CFI Brief: Fireworks, Drones and Airplanes Don’t Mix

The ASA offices will be closed July 3rd and 4th for Independence Day. Happy 4th of July!

Now for a public service announcement from the FAA!

June 30– As people travel, purchase fireworks and fly drones over the Independence Day holiday, the FAA reminds them to know and follow the aviation safety rules.

Here are general guidelines for people flying drones:

  • Don’t fly your drone in or near fireworks
  • Don’t fly over people
  • Don’t fly near airports

To learn more about what you can and can’t do with your drone go to or download the B4UFLY app for free in the Apple and Google Play store. Also, check out the FAA’s July 4th No Drone Zone PSA video.
There are also strict rules prohibiting airline passengers from packing or carrying fireworks on domestic or international flights. Remember these simple rules:

  • Don’t pack fireworks in your carry-on bags
  • Don’t pack fireworks in your checked luggage
  • Don’t send fireworks through the mail or parcel services

Passengers violating the rules can face fines or criminal prosecution. When in Doubt…Leave it out!

For more information on the passenger rules for fireworks and other hazardous materials, please go to  Leave the fireworks at home–Fireworks Don’t Fly (PDF) (Poster)

As FAA works to ensure that passengers arrive at their destinations safely, it is important that you follow the rules while enjoying your drones as well as celebrating the July 4th holiday.

FAA 123

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CFI Brief: Significant Weather (SIGWX) Forecast Charts

The updated Airman Knowledge Testing Supplement for Instrument Rating (FAA-CT-8080-3F) has replaced 4 panel Low Level SIGWX Prognostic charts with updated 2 panel charts. These new figures as seen below show outlooks for both 12  and 24 hour forecast periods, with the left display being 12 hours and right 24 hours. The High Level SIGWX Prognostic chart has been updated as well with a much clearer chart. The following study information and sample test questions will help to prepare you for answering questions relating to these updated charts.

The Low-Level Significant Weather Prognostic Chart (FL240 and below) portrays forecast weather hazards that may influence flight planning, including those areas or activities of most significant turbulence and icing. It is a two-panel display representing a 12-hour forecast interval (left) and 24-hour forecast interval (right). Turbulence intensities are identified by standard symbols as shown in the figure below. The vertical extent of turbulence layers is depicted by top and base heights separated by a slant and shown in hundreds of feet MSL (180/100 = 18,000’ MSL to 10,000’ MSL). Freezing levels above the surface will correspond with a given altitude in hundreds of feet MSL (080 = 8,000’ MSL). Low-level SIGWX charts are issued four times daily, and valid time, date, and chart type are depicted in the lower left corner of each panel.

The High-Level Significant Weather Prognostic Chart (FL250 to FL630) outlines areas of forecast turbulence and cumulonimbus clouds, shows the expected height of the tropopause, and predicts jet stream location and velocity. The chart depicts clouds and turbulence as shown in the figure below.


Cumulonimbus cloud (CB) areas are enclosed by a red scalloped line. The height of the tropopause is shown in hundreds of feet MSL and enclosed in a rectangular box; centers of high (H) and low (L) heights are enclosed in polygons. Areas of turbulence are enclosed in yellow dashed lines and labeled with the appropriate severity symbol and top and base altitudes. A jet stream axis containing a wind speed of 80 knots or greater is identified by a bold green line and directional arrowhead. A standard wind symbol is placed on the jet stream to identify velocity and an associated flight level is placed adjacent to it. An omission of a base altitude (XXX) identifies that the weather phenomena exceeds the lower limit of the high-level SIGWX prog chart (FL250).

1. (Refer to Figure 18.) The right panel of the significant weather prognostic chart provides a forecast of selected aviation weather hazards up to FL240 until what time?
A—March 18th at 0600.
B—March 17th at 1800.
C—March 18th at 1800.

