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CFI Brief: Fatigue

IMSAFE, the not-so-subtle-phrase within the acronym. I think by this point in your training you have probably begun to realize that aviation is flooded with acronyms and abbreviations for a myriad of things. PAVE stands for Pilot, Aircraft, Environment, and External Pressure and is an essential risk management tool that assists the pilot in running a checklist of potential hazards and risks associated with a flight. The first checklist item, Pilot, is there to identify any risks associated with the pilots overall health, which is where this first acronym I mentioned comes in. IMSAFE (Illness, Medication, Stress, Alcohol, Fatigue, and Emotion) is a self-assessment checklist of you, the pilot, to determine if you are fit for duty. Honestly, we could spend all day talking about PAVE and IMSAFE but in today’s post I don’t intend to do that. I want to concentrate on one area which just happens to be one of the most “insidious hazards to flight safety,” according to the FAA.
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Fatigue, the fifth item on the IMSAFE checklist, is often one of the most overlooked and undetected by a pilot. It’s extremely hard to narrow down a singular definition for fatigue because of the various causes; these can include a lack of sleep or excessive physical exertion. There are also some causes of fatigue you might not think of, for example grief, emotional stress, boredom, or even a lack of activity. The FAA best describes fatigue from an operational standpoint: “Fatigue is a condition characterized by increased discomfort with lessened capacity for work, reduced efficiency of accomplishments, loss of power or capacity to respond to stimulation, and is usually accompanied by a feeling of weariness and tiredness.”

Over recent years the FAA has expressed special emphasis on fatigue, particularly in commercial operations. We have seen numerous aviation accidents as a result of pilot error which often directly correlate to a pilot being fatigued. This was the case in the very high profile 2009 Colgan Air crash; this accident in part can be attributed to pilot fatigue.

The Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25) broadly classifies fatigue into two different categories: acute and chronic.

Acute fatigue is something seen in everyday life, often lasting for a short period of time. This type of fatigue results mostly from a lack of sleep or over-exertion of a physical or strenuous activity. A fluffy pillow and a good night’s rest is often the cure (8 hours of sleep is recommended).

Chronic fatigue as the name suggests is something that last over a long period of time or is constantly recurring. Continuous high stress levels or an underlying disease are often to blame. This type of fatigue leads to several other health related concerns and is not easily remedied by a good night’s rest but requires consultation with a physician. Chronic fatigue is not to be considered “normal” and you should take a hard look if this is something you are experiencing and get expert help.

No matter the classification of fatigue, it is highly advisable to stay on the ground! As the FAA says, no amount of training or experience can overcome the detrimental effects of fatigue.

The FAA provides a Fatigue Countermeasure Training Course at FAASAfety.gov , it’s about a 2.5 hour course and will provide you with Wings credit at the conclusion. Check it out!

https://www.faasafety.gov/gslac/ALC/CourseLanding.aspx?cID=174

I would also recommend you take a look through this educational brochure published by the FAA:

https://www.faa.gov/pilots/safety/pilotsafetybrochures/media/Fatigue_Aviation.pdf

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Enroute Flight: Mental Workload

We tend to think of piloting an airplane as a physical skill, but there is much more to it. The pilot must assemble information, interpret data, assess its importance, make decisions, act, communicate, correct and continually reasses. Over time, all of this contributes to fatigue. Today on the Learn to Fly Blog we’ll talk about mental workload. This post is excerpted from The Pilot’s Manual Volume 2: Ground School.

Best performance is achieved by a combination of high levels of skill, knowledge, and experience (consistency and confidence), and with an optimum degree of arousal. Skill, knowledge and experience depend upon the training of the pilot; the degree of arousal depends not only upon the pilot’s flying ability but also upon other factors, such as the design of the cockpit, air traffic control, as well as upon the environment, motivation, personal life, weather, and so on. Low levels of skill, knowledge and experience, plus a poorly designed cockpit, bad weather, and poor controlling will lead to a high mental workload and a poor performance. If the mental workload becomes too high, decision making will deteriorate in quality, or maybe not even occur. This could result in concentrating only on one task (sometimes called tunnel vision) with excessive or inappropriate load-shedding. You can raise your capability by studying and practicing, and by being fit, relaxed and well rested.

