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CFI Brief: Flying into EAA AirVenture 2016?

Flying to EAA AirVenture in Oshkosh, Wisconsin this year? Well if so you will be just one of the more than 10,000 landings that will take place at Whitman Regional Airport over the week. Insane yes, but don’t let that high number deter you from flying in, it’s almost a rite of passage and will end up being a highlight you look back on for years to come.

If this will be your first time flying in, you should note that because of the increase of traffic at and around the airport, typical procedures are not in effect. Things can get a little different, so don’t be surprised if ATC assigns you a colored dot as your touch down point. It’s just one of those things that will make this fly-in experience a highlight in your logbook.

Runway Pink Dot

Every year a special Notice to Airmen (NOTAM) is issued. This NOTAM is available as a free 32-page publication containing a wealth of pertinent information including arrival/departure procedures, radio frequencies, and various other airport information. It’s a must that you conduct a thorough preflight plan that includes reading through and understanding the information contained within this NOTAM. As the pilot in command, this will ensure your safety, as well as those around you. You can download a free copy by clicking on the image below. Also be sure to check out additional information on the EAA Fly In page: http://www.eaa.org/en/airventure/eaa-fly-in-flying-to-oshkosh

NOTAM Oshkosh

I will not be flying myself in this year, but rather kicking back in row 11 of a 737 eating peanuts. But I will be there along with the rest of the ASA crew! Be sure to come by and check us out in Hanger B isle D taking up just about half the row! We will have a ton of pilot supplies and training materials onsite – old favorites and brand new titles. So if you’re looking to start a new rating or certificate and need training content we’ve got you covered. Or if you’re getting ready to fill up your logbook and need a new one, we will have a bunch to choose from, including pink!

See you at EAA AirVenture 2016!

 

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Regulations: Accident Reporting

You’ve planned for every outcome but what do you do when the unexpected happens? Here’s what Bob Gardner says in The Complete Private Pilot.

National Transportation Safety Board Regulations, Part 830: These regulations govern accidents and accident reporting. They are not Federal Aviation Administration regulations, but need discussion as they lay out the rules for accident and incident reporting that pilots need to know.

The first thing you should know about Part 830 is the difference between an accident and an incident. An accident is an occurrence during which any person suffers death or serious injury, or one in which the aircraft receives substantial damage. There are fine points on just what constitutes serious injury, of course. The NTSB definition is hospitalization for more than 48 hours commencing within 7 days of the injury. An incident is an occurrence, other than an accident, which affects the safety of operations.

The following incidents require that the NTSB be notified:

  1. Flight control malfunction or failure.
  2. Inability of a required flight crewmember to perform flight duties as a result of injury or illness.
  3. Failure of structural components of a turbine engine, excluding compressor and turbine blades and vanes.
  4. In-flight fire.
  5. Aircraft collide in flight.
  6. Failure of Electronic Flight Information System and/or primary flight display.
  7. Collision avoidance system warnings received while operating under instrument flight rules.
  8. Propeller failure resulting from anything other than a ground strike.
  9. The NTSB must also be notified when an aircraft is overdue and is believed to have been involved in an accident.

The following types of damage are exempt from being defined as “substantial damage”:
Engine failure, damage limited to an engine, bent fairings or cowling, dented skin, small puncture holes in the skin or fabric, ground damage to rotor or propeller blades, damage to landing gear, wheels, tires, flaps, engine accessories, brakes, or wing tips.

In practical terms, this means that a gear-up landing in which no one was seriously injured is not a reportable accident. A fire while taxiing is not a reportable accident. Running into a structure or another airplane on the ground is not reportable. Failure of flaps to extend (or failure of one flap to extend) is not reportable, because flaps are not flight controls.

When a reportable accident does occur, the NTSB is to be notified immediately (this is usually, but not always, done by the FAA). If a written report is required, it must be submitted within 10 days. Also, don’t let anyone touch or move the airplane until the NTSB arrives at the scene, except to protect the wreckage from further damage or to protect the public from injury.

Memory Aid: Notify immediately, report within 10 days.

