The main idea is that the two parts of an ILS provide different kinds of guidance and must be received separately. The localizer gives horizontal guidance and operates in a VHF band, while the glideslope provides vertical guidance and uses a different frequency band (UHF-like). Because these signals live in separate frequency ranges, they can be transmitted and received without interfering with each other, allowing the aircraft to tune and process both streams simultaneously with dedicated receivers. This separation also lets each antenna be optimized for its specific beam pattern and coverage—one located at the far end of the runway for the localizer, and another near the approach end for the glideslope. The other ideas—more power, the same frequency with different polarizations, or relying on redundancy—don’t explain why two antennas are used for the dual guidance signals.

Anti-skid braking relies on electronically sensing wheel speed and quickly modulating the actual braking force using hydraulic power. The system combines electronic control with hydraulic actuation: wheel-speed sensors feed data to a brake control unit, which then commands hydraulic valves to increase or release pressure at each brake to keep wheels from locking. That blend of electronic processing and hydraulic power makes it an electro-hydraulic system. A purely hydromechanical setup wouldn’t have electronic processing to modulate pressure based on wheel slip, and a purely pneumatic or electrical system wouldn’t provide the necessary hydraulic braking pressure that anti-skid requires. The electrical part handles sensing and control logic, while the hydraulic part provides the actual braking force, so electro hydraulic is the correct description.

The display controller’s job is to configure how information is shown on the EFIS displays. It lets the pilot choose the appropriate display layout and data presentation for the current phase of flight or situation, such as switching between primary flight data, navigation/map views, plan view, or different overlays and ranges. This makes the cockpit information adaptable and easy to interpret for the task at hand. Cockpit lighting is handled by a separate lighting system, so it isn’t the function of the display controller. Weather information is provided by weather radar or other sensors, and while the controller can switch to a weather overlay, it doesn’t generate that data itself. Autopilot modes and the flight director are managed by the flight control logic, not by the display controller.

An emergency locator transmitter is designed to keep broadcasting even if the aircraft’s electrical system fails, so it has its own dedicated power source. The transmitter is powered by a built-in battery inside the ELT, ensuring it can operate and send the distress signal independently of the aircraft’s battery, external power, or any generator. This independence is what guarantees the beacon can function after a crash or power loss.