2. (Refer to Figure 19.) The next issuance of the 12-hour significant weather prognostic chart will become valid at

3. (Refer to Figure 20.) What is the height of the tropopause over the northwest United States?
A—45,000 feet MSL.
B—45,000 meters.
C—450,000 feet MSL.

Answers posted in the comments section. 

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CFI Brief: June 2017 Test Roll

June has been a busy month here at ASA headquarters and for the FAA. Let’s recap what all is going down in terms of Airman Testing.

The FAA has released updated Airman Certification Standards for both Private Pilot Airplane (FAA-S-ACS-6A) and Instrument Pilot Airplane (FAA-S-ACS-8A) effective June 2017. Additionally, the Commercial Pilot Airplane ACS was released, replacing the Practical Test Standards (8081-12). These are now available for purchase through the ASA website and can be found following the two links below, out with the old in with the new!

Private Pilot Airplane (ACS-6A)
Instrument Pilot Airplane (ACS-8A)
Commercial Pilot Airplane (ACS-7)


Getting ready to take the Instrument Knowledge Exam? Be aware the FAA has released the new Airman Knowledge Testing Supplement for Instrument Rating (FAA-CT-8080-3F) now in effect at all testing centers. This supplement includes several new and updated figures and is available for purchase through the ASA website. This new supplement will be included in the 2018 Instrument Pilot Test Prep books and Prepware software and apps, available late July.

Airman Knowledge Testing Supplement for Instrument Pilot (FAA-CT-8080-3F)


In terms of the Airman Knowledge Exams, the FAA is reporting no substantial changes with respect to topics covered in pilot certificate/rating test banks for this June test roll cycle. We are getting a lot of calls asking if the FAA has begun testing on the new BasicMed rules and the answer is no. The FAA expects to develop test questions on the new BasicMed regulation in the future. Third-Class Medical questions will remain, since BasicMed is an addition to the medical certification structure, not a replacement of the Third-Class Medical Certificate.

The following topics have been removed from FAA Knowledge Tests (effective June 12, 2017):

  • 4-panel prog charts
  • Weather depiction chart
  • Area forecasts
  • Aerobatic flight

June 2017 ASA Test Prep Question Updates are now available! Check the link below.



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CFI Brief: 5 Major Items Pilots Miss During Their Preflight Inspection – InfoGraphic

Today on the Learn to Fly Blog we are featuring a guest article by Alec Larson of Sun State Aviation. Thanks for the excellent article, Alec, and for all the hard work that went into producing this this!

Perhaps the most critical part of any general aviation flight is the preflight inspection of the aircraft. For most pilots, the preflight inspection follows a checklist along with a routine flow around the aircraft. Most pilots and student pilots perform what would be considered a sufficient inspection, following their checklist and routine items.

Surely 100% of pilots would be able to find discrepancies if they were present right?

Sunstate 1

Well………not exactly. Sit down, strap yourself in and get ready to read some interesting real-life statistics!

Every year at the Sun N Fun airshow the FAA partners with a local flight school to host the Project Preflight event. The purpose of the event is to test the preflight efficiency of pilots and student pilots of all ages, hours and experience. A flight school volunteers one of their airplanes for the event.

Participants are invited to preflight the aircraft like they would before any other flight – checking the fuel, oil, tire pressure and anything with blue tape is unnecessary. The catch is, the aircraft has several intentional discrepancies, some are major squawks! This year we hosted the event and gathered the data from 144 total participants.

Here are the results………

Water Bottle Lodged Behind Rudder Pedals – Out of 144 participants only 30% found this major discrepancy.

Cotter Pin Missing In Right WheelOnly 28% found this one!

Elevator Nut Missing – 39% found the nut to missing from the right side of the elevator.

Rag Behind The Alternator – Easy to spot but only 63% of participants found the rag!

Cotter Pin In Control Lock – Only 42% found a small cotter pin in place of the control lock, hard to miss but deadly if left in.

Sunstate 2

Interesting right?! The statistics are concerning to say the least, but what a great insight into a previously unknown sector of general aviation that can be used to educate pilots and future pilots.

