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CFI Brief: Pressure Altitude Conversions

Pressure altitude is the height above the standard datum plane (SDP). The aircraft altimeter is essentially a sensitive barometer calibrated to indicate altitude in the standard atmosphere. If the altimeter is set for 29.92 “Hg SDP, the altitude indicated is the pressure altitude—the altitude in the standard atmosphere corresponding to the sensed pressure.

The SDP is a theoretical level at which the pressure of the atmosphere is 29.92 “Hg and the weight of air is 14.7 psi. As atmospheric pressure changes, the SDP may be below, at, or above sea level. Pressure altitude is important as a basis for determining aircraft performance, as well as for assigning flight levels to aircraft operating at above 18,000 feet.

The pressure altitude can be determined by any of the three following methods:

  1. By setting the barometric scale of the altimeter to 29.92 “Hg and reading the indicated altitude,
  2. By applying a correction factor to the indicated altitude according to the reported “altimeter setting,” see figure below.
  3. By using a CX-3 Flight Computer.

Let’s try a sample problem using the above chart.

1. Determine the pressure altitude at an airport that is 1,386 feet MSL with an altimeter setting of 29.55.
A—1,631 feet MSL.
B—1,731 feet MSL.
C—1,778 feet MSL.

Looking at the above chart you will see that 29.65 is not actually shown so we will need to interpolate between 29.50 and 29.60. Subtract 298 from 392 to get 94 and then divide by 2 since 29.55 is directly in the middle. You get 47 which you can now add to 298 to come up with 345 altitude correction. Add 345 onto you airport elevation to find the pressure altitude, 1,386 + 345 = 1,731 PAlt.

The correct answer is B, 1,731 feet MSL.

Here is another problem which can be solved by using your CX-3 Flight Computer.

2. Determine the pressure altitude at an airport that is 3,563 feet MSL with an altimeter setting of 29.96.
A—3,527 feet MSL.
B—3,556 feet MSL.
C—3,639 feet MSL.

Using you CX-3 open the FLT menu and select Altitude from the list. Enter your IAlt (indicated altitude) or airport elevation of 3,563 feet. Scroll down to the Baro field and enter your altimeter setting of 29.96. The CX-3 will then give you a PAlt of 3,527 feet MSL. The correct answer is A.

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CFI Brief: Altimeter Pressure Errors

High to low look out below, low to high clear the sky! If you have never heard that saying before you are probably pretty confused right now. Let me help ease that confusion and explain that today we are discussing altimeter errors when flying in areas of changing atmospheric pressures. The discussion will revolve around two specific Private Pilot Knowledge Test questions that I get calls about regularly. These questions outline common areas that trip students up, resulting in mass confusion.

1. If a flight is made from an area of low pressure into an area of high pressure without the altimeter setting being adjusted, the altimeter will indicate
A. the actual altitude above sea level.
B. higher than the actual altitude above sea level.
C. lower than the actual altitude above sea level.

2. If a flight is made from an area of high pressure into an area of lower pressure without the altimeter setting being adjusted, the altimeter will indicate
A. lower than the actual altitude above sea level.
B. higher than the actual altitude above sea level.
C. the actual altitude above sea level.

If you answered B an A, respectively, then you are also having some of the same confusion about this topic that many other students experience. Let’s start with the knowledge required to answer these questions.

It is easy to maintain a consistent height above ground if the barometric pressure and temperature remain constant, but this is rarely the case. The pressure and temperature can change between takeoff and landing on a local flight and even more drastically when flying cross country between areas of varying pressure and temperature. If these changes are not taken into consideration, flight becomes dangerous.

For example, when flying from an area of high pressure to an area of low pressure without adjusting the altimeter, a constant indicated altitude will remain but the aircraft’s actual altitude above ground level will be lower than indicated. Conversely, when flying from an area of low pressure to an area of high pressure the aircraft’s actual altitude above ground level will be higher than the indicated altitude on the altimeter. The image below is a good visual depiction of flying from an area of high pressure to an area of low pressure and the resulting altitude of the aircraft above the ground level if the altimeter is not adjusted. 