The pilot’s tasks need to be analyzed so that at no time do they demand more of the pilot than the average, current and fit pilot is capable of delivering. There should always be some reserve capacity to allow for handling unexpected abnormal and emergency situations. At the aircraft design stage, the pilot is taken to be of an average standard. On this basis, skills and responses are established during testing so that the aircraft can be certificated as compliant. But there is some argument that the specimen should not be the average pilot, because half of the pilot population would be below this standard.

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Reserve capability.

The legislators establish the minimum acceptable standards for licensing but the marginal pilot, who maintains only the minimum required standard, is not really of an acceptable standard. You can each ensure that you are at an acceptable standard by honestly reviewing the demand that the aircraft and the flight placed upon you. If your capabilities, mental or physical, were stretched at all, then you need more practice, more study or more training—at least in those aspects that challenged you. Many pilots feel that, under normal conditions, they should be able to operate at only 40–50% of capacity, except during takeoffs and landings, when that might rise to 70%. This leaves some capacity to handle abnormal situations.

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CFI Brief: www.1800wxbrief.com

Obtaining a weather briefing in my opinion is one of the single most important parts of any pre-fight. Whether you plan on conducting a flight in the vicinity of an airport or are heading out on a 100 NM cross country trip, having current and updated weather information is crucial for a successful flight. If you read Monday’s post, and I highly suggest you do, you learned about the various sources of weather information available to a pilot. You can see that in today’s day and age there are so many various sources of weather made available and absolutely no excuse not to use them. As a pilot myself, one of my go-to ways to obtain weather information is through the Lockheed Martin Flight Service system website at www.1800wxbrief.com. This is a government sponsored site, so a record of your briefing will be retained and put on file—this is a good thing.

If you’ve never used www.1800wxbrief.com, the first step is to  register for an account, it’s a free and simple process. Lockheed Martin, who manages the site, provides several how-to videos in an effort to simplify the process even more. I will provide you with a couple of these videos to check out and provide you with a link to where you may find the remaining how to videos from Lockheed Martin.

This first video will give you a quick 3 minute overview on how to register and login to the system.

This next video is going to actually teach you how to obtain your first flight plan route briefing. Now maybe you’ve used the system before and have already obtained route briefings. If so, it’s not going to hurt to still take a look at this video, you may learn something new or at the very least pick up on a few new tricks of the system.

There are several additional how-to videos posted on the Lockheed Martin Flight Services YouTube Page and other useful information posted under the help menu at www.1800wx.brief.com.


Airman Certification Standards: Private Pilot Airplane and Instrument Rating Airplane eBook PDFs are now available!

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Looking for more information? Check out our interview with ASA Curriculum Director and ARAC ACS WG member Jackie Spanitz. You can also read her article “Certifying Pilots: The New Airman Certification Standards” on airfactsjournal.com. AOPA also offers their take as well. Softcover copies of each edition are also now available for preorder and will begin shipping later this month.

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Weather Services: Sources of Information


There’s a lot of weather information available to pilots, most of which we’ve already talked about. Here’s what Bob Gardner recommends you do with all of it in his textbook The Complete Private Pilot. And we recommend you bookmark these links!

Self-brief first, to get the big picture before calling or logging onto the briefing site. Your first choice when looking for weather reports and forecasts should be the Aviation Digital Data Service (ADDS) webpage. It has recently been revised and improved. The next best is http://digital.weather.gov. It is loaded with information but in a different format than the ADDS page. In some cases that ADDS page will refer you to this site.

URL Name
aviationweather.gov/adds Aviation Weather Center ADDS Page
digital.weather.gov NWS Graphical Forecasts page
www.aviationweather.gov ASOS Information
www.accuweather.com AccuWeather Website
www.weather.unisys.com Unisys Weather
www.wunderground.com Weather Underground
www.spc.noaa.gov Storm Prediction Center
www.weathermeister.com general weather information
www.youtube.com/avwxworkshops Videos on weather subjects
www.lightningmaps.org Lightning = thunderstorm

To learn how to interpret the reports and forecasts, refer to Aviation Weather Services, FAA Advisory Circular 00-45 (or, “AWS”). Ideally, you should have a copy of the AWS in your library, but it is available for reading and download at the FAA website (www.faa.gov). The advantage of the online publication over the book is that the online version includes changes and updates; the disadvantages are that it is a huge file and it is not searchable. Still, it is the only place where you can find explanations for all of the online weather charts and graphics—and a list of abbreviations used in text products.