So how can we improve these statistics?

Yes, of course we can say “pilots need to be more thorough in their inspections” or “we need to apply more focus and attention to detail during a preflight” but what are some other realistic strategies we can implement to actually achieve that?! Here’s one – maybe it’s extreme and definitely hypothetical but it’s worth pondering.

“Try to preflight the airplane as if you had just built it part by part, or just finished working on it yourself”. 

Again, hypothetical but let’s break it down. We need pilots to perform thorough inspections, how can you put yourself in that “attentive” frame of mind? If you’ve ever rotated the tires on your vehicle yourself, isn’t it likely that you’ll double check and triple check the tightness of the lug nuts before you call it a job done? The theory is that you’ll be taking more responsibility for the state of the aircraft rather than assuming the mechanic or previous pilot left the aircraft in an airworthy condition. This doesn’t mean you should become an aircraft mechanic or add an hour to your preflight, the goal is to find a way to improve our attention and focus when preflighting an airplane.

Project Preflight was certainly educational and we had an absolute blast hosting the event. On behalf of SunState Aviation we would like to thank all of the 144 participants for stopping by and giving us your time, without you this educational piece and the safety of future pilots would not be a reality!

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Ground School: Preflight Inspection

The success of a flight depends largely on thorough preparation. In the course of your training, a pattern of regular preflight actions should be developed to ensure that this is the case. This includes planning the flight, and checking the airplane. These preflight actions must be based on the checks found in the pilot’s operating handbook (POH), manufacturer’s information manual or the FAA-approved airplane flight manual (AFM) for your airplane. Today we’ll share an excerpt from The Pilot’s Manual: Flight School (PM-1C) regarding the preflight inspection of your airplane.

Preparing the Airplane
The information manual for your airplane will contain a list of items that must be checked during:

  • the preflight inspection (external and internal);
  • the preflight cockpit checks;
  • the engine power check; and
  • the before-takeoff check.

At first, these checks may seem long and complicated, but as you repeat them thoroughly prior to each flight, a pattern will soon form. It is vital that the checks are carried out thoroughly, systematically and strictly in accordance with the manufacturer’s recommended procedure. Use of written checklists, if performed correctly, will ensure that no vital item has been missed, but some pilots prefer to memorize checks. The comments that follow are only general comments that will apply to most airplanes.

The External Inspection
Always perform a thorough external inspection. This can begin as you walk up to the airplane and should include:

  • the position of the airplane being safe for start-up and taxi (note also the wind direction and the likely path to the takeoff point); and
  • the availability of fire extinguishers and emergency equipment in case of fire on start-up (a rare event, but it does happen).

Some of the vital items are:

  • all switches off (master switch for electronics, magneto switch for engine) as a protection against the engine inadvertently starting when the propeller is moved;
  • fuel check for quantity and quality (drain into a clear cup);
  • oil check; and
  • structural check.

A list of typical walkaround items is shown below. Each item must be inspected individually, but do not neglect a general overview of the airplane. Be vigilant for things such as buckling of the fuselage skin or popped rivets since these could indicate internal structural damage from a previous flight. Leaking oil, fuel forming puddles on the ground, or hydraulic fluid leaks from around the brake lines also deserve further investigation. With experience, you will develop a feel for what looks right and what does not. The walkaround inspection starts at the cockpit door and follows the pattern specified in the checklist provided by the aircraft manufacturer.

  • Parking brake on.
  • Magneto switches off.
  • Landing gear lever (if retractable) locked down.
  • Control locks removed.
  • Master switch on (to supply electrical power).
  • Fuel quantity gauges checked for sufficient fuel for the planned flight.
  • Fuel selector valves on.
  • Flaps checked for operation; leave them extended for external inspection.
  • Stall warning (if electrical) checked for proper operation.
  • Rotating beacon (and other lights) checked, then off.
  • Master switch off.
  • Primary flight controls checked for proper operation.
  • Required documents on board: MAROW plus airman certificate and medical certificate for the pilot. (Note: under some circumstances a medical certificate may not be required.)
  • Cabin door securely attached, and latches working correctly.
  • Windshield clean (use correct cloth and cleanser).


