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Файл:Aircraft Maintenance. Учебное пособие
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UNIT 4. INSTRUMENTS
Exercise 11. Write a summary of the text.
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AIRCRAFT MAINTENANCE
SUPPLEMENTARY READING
Skimming a text
Exercise 12. Read how to skim a text and try to do the task.
Skimming a text is a fast reading technique to look for main ideas in a text.
Skimming is used to obtain the gist (the overall sense) of a text.
Do the following tasks:
- read the title, subtitles and subheading to find out what the text is about;
- look at the illustrations to give you further information about the topic;
- read the first and last sentence of each paragraph;
- don't read every word or every sentence; let your eyes skim over the text, taking in key words;
- continue to think about the meaning of the text.
By Sarina Houston
Updated November 27, 2017
There are six traditional flight instruments in most aircraft cockpits. Many of
these instruments have taken on a more modern appearance over time, but even
technologically advanced aircraft have trad itional inst rument s to use as back -ups
in case the primary system fails. The following instruments make up what's
called the "six-pack" in a traditional coc kpit where three ins truments are stacked
on top of three other instruments. Th ese six b asic flig ht inst ruments are th e main
source of cockpit flight information fo r pilots and are divided into two catego ries: static (or pitot-static) instruments and gyroscopic instruments.
Static/Pitot-Static Instruments
Airspeed Indicator: The airspeed indicator tells the pilot the indicated airspeed
in knots (or in some cases, a Mach number). Airspeed is sometimes also depicted
in true airspeed, which is valuable information for flight planning. (True airspeed
is the actual speed of the airplane in relation to the air and is corrected for temperature and density effects. It's usually just a few knots different than indicated
airspeed in small aircraft.) In a nutshell, the airspeed indicator works by comparing ram air pressure from the pitot tube to static air pressure from one or more
static ports. The diaphragm inside the instrument casing measures the pressure
differential and depicts it on the instru ment pointer. Airspeed indicators are color
coded so the pilot can easily identify ranges such as the normal operating range,
flap operating range, and caution range. Minimum and maximum speeds, as well
as other important speeds (known as V-speeds), are marked as well.
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UNIT 4. INSTRUMENTS
Altimeter: The altimeter reflects the aircraft's vertical height above MSL (mean
sea level) corrected for outside air pressure. The pilot sets the appropriat e pressure setting (a local setting for those fl ying below 18,000 feet ) and the altimeter
will depict the corresponding altitude above MSL. The altimeter works similar to
a basic barometer, by comparing the static pressure inside of a sealed aneroid
capsule to the expanding or co ntracting pressure surrounding it. When the ai rplane ascends or descends, the air pressure will decrease or increase, respectively. This outside air pressure is co nstantly being compared to the pressure inside
the aneroid capsule, and with the help of linkage and a pointer, the altitude is
displayed on the cockpit instrument.
Vertical Speed Indicator: Vertical speed is the rate of the aircraft's climb or descent, usually depicted in feet per minute (fpm) on a vertical speed indicator (VSI). In level flight, the VSI needle points to '0' feet. The VSI works by
measuring and comparing the static pressure inside of an expandable capsule to
the metered static pressure outside of the capsule. The pressure inside the capsule
changes very quickly as the plane climbs or d escends, while the pressure ou tside
of the capsule changes very slowly due to the metered leak. During climbs and
descents, the caps ule compresses or expan ds, respectively. The pressu re difference is measured and linked to the pointer, where it's depicted on the instrument
face. The VSI is valuable in determining if the airplane is climbing or descending and the rate of the climb or descend. There can be a slight lag in information
depicted on the VSI if the aircraft is maneuvered abruptly. In turbulence, the indications can be slightly erratic.
Gyroscopic Instruments
Attitude Indicator: The attitude indicator is possibly the most important in-
strument for pilots. In one glance, a pilot can tell if the aircraft is climbing, descending, turning or straight and level. It gives a direct indication of changes to
pitch attitude and bank. The attitude indicator consists of an artificial horizon
that is a background for a miniature airplane. The instrument is meant to depict
the sky (usually blue in color) and the ground (typically brown), with a miniature
airplane positioned on the artificial horizon (a white line) in level flight. In most
cases, the miniature airplane is attached to the instrument viewing case, and it
moves with the airplane. The artificial horizon senses movement from the gyroscope and remains suspended in relation to a self-erecting gyroscope, which
"holds" its position in reference to the actual horizon. The gyroscope itself can be
vacuum-driven or electric.
