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Monday, December 26

  1. page Mode S Transponder Operation & Testing edited ... Mode A/C squawk codes are assigned by ATC at time of departure of each flight, and may be chan…
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    Mode A/C squawk codes are assigned by ATC at time of departure of each flight, and may be changed by ATC in mid-flight. One problem is that being a 4-digit octal code, there are only 4096 possibilities. The Mode S system requires that every aircraft that has a Mode S transponder must be registered, and upon registration will be issued at unique 24-bit identity code. Issued by ICAO or a designated national aviation authority on its behalf, this identity is coded into the aircraft’s transponder, and will not change as long at that aircraft is registered in that country. If the transponder needs to be changed, then the new transponder will be programmed with the same code. With a 24-bit address, there are 16 million different codes available, enough for the foreseeable future.
    The major advancement with Mode S is that the ground station can interrogate one single aircraft by using that aircraft’s ICAO unique identifier. Also, aircraft can send out Mode S interrogations to other aircraft. This feature is the basis of collision avoidance systems (e.g., TCAS) and non–radar-based traffic control systems such as ADS-B.
    {ads-b-arch_dynavtech.jpg} Figure 2. Mode S
    Mode S interrogations
    With an ATC system that uses all three modes, A, C, and S, the system can do a variety of different interrogations:
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    P2 is send by the directional SSR transmitter at full strength to suppress Mode A/C replies. There is no P4, but there is a P5 and P6. The P6 pulse has the interrogation request, specifying which aircraft is to reply, and what information is wanted.
    Replies: Only one aircraft, the one whose identity is in the P6 encoding, will reply. What it sends back depends on the question encoded in the interrogation.
    {Mode_S_long_form_interrogation.jpg} Figure 3. Mode S
    What interrogates what?
    In Mode A and C, it is always a ground station that does the interrogation, and always an aircraft that replies. Therefore the terms uplink and downlink have been considered synonymous with interrogation and reply. In contrast, Mode S interrogations can also be from an aircraft, and replies may be intended for, or received by, other aircraft, so the terms uplink and downlink are no longer technically accurate. However, because uplink and downlink have been used for so long, they are still used to mean interrogation and reply.
    (view changes)
    12:37 pm
  2. page Mode S Transponder Operation & Testing edited ... Introduction A Mode S transponder is a aircraft radio receiver & transmitter that, when i…
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    Introduction
    A Mode S transponder is a aircraft radio receiver & transmitter that, when it receives an interrogation signal from a ground-based secondary surveillance radar (SSR) or another aircraft, replies with a specific digitally-encoded data burst, allowing the interrogating station to know the identity, location, heading and other information about the answering aircraft. Even though the SSR is called a radar, it is really a two-way radio system whose ground antenna is a highly directional one that is mounted on top of the the primary surveillance radar (PSR), and rotates with it. The PSR and SSR outputs are combined by computer and the information gathered by them is displayed together on air traffic controllers’ “radar” screens.
    {Becker_BXP6401_Mode_S_transponder.jpg} Figure 1. Becker Mode-S
    History
    Transponders date back to World War II, when radar first came into use. Germany was the first to produce transponders so its radar could identify friendly aircraft. But the British learned how the system worked, so Mosquito nightfighters could interrogate a German aircraft, causing it to betray its position [14].
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    12:36 pm
  3. page Mode S Transponder Operation & Testing edited ... {ads-b-arch_dynavtech.jpg} Mode S & ADS-B schematic Mode S interrogations With a an A…
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    {ads-b-arch_dynavtech.jpg} Mode S & ADS-B schematic
    Mode S interrogations
    With aan ATC system
    Mode A/C request
    P2 is sent by the omnidirectional transmitter, timing of P3 differentiates between Mode A and Mode C interrogation, there is no P4, P5 or P6.
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    Replies: All Mode A or all Mode C transponders reply. The duration of the P4 pulse tells all Mode S aircraft not to reply.
    Mode A/C/S all-call interrogation
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    a Mode A?CA/C interrogation, P3
    Replies: All Mode A or all Mode C transponders reply. All Mode S aircraft reply because of the P4 pulse length, and each reply contains the aircraft’s unique ICAO code. The Mode S aircraft will then not reply again to this type of interrogation from this interrogator, as identified by the IC, for 18 seconds (unless an override signal is sent by the same station[4]).
    Mode S reply wanted
    (view changes)
    12:31 pm

Wednesday, December 21

  1. page home edited ... Hi Everyone! Welcome to our WIKI leagueofextraordinarytechnicians All This site has been b…
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    Hi Everyone!
    Welcome to our WIKI leagueofextraordinarytechnicians
    AllThis site has been built as a reference project by the Avionics Class of the pages we discussed2012 at SAIT POlytechnic.
    All materials contained herein
    are list on the left menu. Thefor reference only content that exists in each page at this time is the name of the person responsible for the page.
    To edit your page you simply go to that page
    and click on EDIT in no way should replace the top right corner.
    Play with it to start with and have some fun.
    Cheers
    Lisa
    appropriate maintenance manuals.
    Enjoy!
    Thanks