  • All surfaces, the wing tip, leading and trailing edge checked for no damage or contamination; remove any frost, snow, ice or insects (on upper leading edge especially, since contamination here can significantly reduce lift, even to the point where the airplane may not become airborne).
  • Wing tip position light checked for no damage.
  • Flaps firmly in position and actuating mechanism firmly connected and safety-wired.
  • Aileron locks removed, hinges checked, correct movement (one up, the other down) and linkages safety-wired, mass balance weight secure.
  • Pitot tube cover removed and no damage or obstructions to tube (otherwise airspeed indicator will not respond).
  • Fuel contents checked in tanks and matching fuel quantity gauge indications; fuel caps replaced firmly and with a good seal (to avoid fuel siphoning away in flight into the low-pressure area above the wing).
  • Fuel sample drained from wing tanks and from fuel strainer into a clear container. Check for correct color (blue for 100LL, green for 100-octane), correct fuel grade, correct smell (aviation gasoline and not jet fuel or kerosene), no water (being denser, water sinks to bottom), sediment, dirt or other contaminant (condensation may occur in the tanks overnight causing water to collect in the bottom of the tanks, or the fuel taken on board may be contaminated).
  • Fuel port, or fuel vent (which may be separate or incorporated into the fuel cap) clear (to allow pressure equalization inside and outside the tanks when fuel is used or altitude is changed, otherwise the fuel tanks could collapse or fuel supply to the engine could stop as fuel is used).
  • Stall warning checked (if possible).
  • Inspection plates in place.
  • Wing strut checked secure at both ends.


  • All surfaces, including underneath checked for skin damage, corrosion, buckling or other damage (corrosion appears as surface pitting and etching, often with a gray powdery deposit); advise a mechanic if you suspect any of these.
  • No fuel, oil or hydraulic fluid leaking onto the ground beneath the aircraft.
  • Inspection plates in place.
  • Static ports (also called static vents)—no obstructions (needed for correct operation of airspeed indicator, altimeter and vertical speed indicator).
  • Antennas checked for security and no loose wires.
  • Baggage lockers—check baggage, cargo and equipment secure, and baggage compartments locked.

Main Landing Gear

  • Tires checked for wear, cuts, condition of tread, proper inflation, and security of wheel and brake disk.
  • Wheel oleo strut checked for damage, proper inflation, and cleanliness.
  • Hydraulic lines to brakes checked for damage, leaks and attachment.
  • Gear attachment to the fuselage—check attachment, and be sure there is no damage to the fuselage (buckling of skin, popped rivets).

Nose Section

  • Fuselage checked for skin buckling or popped rivets.
  • Windshield clean.
  • Propeller checked for damage, especially nicks along its leading edge, cracks and security (and for leaks in the hub area if it is a constantspeed propeller).
  • Propeller spinner checked for damage, cracks and security.
  • Engine air intake and filter checked for damage and cleanliness (no bird nests or oily rags).
  • Nose wheel tire checked for wear, cuts, condition of tread, proper inflation, and security of nose wheel.
  • Nose wheel oleo strut checked for damage, proper inflation (four to six inches is typical), security of shimmy damper and other mechanisms.
  • Open engine inspection panel; check engine mounts, engine, and exhaust manifold for cracks and security (to ensure that no lethal carbon monoxide in the exhaust gases can enter the cockpit—exhaust leaks may be indicated by white stains near the cylinder head, the exhaust shroud or exhaust pipes).
  • Check battery, wiring and electrical cables for security (firmly attached at both ends).
  • Check the oil level; top up if necessary (know the correct type and grade of oil to order); ensure that the dipstick is replaced properly and the oil cap is firmly closed to avoid loss of oil in flight.
  • Close the inspection panel and check its security.