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AIRCRAFT MAINTENANCE
Heading In dicator: A basic tool for navigation, the heading indicator provides
directional information to the pilot similar to the way a magnetic compass does.
The heading indicator itself is not nort h -seeking but can depict an accurate heading when aligned to a magnetic compass. The head ing indicator is a gyroscopic
instrument and can be vacuum-driven or electrically powered. As the aircraft
turns left or right, the heading indicator will change to depict a new heading between zero and 359 degrees on a compass card. A miniature aircraft is located in
the center of the indicator and turns with the airplane while the gyroscope (and
coinciding linkage) turn the compass card on the instrument. In a left turn, the
miniature airplane appears to turn left while the compass card turns right.
Turn Coordinator: The turn coordinator is another gyroscopic instrument that
can be either electric or vacuum-driven. It's one of the simplest instruments, with
a miniature airplane that dips its wings one way or another to show the rate of
turn or rate or roll. When a pilot rolls the airplane into a turn, the miniature airplane quickly shows a corresponding roll. There are tick marks on the instrument
that are calibrated to depict a standard rate turn for an airplane (a 360-degree
standard-rate turn takes two minu tes). The turn coordi nator also includes an inclinometer, which is a ball suspended in fluid that reacts like a pendulum during
turning flight. The ball acts in respons e to gr avit y and turn ing fo rces an d wil l depict a coordinated or uncoordinated turn. The pilot can then counteract an uncoordinated turn with the use of rudder movement, avoiding a slipping or skidding
turn.
https://www.thebalance.com/aircraft-flight-instruments-the-basic-six-pack282852
Are Airplane Black Boxes Really Black?
Like many inventions, versions of an airplane “black box” were independently
invented by several people, in this case beginning around the 1930s and
1940s. As for the version that began being installed on commercial aircraft, it
was invented in response to a tragic loss of life. A De Havilland Comet 1, the
world’s first commercial jet-powered airplane, disintegrated over India in early
1953. Of the 43 passengers and crew members, none survived. Australian chemist Dr. David Warren joined an expert panel looking in to the cause of that crash
and two other crashes involving the Comet 1. Australia had a vested interest in
the success of the Come t because of its possibl e use by Australian airl ines for a
route between Australia and the United Kingdom. While Dr. Warren was an expert in fuel research, the plane crashes resonated with him for another reason; his
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UNIT 4. INSTRUMENTS
father died in 1934 when the plane he was on crashed into the ocean off Austral-
ia’s southern coast; investigators never discovered the cause of that crash. War-
ren’s part in the investigation of the Comet accident led him to believe that a
simple voice recorder located on the plane during the crash would have saved the
investigators time and energy trying to determine what went wrong. “If a businessman had been using one of these in the plane… and we could find it in the
wreckage and we played it back, we’d say, ‘We know what caused this.’”
Warren drew on his background in electroni cs, expe rien ce he gain ed from b uilding “crystal sets” or unpowered radio receivers in school, and he created a prototype of the ARL Flight Memory Unit. This device recorded both conversations in
the cockpit and a small number of instrument readings for up to four hours of the
flight. Once the four hour recording time had been reached, the recording device
recycled and recorded over the oldest information. While the ARL Flight
Memory Unit prototype, named in part for the Aeronautical Research Laboratories where Warren worked, showed success during flights condu cted by the Australian Department of Civil Aviation, the Australian government and military
failed to show further interest in the device. In 1958, a British official visiting
Australia learned of Warren’s Flight Memory Unit and invited him to England to
continue work on the device with scientists and manufacturers. It soon went into
production in England and in the United States before being installed in aircraft
around the world. In an ironic twist, Australia became the first country to require
all turbine-powered airplanes weighing over 12,500 pounds to have these devices
onboard.
So how did the ARL Flight Memory Unit become known as a black box? That’s
a bit of a mystery, especially considering that within the industry it is almost
never called this and the devices th emselves are a color called international orange which allows them to be more easily found at the site of a plane crash. That
said, the first known instance of these devices being called a “black box” was
very early on at an Aeronautical Research Council meeting in August of 1958.