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CFI Brief: Status on Third-Class Medical Reform

Good news: the FAA will not be shutting down on July 15th! Say what?  That’s right the current FAA extension act was set to expire on July 15th. Lucky for us, and pretty much anyone who travels by air, the House,after much back and forth between senate, passed the “FAA Extension, Safety, and Security Act of 2016,” (technically known as H.R. 636) which will keep the FAA running through September 2017. H.R. 636 now moves on to be signed into law any day now by the President of the United States.

H.R. 636 contains numerous legislation and bills un-related to aviation, so other than the obvious that the FAA will be continuing operations, what about all this is important? Medical reform. The same third-class medical reform that has already passed three previous times in the senate has now passed through the house as part of this legislation and is set to be signed into law! This does not mean that the Title 14 Code of Federal Regulations will change immediately, the FAA has up to one year to develop and issue such exemptions.  As the FAA goes through this process it will be important to keep a close eye on all regulatory changes over the next 12 months.

Pre-Order Today, Shipping August 10th!

Pre-Order Today, Shipping August 10th!

Be sure to pick up your 2017 FAR/AIM which begins shipping August 10th, this is your best resource for current regulatory and procedural information. Changes to the Federal Aviation Regulations can occur daily via the Federal Registers, and the Aeronautical Information Manual is updated every 6 months. ASA keeps you current by publishing the FAR/AIM Series annually, providing online Updates and an email subscription service so you’re notified when a change has been made affecting the information in your books. To be advised when regulatory changes occur due to third-class medical reform, make sure to sign up by following the link below.

Sign up for Federal Aviation Regulatory Changes

AOPA has been at the forefront of the fight for medical reform and for more information I recommend you check out their FAQ page or shoot us a question in the comments section.

AOPA FAQ’s on Medical Reform

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IFR: Instrument Scanning

This week we’re back with more on IFR. Go back and familiarize yourself with the basics we’ve introduced in earlier introductory posts from this year. Today, we’ll look at instrument scanning techniques. This post features text and images from The Pilot’s Manual Volume 3: Instrument Flying.

In instrument conditions, when the natural horizon cannot be seen, pitch attitude and bank angle information is still available to the pilot in the cockpit from the attitude indicator. The pitch attitude changes against the natural horizon are reproduced in miniature on the attitude indicator.

In straight-and-level flight, for instance, the wings of the miniature airplane should appear against the horizon line, while in a climb they should appear one or two bar widths above it.

02-01

The AI is the master instrument for pitch attitude and bank angle.

In a turn, the wing bars of the miniature airplane will bank along with the real airplane, while the horizon line remains horizontal. The center dot of the miniature airplane represents the airplane’s nose position relative to the horizon. Today, there are a variety of attitude indicators you might see. Some are referred to as a primary flight display (PFD). In any display, the principles remain the same: the center dot or center point’s position relative to the horizon indicates a climb or descent.

Scanning the instruments with your eyes, interpreting their indications and applying this information is a vital skill to develop if you are to become a good instrument pilot. Power is selected with the throttle, and can be checked (if required) on the power indicator. Pitch attitude and bank angle are selected using the control column, with frequent reference to the attitude indicator. With both correct power and attitude set, the airplane will perform as expected. The attitude indicator and the power indicator, because they are used when controlling the airplane, are known as the control instruments. The actual performance of the airplane, once its power and attitude have been set, can be cross-checked on what are known as the performance instruments—the altimeter for altitude, the airspeed indicator for airspeed, the heading indicator for direction, and so on.

02-02

ASA flight timer.


A valuable instrument, important in its own right, is the clock or timer. Time is extremely important in instrument flying. The timer is used:

  • in holding patterns (which, for example, may be racetrack patterns with legs of 1 or 2 minutes duration);
  • in timed turns (a 180° change of heading at standard-rate of 3° per second taking 60 seconds); and
  • to measure time after passing certain radio fixes during instrument approaches (at 90 knots groundspeed, for instance, it would take 2 minutes to travel the 3 NM from a particular fix to the published missed approach point).
02-03

Layout of a typical instrument pane:on the left, a PFD, on the right, an MFD.