Too many accident reports include the words “There was no record of a weather briefing.” You definitely want to get a weather briefing, and you definitely want that briefing on record. The way to do this is to use a government-sponsored site such as DUATS (1-800-767-9989) or the Automated Flight Service Station system. Go to www.1800wxbrief.com and register. You will not only be able to get a briefing and file your flight plan, but if you have a smartphone you will be able to use EasyActivate and EasyClose: about 30 minutes before your ETD you will get a text message with a link to open the flight plan, and about 30 minutes before your ETA you will get a text with a link to close the flight plan. In either case, just tap the link to open/close your flight plan. This does not work with other providers. The Lockheed-Martin website www.1800wxbrief.com has a weather tab with a treasure trove of weather data. There is some duplication with the ADDS page, but there are also sites not covered by ADDS. You do not have to be registered in order to access the weather pages.

Of course, if you want to talk to a human being, 1-800-WXBRIEF will do the trick. Three types of briefings are available: standard, abbreviated, and outlook. If you have not collected any weather information before calling the FSS, ask for the standard briefing—then you can be sure that nothing will be left out. Ask for an abbreviated briefing if you want to update an earlier standard briefing or add to information you have already received from other sources. In this situation, tell the briefer where you got the original information so that he or she can fill in any gaps. It is possible to get an in-flight briefing, but doing so ties up the radio frequency and is not good manners.

Request an outlook briefing when your proposed departure time will be more than six hours after the briefing, then back it up with a standard briefing closer to takeoff time.

You can listen to the Hazardous Inflight Weather Advisory Service (HIWAS) on selected radio navigational aids (VORs and NDBs) for weather updates. Check your sectional chart, paper or digital, and the Chart Supplements U.S. to identify navaids that broadcast weather information—a blue circle with a reversed “H” in the upper corner for HIWAS. If you have a radio in your airplane you will always have access to up-to-date weather information from Flight Service and should not rely solely on a pre-takeoff briefing; weather changes.

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CFI Brief: Firsthand Insight on the ACS—an Interview with Jackie Spanitz

It’s official! Final versions of the Airman Certification Standards (ACS) for Private and Instrument Pilot Airplane have been published and will go into effect in just a few days (June 15th, 2016). These new ACS will replace the Practical Test Standards. The anticipation has been building for weeks now in our small tight-knit aviation community. I have seen reactions from student pilots and flight instructors ranging from excitement to sheer panic. A lot of this anxiety and panic I think can be attributed to lack of understanding or misconceptions about how the ACS implementation will affect airman training and testing.

Earlier in the week I sat down with ASA’s Director of Curriculum Development, Jackie Spanitz, to give us some firsthand insight as it relates to the ACS and to address some of those misconceptions. Ms. Spanitz has been a part of the ACS process since day one and a charter member of the Aviation Rulemaking Advisory Committee (ARAC) Airman Certification Standards (ACS) Working Group (WG) or ARAC ACS WG for short. Our Q&A session went as follows.

Ms. Spanitz what is your position on the ARAC ACS Working Group?

I am the ACS Workgroup Subgroup Lead for the (1) Private, Instrument Commercial, ATP ACS Development committee, (2) Handbook Review committee, and (3) AMT ACS Workgroup. This means I work with the FAA and Industry committee members to execute the tasks assigned to us by the ARAC ACS committee chairs and FAA sponsors.

What made you want to get involved?

I have been working with airman certification training and testing for more than 20 years—resulting in a very intimate familiarity with the FAA Knowledge Exam, training curriculums, and practical exams (checkrides). In 2011 we noticed a dramatic increase in failures on the Fundamentals of Instructing (FOI) FAA Knowledge Exam which directly correlated to a test change we didn’t feel supported safety or reflected a meaningful and relevant exercise. We worked with AOPA and NAFI to voice these concerns to the FAA office responsible for airman training and testing. The FAA was receptive to our input and asked us to join them in seeking a resolution—not only to the immediate problem at hand, but to establish a process by which all airman testing would be meaningful and relevant, training and testing would be correlated for an effective system, and ultimately further the safety initiatives. The first committee established nine recommendations to the FAA—seven of which the FAA accepted and began implementing (including the transition from Practical Test Standards to Airman Certification Standards). The second committee established sample ACS for the Private, Instrument, and Commercial airplane certificates/ratings, as well as the associated FAA guidance and testing changes that were necessary and began a prototype process to test the new ACS in actual training environments. The current and third committee I’m participating on is continuing the prototypes, finalizing the Private and Instrument documents, and continuing to refine the Commercial, Instructor, and ATP ACS.

