Monday, January 8, 2018

THE FALLING LEAF

There is a certain grace in the fall of a leaf. It floats and then it does not. It flies and then it ceases to fly and having spent all its kinetic energy, it falls inexorably to its fate by the pull of gravity. The falling leaf symbolizes the dance of nature. It is a slow graceful dance to behold. Plucked by the breeze drifting slowly, but filled with beauty. A portent of struggle, between the lift and the drag and also perhaps of unusual potential transfer from one force over to the other. It is a disorienting phenomenon filled with potential gifts of capacity, experience and facility and learning for a pilot.



The Falling Leaf maneuver is similar in every respect, except it is not meant to fall all the way down to the earth, but be held up in the air by the pilot. It is disorienting in nature but cannot be executed by an unfocused or untrained pilot.

CAUTION: DO NOT TRY THIS ON YOUR OWN WITHOUT AN EXPERIENCED INSTRUCTOR!

Let us look at a Stall first…



If you carefully fly into a slow coordinated flight and bring the aircraft to a stall, what happens? Most of you would say, that the aircraft first buffets a bit giving you a warning. In the big irons the “stick shaker” will be the corresponding alert. Once the shudder is past, the aircraft nose simply falls down. What exactly is happening there?



Noting that Lift is created as a consequence of the angle of the airfoil to the Relative Wind. It is a dance between the "pull" of the Lift being created by the wind over the upper surface of the cambered wing (Bernouille) and the "push" of the wind on the underside of the wing (Newton). The higher the angle of attack, the more the lift but equally with increasing AoA, the more the drag. That drag, is mostly a form drag that keeps increasing, ultimately exceeding the Lift when Stall occurs. There is separation of airflow from the upper surface of the wing starting from the trailing edge of the wing (airfoil) slowly migrating to the leading edge. Once the separation is complete, the drag takes over and gravity plays its part. Ok, so having figured the mechanics of that out, if one were to ask, how would you recover from a stall? The answer is simple, isn’t it? Put the nose down, let the wings gain lift and it will fly again. At low altitude added thrust (power) and the correct positive attitude with right rudder to counter the p-force etc. (per the aircraft being flown) is required. Remember the Center of Gravity or CG is forward of the Center of Lift or CL. As the Angle of Attack increase  past the criticalAoA, the Lift decreases and the Gravity pitches the nose down (Aircraft designers are pretty smart - the CL initially becomes the fulcrum, so to speak). This nose down is further helped by the loss of the horizontal stabilizer efficacy, being buffeted by the high angle of attack. And with the nose down, the wing flies again. Remember, if it buffets accidentally (wind shear etc.) nose down and power up (i.e. if engine is running).

Quite simple, isn’t it? Next time, ask your instructor to demonstrate this to you. It will remove the demons that irritate and create unnecessary fear, off your shoulders.



Now assume you have mastered the Stall characteristics and the recovery mechanism (before you dare to go any further). Again, with a trained and able instructor by your side, who has experience in the maneuver, go fly up at a decent altitude say 4500 feet AGL and put the aircraft into a stall. Now instead of recovery keep the back pressure on the yoke.



What happens next? One or the other wing of the aircraft will fall away from level flight (usually the left one). When that happens, most pilots even with many thousands of hours will do the same thing...use the ailerons to level the wings. Here is the warning, Using the ailerons to level the wings, increases angle of attack and deepens the stall by increasing drag and lift loss and further aggravates the situation. The correct method is to use the opposite rudder to the low wing.



Let us look at it from a perspective of understanding. A falling leaf maneuver is a dance between multiple potential, imminent spins corrected by the judicious use of the rudder. You are not falling out of the sky, so to speak, just have less lift, more drag and you are controlling the loss of lift by coordinating the creating of the lift (as wings level momentarily) and losing it (when one wing drops and the other sustains the aircraft transiently) and doing the dance with expertise. The pitching and side to side motions can be abrupt and I don’t want it to sound gracefully benign but with expertise it can be made to look and feel comfortably benign.

No heavy lead feet needed in this maneuver. Just judicious anticipation and effective use of the opposite to the lower wing, rudder to keep the wings level (preventing a wing-over into an incipient spin is the key. Delay in opposite rudder input can deepen the roll). Remember there is grace in a falling leaf.



You might ask, “what is the benefit of putting myself through this ordeal?” Good question! The answer is quite simple, it helps understand that even during a stall the VSI stays at a 500+/- rate of descent, which means the aircraft is still flying, albeit poorly! It teaches the importance of the rudder use and gives you, the pilot, confidence. Or simply put, it teaches you to dance on the rudders with a deft touch when needed. It will also help you make expert, coordinated turns without skids and slips (which create drag and slow you down). So, learn to tap-dance gently on those rudders.