Another area on the instrument panel contains the navigation instruments, which indicate the position of the airplane relative to selected navigation facilities. These NAVAIDs will be considered in detail later in your training, but the main ones are:

  • VHF omni range (VOR) cockpit indicator, which indicates the airplane’s position relative to a selected course to or from the VOR ground station;
  • automatic direction finder (ADF), which has a needle that points to a nondirectional beacon (NDB); and
  • distance measuring equipment (DME) or VORTAC, which indicates the slant distance in nautical miles to the selected ground station.

Instrument scanning is an art that will develop naturally during your training, especially when you know what to look for. The main scan to develop initially is that of the six basic flight instruments, concentrating on the AI and radiating out to the others as required. Then as you move on to en route instrument flying, the navigation instruments will be introduced. Having scanned the instruments, interpreted the message that they contain, built up a picture of where the airplane is and where it is going, you can now control it in a meaningful way.

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CFI Brief: Packing your first flight bag!

Hot off the press, July/August issue of FAA Safety Briefing! This summer’s issue contains some great content specifically for the student pilot and airman-in-training. It’s the third part in a string of Student Pilot Guides that will provide the reader with tips and resources for success in initial pilot certification. I enjoyed reading this article in particular, Here’s My Advice – Tips from Top CFIs on page 14. The article provided invaluable insights from the past winners of the “Flight Instructor of the Year” award, many of whom are also notable ASA authors.

FAA Safety Brief

Another article that hit home was Perfect Picks for Potential Pilots, on page 8. The article is spot on and goes over the basics of what every student pilot needs. It addresses an all too familiar question: what books and pilots supplies do I need as a student pilot? ASA is the leading publisher of aviation books and largest provider of training supplies in the U.S. so you can imagine how often this question comes up. Truly though it’s a fun question to answer; students are often extremely excited about purchasing their initial training material and I often get to be there to help point them in the right direction. Packing your first flight bag is more fun than any back-to-school backpack! Today I would like to further expand upon the article and point you in a direction for success.

First and foremost you will need a textbook that covers the aeronautical knowledge areas required to earn your initial pilot certification. There are many different options available to you and I have narrowed it down to three of ASA’s top sellers and my personal recommendations.

(Choose 1)

Next up is a must for every aviator! A current and valid copy of the FAR/AIM; this is a yearly publication so it will need to be purchased once a year. It is a combination of the Federal Aviation Regulations pertinent to pilots and Aeronautical Information Manual, hence the title FAR/AIM. Trust me you will become very familiar with this publication…very familiar.

The Airman Certification Standards: Private Pilot Airplane, this is a new publication and replaces the Practical Test Standards. The ACS serves as a guide to help you understand what you must know, do, and consider for your FAA Knowledge Exam and Checkride to earn your private pilot certificate.

To prepare you further for the FAA Knowledge Exam you will want to pick up a copy of either a Test Prep book or Prepware software. Both contain the same pertinent information, it is just delivered in two different media formats, it’s more of a personal preference as to which you choose, depending on your preferred study methods.

(Choose 1, or pick up a bundle package of both)

I have outlined just the basic training materials in which you will need to get started. Although some books titles may still be required you might find yourself more of a digital or visual learner. Rather than purchasing the above listed books you might try the comprehensive ASA Private Pilot Online Ground School.

GS-PVT_HiRes

Private Pilot Online Ground School

In addition to the training materials you will need to pick up a few pilot supplies to get started.

AirClassic Pilot Backpack

AirClassic Pilot Backpack

As I’ve said these are just some basics to help get you pointed in the right direction. It’s poignant to note that not everyone learns in the same manner, one might prefer physical books and reading compared to another who prefers more visuals and online content. I am happy to help tailor a custom list of materials to help get you on your way, whether for a Private Pilot Certificate or Flight Instructor Certificate feel free to drop us an email or call.