The reason so many students answer these questions incorrectly is not so much because they don’t understand the principle knowledge, but rather because they are not understanding what the question is asking. Both questions are asking what the ALTIMETER will indicate, not what the aircraft’s actual altitude is relative to the ground.

The correct answer to question 1 is C: the altimeter will indicate lower than the actual altitude above sea level. When flying from a low pressure area into a high pressure area the aircraft’s altitude will slowly increase while the altimeter remains constant; therefore, the ALTIMETER is indicating a LOWER altitude then what the aircraft is actually flying.

Vice versa, the correct answer to question 2 is B: the altimeter will indicate higher than the actual altitude above sea level. When flying from a high pressure area into a low pressure area, the aircraft’s altitude will slowly decrease while the altimeter remains constant therefore the ALTIMETER is indicating a HIGHER altitude then what the aircraft is actually flying.

Tricky questions yes, but also a very important piece of knowledge to fully understand. You should now be able to correctly answer these on your knowledge test as well as remember to adjust the altimeter when flying between different air pressure systems.

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Editor’s Picks for the 2017 Holiday Season

2017 was a big year for us at ASA. We’ve been busy, releasing new editions of all three Pilot’s Manual textbooks (Flight School, Ground School, and Instrument Flying), William Kershner’s The Student Pilot’s Flight Manual, Bob Gardner’s The Complete Private Pilot, our Oral Exam Guide titles (Private, Instrument, CommercialMulti-Engine, CFI, and Aircraft Dispatcher), Dale Crane’s Dictionary of Aeronautical Terms and Aviation Mechanic Handbook, multiple FAA Handbooks, and of course our Test Prep and FAR series titles. Today, I’d like to recommend three brand-new products from ASA, sure to suit the aviator on your holiday shopping list.

Small Unmanned Aircraft Systems Guide
by Brent Terwilliger, David Ison, John Robbins, Dennis Vincenzi

This is the perfect gift for a remote pilot, whether they’re just a hobbyist or looking into monetizing their drone flying. Written by a team of UAS-industry experts, this book covers the history of drones, design philosophies, technology, and safety practices, as well as resources to help you make well-informed decisions regarding purchase and use and determine a path forward through the complex legal, business, operational, and support considerations.

The Flight Instructor’s Survival Guide
by Arlynn McMahon

For the CFI in your life, Arylnn McMahon shares forty-four stories that demonstrate the fundamentals of instructon (FOI) principles in flight and offer practical strategies for dealing with both common and unexpected situations—all with wisdom, grace, and humor. Through artful storytelling, McMahon shows how a successful instructor is sometimes a psychologist, other times a detective, and always a gatekeeper enforcing rules and cultivating the behaviors required to be a responsible aviation citizen.

CX-3 Flight Computer
by Aviation Supplies & Academics, Inc.

Years in the making, the new CX-3 Flight Computer is the ultimate gift to the pilot on your list. Check out our rundown of all of it’s features in last month’s blog post. The CX-3 Flight Computer makes flight planning simple by taking confusion out of the equation. Fast, versatile and easy to use, the CX-3 delivers accurate results quickly and efficiently. It can even be used on all FAA and Canadian pilot, mechanic, and dispatcher knowledge exams. Whether used for flight planning, ground school, or knowlledge testing, the menu organization reflects the order in which a flight is normally planned and executed, resulting in a natural flow from one function to the next with a minimum of keystrokes.


For more holiday gift ideas, check out our 2017 Holiday Gift Guide. And stay tuned, we’re working hard to deliver a lot of new books in 2018 which we will be able to tell you about soon!

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CFI Brief: Airport Rotating Beacon

Have you ever wondered how pilots are able to determine the location of an airport at night or in reduced visibility? Well the answer is actually very simple. At night, the location of an airport can be determined by the presence of an airport rotating beacon light like the one seen in the image below. An airport beacon will assist you as a pilot in identifying the location and type of airport by the color combination the beacon is emitting.