The "falling leaf" maneuver is a series of full stall where you never release back pressure, but play the forces of the aerodynamic lift of the aircraft, relative wind, the angle of attack and form drag of the aircraft, all the while keeping the wings level. During the maneuver, your plane should look like a leaf gently rolling and falling but continue in its flight! Learning the Falling Leaf maneuver will help prevent you from making preventable mistake and inadvertently falling to the ground. 

CAUTION: DO NOT TRY THIS ON YOUR OWN WITHOUT AN EXPERIENCED INSTRUCTOR!




Wednesday, December 27, 2017

IMPERTINENT IMPOSTERS


I couldn’t find a word in between impertinent and impatient that carried a joint meaning. We dwell in a society of, as Walt Whitman called it, "misshapen beauteous forms." The land is awash with the dutiful bowing to the heavy velvet and the coruscating diamonds that blink and blind. And yet the wizard within the velvet has no idea of what is going on, save the faithful that keep bringing gifts with fixed smiles of servitude.



Science is in the throes of such a cannibalistic transformation. Don’t get me wrong, there are a few innovators out there tinkering away at the next achievement, but majority of the sad class of yesteryear seems to have a new-found love for “manipulation.”

"So how come these impertinent imposters that play with our reality under the guise of science and write papers upon papers (mostly to get tenure and prestige) don’t tell the truth. Perhaps the revenue stream of the sponsor is a gift that keeps giving?"

Ah, the class of yesteryear continues to shine in the field of bastardizing scientific rigor, you know, the kind that helps make their kind replete with financial progress. These minted “old know-little but act-big somethings” have perfected the art of tom-foolery. Why toil for months and months or years on ponderous and excruciatingly difficult experimentations, verifications and ultimate validation only to have a 50-50 chance of “success” and a “bust” lurking on the horizon, staring back at you in the face with the certain feel of time, money and effort loss. Would one go the way, knowingly? Especially given the “get rich quick,” “trade like a millionaire” books flying off the shelf. And if you haven’t noticed Bitcoin at $15,000.00 per imaginary coin life we are living today.

There must be a better method? One asks.

And voila, the answer is there!

The phoenix of little work and large gains has arisen. The hard work is a thing of the past. Now it is a matter of a few clicks, a few number “manipulations” and the results are monumentally deafening in their emergent applause.



Today, scientific discovery is based on computing power and a few biased and sometime shady statistical methodologies. Flawed and pseudoscientific misleading research is ruinous to societies and create unwise regulations. Usually a “strawman” (an intentionally misrepresented proposition that is set up because it is easier to defeat than an opponent's real argument) hypothesis is advanced, for example, two treatments A and B are equally effective, the two treatments are then compared, and any p-value less than 0.05 (p<.05) is, by convention, usually considered “statistically significant” and that tends to disprove the strawman hypothesis and prove that effects of the treatments are similar.


When scientists explore many questions to look for their “shiny” needle in a haystack (That they will find (false positives) through tortuous manipulation of the data) that is known as “data dredging.” (Data dredging - also data fishing, data snooping, and p-hacking is the use of data mining to uncover patterns in data that can be presented as statistically significant, without first devising a specific hypothesis as to the underlying causality). It is wise to ignore studies that pose too many questions.

Another mechanism utilized commonly is the desire to formulate a hypothesis after the analysis is done, which is known as HARKing- Hypothesis After the Result is Known. https://www.ncbi.nlm.nih.gov/pubmed/15647155

These mechanisms create false-positive-generating machines.



Remembering that when 17 comparisons are made there is a 5% chance of a false positive leading to a 58% chance of the false conclusion that at least 1 difference exists!
Subverting the self-correcting nature of the critical inquiry in science can and lead to a decade-long politically-sustained funding source for this pseudo-scientific scholarship. This exercise is furthered by the consensus-seeking crowd who offer mostly rhetoric in response to critical inquiry and ultimately hurl ad hominems when pushed to the wall.  This collaborative consensus-based censorship continues to keep the revenue stream from drying up.
As Marcia McNutt, President, National Academy of Sciences stated, “Memory-based research methods produce self-reported data that are implausible and should not be used to establish the Dietary Guidelines for Americans or regulate the $5 trillion US food industry.” A reminder for those watching television and ogling at magazine ads; chocolate does not cure cancer and sugar only tastes sweet but has some nasty properties against the health of the body.

"Subverting the self-correcting nature of the critical inquiry in science can and lead to a decade-long politically-sustained funding source for this pseudo-scientific scholarship."

Moving through the statistical landscape of selection, scientist-based, industry-based and political-gain-based bias, we arrive at a slightly better form of rigor, but no less flawed…

Let us for instance take into account the “Confidence Level” to start with. I have written about the p-Value HERE. But let me take you on a different excursion.