    (view changes)
    8:56 am

Friday, December 16

  1. page Weather Radar - Operation and Testing edited ... Bendix King RDS-82 Maintenance Manual Aircraft Electrictrity and Electronics by Thomas Eismin…
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    Bendix King RDS-82 Maintenance Manual
    Aircraft Electrictrity and Electronics by Thomas Eisminn
    http://fr.wikipedia.org/wiki/Fichier:Airborne_weather_radar_NASA.jpghttp://www.equipmatching.com/uploads/images/1199851406.jpg
    (view changes)
    11:56 am
  2. page Weather Radar - Operation and Testing edited ... False Alarm Manual Tilt Alignment References IFR RD-300 User Manual Bendix King RDS-82 Ma…
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    False Alarm
    Manual Tilt Alignment
    References
    IFR RD-300 User Manual
    Bendix King RDS-82 Maintenance Manual
    Aircraft Electrictrity and Electronics by Thomas Eisminn

    (view changes)
    11:55 am
  3. page Inertial Navigation Systems - Operation & Testing edited Natalie Note: This material is for reference purposes only Operation Inertial Navigation Syste…
    Natalie
    Note: This material is for reference purposes only
    Operation
    Inertial Navigation System does not have frequency.
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    8:59 am
  4. page Inertial Navigation Systems - Operation & Testing edited ... èRemote reading compass system is not required èWith aid of FMC and navigation database IRU b…
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    èRemote reading compass system is not required
    èWith aid of FMC and navigation database IRU becomes INS
    References
    http://pilotjocky.blogspot.com/2008/09/inertial-navigation-system-ins.html
    Instructor Notes
    http://www.electronic-engineering.ch/study/ins/ins.html
    http://fourier.eng.hmc.edu/e80/inertialnavigation/node4.html

    (view changes)
    8:58 am
  5. page ILS Glideslope - Operation & Testing edited ... Glideslope is a part of the Instrument Landing System (ILS). Its purpose is to provide the abi…
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    Glideslope is a part of the Instrument Landing System (ILS). Its purpose is to provide the ability to land an aircraft in poor visibility or in good conditions. Using Localizer paired with Glideslope is considered a precision approach. Glideslope is a system that is paired with the Localizer. It is a navigational aid which can be used in IFR flight and is designed to give the pilot a glide path (GP) centered at 2.5 - 3 degrees from the horizontal plane of the runway. The beam is only 1.4 degrees deep: 0.7 degrees below the GS centerline and 0.7 degrees above.
    {GS_illustration.jpg}
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    of an aircraft.aircraft or with a combination VOR / localizer / GS antenna. This antenna
    {gs.gif}
    Glideslope information is displayed by either a horizontal pointer or GS "bug" which displays high when the aircraft is below the GP or it will display on the low side of center when the aircraft is above the GP. When there is no signal the GS bug is hidden from view or a GS flag will display.
    {hsi.jpg}
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    1400 feet (typically 1000 ft) from the
    {gs300.jpg} {ws_gs2.jpg}
    The glideslope transmitter by the runway transmits an AM (DSBFC) modulated at 40% for each side band. The upper signal beam is modulated at 90Hz and the lower signal beam is modulated at 150Hz. Both signals are designed to overlap in the middle which has the effect of both signals being received at varying strength when an aircraft is inside the overlap zone. Each signal is at the same carrier frequency and is interpreted by the GS receiver as one DSBFC signal with a 150Hz and 90Hz sideband.
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    Ramp Test Procedure
    1. Set up the NAV-402A on an appropriate workbench near the aircraft GS antenna.
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    connector (15) and start with an output level of -80dBm.
    3. Place the antenna tripod undernear the belly of the aircraft AT LEAST 15 inches from the GS antenna but no farther than 30".aircraft.
    4. Set the MODE switch (5) to G/S fixed.
    5. Set the G/S DDM switch (6) to 0.
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    8. Power on the aircraft avionics bus and turn on the Navigation receiver(s) under test.
    9. Tune the Nav Rx to 108.10.
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    and centered. Adjust output power if the signal is erratic or the flag does not pull on the GS indicator.
    11. Set the G/S switch to .091 on the 150 side. The indicator should be on the 1st mark ABOVE 0.
    12. Set the G/S switch to .175 on the 150 side. The indicator should be on the 5th mark ABOVE 0.
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    http://www.dbsant.com/GlideS.php
    IFR NAV-402AP User Manual
    Avionics class notes and handouts
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    7:37 am

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