Does this mean you’ve gotten to see the FAA Knowledge Exam test questions for the last five years?

No. The FAA Knowledge Exams remain closed tests. No one outside the FAA sees the test questions. However, the committee established a process by which the FAA review board evaluated each test question. The FAA releases public sample exams and a “What’s New” document each test cycle which is their way of communicating how training should evolve to remain correlated to the tests.

As many of us know, or have at least heard, the ACS implementation will be taking place next week. What are the primary changes we can expect in terms of training and testing once the ACS goes into full effect?

The biggest change is the sunset of the Practical Test Standards for Private Pilot Airplane and Instrument Rating Airplane—those books will be replaced by the new 8.5 by 11” format ACS books. This new book collates FAA information which was previously published in multiple documents: the ACS = the PTS or 8081 series + Test Guides, or 8082 series + Learning Statement Reference Memo + Testing Matrix. This single resource for airman certification doesn’t increase the testing standards—it just puts it all together as a single-source document. Where the PTS just described the skill associated with each task, the ACS adds to this the knowledge and risk management associated with each task. This means each task details what an applicant must know, consider, and do to be successful in each flight maneuver.

Another change applicants will notice is the new risk management section associated with each task. These represent the special emphasis items and Aeronautical Decision Making from the PTS Introduction. Put in context, the ACS risk management elements will allow applicants, instructors and evaluators to understand the risks specific to each task so they can better mitigate and handle these considerations.

Applicants must retrain in any area proven deficient during their FAA Knowledge Exam—and evaluators must retest these areas. The ACS will make this retraining and retesting easier by keeping the information in context. This encourages all the information to be taught for the purpose of safe flight operations. Gone will be the days when applicants learned something simply because it was on the FAA Written—instead, applicants will learn what they need to be a safe pilot, and by default will be prepared and successful on the FAA tests.

Is this going to affect student pilots who have already begun training or are getting ready for a knowledge test or checkride?

No. Pilots don’t need to retake their test nor do they need to “backup” to retrain under the guidance of the ACS. The PTS is “in” the ACS—applicants will find the same tasks, objectives, and skill items. The Knowledge Exam is then “layered in” which will facilitate the retraining and retesting required between the knowledge exam and practical exam. Essentially, the ACS provides a single-source reference for applicants to understand what they must know, consider, and do to earn a pilot certificate—but it doesn’t change the training requirements—it simply presents them more clearly.

So in terms of knowledge tests, they are not changing this month into something entirely new?

No—this test role is not resulting in an all-new test. Aside from the new test figures book, this is a relatively light change in tests. In fact, the FAA began “cleaning up” the FAA Knowledge Exams more than two years ago. The FAA makes revisions to the test three times per year—typically in June, October, and February. Each test cycle, the FAA makes revisions to reflect any rule or procedure changes, as well as removing topics no longer relevant. The ACS has provided the guidance by which the FAA evaluates each test question. If a question could not be directly correlated to a task element within the ACS it was either tossed out or rewritten to be relevant and meaningful to flight operations. Over the last two years the FAA has done a fantastic job improving the tests—which so far have included more question removals than additions.

There has been a lot of talk about the FAA tests changing to include more risk management and scenario-based questionswhat does this mean in terms of what applicants can expect?

Scenario-based questions have been added to the tests over the last two years—this isn’t anything new. All this means is that a question may cross into two subjects (for example, testing your knowledge of both weather and regulations) and will be phrased to be in context with actual flight operations. As for more risk management testing, again, this is not new as the PTS has required risk management since it was included as a Special Emphasis Item. What the ACS does is detail the specific risks unique or applicable to each task. In other words, the ACS isn’t testing the operator’s “judgment” of risk management, so much as it’s testing the pilot’s awareness of what risks are inherent to the task they’re about to demonstrate. For example, when demonstrating ground reference maneuvers, you are flying lower than normal so it’s important to be aware of wirestrike avoidance procedures and have an emergency landing area selected.

As Director of Curriculum for ASA can you speak on the topic of how this is going to affect your product line, particularly in reference to ASA’s study materials?