CFI@asa2fly.com

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Aerodynamics: Propeller Basics

Back to basics today on the Learn to Fly Blog: your propeller. The aircraft propeller consists of two or more blades and a central hub to which the blades are attached. Each blade of an aircraft propeller is essentially a rotating wing, and thus the blades act like airfoils producing thrust. Today’s post comes from the Pilot’s Handbook of Aeronautical Knowledge.

A cross-section of a typical propeller blade is shown in figure 1. This section or blade element is an airfoil comparable to a cross-section of an aircraft wing. One surface of the blade is cambered or curved, similar to the upper surface of an aircraft wing, while the other surface is flat like the bottom surface of a wing. The chord line is an imaginary line drawn through the blade from its leading edge to its trailing edge. As in a wing, the leading edge is the thick edge of the blade that meets the air as the propeller rotates.
4-35
Figure 1. Airfoil sections of propeller blade.

Blade angle, usually measured in degrees, is the angle between the chord of the blade and the plane of rotation and is measured at a specific point along the length of the blade. Because most propellers have a flat blade “face,” the chord line is often drawn along the face of the propeller blade. Pitch is not blade angle, but because pitch is largely determined by blade angle, the two terms are often used interchangeably. An increase or decrease in one is usually associated with an increase or decrease in the other.
4-36
Figure 2. Propeller blade angle.

The pitch of a propeller may be designated in inches. A propeller designated as a “74-48” would be 74 inches in length and have an effective pitch of 48 inches. The pitch is the distance in inches, which the propeller would screw through the air in one revolution if there were no slippage. When specifying a fixed-pitch propeller for a new type of aircraft, the manufacturer usually selects one with a pitch that operates efficiently at the expected cruising speed of the aircraft. Every fixed-pitch propeller must be a compromise because it can be efficient at only a given combination of airspeed and revolutions per minute (rpm). Pilots cannot change this combination in flight.

When the aircraft is at rest on the ground with the engine operating, or moving slowly at the beginning of takeoff, the propeller efficiency is very low because the propeller is restrained from advancing with sufficient speed to permit its fixed-pitch blades to reach their full efficiency. In this situation, each propeller blade is turning through the air at an AOA that produces relatively little thrust for the amount of power required to turn it.

To understand the action of a propeller, consider first its motion, which is both rotational and forward. As shown by the vectors of propeller forces in figure 2, each section of a propeller blade moves downward and forward. The angle at which this air (relative wind) strikes the propeller blade is its AOA. The air deflection produced by this angle causes the dynamic pressure at the engine side of the propeller blade to be greater than atmospheric pressure, thus creating thrust. The shape of the blade also creates thrust because it is cambered like the airfoil shape of a wing. As the air flows past the propeller, the pressure on one side is less than that on the other. As in a wing, a reaction force is produced in the direction of the lesser pressure. The airflow over the wing has less pressure, and the force (lift) is upward. In the case of the propeller, which is mounted in a vertical instead of a horizontal plane, the area of decreased pressure is in front of the propeller, and the force (thrust) is in a forward direction. Aerodynamically, thrust is the result of the propeller shape and the AOA of the blade.

Thrust can be considered also in terms of the mass of air handled by the propeller. In these terms, thrust equals mass of air handled multiplied by slipstream velocity minus velocity of the aircraft. The power expended in producing thrust depends on the rate of air mass movement. On average, thrust constitutes approximately 80 percent of the torque (total horsepower absorbed by the propeller). The other 20 percent is lost in friction and slippage. For any speed of rotation, the horsepower absorbed by the propeller balances the horsepower delivered by the engine. For any single revolution of the propeller, the amount of air handled depends on the blade angle, which determines how big a “bite” of air the propeller takes. Thus, the blade angle is an excellent means of adjusting the load on the propeller to control the engine rpm.

The blade angle is also an excellent method of adjusting the AOA of the propeller. On constant-speed propellers, the blade angle must be adjusted to provide the most efficient AOA at all engine and aircraft speeds. Lift versus drag curves, which are drawn for propellers, as well as wings, indicate that the most efficient AOA is small, varying from +2° to +4°. The actual blade angle necessary to maintain this small AOA varies with the forward speed of the aircraft.

