1449]

From the UK i had a check ride before renting an aircraft. The instructor had me close my eyes and he put it into an unusual attitude. He said keep eyes closed and put aircraft into straight and level. I did, he said open eyes, i was straight and level, i thought now what? I suppose at the time having done +10,000 hours in Pipers and Cessnas helped.

[@TheAirplaneDriver]

Great video. I had to throw away my sweat stained clothes when I finished my CFIA checkride 20 years ago. I’m never going through that again!

[@TakingOff]

I don’t think I could do it again!

[@ssairshows]

Showing a stall at a 45° bank while holding altitude is a presumption of an accelerated stall which is missing some context for instructional purposes. First you have to know the straight and level stall speed so you ask the student to do a power off stall and note the speed at which the first buffet is felt. Then you roll into a 45° bank at a low power setting while holding altitude and pull back the yoke while noticing the airspeed at which the first buffet is felt which will be a few MPH/Knots above the straight and level stall speed. If there is a G-meter in the plane note the reading in the turn prior to the stall buffet.

[@sblack48]

It doesn’t really matter if you do it pitching up or banking. Either way you are pulling G and that means you are accelerating. It might not meet some arbitrary test standard but in terms of the physics of the maneuver and the real world scenario that it is intended to emulate it is the same thing.

[@LarryPortouw]

Did you adjust Va for your reduced weight?

[@TakingOff]

Actually yes. One of the few things I did right. Fully loaded, Va over 130.

[@mytech6779]

Its kind of sad how deeply this incorrect bit of physics has become embedded in the industry. I mean for tests and training go ahead and make the adjustment so you don't fail, and I wouldn't argue the point with an instructor beyond a casual discussion,(even then be sure you really know the subject material) but just know the math is being incorrectly applied. It is notable that as far as my searches have gone, this adjustment is not in the current title 14 nor the AIM. There is 25.335 which sets a *minimum* design limit on Va of Vs1*sqrt(n) but this is a design minimum(ie worst case at max gross weight) not an operational target for non max loadings. (n is the design load factor) I think this mistake may have arisen with the old normal, utility, aerobat category designations and a mis-interpretation of the load factor *design* limit as an operational g-force limit and then it was never corrected because that is a hassle and the error is on the conservative side so no physical harm was caused. Interpreting the design load factor limit as a fixed operational g-force limit when the mass is variable would just be bad engineering, the structure responds to the forces generated by acceleration of mass not to the accelerations directly, IOW total force regardless of the source of the force. I could just be some interwebs quack but several aerodynamics and physics texts along with some basic maths all agree with me.(see aerodynamics for navel aviators and Newton's F=MA) As far as Va is used to limit positive wing load forces, Va needs no adjustment for gross weight as the maximum force is determined by the maximum lift which is a function of speed, AoA, and wing shape.(notice it does not include acceleration or mass) because f=ma you can get the same F with an infinite range of M and A combinations. The purpose of a design limit is a reference point generally at an extreme edge, in this case a normal cat plane must withstand a minimum load factor of 3.8 at max gross weight the plane is not limited to 3.8g. A nice example are the older C172s which were dual rated normal(design limit loadfactor 3.8) and utility(4.4) categories, you will see in the Poh that max weight for utility is 2000lb and normal is 2300lb. hmmm same structure... 2300*3.8 = 8740lb, 2000*4.4 = 8800lb Practically equal, assuming there was some minor rounding in the writing of the Poh. Similarly if you overloaded the plane to 2600lb gross you would not increase Va, you would instead have a reduced maximum positive g limit of 3.4 (and of course you would also need other allowances for longer runways and climb angles, etc, but these are power limits not structural frame limits) As for other uses of Va regarding dynamic loading from sudden full control deflections that is a bit more complex than a youtube comment, but more load mass generally means higher moments of inertia and angular momentum, thus higher peak forces. (we are comparing changes in loading of a single aircraft here not two separate designs) This post is a bit long...

[@nismology]

@@mytech6779 Feel free to correct me if I'm wrong, but my understanding is that Va goes down with gross weight for the same reason that stall speeds (in general) do. We know that lift is related mostly to coefficient of lift (AoA and/or camber) , speed, and wing area. So, if speed and wing area are held constant, a lower coefficient of lift is required as weight goes down. Va is essentially a stall speed such that damaging wing loads are not possible because CLmax occurs prior to damage. Lower AoA required at each airspeed, due to lower weight, widens the stall margin such that the Va (at max gross wt) could allow wing loading to exceed design limits prior to a stall. In other words, speed or wing area would have to be reduced to (indirectly) narrow the stall margin by once again requiring a higher AoA. Since speed is much easier to manipulate than wing area, the lower Va is the simple solution.

[@flyguy1637]

As soon as you hear the horn just unload the wing and he stall ends and add power and roll the wings level. Easy!

[@mdb831]

Any actual PPL student should know that in a real emergency please by all means land on the private strip. Permission or not mud or not it will most likely be safer than landing elsewhere.

[@1shARyn3]

In an emergency descent, you don't need (to ask for) permission to land

[@TakingOff]

Good point.

[@badmonkey2222]

Only if you declare an emergency

[@ibgarrett]

Ouch... not a good way to lead off the video (other than it being a fantastic tease)...

[@esalenchik]

I assume you’ve already had that real check ride... and you’re not spending the day before uploading 😬 I hope it went well.

[@TakingOff]

It did. I took this ride at the end of April. (Yes, I'm waaay behind on posting the flying videos).

[@esalenchik]

Taking Off and congrats...

