Volume 4 2A851 Aircraft

Drift correction is used to correct the true heading and allow the aircraft to make good the desired true course. Drift refers to the sideways movement of the aircraft caused by wind. By applying drift correction, the pilot can adjust the heading of the aircraft to counteract the effect of wind and maintain the desired true course. This ensures that the aircraft stays on track and reaches its intended destination accurately. Wind disbursement, airspeed correction, and ground speed correction are not directly related to correcting true heading and making good the desired true course.

Parallels of latitude are lines on a map or globe that run parallel to the equator. These lines are used to measure distances north or south of the equator and are important for navigation and determining locations on the Earth's surface. Therefore, the correct answer is a. equator.

Almanac data in the global positioning system (GPS) are transmitted to each satellite to update the navigation data message once every 24 hours. This data includes information about the satellite's orbit, clock correction, and health status. By updating this information regularly, the GPS system ensures accurate positioning and navigation for users around the world.

The correct answer is c. temperature and pressure changes. Inertial navigation systems use accelerometers to measure changes in velocity and acceleration. These accelerometers are sensitive to temperature and pressure changes, which can affect their accuracy. Temperature changes can cause the accelerometers to expand or contract, leading to errors in the measurements. Pressure changes can also affect the performance of the accelerometers, as they rely on a stable pressure environment for accurate readings. Therefore, it is crucial to protect the accelerometers in an inertial navigation system from temperature and pressure changes to ensure accurate navigation data.

When an aircraft is flying inbound on the 90° radial of a VOR station, the outbound radial will be 180° opposite to the inbound radial. Since the inbound radial is 90°, the outbound radial will be 90° + 180° = 270°.

The symbols generated by the Traffic alert and collision avoidance system (TCAS) represent increasing levels of urgency or threat by changing their shape and color. This means that as the urgency or threat level increases, the shape and color of the symbols will also change. This allows pilots to quickly and easily identify the level of danger and take appropriate action to avoid a collision.

The main reference burst (MRB) is transmitted when the main lobe of the tactical air navigation (TACAN) surface beacon radiation pattern is due east. This means that the MRB is transmitted when the strongest signal from the TACAN beacon is in the east direction.

The correct answer is b. Alternate airway. When two or more aircraft are operating on instrument flying rules between the same two points, they are kept apart by using alternate airways. These airways provide an additional route option for aircraft to follow, helping to maintain separation and prevent conflicts between aircraft.

When the IDENT-OUT-MIC switch is in the MIC position, identification, friend or foe (IFF) identification of position (I/P) replies are triggered every time the UHF radio system is keyed.

The correct answer is b. ARINC interface. The question is asking for the global positioning system interface that uses simplified computer words of specific high- and low-voltage levels. Among the options given, the ARINC interface is the most likely answer as it is a widely used standard in the aviation industry for avionics systems. It provides a standardized communication protocol for various systems, including GPS interfaces, using specific voltage levels to transmit data.

After a successful stored heading alignment, the circle error of probability for the inertial navigation unit (INU) is better than 1.0 nautical miles/hour.

When the AN/ARN-118 is in the transmit-receiver (T/R) mode, it produces signals that include bearing, distance, and Built-In Test (BIT) information from a surface beacon. This means that the AN/ARN-118 can receive and transmit signals to determine the direction, distance, and perform self-diagnostic tests with a surface beacon. The signals do not include information from a cooperating aircraft, and only distance and BIT information is not produced.

The correct answer is c. 16-bit ternary control word. This means that the TACAN channel data and selected mode information are sent to the receiver transmitter using a 16-bit control word that has three possible values. This control word is used to configure and control the TACAN system, allowing it to communicate and navigate effectively.

If an aircraft does not reply to a ground radar station interrogation, the radar echo appears on the station's plan position indicator by itself. This means that even if the aircraft does not respond to the radar signal, the radar station can still detect and display the echo of the aircraft on its screen. The echo will only show the presence of an aircraft but will not provide any additional information such as the aircraft's identity or altitude.

If a change to the aircraft's present flight path is necessary for safe separation of aircraft, the traffic alert and collision avoidance system (TCAS) will generate a corrective advisory. This means that the system will provide guidance or instructions to the pilot on how to correct their current flight path in order to avoid a potential collision with another aircraft. This advisory is triggered when there is an immediate threat of collision and requires immediate action to ensure safety.

When the AN/ARN-127 is operating in the instrument landing system (ILS) mode, it provides glide slope information to the attitude director indicator (ADI) in the form of up/down deviations. This means that the ADI will receive information about whether the aircraft is above or below the glide slope, helping the pilot maintain the correct descent path during an instrument landing. This information is crucial for a safe and accurate approach and landing.

The purpose of the instrument landing system (ILS) is to provide guidance to pilots during the approach and landing phase of flight. It helps pilots maintain the correct glide slope (up/down guidance) and stay aligned with the runway centerline (left/right guidance). Additionally, the ILS provides accurate distances along the approach (d), allowing pilots to gauge their position relative to the runway. However, providing bearing to a station (c) is not a purpose of the ILS.

In the tactical air navigation (TACAN) receiver transmitter (RT) adapter, the TO/FROM information is developed by combining the magnetic bearing with the magnetic heading. The magnetic bearing provides the direction from the aircraft to the TACAN station, while the magnetic heading indicates the direction in which the aircraft is actually pointing. By combining these two pieces of information, the TACAN system can determine whether the aircraft is flying towards or away from the TACAN station.

The XTAL CUR monitor light on the front of the identification, friend or foe (IFF) receiver-transmitter (RT) illuminates to indicate satisfactory operation of the local oscillator mixer circuits. The XTAL CUR refers to the crystal current, which is a measure of the current flowing through the crystal oscillator circuit. When the XTAL CUR monitor light is illuminated, it indicates that the crystal oscillator is functioning properly and generating the correct frequency for the IFF system.

The correct answer is d. Antenna controller. The antenna controller in the ARN-151 global positioning system unit is responsible for producing the intermediate frequency signal. The antenna controller is a crucial component that manages the operation of the antenna and ensures the proper transmission and reception of signals. It controls the positioning and orientation of the antenna to optimize signal strength and accuracy.

The correct answer is c. four 0.5 microsecond pulses, spaced 2 microseconds apart. In IFF mode 4 interrogation, the pulses are used to transmit a specific code to identify whether an aircraft is friendly or hostile. The pulses are short in duration (0.5 microseconds) and are spaced closely together (2 microseconds apart) to ensure accurate transmission and reception of the code. This configuration allows for efficient and reliable communication between aircraft and ground control.

In glide slope, each deviation dot on the attitude director indicator (ADI) glide slope indicator represents a 0.3° deviation.

In the tactical air navigation (TACAN) mode, the horizontal situation indicator (HSI) uses a course deviation bar to indicate the deviation from the desired course. Each dot on the deviation bar represents 5 degrees off course. Therefore, if the bar is deflected two dots to the right, it means that the aircraft is 10 degrees off course. So, the correct answer is d. 10.0°.

During instrument landing system (ILS) operation, the horizontal situation indicator (HSI) is used to indicate the aircraft's position in relation to the desired course. A full-scale deflection of the HSI vertical needle indicates that the aircraft is off course by a significant amount. In this case, a full-scale deflection corresponds to 2.5° off course. Therefore, the correct answer is d. 2.5°.