The colors and color combinations that denote the type of airports are:

*Note: Green alone or amber alone is used only in connection with a white-and-green or white-and-amber beacon display, respectively.

A civil-lighted land airport beacon will show alternating white and green flashes. A military airfield will be identified by dual-peaked (two quick) white flashes between green flashes.

In Class B, C, D, or E airspace, operation of the airport beacon during the hours of daylight often indicates the ceiling is less than 1,000 feet and/or the visibility is less than 3 miles. However, pilots should not rely solely on the operation of the airport beacon to indicate if weather conditions are IFR or VFR.

The beacon has a vertical light distribution to make it most effective from 1–10° above the horizon, although it can be seen well above or below this spread.

Here is another nifty little tidbit you will learn once you start night flight training. Radio control of lighting is available at some airports, providing airborne control of lights by keying the aircraft’s microphone. The control system is responsive to 7, 5, or 3 microphone clicks. Keying the microphone 7 times within 5 seconds will turn the lighting to its highest intensity; 5 times in 5 seconds will set the lights to medium intensity; low intensity is set by keying 3 times in 5 seconds. Many airports, particularly airports without an operating control tower, will not keep runway lights on constantly throughout the night so it becomes the pilots responsibility to turn the runway lights on for landing or takeoff. Once the lights are keyed on they will typically remain on for 15 minutes. A quick glance in the Chart Supplement U.S. will identify an airport with pilot controlled lighting.

 

 

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IFR: Precision Instrument Runway Markings

Today, we’re sharing an excerpt from The Pilot’s Manual Volume Three: Instrument Flying. This post is a follow-up to last month’s IFR: The Instrument Landing System (ILS).

To assist pilots transitioning to a visual landing at the conclusion of a precision instrument approach, precision instrument runways have specific markings.

A displaced threshold on an instrument runway is indicated by arrows in the middle of the runway leading to the displaced threshold mark. The runway edge lights to the displaced threshold appear red to an airplane on approach, and to an airplane taxiing to the displaced threshold from the absolute end of the runway. They appear white when taxiing back from the displaced threshold toward the absolute end of the runway. The green runway end lights seen on approach to a runway with a displaced threshold are found off the edge of the runway.

The runway surface with arrows to the displaced threshold is available for taxiing, takeoff and landing roll-out, but not for landing. The initial part of this runway is a non-touchdown area. If chevrons rather than arrows are used to mark the displaced threshold, then the surface is not available for any use, other than aborted takeoff from the other direction.

Displaced threshold markings with preceding blast pad or stopway.

Displaced threshold markings with preceding blast pad or stopway.

A precision instrument runway will contain a designation, centerline, threshold, aiming point, touchdown zone, and side strips as seen in the figure below. Runway threshold strips can be configured in two ways. Four solid strips on either side of the centerline or configured as such that the number of strips correlates to the width of the runway (see table). The runway aiming point markers are large rectangular marks on each side of the runway centerline usually placed 1,000 feet after the threshold and serve as a visual aiming point for the pilot. Touchdown zone markers identify the touchdown zone for landing operations, providing coded distance information in 500 foot intervals and shown as either one, two, or three vertical stripes on either side of the centerline.

Runway width based on number of runway threshold strips.

Runway width based on number of runway threshold strips.

Markings on a precision instrument runway.

Markings on a precision instrument runway.

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Aircraft Performance: Runway Surface and Gradient

Today’s post comes from the Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25B), which is now available as an eBook from ASA, iTunes, and Kindle.

Runway conditions affect takeoff and landing performance. Typically, performance chart information assumes paved, level, smooth, and dry runway surfaces. Since no two runways are alike, the runway surface differs from one runway to another, as does the runway gradient or slope.