The most significant change is the opportunity to remove items from training programs which were only included because they were still being tested on. Those items which instructors said “remember this for your test, but then you’ll never see this again.” These items have been removed in sync with the FAA’s announcement of topics coming off the test. The ACS has also provided a framework for continued improvements to the FAA training documents (handbooks) which will filter into private publications as well. The training and testing will be better correlated than it has ever been—which means people can train to be safe and effective pilots, and by default will be prepared for their FAA Knowledge Exams.

Are the Private and Instrument Pilot Airplane ACS guides beneficial for a student pilot to read and when will they become available?

Yes. Student pilots should use the Private Pilot ACS guide to understand what they will have to know, consider, and do to earn a pilot certificate. Pilots interested in earning an instrument rating should use the Instrument Rating ACS guide for the same reason. These books will provide the training outline on which their curriculums will be built. Both books will be available by the end of June.

Available from ASA in late June.

To date, what do you feel is your greatest achievement as part of the ACS Working Group?

This would be a tie between the ACS providing a systematic and sustainable approach to continued improvements to the FAA Knowledge Exams and the strong correlation the ACS provides between training and testing. Ultimately, the ACS means pilot testing is meaningful and relevant to safe flight operations. The work group members volunteered a huge number of hours to bring these to light and I am very proud of the collaborative approach my industry and FAA colleagues used to complete the ACS. The people who worked on these committees were dedicated to improving the certification standards and tests with the shared goal of improved safety—and I truly believe we’re going to have safer skies as a result.

Any final thoughts?

The ACS is a good thing. This is not a dramatic change, but it is a systematic approach to facilitate continued improvements which is a great thing.

Jackie Spanitz

Jackie Spanitz, Director of Curriculum Development for ASA Inc.

You can catch Ms. Spanitz next Wednesday, June 15th, for a special NAFI webinar “The ACS is Here!” If you wish to attend, additional information can be found below. In the meantime, if you should have any questions or comments feel free to drop us a line below.

At 7 p.m. Central time on June 15, ASA’s Director of Curriculum Development, Jackie Spanitz will join NAFI’s Vice President of Industry and Government Affairs Phil Poynor for a Webinar entitled “The ACS is Here!” Also taking part in the conversation will be John King of Kings Schools, and Susan Parson, special assistant to the director of the FAA’s Flight Standards Service and editor of the FAA Safety Briefing magazine.

NAFI Webinar: “The ACS is Here!”

Date and Time: June 15, 2016 7:00 p.m. – (US/Central)

Meeting Wall: www.startmeeting.com/wall/540-716-061

US Toll Number: (530) 881-1212

Meeting ID: 540-716-061

NAFI Webinar Instructions: At the scheduled date and time, dial into the conference line. When prompted, enter the meeting ID, followed by the pound key. To join the online meeting, click on the meeting link listed above, then press “Join.” On the next page, complete your name and email address, then press “Submit.” The system will guide you through the process of downloading the meeting dashboard to participate in the online meeting.

To ensure easier access to the NAFI Webinar at the scheduled time, we recommend downloading the Start Meeting software in advance. For 24/7 customer service please call them at (800) 644-9070.

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Aircraft Performance: Airplane Stability

Today, we’ll introduce airplane stability. As you’re well aware of by now, there are three axes around which the airplane moves (yaw, pitch, and roll). These axes pass through the airplane’s center of gravity, or the point where the airplane weight is considered to be concentrated. An airplane that is stable requires little pilot attention after it is trimmed for a certain airspeed and power setting. Today’s post is excerpted from The Advanced Pilot’s Flight Manual by William Kershner.

Fig10-01
Figure 1. The three axes.

Stability, as defined by the dictionary, means “fixedness, steadiness, or equilibrium.” An object that is positively stable resists any displacement. One that is negatively stable does not resist displacement; indeed, it tends to displace itself more and more if acted upon by an outside force. An object that is neutrally stable doesn’t particularly care what happens to it. If acted on by a force it will move, but it does not tend to return to its position or to move farther after the force is removed.

Static Stability
Static (at rest) stability is the initial tendency of a body to return to its original position after being disturbed. An example of positive static stability is a steel ball sitting inside a perfectly smooth bowl. You can see that the ball has an initial tendency to return to its original position if displaced.

Fig10-02
Figure 2. Positive static stability.

Figure 3 is an example of negative static stability. The ball is carefully balanced on the peak of the bowl, and the application of outside force results in its falling. It does not tend to return to its original position; on the contrary, it gets farther and farther from the original position as it falls.

Fig10-03
Figure 3. Negative static stability.