Other Side of Airplane
Repeat as appropriate.


  • Remove control locks if fitted.
  • All surfaces checked for skin damage (vertical stabilizer and rudder, horizontal stabilizer, elevator and trim tab); remove any contamination such as ice, frost or snow.
  • Control surface hinges checked for cracks, firmness of attachment, safety-wiring and correct movement.

Chocks and Tiedown Ropes
Chocks and tiedowns removed and stowed (after checking the parking brake is on).

Overall View
Stand back and check the overall appearance of the airplane. It cannot be emphasized too greatly just how important this preflight inspection by the pilot is. Even if you have no experience in mechanical things, you must train yourself to look at the airplane and notice things that do not seem right. Bring any items that you are unsure of to the attention of your flight instructor or a mechanic. At this stage, you are now ready to seat yourself in the airplane and begin the internal cockpit inspection.

The Cockpit Inspection
Always perform a thorough cockpit inspection. The cockpit inspection involves preparing the cockpit and your personal equipment for flight. It should include:

  • Parking brake set (on).
  • Required documents on board (MAROW items).
  • Flight equipment organized and arranged in an efficient manner so they are readily available in flight (flight bag, charts prefolded to show your route, computer, pencils, flashlight, and so on).
  • Fuel on.
  • Seat position and harness comfortable and secure, with the seat definitely locked in position and rudder pedals (if adjustable) adjusted and locked into position so that full movement is possible.
  • Ignition switch (magnetos) off (so that the engine is not live).
  • Master switch on (for electrical services such as fuel gauges).
  • Flight controls checked for full and free movement (elevator, ailerons, rudder and trim wheel or handle). Trim set to takeoff position.
  • Engine controls checked for full and free movement (throttle, mixture control and carburetor heat).
  • Scan the instruments systematically from one side of the panel to the other for serviceability and correct readings.
  • No circuit breakers should be popped nor fuses blown (for electrical services to operate).
  • Microphone and/or headsets plugged in (if you are to use the radio) and test intercom if used.
  • Safety equipment (fire extinguisher, first aid kit, supplemental oxygen if planning to fly high, flotation equipment for overwater flights) on board and securely stowed.
  • Loose articles stowed.
  • Checklists on board and available.
  • Read the preflight checklist, if appropriate.

Normal checklists are found in Section 4 of the typical pilot’s operating handbook, and emergency checklists are found in Section 3. Written checklists are used to confirm that appropriate procedures have been carried out, for example, the before-takeoff checklist or the engine fire checklist. In earlier days, when airplanes were simpler, checks were usually memorized. Nowadays, in more complex airplanes and in a much busier operating environment, many checks are performed with the use of standard written checklists for that airplane. Checklists are usually compiled in a concise and abbreviated form as item and condition (for example, fuel—on), where the item to be checked is listed, followed by a statement of its desired condition. Explanations for actions are usually not included in the concise checklist, but may generally be found in the pilot’s operating handbook if required.

Vital checklists are best committed to memory so that they may be done quickly and efficiently, followed by confirmation using the printed checklist if required. Emergency checklists, such as the engine fire checklist, often have some items that should be memorized, since they may have to be actioned immediately, before there is time to locate the appropriate checklist and read it. These items are often referred to as memory items or phase-one items, and are often distinguished on checklists by bold type or by being surrounded with a box. The method of using checklists may be one of:

  • carrying out the items as the checklist is read; or
  • carrying out the items in full, followed by confirmation using the checklist.

Be sure to check back Thursday for more on preflight from our CFI as well as something interesting from SunState Aviation!

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CFI Brief: FAA Taxi Test

Monday on the blog we briefly discussed runway incursions and recommended practices for pilots to avoid such an occurrence. As air traffic grows and airports become busier, both general aviation and commercial, runway incursions become more of a growing concern to pilots and airport operators. In an effort to cut down on the potential of surface movement issues the FAA has implemented programs such as defining runway hotspots and identifying standardized taxi route.