Takeoff distance chart

Takeoff distance chart

Runway surfaces vary widely from one airport to another. The runway surface encountered may be concrete, asphalt, gravel, dirt, or grass. The runway surface for a specific airport is noted in the Chart Supplement U.S. (formerly Airport/Facility Directory). Any surface that is not hard and smooth increases the ground roll during takeoff. This is due to the inability of the tires to roll smoothly along the runway. Tires can sink into soft, grassy, or muddy runways. Potholes or other ruts in the pavement can be the cause of poor tire movement along the runway. Obstructions such as mud, snow, or standing water reduce the airplane’s acceleration down the runway. Although muddy and wet surface conditions can reduce friction between the runway and the tires, they can also act as obstructions and reduce the landing distance. Braking effectiveness is another consideration when dealing with various runway types. The condition of the surface affects the braking ability of the aircraft.

The amount of power that is applied to the brakes without skidding the tires is referred to as braking effectiveness. Ensure that runways are adequate in length for takeoff acceleration and landing deceleration when less than ideal surface conditions are being reported.

The gradient or slope of the runway is the amount of change in runway height over the length of the runway. The gradient is expressed as a percentage, such as a 3 percent gradient. This means that for every 100 feet of runway length, the runway height changes by 3 feet. A positive gradient indicates the runway height increases, and a negative gradient indicates the runway decreases in height. An upsloping runway impedes acceleration and results in a longer ground run during takeoff. However, landing on an upsloping runway typically reduces the landing roll. A downsloping runway aids in acceleration on takeoff resulting in shorter takeoff distances. The opposite is true when landing, as landing on a downsloping runway increases landing distances. Runway slope information is contained in the Chart Supplement U.S. (formerly Airport/ Facility Directory).

Chart Supplement U.S. information

Chart Supplement U.S. information

Water on the Runway and Dynamic Hydroplaning
Water on the runways reduces the friction between the tires and the ground and can reduce braking effectiveness. The ability to brake can be completely lost when the tires are hydroplaning because a layer of water separates the tires from the runway surface. This is also true of braking effectiveness when runways are covered in ice.

When the runway is wet, the pilot may be confronted with dynamic hydroplaning. Dynamic hydroplaning is a condition in which the aircraft tires ride on a thin sheet of water rather than on the runway’s surface. Because hydroplaning wheels are not touching the runway, braking and directional control are almost nil. To help minimize dynamic hydroplaning, some runways are grooved to help drain off water; most runways are not.

Tire pressure is a factor in dynamic hydroplaning. Using the simple formula in the figure below, a pilot can calculate the minimum speed, in knots, at which hydroplaning begins. In plain language, the minimum hydroplaning speed is determined by multiplying the square root of the main gear tire pressure in psi by nine. For example, if the main gear tire pressure is at 36 psi, the aircraft would begin hydroplaning at 54 knots.

Tire pressure

Tire pressure

Landing at higher than recommended touchdown speeds exposes the aircraft to a greater potential for hydroplaning. And once hydroplaning starts, it can continue well below the minimum initial hydroplaning speed.

On wet runways, directional control can be maximized by landing into the wind. Abrupt control inputs should be avoided. When the runway is wet, anticipate braking problems well before landing and be prepared for hydroplaning. Opt for a suitable runway most aligned with the wind. Mechanical braking may be ineffective, so aerodynamic braking should be used to its fullest advantage.

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Navigation: Automatic Dependent Surveillance-Broadcast

Today, we’re featuring an excerpt from The Pilot’s Manual: Instrument Flying (PM-3D).

Automatic Dependent Surveillance-Broadcast (ADS-B) is a surveillance technology being deployed throughout the entire National Airspace System. ADS-B enables improved surveillance services, both air-to-air and air-to-ground, especially in areas where radar is ineffective due to terrain or where radar is impractical or cost prohibitive. Eventually, ADS-B will replace most ground-based surveillance radars.