Assume you are an individual within a neighborhood, within a city, within a county, within a state and within a country and within the world. Ok you don’t have to assume, you are! You have been living there for quite a while. Hence as Lamarckian twists would have it, you do share the plentitudes of genetic markups that have happened in over that period of time. Assume you arrived from another country and brought a package of genes from that country and your progeny spread in different states. Does that mean that the host nation now shares the same genomic makeup within their genetic and other epi-genomic structures, with you? Any half-wit will tell you, No! You have your own genomics cobbled together by your parents and that from your previous and present environment and your life style.



So, when we use the Bell curve as a standard and quickly create the means and standard deviations to ascertain the z-values

from these numbers or use the standard deviation and the sampling error to create the Confidence Intervals, what are we doing?



Are we not creating a virtual genetically homogenized society that belongs under the same Bell Curve? And the Mean or center of that Bell curve then constitutes the entirety of the world population and furthermore if the statisticians and clever physicians believe that within that 95% CI, the chance of not conforming within is essentially considered an outlier status (a rare event). Well, if you follow the argument, the case for the world population mean in genomics and infectious agents has never been tallied and with 7.2 Billion it is unlikely to ever be accurately tallied to discern the real mean and therefore for comparative purposes ever to be the central part of the Theorem to give you that lusted after 95% CI, the confines of which entitle one to say that the Ho (Null Hypothesis) is rejected. (In other words the outlier status might encompass a much larger population then is deemed accurate in the 95% CI of the two statistical deviations. So, to say that we have 95% certainty that Treatment A will work in a large subset of the population is patently false and falls flat. Because the genomic/epigenetic structure of the group does not guarantee enough variability to have an assigned mean. If there is no real assigned mean then sampling error goes out of the window as well as the standard deviations as well as the mean of means. Don’t they? The reference point is therefore a false premise from the outset!

"And for any species to survive and thrive it needs to diversify through natural selection, not by artificial means."

That felt like gobbledygook, didn’t it, perhaps? Let me try another way… It is different to take a Rajeev from India, a Tolstoy from Russia, a Smith from England and a Lee from China and consider their genomics (exposure to viral inclusions and other Lamarckian forces) as similar enough to constitute the porridge of the central theorem with its 2 standard deviations. Since we have determined that if the real mean is not known, how then can the STDEVS be? Now if we cannot do that, then the results of the Null Hypothesis generating studies flies in the face of reality with speed. The n can go to a 1000 in a society (a large number for a study) even within the melted-pot social variety and still not have real homogeneity to give us a good calculated probability finding. No wonder landmark studies (47 in 53 or 89% in AMGEN’s study) done on cancer patients in different countries bear different results. From academe to the real physician work, the translation of a drug activity and benefit fails to consistently show similar advantages. All one has to do is look at the Immunogenic forces on the Hepatitis B virus in different parts of the world that have yielded different Hepatitis B genetic subgroups of those viruses (Baltic population with Hepatitis B "D2" variety and the SouthEastern with a Subgroup "C" and in Brazil with mostly an "A" subgroup variety. And the subgroup numbers keep getting longer and longer with time and exposure. Diversity is nothing more than a mutation. And a mutation means a different host against a different guest. And for any species to survive and thrive it needs to diversify through natural selection, not by artificial means.

So how come these impertinent imposters that play with our reality under the guise of science and write papers upon papers (mostly to get tenure and prestige) don’t tell the truth. Perhaps the revenue stream of the sponsor is a gift that keeps giving?

Am I biased? Sure! Aren’t you?

To pass on our biases with a certain degree of gravitas is what makes this whole game kind of sinister. It would behoove the “experts” to stop rattling the chains of “Look at Me, Look at Me, I have a new paper,” and do some real unadulterated science for a change, that is, if they still know what real science is.


Take this with a grain of salt, too. Remember, I have my own personal biases.

Sunday, December 10, 2017

WHEN SILENCE BECKONS

We are all spacefarers, hurtling through space whether our feet are on the ground or traversing through the air. Humans were meant to fly but with artificial wings. Once you have broken the surely bonds and catapulted through the air, there is no turning back from that delight. The desire forever haunts you for more.

But when there is silence from the artificial means of thrust, we want to get down and kiss the ground too. And therein lies a tale of nonfiction.

Engine Out procedures are practiced daily by scores of students and those undergoing recurrent training. But… but, and here is the logical question, does that practice translate to the real thing? Mostly, I hate to say…Depends!

The answer is quite simple, really. If you practice “feel good” maneuvers, then the real live scenarios, when they come your way one day, the mind will be rattled. Practicing good real world scenarios with a fund of knowledge in real world is like executing a bicycle ride. Let me add in some comforting mathematics and some simple calculations along the way to make it more palatable.