Fixed-pitch and ground-adjustable propellers are designed for best efficiency at one rotation and forward speed. They are designed for a given aircraft and engine combination. A propeller may be used that provides the maximum efficiency for takeoff, climb, cruise, or high-speed flight. Any change in these conditions results in lowering the efficiency of both the propeller and the engine. Since the efficiency of any machine is the ratio of the useful power output to the actual power input, propeller efficiency is the ratio of thrust horsepower to brake horsepower. Propeller efficiency varies from 50 to 87 percent, depending on how much the propeller “slips.” Propeller slip is the difference between the geometric pitch of the propeller and its effective pitch. Geometric pitch is the theoretical distance a propeller should advance in one revolution; effective pitch is the distance it actually advances. Thus, geometric or theoretical pitch is based on no slippage, but actual or effective pitch includes propeller slippage in the air.
4-37
Figure 3. Propeller slippage.

The reason a propeller is “twisted” is that the outer parts of the propeller blades, like all things that turn about a central point, travel faster than the portions near the hub.  If the blades had the same geometric pitch throughout their lengths, portions near the hub could have negative AOAs while the propeller tips would be stalled at cruise speed. Twisting or variations in the geometric pitch of the blades permits the propeller to operate with a relatively constant AOA along its length when in cruising flight. Propeller blades are twisted to change the blade angle in proportion to the differences in speed of rotation along the length of the propeller, keeping thrust more nearly equalized along this length.
4-38
Figure 4. Propeller tips travel faster than the hub.

Usually 1° to 4° provides the most efficient lift/drag ratio, but in flight the propeller AOA of a fixed-pitch propeller varies—normally from 0° to 15°. This variation is caused by changes in the relative airstream, which in turn results from changes in aircraft speed. Thus, propeller AOA is the product of two motions: propeller rotation about its axis and its forward motion.

A constant-speed propeller automatically keeps the blade angle adjusted for maximum efficiency for most conditions encountered in flight. During takeoff, when maximum power and thrust are required, the constant-speed propeller is at a low propeller blade angle or pitch. The low blade angle keeps the AOA small and efficient with respect to the relative wind. At the same time, it allows the propeller to handle a smaller mass of air per revolution. This light load allows the engine to turn at high rpm and to convert the maximum amount of fuel into heat energy in a given time. The high rpm also creates maximum thrust because, although the mass of air handled per revolution is small, the rpm and slipstream velocity are high, and with the low aircraft speed, there is maximum thrust.

After liftoff, as the speed of the aircraft increases, the constant speed propeller automatically changes to a higher angle (or pitch). Again, the higher blade angle keeps the AOA small and efficient with respect to the relative wind. The higher blade angle increases the mass of air handled per revolution. This decreases the engine rpm, reducing fuel consumption and engine wear, and keeps thrust at a maximum. After the takeoff climb is established in an aircraft having a controllable-pitch propeller, the pilot reduces the power output of the engine to climb power by first decreasing the manifold pressure and then increasing the blade angle to lower the rpm.

At cruising altitude, when the aircraft is in level flight and less power is required than is used in takeoff or climb, the pilot again reduces engine power by reducing the manifold pressure and then increasing the blade angle to decrease the rpm. Again, this provides a torque requirement to match the reduced engine power. Although the mass of air handled per revolution is greater, it is more than offset by a decrease in slipstream velocity and an increase in airspeed. The AOA is still small because the blade angle has been increased with an increase in airspeed.

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CFI Brief: Hot Tips from ASA

It’s almost 2017! Wait, what? Well that’s the way it feels here at ASA Headquarters. As I write this the entire ASA Team is preparing for the upcoming 2016-2017 school year, and that means lots of new and updated training material is coming your way soon! Some of our 2017 products are already shipping and will continue to do so over the next couple of months. Other new products are in development as well, and as always, the FAA is making changes, posting updates, and releasing new information that may affect your aviation training. So, how are you as a busy student pilot going to keep up with it all? Don’t worry, we’ve got you covered.