The basic principle of ADS-B is that each aircraft broadcasts a radio transmission approximately once per second, which contains the aircraft’s position, velocity, identification, and other information. This capability is referred to as “ADS-B out.” This transmission is received by the ground-based transceivers (GBTs) and by other appropriately-equipped aircraft. (The capability to receive ADS-B information is referred to as “ADS-B in.”) The ADS-B ground station processes the information and uses it to provide surveillance services. The composite traffic information is uplinked as the product, “Traffic Information Service-Broadcast (TIS-B).” In order to detect each other, no ground infrastructure is necessary for ADS-B equipped aircraft (i.e., those with both ADS-B out and in).

ADS-B ground based transceiver (GBT) antenna.

ADS-B ground based transceiver (GBT) antenna.

There are two completely different methods for aircraft to transmit and receive the ADS-B information. Aircraft that primarily operate in high-altitude airspace send and receive the information using an enhanced Mode S transponder. Aircraft that primarily operate in the low-altitude airspace send and receive the information using the Universal Access Transceiver (UAT). The GBT receives information from both sources and rebroadcasts (ADS-R) it so that all aircraft have all the information.

ADS-B, TIS-B, and FIS-B: broadcast services architecture.

ADS-B, TIS-B, and FIS-B: broadcast services architecture.

Another feature related to ADS-B is called Flight Information Services-Broadcast (FIS-B). FIS-B provides current weather products via an uplink from the GBT antennas to the UAT on the airplane. There is no fee for this weather service. More information on FIS-B is given in the “Datalink Weather Systems” section ahead on page 208.

Before FIS-B and datalink weather capability, pilots had to contact Flight Watch or a flight service station to have someone describe the weather radar picture for them. Now that picture is available in the cockpit. For example, NOTAMs and Temporary Flight Restrictions (TFRs) can be graphically presented over the top of electronic charts, so pilots know what areas to avoid.

The ADS-B system also has downlink capabilities that may someday transmit actual weather data to the ground. In the future, airplanes could send down actual (not forecast) wind direction, velocity, freezing levels, turbulence, and more, to be analyzed in real time. The information could be constantly sent to the ground to build an enhanced, comprehensive, and current weather picture. This information is called an electronic PIREP.

Mandatory ADS-B Out Requirement
The term “ADS-B out” refers to the broadcast of ADS-B transmissions from aircraft, without the installation of complementary receiving equipment to process and display ADS-B data on cockpit displays to pilots. This complementary processing is called “ADS-B in.” ADS-B out is needed for cockpit displays to be able to directly observe traffic. ADS-B out can be deployed earlier than ADS-B in, since ATC surveillance (air-ground) can operate without ADS-B in.

Effective January 1, 2020, ADS-B out capability will be required for aircraft in the following airspace areas:

  • Class A, B, and C airspace;
  • all airspace above 10,000 ft MSL over the 48 contiguous states and the District of Columbia (excluding the airspace above 10,000 feet, but within 2,500 feet of the ground);
  • within the 30 NM veil of airports listed in 14 CFR §91.225; and
  • Class E airspace over the Gulf of Mexico from the coastline of the United States out to 12 nautical miles, at and above 3,000 feet MSL.
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CFI Brief: The ASA CX-3 Flight Computer—Coming REAL soon!

You have been asking us for an aviation flight computer with a backlit display, and trust us we’ve been listening. But we thought, if we are going to design a flight computer with a backlit display, why stop there? Wouldn’t it be cool if we had a backlit keypad as well? It sure would, so today I would like to introduce you to the next generation aviation flight computer: the ASA CX-3—complete with backlit display and keypad!

Image-1

The CX-3’s new display technology now incorporates settings for varying light conditions as well as display themes for standard, night, and daylight environments on a massive 3.2-inch LCD display. Even with the large display, we have managed to design a sleek compact unit that will fit comfortably in the palm of your hand.

The ASA CX-3 will become available in November at pilot shops and online retailers nationwide. To stay up-to-date on the latest news, check out www.asa2fly.com/CX3. We’ll be featuring CX-3 user tips on the Learn to Fly Blog very soon.