Runway Hotspots
ICAO defines runway hotspots as a location on an aerodrome movement area with a history or potential risk of collision or runway incursion and where heightened attention by pilots and drivers is necessary. Hotspots alert pilots to complex or potentially confusing taxiway geometry that could make surface navigation challenging. Whatever the reason, pilots need to be aware that these hazardous intersections exist, and they should be increasingly vigilant when approaching and taxiing through these intersections. These hotspots are depicted on some airport charts as circled areas. [Figure 1-6] The FAA Office of Runway Safety has links to the FAA regions that maintain a complete list of airports with runway hotspots at

Hot Spots

Standardized Taxi Routes
Standard taxi routes improve ground management at high-density airports, namely those that have airline service. At these airports, typical taxiway traffic patterns used to move aircraft between gate and runway are laid out and coded. The ATC specialist (ATCS) can reduce radio communication time and eliminate taxi instruction misinterpretation by simply clearing the pilot to taxi via a specific, named route. An example of this would be Los Angeles International Airport (KLAX), where North Route is used to transition to Runway 24L. [Figure 1-7] These routes are issued by ground control, and if unable to comply, pilots must advise ground control on initial contact. If for any reason the pilot becomes uncertain as to the correct taxi route, a request should be made for progressive taxi instructions. These step-by-step routing directions are also issued if the controller deems it necessary due to traffic, closed taxiways, airport construction, etc. It is the pilot’s responsibility to know if a particular airport has preplanned taxi routes, to be familiar with them, and to have the taxi descriptions in their possession. Specific information about airports that use coded taxiway routes is included in the Notices to Airmen Publication (NTAP).

Standardized Taxi Routes
The best way you as a pilot can prevent a runway incursions is by being familiar with your surroundings and understanding the airport environment and standardized procedures that are in place. The FAA Safety Team has put together an excellent video and taxi test that will test your knowledge of procedures and operations on the airport movement area. I encourage you to spend 60 minutes and take the course.

The FAA Taxi Test

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Procedures and Airport Operations: Runway Incursions

Learn to reduce your risk of a runway incursion by following these simple FAA recommendations outlined in the Instrument Procedures Handbook (FAA-8083-16A).

On any given day, the NAS may handle almost 200,000 takeoffs and landings. Due to the complex nature of the airport environment and the intricacies of the network of people that make it operate efficiently, the FAA is constantly looking to maintain the high standard of safety that exists at airports today. Runway safety is one of its top priorities.

The FAA defines a runway incursion as:
“Any occurrence at an aerodrome involving the incorrect presence of an aircraft, vehicle, or person on the protected area of a surface designated for the landing and takeoff of aircraft.”

The four categories of runway incursions are listed below:
Category A—a serious incident in which a collision was narrowly avoided.
Category B—an incident in which separation decreases and there is a significant potential for collision that may result in a time critical corrective/evasive response to avoid a collision.
Category C—an incident characterized by ample time and/or distance to avoid a collision.
Category D—an incident that meets the definition of runway incursion, such as incorrect presence of a single vehicle/person/aircraft on the protected area of a surface designated for the landing and takeoff of aircraft but with no immediate safety consequences.

The below figure highlights several steps that reduce the chances of being involved in a runway incursion.

Fig 1-5


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Aerodynamics: Power

Today’s post is excerpted from the second edition of our textbook Aerodynamics for Aviators. This book features extensive illustrations and covers everything from the fundamentals of flight to high-speed flight, and includes an excellent compendium of formulae and equations used at all levels of aviation.

Aircraft aerodynamics involves the interaction of the four forces: lift, weight, thrust, and drag. The first basic issue to understand is the difference between propeller-driven aircraft power and jet engine thrust. Power is what a propeller-driven engine produces; thrust is what a jet engine produces. In a propeller-driven aircraft, the propeller—not the engine—is said to produce thrust. The thrust on a propeller-driven aircraft decreases with an increase in velocity; in a jet aircraft, thrust remains relatively constant with an increase in aircraft velocity.