The man who called it that was one E. Newton. Why he did so isn’t known.
As such, there are a number of theories about how the term “black box” came
about. One theory states that the name came from the fact that the boxes were
often blackened and charred from fires occurring after the crash. Given the first
known instance of someone calling it this was about the time Warren was invited
to England to further his work on the devices (before they were widely installed
on planes, other than for testing purposes), this seems unlikely. Another, much
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AIRCRAFT MAINTENANCE
more plausible, theory is that it’s a holdover from WWII where the Royal Air
Force used to refer to various experimental devices put on planes , such as the
Oboe targeting system, as a “black-box.” Another very plausible explanation is
that it is originally from the engineering practice of calling a system that takes
input, does something to it, then gives some output, without specifically refe rencing the internal workings of the device- how it actually accomplishes the
thing it’s meant to do- a “black box.” Either way, the nickname was (and still is)
particularly popular with members of the media, while aviation experts almost
always refer to them as flight data recorders.
As for modern black boxes, they have undergone a number of improvements
over the years, though the basic thing they do is the same as the original. Specifically, they consist of two separate devices: the Cockpit Voice Recorder (CVR)
and the Flight Data Recorder (FDR).
The CVR records all of the noise inside the cockp it. That includ es the convers ation between the crew members, radio transmissions, any alarms, the sounds of
the controls being used, and even noise from the engine and air moving around
the plane. Today, CVRs record a total of two hours of audio before the newest
audio recording overwrites the oldest part of the recording. The FDR records a
variety of flight data, though the exact requirements depend on things like the
age and size of the plane and what sort of equipment is on board. However, all
black boxes are required to record, at a mi nimum, the pressure altitude, indicated
airspeed, magnetic heading, normal acceleration, and microphone keying. The
final item, microphone keying, lets investigators match the data with the CVR
recording. While the FDR records on the same endless-loop principle as the
CVR, it records a total of 25-hours before o verwri tin g the olde st inf ormation.
Black boxes need to survive the impact of the crash along with any fire that
might occur afterwards if they are to be of any use to investigators. While they
occasionally change in response to crashes, recorder crash-worthiness standards
typically require boxes be able to survive such circumstances as a 1,100° Celsius
fire for an hour, 33 km/s² of acceleration for 6.5 milliseconds (about what would
be produced in a crash at 310 mph), and being immersed in saltwater at specific
depths, among other such specifications. The placement of the black box in the
tail of the plane also raises the likelihoo d of survival as the tail section d oesn’t
usually bear the brunt of the crash impact. Additionally, a locator beacon is included which can also help investigators find the black box if the aircraft crashes
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UNIT 4. INSTRUMENTS
in the water as it emits a “pinger” signal for at least thirty days (and it will soon
likely be raised to a ninety day requirement).
Thanks to the Malaysian Airline Flight 370 crash, a marked upgrade in how
flight data recorders work has also been proposed, utilizing more modern technology since the last major overhaul of the “black box.” The most significant
change, and p erhaps the most helpful, suggested is to decentralize the box. Instead of just having an on-board recording, add in a system for broadcasting in
real time the data it’s storing to some central database on the ground. This way,
even if the on board recorder can’t be located (such as when the plane itself can’t
be found), the ground crew s till has the data they need to analyze what caused
the crash, and with last broadcast coordinates, even more accurately where to
start looking for the plane and potential survivors.
http://www.todayifoundout.com/index.php/2014/09/airplane-black-box-isntreally-black/
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UNIT 5. ELECTRICAL POWER
Vocabulary
AC POWER PHILOSOPHY
AC (alternating current) – сеть переменного тока
APU (auxiliary power unit) – вспомогательная силовая установка
CSD (constant speed drive) – постоянная скорость вращения генератора при
различных оборотах двигателя
RPM (revenue passenger-mile) – коммерческая пассажиро-миля
VSCF (variable speed constant frequency) – переменная скорость и неизменная частота
engine gear – распределительная шестерня двигателя
high power inverter – инвертор большой мощности
sources of power – источник питания
operation – работа; эксплуатация
manually – вручную
generator bus – генераторная шина; генераторная электрошина
inoperative – неисправный, не работает
transfer bus – обходная шина
associated transfer bus – вспомогательная обходная шина
Electrical power is generated by one generator on each engine and by one APU
generator. Two different types of generators may be installed at the same time.