Neutral static stability can be likened to a steel ball on a perfectly flat smooth surface. If a force is exerted on it, the ball will move and stop at some new point after the force is removed.

Fig10-04
Figure 4. Neutral static stability.

Dynamic Stability
The actions a body takes in response to its static stability properties show its dynamic (active) stability. This dynamic stability usually is considered to be the time history of a body’s response to its inherent static stability.

Take the example of the steel ball and the bowl. Figure 2 shows that the ball, when inside, tends to stay in the center of the bowl—it has positive static stability. It requires force to displace it up the side, and it returns immediately to its original position.

Now suppose you push the steel ball well up the side of the bowl and quickly release it. The ball will roll toward the center position, overshoot, and return, keeping this up with ever shortening oscillations until finally it returns to rest in the center. The ball has positive static stability because it resists your pushing it up the side and has positive dynamic stability because its actions tend to return it to the original position. That is, the oscillations about its original position become less and less until it stops at the original point. This is called periodic motion; the ball makes a complete oscillation in a given interval of time or period. These periods remain approximately the same length (exactly the same under theoretical conditions) even though the amplitude (movement) is less and less.

You can also see periodic motion by suspending a heavy weight on a string, making a homemade pendulum. The pendulum at rest has positive static stability—it resists any attempt to displace it. It has positive dynamic stability in that it finally returns to its original position through a series of periodic oscillations of decreasing amplitude.

The ball in the bowl could be given the property of aperiodic (nontimed) positive dynamic stability by filling the bowl with a heavy liquid such as oil (Figure 5). The liquid would damp the oscillations to such an extent that the ball would probably return directly, though more slowly, to the original position with no overshooting and hence no periodic motion. Through manipulation of the system (adding oil), you have caused its motions to be aperiodic.

Fig10-05
Figure 5. A periodic positive dynamic stability.

Unlike the steel ball inside the bowl, which is statically stable, resists any displacement, and has positive dynamic stability, a properly designed airplane does not necessarily have positive dynamic stability under all conditions (see the section, Longitudinal Dynamic Stability of the Airplane, later in this chapter). And the fact that an airplane sometimes has positive static stability does not mean that its dynamic stability is also positive. Outside forces may act on the airplane so that the oscillations stay the same or even become greater.

Back to the ball inside the bowl. Suppose you start the ball rolling and then rock the bowl with your hand so that the oscillations do not decrease. Because of the outside force you set up, the ball’s oscillations retain the same amplitude. The system has positive static stability but neutral dynamic stability—the ball’s oscillations continue without change. The airplane may also be affected by outside (aerodynamic) or inside (pilotinduced) forces that result in undiminishing oscillations, or neutral dynamic stability, even though it is properly balanced, or statically stable.

Now suppose you rock the bowl even more violently. The ball’s oscillations get greater and greater until it shoots over the side. You introduced an outside factor that resulted in negative dynamic stability—the oscillations increasing in size until structural damage occurred (the ball went over the side).

Thus, the system (or airplane) with positive static stability may have positive, neutral, or negative dynamic stability. A system that is statically stable will have some form of oscillatory behavior. This tendency may be so heavily damped (the oil in the bowl) that it is not readily evident. The oscillations show that the system is statically stable; the ball (or airplane) is trying to return to the original position. Outside forces may continually cause it to equally overshoot this position or may be strong enough to cause the oscillations to increase until structural damage occurs.

For a system that has neutral static stability such as a ball on a smooth flat plate, there are no oscillations because the ball isn’t trying to return to any particular position. It’s displaced and stays displaced.

A system that has negative static stability or is statically unstable (the terms mean t he same thing) will have no oscillations; there will be a steady divergence. Let’s use the ball and bowl again. This time turn the bowl over and balance the ball carefully on the peak (sure you can) and take another look at the statically unstable system (Figure 6).

Fig10-06
Figure 6. A statically unpredictable system.

If even a small force is applied, the ball rolls down the side of the bowl. The ball does not resist any force to offset it from its position—on the contrary, it wants to leave in the first place and when displaced leaves its original position at a faster and faster rate. There are no oscillations because there is no tendency to return at all. The statically unstable system has no dynamic (oscillatory) characteristics but continually diverges. The action this system takes in diverging is not always that simple, but that we’ll leave for the programmers. A statically stable system (or airplane) may have either positive, neutral, or negative dynamic stability characteristics.