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Introducing the New CX-3 Flight Computer

Today on the Learn to Fly Blog, we’d like to share some information on ASA’s next generation CX-3 Flight Computer, available this November. The CX-3 is an excellent companion in the cockpit, on the tarmac, or the ground school classroom, whether you need to make a rate of descent calculation or plan a flight. You can even use it when you take your FAA Knowledge exam. Using the latest microchip and display technologies, the CX-3 features make it the most versatile and useful aviation calculator available.

CX-3_HiRes

May be used during FAA and Canadian Knowledge Exams. The CX-3 complies with FAA Order 8080.6 and Advisory Circular (AC) 60-11, “Test Aids and Materials that May be Used by Airman Knowledge Testing Applicants”; therefore you may bring the CX-3 with you to the testing centers for all pilot, mechanic, and dispatcher FAA exams.

Numerous aviation functions. You can calculate everything from true airspeed and Mach number, fuel burn, holding patterns, to headwind/crosswind components, center of gravity (CG), and everything in between. The menu structure provides easy entry, review, and editing within each function. Multiple problems can be solved within one function.

User-friendly. The color LCD screen displays a menu of functions and the inputs and outputs of a selected function, for easy-to-read menus and data displays. The inputs and outputs of each function are separated on the display screen so it’s clear which numbers were entered and which were calculated, along with their corresponding units of measurement. The menu organization reflects how a flight is normally planned and executed. The result is a natural flow from one function to the next with a minimum of keystrokes. To plan a flight, simply work from the menus in sequential order as you fill in your flight plan form.

1_LTFBCX3

Non-volatile memory. All settings including aircraft profile, weight and balance data, trip plan data, values entered by the user, and calculations performed by the device will be retained until the batteries are removed or the user performs a memory reset. Aircraft profiles for multiple aircraft can be created and saved, and imported from or exported to a computer via a micro-usb port.

Ergonomic design. The CX-3 features a simple keyboard and slim design. The non-slip cover will protect your computer inside the flight bag and it fits on the backside of the unit for easy storage while in use.

Unit conversions. The CX-3 has 12 unit conversions: Distance, Speed, Duration, Temperature, Pressure, Volume, Rate, Weight, Rate of Climb/Descent, Angle of Climb/Descent, Torque, and Angle. These 12 conversion categories contain 38 different conversion units for over 100 functions. Unit conversions can be performed during any step in a calculation.

3_LTFBCX3

Timers and clocks. The CX-3 has two timers: a stopwatch that counts up and a countdown timer. The stopwatch can be used to keep track of elapsed time or to determine the time required to fly a known distance. The countdown timer can be used as a reminder to switch fuel tanks, or to determine the missed approach point on a non-precision instrument approach. An internal clock continues running even when the flight computer is turned off. UTC and local time can be displayed, and the time can be set with UTC, destination or local time.

Interactive functions. The CX-3 is designed so the functions can be used together. You can perform “chain” calculations where the answer to a preceding problem is automatically entered in subsequent problems. Standard mathematical calculations and conversions can be performed within each aviation function.

Up to date. Check often for new CX-3 updates online at www.asa2fly.com/CX3. Firmware updates and user-data backups are made easy with a micro-usb port to connect the CX-3 to computer.

4_LTFBCX3

The CX-3 will begin shipping in November. Check in with your local FBO, favorite online retailer, or ASA for availability. On Thursday, our CFI will share some sample calculations and tips on using the CX-3.

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CFI Brief: It’s Getting Hot in Here.

Today, I would like to recap Monday’s post on the aircraft engine cooling system and go over some typical questions you will likely see on your FAA Private Pilot knowledge test. First off, we learned about the effects of operating with an excessively high aircraft engine temperature and that it can lead to loss of power, excessive oil consumption, detonation, and serious engine damage. Neither of which are ideal situations when 6,000 in the air. That is why a thorough understanding of the aircraft engine and cooling system is required knowledge for any pilot. Understanding how your engine cools will help you to prevent operating outside of normal temperature ranges.