They will have no differences in system behavior and indication.
• Type 1: Each engine generator is connected to it s respective engin e through
a CSD which converts variable engine RPM to the constant speed needed to
produce 400 Hz used by the electrical system components.
• Type 2: Each VSCF (Variable Speed Constant Frequency) Generator is
driven directly from the engi ne gear box, rotating at a variable speed. The
variable frequency is converted to constant 400 Hz using a solid state, high
power inverter.
There are three basic principles of operation for the electrical system:
• 1. There is no paralleling of the AC sources of power.
• 2. The last source of power switched onto the system takes priority and will
automatically disconnect the existing source.
• 3. There is no automatic connection of electri cal power sou rces. All sources
must be manually connected through the movement of a switch.
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UNIT 5. ELECTRICAL POWER
In flight each generator normally powers its own generator bus. If one generator is inoperative, the APU generator may be used to power the inoperative generator’s bus. Each Generator system consists of a generator bus and a transf er
bus. If there is a failure of a generator bus, the associated transfer bus can be
supplied automatically from the powered generator bus. Each transfer bus has an
associated transfer relay which automatically selects the opposite generator bus
as a power supply if its normal generator bus fails and the transfer switch is in
AUTO position.
Exercise 1. Answer the questions:
1. How is the electrical power generated?
2. What is the difference between two types of generator s?
3. What are the three basic principles of operation for the electrical system?
4. What does each generator normally power in flight?
5. What happened if there is a failure of a generator bus?
POWER SUPPLY. AC POWER SUPPLY
power supply – источник электропитания
inflight configuratio n – положение в полёте
trip – отключать
respective control switches – соответствующий тумблер управления, пере-
ключатель
load-shedding – аварийная разгрузка, сброс нагрузки
galley – бортовая кухня
overloaded – перегружен
voltage – напряжение,
frequency – частота тока
ground faults –
замыкание на землю
excessive current draw – завышенное потребление тока
malfunction – неисправность, сбой функционирования
The normal inflight configuration of the power system has engine generator 1
connected to generator bus 1, main bus 1 and transfer bus 1. Generator 2 is connected to generator bus 2, main bus 2 and transfer bus 2. These systems are separate. In the event of an inoperative generator, the APU generator can be connected to one of the generator busses thereby restoring full electrical power. With the
airplane on the ground and external power connecte d, placing the Ground Power
switch momentarily to ON will trip both engine generators and connect external
power to both generator busses simultaneously. When the APU is operating,
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AIRCRAFT MAINTENANCE
electrical power output of its generator can be connected to generator bus 1
and/or generator bus 2 through the respective control switches. Whenever ground
power is on both generator busses, and APU or an engine generator power is applied to one generator bus, ground power continues to supply power to the other
generator bus. The transfer busses normally receive their power from the respe ctive generator bus. If a generator bus loses power, the respective transfer bus will
automatically receive power from the other generator bus. In addition the protective auto load-shedding circuit turns off all galley power. This feature ensures
that the remaining generator will not be overloaded. The electrical system monitors itself for correct voltage, frequency, ground faults in the generator or excessive current draw from any generator. If any malfunction develops, the generator
affected will be automatically disconnected from its generator bus.
Exercise 2. Answer the questions:
1. What does the normal inflight configuration of the power system have?
2. How does the system operate in the event of an inoperative generator?
3. How do the engine generators operate when the airplane is on the ground?
4. When can APU or an engine generator power be applied to one generator
bus?
5. How do the transfer busses normally receive their power?
6. How does the electrical system monitor itself?
POWER SUPPLY. DC POWER SUPPLY
DC direct current – постоянный ток
transformer rectifier units – трансформатор-выпрямитель
TR (Tyu-gata Ryokaku-ki) средний транспортный самолет
primary power source – основной источник питания
alternate power source – резервный источник питания
backup power source – резервный источник электропитания
glide slope capture – вход в глиссаду; захват глиссадного луча
navigation receiver – приёмник навигационной системы
battery charger – зарядное устройство аккумулятора
BAT (battery) – батарея
standby power – резервный источник питания
hot battery bus – шина горячего резерва батареи
regardless – независимо от
attendant’s panel – пульт бортпроводника
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