(A) Thrust vs. velocity, jet engine; (B) Thrust vs. velocity, propeller-driven engine.

(A) Thrust vs. velocity, jet engine; (B) Thrust vs. velocity, propeller-driven engine.

Therefore, the power required curve versus the power available curve for a propeller driven aircraft and a jet aircraft will look different.

Power required versus power available (A) for a jet engine and (B) for a propeller-driven aircraft.

Power required versus power available (A) for a
jet engine and (B) for a propeller-driven aircraft.

Propeller Efficiency
Propeller efficiency is a measure of how much power is absorbed (transmitted) by the propeller and turned into thrust. In order to understand propeller efficiency, it’s helpful to start with a basic review of propeller principles. Propellers on aircraft consist of two or more blades and a hub. The blades are attached to the hub, and the hub is attached to the crankshaft on a piston-powered aircraft and to a gear reduction box on most turbo-prop aircraft. The propeller is simply a rotating wing that produces lift along the vertical axis. We call this lift force thrust.

Forces in flight.

Forces in flight.

Looking at a cross section of the propeller blade, we can see that it is similar to a cross section of an aircraft wing. The top portion of the blade is cambered like the top surface of a wing. The bottom portion is flat like the bottom surface of a wing.

Propeller cross section.

Propeller cross section.

The chord line is an imaginary line drawn from the leading edge of the propeller blade to the trailing edge of the propeller blade. Blade angle, measured in degrees, is the angle between the chord of the blade and the plane of rotation. The pitch of the propeller is usually designated in inches. A “78-52” propeller is 78 inches in length with an effective pitch of 52 inches. The effective pitch is the distance a propeller would move through the air in one revolution if there were no slippage. On a “78-52” propeller this distance would be 52 inches.

Propeller blade angle.

Propeller blade angle.

There are two types of propellers that can be installed on most general aviation aircraft: a fixed-pitch propeller or a controllable-pitch propeller. The fixed-pitch propeller is at the blade angle that will give it the best overall efficiency for the type of operation being conducted and for which the aircraft was designed. For most aircraft this would be a cruise setting. A controllable-pitch propeller allows the pilot to adjust the blade angle for the different phases of flight. On takeoff and climb out, a low pitch/high RPM setting is used. During cruise flight a high pitch/low RPM setting is generally used.

On the ground with the aircraft in a static condition, the propeller efficiency is very low because each blade is moving through the air at an angle of attack that produces a very low thrust to power ratio. This means that a lot of power is being used to sustain the engine and rotate the propeller while very little thrust is being produced. The propeller, unlike the wing, moves both rotationally and forward (dynamically). The angle at which the relative wind strikes the propeller blade is the AOA. This produces a higher dynamic pressure on the engine side, which in turn is called thrust. Thus thrust is the relationship of propeller AOA and blade angle.

Propeller blade angle with forward velocity.

Propeller blade angle with forward velocity.

Since an aircraft moves forward through the air, it is important that the pilot understands how forward velocity affects the AOA of the propeller. The figure above shows the propeller in a static condition on the ground. At this point the relative wind is opposing propeller rotation. As forward velocity increases, the relative wind moves closer to the chord line, decreasing the propeller AOA. This can easily be demonstrated in an aircraft with a fixed-pitch propeller by pitching up or down without changing power. When the aircraft is pitched down, RPM will increase as the relative wind moves closer to the chord line and the AOA is decreased. When the aircraft is pitched up, the RPM will decrease as the relative wind moves farther from the chord line and the AOA is increased.