We’ll show how this applies to you as a pilot in our next posts on aircraft performance.

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CFI Brief: Flight Safety in the Drone Age (FSDA)

Drones, yes drones. A very common term you hear these days, they just seem to be everywhere (LITERALLY)! As a matter of fact there are actually more registered drone operators then there are aircraft pilots. This is pretty astonishing, particularly when you put into perspective just how new of a concept drone use is to the general public.

What many drone operators fail to understand is the safety risks associated sharing airspace with an existing community of manned aircraft. The FAA is working feverishly to educate the public on drone safety but it is also important to educate yourself as an aircraft pilot on these new challenges within the national airspace system. The most obvious concern is that of a midair collision between a manned aircraft and drone, the likelihood of which is ever increasing as drone flight becomes more commonplace.

On June 1st, the Aviators Model Code of Conduct (AMCC) Initiative released its latest product, Flight Safety in the Drone Age (FSDA).

“FSDA offers voluntary guidance to advance the safety of flight when operating near unmanned aircraft, or drones.” –AMCC Initiative

FSDA

You can view the FSDA Guidance document by clicking on the image above. The AMCC Initiative considers the FSDA to be a living guidance document that will be updated as needed. It is organized into 5 sections in alignment with the phases of flight (General Education and Preparation, Preflight Operations, In-flight Operations, Post-flight Operations, and Aviation Community). Also available are an FSDA Safety Awareness Poster and technical paper, Managing Risks in the Presence of Unmanned Aircraft. This is excellent information for you to get acquainted with your new airspace neighbors. For additional file formats of this information visit secureav.com/drones.

And to wrap up today’s post I’ll leave you with this classic, sure to be stuck in your head the rest of the day!

Highway to the danger drone zone!

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Weather: Turbulence

This week: turbulence. Some degree of turbulence is almost always present in the atmosphere and pilots quickly become accustomed to slight turbulence. Moderate or severe turbulence, however, is uncomfortable and can even overstress the airplane. Today we’ll talk about its causes and share some best-practices when encountering turbulence. Words and pictures have been excerpted from our textbook The Pilot’s Manual Volume 2: Ground School.

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Friction and obstacles affect the surface wind.

Where to Find Turbulence
The surface wind may bear no resemblance to the gradient wind at 2,000 feet AGL and above if it has to blow over and around obstacles such as hills, trees, and buildings. The wind will form turbulent eddies, the size of which will depend on both the size of the obstructions and the wind strength. This is known as frictional turbulence or mechanical turbulence.

Winds that flow over a mountain and down the lee side can be hazardous to aviation, not only because the air may be turbulent, but also because an airplane flying toward the mountain from the downwind or lee side will have to “climb” into the downflowing winds even to maintain altitude. For this reason, you should maintain a vertical clearance of several thousand feet above mountainous areas in strong wind conditions. Weather phenomena associated with mountains are known as orographic effects. There may also be local wind effects near mountains, such as valley winds and the katabatic winds that flow down cool slopes at night and in the morning.

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Avoid flying near mountains in strong winds.

Large mountains or mountain ranges cause an effect on the wind that may extend well above ground level resulting in mountain waves, possibly with associated lenticular clouds. These clouds are continuously forming and dissipating as they stand over the mountain, and do not appear to move. This may lead you to think that there is little or no wind present—definitely not the case.The up-currents and down-currents associated with mountain waves can be quite strong, and can extend for 30 or 40 miles downwind of the mountains.

Turbulence can also be expected at high altitudes in the vicinity of any jet streams (tubes of strong wind flowing for many hundreds or thousands of miles, usually from west to east). Turbulence above 15,000 feet AGL that is not associated with cumuliform clouds is known as clear air turbulence (CAT). If there is a change in wind strength of more than about 6 knots per 1,000 feet of altitude change, then moderate or stronger clear air turbulence is likely to exist.

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Vertical gusts increase the angle of attack, and will increase the load factor and/or stall the wings.