Below are some great ASA resources for student pilots. You may not need them all, but there are surely some that can help you stay in-the-know and be prepared when it comes to that upcoming knowledge test or checkride.

Learn to Fly Blog email notifications—If this is your first time here, or the subscription sign-up box on the right-hand side of this page just hasn’t caught your eye, consider signing up to receive an email when a new Learn to Fly Blog post is made.

FAR/AIM Updates—The ASA FAR/AIM Series contains the most complete and up-to-date information available. With regulatory changes occurring frequently (these can happen at any time), ASA offers a free email Update subscription service. As a subscriber to this service, you will receive update notices automatically when a regulatory or procedural change is released by the FAA. Click here to subscribe.

FAA Knowledge Exam Updates—ASA provides free updates to question databases (approximately 3 times a year). The files found on this page are for use with the current and preceding year Test Prep books and Fast-Track manuals. The most recent updated took place earlier this month. The next update is expected in October 2016. Click here to subscribe to the database(s) that apply to you.

FAA Test Standard Updates—This page shows the current editions (part numbers), effective dates, and updates for the Practical Test Standards (PTS) and Airman Certification Standards for both pilots and maintenance technicians. There is no subscription for this, but you can use this online resource to check for updates prior to your checkride. Your DPE (Designated Pilot Examiner) will expect you to know the current standards at the time of your test. Visit this page and bookmark it for future reference.

Textbook Updates—This online resource contains updates to textbooks published by ASA and the FAA. Sometimes an update does not warrant a new edition, or new printing of the book. In these cases we publish (when necessary) an update or addendum to the most current printing of the book. Check here on occasion to see if there are any updates to ASA books you might have in your library.

ENROUTE—Your all-in-one resource. This monthly newsletter provides information on the newest products from ASA, as well as changes and updates to all of the resources mentioned above including updates to existing ASA products and textbooks, Federal Aviation Regulation updates, changes to the Practical Test Standards and Airman Certification Standards, updates to FAA Knowledge Exams, the latest posts from right here at the Learn to Fly Blog, training tips, links to resources and social media outlets, and much more–all in one place! Click here to subscribe.

As an aviator, it is important that you know as much as you can about current events and changes affecting not only yourself but everyone you share the sky with. Let ASA and the Learn to Fly Blog help you as you pursue your dream of flight.

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Aircraft Performance: Pitch Stability (Stability, part 2)

Before reading today’s post, go back and re-read our post on airplane stability from earlier this month. As promised, we’ll talk today about how static and dynamic stability applies to you as a pilot. We’ll pick up where we left off in Bill Kershner’s The Advanced Pilot’s Flight Manual.

The elevators control the pitch (the movement around the lateral axis). The pilot’s ability to control the airplane about this axis is very important. In designing an airplane, a great deal of effort is spent in making it stable around all three axes. But longitudinal stability (stability about the pitch axis) is considered to be the most affected by variables introduced by the pilot, such as airplane loading.

Fig10-07_fmt

Figure 1. The elevators control movement about the lateral axis (pitch).

Take a look at an airplane in balanced, straight and level flight (Figure 2). Making calculations from the center of gravity (CG), you find the moment (force × distance) about the CG caused by the wing’s lift is 5 × 3,100 or 15,500 lb-in. This is a nose-down moment. To maintain straight and level flight there must be an equal moment in the opposite direction or the airplane would be attempting to do an outside loop. This opposite moment is furnished by a down force on the tail. Its moment must be 15,500 lb-in. in a tail-down direction. The distance shown from the CG to the center of tail lift is 155 inches; therefore the down force at the tail must be 100 pounds (force × distance = 100 pounds × 155 inches). The tail-down moment is also 15,500 lb-in., which balances the nose-down moment. The airplane is statically balanced.

Fig10-08_fmt

Figure 2. Airplane in balanced straight-and-level flight.

In order for the airplane to maintain level flight, the upward forces must balance the downward forces.

Fig10-09_fmt

Figure 3. Summation of vertical forces: total up force 3,100 pounds and total down force 3,100 pounds; forces balanced.