Most light aircraft engines are cooled externally by air. For internal cooling and lubrication, an engine depends on circulating oil. Engine lubricating oil not only prevents direct metal-to-metal contact of moving parts, it also absorbs and dissipates part of the engine heat produced by internal combustion. If the engine oil level is too low, an abnormally high engine oil temperature indication may result.

On the ground or in the air, excessively high engine temperatures can cause excessive oil consumption, loss of power, and possible permanent internal engine damage.

If the engine oil temperature and cylinder head temperature gauges have exceeded their normal operating range, or if the pilot suspects that the engine (with a fixed-pitch propeller) is detonating during climb-out, the pilot may have been operating with either too much power and the mixture set too lean, using fuel of too low a grade, or operating the engine with not enough oil in it. Reducing the rate of climb and increasing airspeed, enriching the fuel mixture, or retarding the throttle will help cool an overheating engine. Also, rapid throttle operation can induce detonation, which may detune the crankshaft.

The most important rule to remember in the event of a power failure after becoming airborne is to maintain safe airspeed. Now let’s go ahead and take a look at some sample knowledge test questions complete with explanations.

Excessively high engine temperatures, either in the air or on the ground, will
A. increase fuel consumption and may increase power due to the increased heat.
B. result in damage to heat-conducting hoses and warping of cylinder cooling fans.
C. cause loss of power, excessive oil consumption, and possible permanent internal engine damage.

High engine temperatures can lead to loss of power, excessive oil consumption, detonation, and serious engine damage.

If the engine oil temperature and cylinder head temperature gauges have exceeded their normal operating range, the pilot may have been operating with
A. the mixture set too rich
B. higher-than-normal oil pressure.
C. too much power and with the mixture set too lean.

Excessively high engine temperatures can result from insufficient cooling caused by too lean a mixture, too low a grade of fuel, low oil, or insufficient airflow over the engine.

Answer (A) is incorrect because a richer fuel mixture will normally cool an engine. Answer (B) is incorrect because high oil pressure does not cause high engine temperatures.

For internal cooling, reciprocating aircraft engines are especially dependent on
A. a properly functioning thermostat.
B. air flowing over the exhaust manifold.
C. the circulation of lubricating oil.

Oil, used primarily to lubricate the moving parts of the engine, also cools the internal parts of the engine as it circulates.

Answer (A) is incorrect because most air-cooled aircraft engines do not have thermostats. Answer (B) is incorrect because, although air-cooling is important, internal cooling is more reliant on oil circulation. Air cools the cylinders, not the exhaust manifold.

An abnormally high engine oil temperature indication may be caused by
A. the oil level being too low.
B. operating with a too high viscosity oil.
C. operating with an excessively rich mixture.

Oil, used primarily to lubricate the moving parts of the engine, also helps reduce engine temperature by removing some of the heat from the cylinders. Therefore, if the oil level is too low, the transfer of heat to less oil would cause the oil temperature to rise.

Answer (B) is incorrect because the higher the viscosity, the better the lubricating and cooling capability of the oil. Answer (C) is incorrect because a rich fuel/air mixture usually decreases engine temperature.

What action can a pilot take to aid in cooling an engine that is overheating during a climb?
A. Reduce rate of climb and increase airspeed.
B. Reduce climb speed and increase RPM.
C. Increase climb speed and increase RPM.

To avoid excessive cylinder head temperatures, a pilot can open the cowl flaps, increase airspeed, enrich the mixture, or reduce power. Any of these procedures will aid in reducing the engine temperature. Establishing a shallower climb (increasing airspeed) increases the airflow through the cooling system, reducing high engine temperatures.

Answer (B) is incorrect because reducing airspeed hinders cooling, and increasing RPM will further increase engine temperature. Answer (C) is incorrect because increasing RPM will increase engine temperature.

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