Flying in Turbulence
Vertical gusts increase the wing’s angle of attack, causing an increase in the lift generated at that particular airspeed and therefore an increased load factor. Of course, if the angle of attack is increased beyond the critical angle, the wing will stall; this can occur at a speed well above the published 1g stall speed (known as an accelerated stall).
The load factor (or g-force) is a measure of the stress on the airplane and each category of airplane is built to take only certain load factors. It is important that these load factors are not exceeded. One means of achieving this is to fly the airplane at the turbulence-penetration speed (VB) which is usually slower by some 10–20% than normal cruise speed, but not so slow as to allow the airplane to stall, remembering that in turbulence the airplane may stall at a higher indicated airspeed than that published. When encountering turbulence:

  • fasten the seat belts;
  • maintain the level flight attitude for the desired flight phase (climb, cruise or descent), using whatever aileron movements are needed to retain lateral control, but be fairly gentle on the elevator to avoid over-stressing the airframe structurally through large changes in angle of attack and lift, and be prepared to accept variations in altitude; and
  • use power to maintain speed, aiming to have the airspeed fluctuate around the selected turbulence penetration speed, which may require reducing power; the airspeed indicator will probably be fluctuating and so will be less useful than normal.

It is obviously better to avoid turbulence, and to some extent this is possible. Avoid flying underneath, in or near thunderstorms where changes to airflow can be enormous. Avoid flying under large cumulus clouds because of the large updrafts that cause them. Avoid flying in the lee of hills when strong winds are blowing, since they will tumble over the ridges and possibly be quite turbulent as well as flowing down and into valleys at a rate which your airplane may not be able to out-climb. Avoid flying at a low level over rough ground when strong winds are blowing.

We’ll have more, as always, from our CFI on Thursday. Want to get the Learn to Fly Blog delivered straight to your email? Subscribe using the form at the top of the sidebar. Your information will never be shared.

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CFI Brief: Runway Safety Areas (RSA)

This video is an update to the FAA’s Runway Safety Area Improvement Program and Runway Incursion Mitigation Program. The majority of the discussion in the video is in reference to commercial-use airports, typically those Class B and C airports in which commercial air traffic operates. However, I believe anyone can benefit from the information presented here. It’s good to have an understanding and knowledge of what the FAA is doing on a daily basis to keep air travel safe for all. One day you may just find yourself operating in these types of environments as a corporate or commercial airline pilot!

RSA Video

May 18, 2016 | Running time 7:49 The video outlines the FAA’s efforts to improve runway safety at the nation’s airports through the runway safety area and the runway incursion mitigation programs.


ASA will be closed on May 30 in observance of Memorial Day. The Learn to Fly Blog’s regular Monday post will appear on Tuesday.

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Procedures and Airport Operations: Visual Glideslope Indicators

It’s been a while since we’ve talked about procedures and airport operations, so today we’ll introduce three visual approach slope indicator (VASI) systems. Visual glideslope indicators provide the pilot with glidepath information that can be used for day or night approaches. By maintaining the proper glidepath as provided by the system, a pilot should have adequate obstacle clearance and should touch down within a specified portion of the runway. Today’s post comes from the Pilot’s Handbook of Aeronautical Knowledge.

VASI installations are the most common visual glidepath systems in use. The VASI provides obstruction clearance within 10° of the runway extended runway centerline, and to four nautical miles (NM) from the runway threshold.

The VASI consists of light units arranged in bars. There are 2-bar and 3-bar VASIs. The 2-bar VASI has near and far light bars and the 3-bar VASI has near, middle, and far light bars. Two-bar VASI installations provide one visual glidepath which is normally set at 3°. The 3-bar system provides two glidepaths, the lower glidepath normally set at 3° and the upper glidepath ¼ degree above the lower glidepath.

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Two-bar VASI system.

The basic principle of the VASI is that of color differentiation between red and white. Each light unit projects a beam of light, a white segment in the upper part of the beam and a red segment in the lower part of the beam. The lights are arranged so the pilot sees the combination of lights (shown in the figure below) to indicate below, on, or above the glidepath.

A precision approach path indicator (PAPI) uses lights similar to the VASI system except they are installed in a single row, normally on the left side of the runway.

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Precision approach path indicator.


A tri-color VASI system consists of a single light unit projecting a three-color visual approach path. Below the glidepath is indicated by red, on the glidepath is indicated by green, and above the glidepath is indicated by amber. When descending below the glidepath, there is a small area of dark amber. Pilots should not mistake this area for an “above the glidepath” indication. NOTE: The FAA is moving away from this system and it will be discontinued soon.

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Tri-color visual approach slope indicator.


As always, we’ll have more on Thursday from our CFI. If you’d like to receive new posts from the Learn to Fly Blog via email, use the form at the top of the sidebar to sign up. And follow ASA on Facebook, Twitter, and Instagram to see what we’re working on.

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