The down forces are the airplane’s weight (3,000 pounds) and the tail-down force (100 pounds), which total 3,100 pounds. In order to balance this, the up force (lift) must be 3,100 pounds. The wing itself contributes some pitching effects.

For airplanes with fixed, or nonadjustable, stabilizers, the stabilizer is set by the manufacturer at an angle that furnishes the correct down force at the expected cruising speed and CG position.

The tail-down force is the result of propeller slipstream, downwash from the wing, and the free-stream velocity (airspeed).

Fig10-10_fmt

Figure 4. Factors contributing to the tail-down force.

Suppose you’re flying straight and level (hands-off) at the design cruise speed and power setting and suddenly close the throttle. The slipstream force suddenly drops to practically nothing; the airplane starts slowing as thrust is no longer equal to drag, and the free-stream velocity also drops. You’ve suddenly lost some of the tail-down force. The result is that the nose drops. This is a healthy situation; the airplane is trying to pick up speed and reestablish the balance.

Fig10-11_fmt

Figure 5.

Of course, as the airplane slows, lift decreases and the airplane starts to accelerate downward for a very short time, but this is not so noticeable to you as the nosing-down action.

We’ll disregard the airplane settling and think only in terms of the rotational movement caused by closing the throttle. One way of looking at it is to return to the seesaw of your earlier days. When the kid on the other end suddenly jumped off you set up your own “nose down” (the moments were no longer balanced).

You set the desired tail force for various airspeeds by either holding fore or aft wheel pressure or setting the elevator trim. If you are trimmed for straight and level flight, closing the throttle requires more up-elevator trim if you want to glide hands-off at the recommended glide speed. A propeller-driven airplane will always require less up-elevator trim for a given airspeed when using power than when in power-off conditions. You can see this for yourself the next pretty day when you’re out just flying around. Trim the airplane to fly straight and level at the recommended glide speed and use whatever power is necessary to maintain altitude. Then close the throttle and keep your hands off the wheel. You’ll find that the airspeed is greater in the power-off condition—the airplane’s nose drops until it picks up enough free-stream velocity to compensate for the loss of slipstream. This may be up to about cruise speed, depending on the airplane.

The arrangement of having the CG ahead of the center of lift, and an aerodynamic tail-down force, results in the airplane always trying to return to a safe condition. Pull the nose up and the airplane slows and the tail-down force decreases. The nose will soon drop unless you retrim it or hold it up with increased back pressure. Push the nose down and it wants to come back up as the airspeed increases the tail-down force. The stable airplane wants to remain in its trimmed conditions, and this inherent (built-in) stability has gotten a lot of pilots out of trouble.

A lifting tail is necessary on this airplane in order to maintain balance. From a purely aerodynamic standpoint, the two lifting surfaces (wing and tail) are a good idea; from a stability standpoint, this type of configuration is not so good.

Fig10-12_fmt

Figure 6. A different loading and tail force.

When you throttle back, the tail lift decreases and the nose tends to go up! This is not conducive to easy pilot control. The engineers would rather have a little less aerodynamic efficiency and more stability. So this arrangement is avoided—although it is not nearly as critical in a jet airplane. Actually, in some conditions (high CL, a tail upload may be present, even for the “standard” airplane that has a tail-down force at cruise.

The canard (horizontal-tail-first) designs have appeared again in the past few years. Some of these airplanes are quite efficient because both the wings and horizontal tail are lifting, versus the more conventional arrangement in Figure 3. One advantage of the canard-type is that it is stall and spin resistant if the forward surface is designed to lose its lift (and pitch the nose down to decrease the angle of attack of the main wing before it reaches the critical angle). The canard arrangement is not new (see photos of the Wright brothers’ first powered flight), but the state of the art has improved so much that the newer designs are making a strong impact on the industry.

We’ll pick up this topic again next month in Part 3. Check back for more on Thursday from our CFI. ASA will be closed on Monday for the Fourth of July. Thanks for reading the Learn to Fly Blog!

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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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