"If you practice “feel good” maneuvers then the real live scenarios, when they come your way one day, the mind will be rattled."

But one thing is for certain, to be able to come out of such a real live scenario without a scratch, it is only the prepared mind that will succeed.

Look into your POHs and you will find some evidence in the Performance section of your aircraft’s abilities. One such ability we need to hone in on. It is Glide Speed. The first and only major thought in any engine out scenario is to trim for best glide speed based on the weight of the aircraft. (direct relationship -  Heavy weight = higher glide speed) most POHs will give you relative glide speeds for different aircraft weights.



In most General Aviation aircraft, the glide distance per 1000 feet varies between 1.5 nautical mile to 2.1 nautical miles. It also varies significantly with whether the gear is extended in complex aircraft, the propeller is low RPM and if the flaps are retracted. Adding any drag significantly affects the glide distance.

Altitude is always your friend. There is inherent Kinetic Energy in an object in the air with or without thrust, the gravitational pull gives it that energy. Dissipating the energy by virtue of the airfoil (wings) gives us the distance gained per altitude lost. Knowing that one can quickly calculate how far one can successfully land and fly another day.

Keeping brevity in mind, let us look at the common scenario. Let us say a pilot loses the thrust at 5000 feet AGL. What are his chances? If we multiply the 5 (000) x 1.7 = 8.5 miles is the answer. Simple and direct. This encounter would favor the prepared pilot and not the panicked one. Of course one has to go through the checklist at that altitude: Fuel (Change tanks & Auxillary pump on for a short time), Spark (Check Magnetos on both) and Air(Pull Alternate Air). If not successful, declare an emergency and plan for a on or off-airport landing.

"There is inherent Kinetic Energy in an object in the air with or without thrust, the gravitational pull gives it that energy. Dissipating the energy by virtue of the airfoil (wings) gives us the distance gained per altitude lost."

Now the easy math part I mentioned earlier. Look at the altitude, your best glide speed and calculate the distance. Remembering that, that distance is in zero-wind condition. Add the prevailing wind speed and the decision making becomes a little bit more complex. Heading into a header will obviously diminish the glide distance, since one must add at least ½ the wind speed to the glide speed to traverse the distance and that will reduce the overall distance. However, if the airport or landing zone is on the leeward side, then flying distance will increase by the factor of the wind. I have calculated a chart attached to this article that might help most GA aircraft based on their descent rate and the glide distance per 1000 feet.

Now for the practical test itself. I have done several simulated engine-out scenarios both in flight simulators and in real time. The margins are definitely lower in real world scenarios, because the pilot's mind plays tricks too. So those pilots thinking that 2.1 miles/1000 feet of altitude loss is their bird’s "Glide Distance" value, should consider a more conservative measure at say 1.8 miles/1000 feet. Arriving over an airport at a 1000 feet is infinitely better that trying to do the most dangerous of all things; “Stretching a glide” to the runway. “There it is! There it is! Oops! @#$%$!

If you wish to have .pdf copy of this image, please request under comments.


Two methods of practicing are helpful. One is to spiral down over the runway, if you have arrived there with altitude to lose, using the fighter pilot "flame out" technique of “High Key, Low Key and Base Key” and the other is the straight-in approach. Both have different calculations. In the former method, based on Altitude loss per 360 degrees turn at 20-30 degrees bank angle must be known and that establishes the “Keys.” So if your aircraft loses 1000 feet in a 360 degree turn, then the start with an upwind “high key” at 1500 feet to arrive at the “low key” (Downwind) at 1000 feet and “base key” at 500 feet. In the latter method, it is based mostly on the distance gained per 1000 feet of altitude loss. So at 9000 feet losing 1400+/- feet/minute (heavy drag), one can traverse 11 miles of distance and that increases with a tailwind and decreases with a headwind component.



Some basic CALCULATIONS on a very “Draggy aircraft” that might help include the following:

 ((nm flown) * (feet per nm)/ Altitude in feet AGL)) = GLIDE RATIO
eg: 11 * 6072 / 9000 = 7.42 : 1
(Distance in nm/speed in knots)*(minutes/hour) = TIME ALOFT
eg: (11 / 100) * 60 = 6.6 minutes
(Altitude in AGL)/(minutes aloft) = SINK RATE
eg: 9000 / 6.6 = 1363 feet per minute.

There you have it. Next section, I plan to discuss “Engine Out” Scenario in an IFR state of mind. And that gets very interesting but no less challenging and mathematically easy to accomplish safely if one keeps one's wits orbiting around one’s head. So let the knowledge and experience shoot up in the air and the roots dig deeper into the ground for familiarity and retrieval.

Safety is No Accident.