[@TheDesperado46]

Correction, who is the student and the instructor..

[@TakingOff]

Well, that is the question. The student is becoming the instructor, the instructor acts the student and instructor at times. All very confusing. LOL

[@Jeffrey-Flys]

License to learn

[@bretdonnelly1652]

Good video! Upload more! I am taking my CFI checkride in 13 days from today!

[@TakingOff]

Hope it goes great for you!

[@ik04]

"Pull back on the rudder." FAIL. LOL

[@TakingOff]

Yup, I got all sorts of verbally twisted.

[@TheDesperado46]

Where the hec is your student!? Tearing a book apart rather than flying the stall with you...

[@TakingOff]

My CFI-- he's looking over the PTS/ACS's.

[@davestrong2971]

Does your student ever pay attention?

[@FlyingbyFaith]

1:28 we do it in the Philippines all the time. That apart of radio calls in this country

[@TheAirplaneDriver]

Flying by Faith - So....you are approaching an uncontrolled field and there are three planes working the pattern calling each leg as they make their way around. You are the fourth. Everyone is already making the calls saying where they are....you make your initial call and ask “any traffic in the area please advise”. Are they all supposed to repeat their position because you weren’t paying attention? So now an already congested CTAF becomes even more plugged up. And, that same freq is used multiple airports and you can hear the other airplanes at the other airports all asking traffic to advise and everyone responding in addition to the usual calls. The freq is now nearly useless. What about other traffic transitioning say three or five miles away from the airport....are they supposed to respond too? What exactly is “in the area?” And, the worst of it is that the call tells you nothing meaningful. How about a non-radioed airplane? Or someone that didn’t hear request? Do you simply assume they are not there and plow ahead? “any traffic in the area please advise” is a total waste of radio resources. It is a distraction to pilots working the pattern and accomplishes nothing. The FAA in the US finally acknowledged this and is telling pilots not to do it.

[@FlyingbyFaith]

It's just how it's done here.

[@TheAirplaneDriver]

Flying by Faith - Yeah, I hear you. It was much more common here about 10 years ago...slowly going away which is good. Maybe you can pave the way in the Philippines 😂. Fly safe!

[@mytech6779]

​@@TheAirplaneDriver That practice also gives a false sense of situational awareness, the other traffic could have a bad radio or you could be on different frequencies, maybe they are task saturated and just don't reply. (Of course, not to be mixed with a simple radio check in a remote area.)

[@evanray8183]

We call for advisories when approaching uncontrolled fields, and the responses are always one pilot responding with "3 in the pattern, runway 35 in use," or something along those lines. Every pilot doesn't need to respond with their exact position. The entering pilot should be well aware of everyone's positions by the time they enter the pattern, though, by listening as they approach. They should also be announcing their own position as much as possible to make traffic aware of their approach position and entry.

[@jefar53]

Cfi is stuck heads down 😧

[@sblack48]

If you do it at exactly at Va at max weight you will hit limit load at stall. That’s the real definition of Va - not that nonsense about “abrupt control input”.

[@brucehomstad5256]

Eyes on the road

[@claytonmcminn1121]

Great. Now explain the physics behind it.

[@TakingOff]

By that time, I couldn't explain the physics behind pushing a pencil across the table.

[@claytonmcminn1121]

@@TakingOff lol... 😎

[@mytech6779]

Behind what, lateral acceleration or stalls?

[@peacepantherproductions]

My vertigo is keeping me from this! Ah

[@jamescaley9942]

Not considering VA sounds like a basic error as exceeding the load factor is worse than a stall.. which is the whole point of having VA. No pilot in the world can recover from a major structural failure. At 45 deg the stall speed will increase by 18%. Assuming the speed was slightly below VA but not very low, what input triggered the stall?

[@TakingOff]

Increasing angle of attack.

[@mytech6779]

First from a physics/engineering perspective and focusing specifically on the positive wing loading aspect, Va does not change with load. The notion that Va is reduced with reductions in gross weight is a horrible bureaucratic mis-interpretation. (*don't try to argue this during tests, that is just not the place for the discussion, and ultimately it is of little consequence in practice either way.) As for the 18% increase in Vs1, that is correct for a stabilized static state, the remainder needed to stall is covered by dynamics. The plane has inertia so it doesn't immediately respond to changes in lift and sort of keeps plowing headlong on its old course which for a moment increases the AOA more than is needed for the static load. Also important is that the ACS wants recovery at first indication of an impending stall and since most stall warning horns are set a few degrees before the stall angle the total load is lower than when pulling to an actual stall. But it is certainly a good point that you probably do not want to do this maneuver very close to Va so you won't need to pull 4g to get a stall warning.

[@lpappas474]

I know this is long after your check ride but on teaching descending spirals you might want to incorporate the instruction used in Turns Around a Point. The only difference is you are descending. Dan', if you want to know how well you are explaining any of these two air maneuvers, ask a non pilot friend to view the video. I don't believe they could tell you much about either maneuver. You mention the wind while preforming spirals but never mention the relationship between your changing bank angle and the wind. Yes, it is very difficult to treat the person on your left as if he or she is mentally challenged. I busted my fist CFI check ride, hope you passed yours.

[@maryjorgensen9200]

Ha is that a student with you I don’t think he’s paying attention

[@edenhunter9904]

I don't want Dan teaching me anything ......

[@TakingOff]

Noted. I can’t teach you anything.

[@jeshua04]

They just don't get along do they LMAO

[@davidsandell7833]

His student is not paying one bit of attention to him.

[@Dub4Yah]

Yall believe in God?