Propeller efficiency is a ratio between thrust horsepower and brake horsepower. Brake horsepower (BHP) is the horsepower actually delivered to the output shaft. Brake horsepower is the actual usable horsepower. Thrust horsepower (THP) is the power that is imparted by the propeller to the air. Propeller efficiency is the relationship between brake horsepower and thrust horsepower. If the BHP of the engine is 200, the THP is less (20–40%). Some power is lost to turn the engine and propeller. Propeller efficiency usually varies between 50 and 80% on light general aviation aircraft.

The measure of efficiency is how much a propeller slips in the air. This is measured by the geometric pitch (theoretical) which shows a propeller with no slippage. Effective pitch is the distance that the propeller actually travels.

Propeller efficiency.

Propeller efficiency.

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CFI Brief: Calling all Student Pilots!

Share your flying story with the Learn to Fly Blog

We’re looking for student pilot stories dealing with overcoming challenges, lessons-learned, or insights-gained, humorous or serious. If selected, your story will be published on the Learn to Fly Blog! This is an ongoing call for submissions and there’s no deadline. Once selected your story will be professionally edited and published this summer to the Learn to Fly Blog for all your family, friends, and future employers to see!

Send you story (minimum 500 words) as a .doc or .rtf file to

Include your name, school, current number of hours, and a short bio (optional).



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Procedures and Airport Operations: Normal Landing

A good landing is most likely following a good approach, so aim to be well established in a stabilized approach with the airplane nicely trimmed by the time you reach short final, the last part of the approach. Short final for a training airplane may be thought of as the last 200 feet.

The landing starts with a flare commencing when the pilot’s eyes are about 15 feet above the runway. The pilot uses texture, height of peripheral objects, width of the runway and the perceived height of the horizon as cues to commence the flare and to judge the rate of rotation to achieve an almost level path over the runway. The landing is not complete until the end of the landing roll.

Once you reach the flaring height, forget the aim point because you will fly over and well past it before the wheels actually touch down. It has served its purpose and you should now look well ahead. Pick a point at the center of the far end of the runway. Transfer your visual attention to this point and slowly retard the throttle.

A normal landing is similar to the approach to the stall, with attitude being increased to keep the aircraft flying at the reducing airspeed. Touchdown will occur just prior to the moment of stall. Do not rush and try not to be tense. The aircraft will land when it is ready. This method of landing allows the lowest possible touchdown speed (significantly less than the approach speed), with the pilot still having full control.

The landing consists of four phases:

  • flare (or round-out);
  • hold-off;
  • touchdown; and
  • landing roll.

During the flare (round-out) the power is reduced and the nose is gradually raised to reduce the rate of descent. A small rate of sink is checked by a slight attitude change, a high rate of sink requiring a greater and quicker backward movement. A greater descent rate may require the pilot to add power momentarily to arrest the descent.

The hold-off should occur with the airplane close to the ground (with the wheels within a foot or so). The throttle is closed and the control column progressively brought back to keep the airplane flying a level path with the wheels just off the ground. If sinking, apply more back pressure; if moving away from the ground, relax the back pressure. The airspeed will be decreasing to a very low figure, but this is of no concern to you. You should be looking well ahead from the beginning of round-out until touchdown. Any sideways drift caused by a slight crosswind can be counteracted by lowering the upwind wing a few degrees and keeping straight with rudder.

On touchdown, the main wheels should make first contact with the ground (which will be the case following a correct hold-off ). The nose wheel will want to drop immediately but should be kept off the ground using the control column while the speed decreases. This may require a significant rearward pressure to allow it to touch gently.

Landing Roll
During the landing roll the airplane is kept straight down the centerline using rudder and the wings kept level with aileron. Look at the far end of the runway. The nose wheel is gently lowered to the ground before elevator control is lost. Brakes (if required) may be used once the nose wheel is on the ground. Remember that the landing is not complete until the end of the landing roll when the airplane is stationary or has exited the runway at taxiing speed.

For more on landing technique, and every maneuver required for certification, check out the brand new fifth edition of ThePilot’s Manual: Flight School (PM-1C).

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