ATPL Instrumentation: What's it all about?

Number of questions in exam: 60
Exam duration: 1 hour and 30 minutes
Pilot Theory Online difficulty rating: Medium/Hard

The instrumentation exam is very similar to the AGK exam. Think of it more as an extension of AGK. In this subject, we cover the systems more closely related to the instruments that are directly in front of your eyes, rather than the systems that we control with the switches above our heads.

Sensors and Instruments

Sensors are critical for collecting data from the environment and aircraft systems, while instruments display that data to pilots. Together, they provide vital information about the aircraft’s position, performance, and external conditions.

Key points:

Types of sensors: Include pitot tubes (for airspeed), static ports (for altitude), and accelerometers (for movement).
Instrument types: Examples include airspeed indicators, altimeters, and artificial horizons.
Accuracy: Proper calibration and maintenance are essential for reliable readings, especially during critical flight phases.

Measurement of Air Data Parameters

Air data parameters are essential for understanding the aircraft’s performance in various flight conditions, such as speed, altitude, and air temperature. These parameters are measured using various instruments connected to sensors.

Key points:

Pitot-static system: Measures airspeed, altitude, and vertical speed.
Temperature sensors: Provide outside air temperature (OAT), crucial for performance calculations.
Altitude measurement: uses barometric pressure for accurate readings of flight altitude.

Magnetism: Direct Reading Compass and Flux Valve

Magnetism plays an essential role in navigation, with devices such as the direct-reading compass and remote-indicating compass helping pilots determine aircraft heading.

Key points:

Direct reading compass: A simple magnetic compass that provides heading information directly to the pilot.
Flux valve: An electromagnetic sensor used in modern aircraft to measure magnetic fields and improve heading accuracy.
Magnetic deviations: Magnetic fields inside the aircraft can distort compass readings, which requires correction.

Gyroscopic Instruments

Gyroscopic instruments provide critical flight attitude information, such as pitch, roll, and yaw, using principles of gyroscopic stability.

Key points:

Artificial horizon: Displays aircraft orientation relative to the Earth’s horizon.
Heading indicator: Shows the aircraft's heading using a gyroscopic mechanism.
Turn coordinator: Measures the rate of turn and coordination of the aircraft’s movements.

Inertial Navigation

Inertial navigation systems (INS) and inertial reference systems (IRS) provide accurate position, speed, and direction information by calculating changes in the aircraft’s motion from a fixed starting point.

Key points:

Gyroscopes: Used in the system to detect changes in direction.
Accelerometers: Measure acceleration to determine changes in speed and position.
Accuracy: The system's accuracy diminishes over time due to drift, requiring occasional updates.

Aeroplane: Automatic Flight Control Systems

Automatic flight control systems (AFCS) help pilots by automatically controlling the aircraft's flight path, reducing workload during critical phases of flight.

Key points:

Autopilot: Automatically controls the aircraft’s flight trajectory.
Flight Director: Provides visual guidance to pilots, allowing them to manually fly the aircraft while maintaining a predetermined flight path.
Modes of AFCS: Includes modes like heading hold, altitude hold, and approach mode.

Trims, Yaw Damper and Flight Envelope Protection

Trimming controls the aircraft's attitude and helps maintain a stable flight path, while systems like yaw dampers and flight envelope protection ensure smooth operation within safe limits.

Trims: Small adjustments to the control surfaces (elevator, aileron, rudder) to relieve pilot control pressures.
Yaw damper: Reduces unwanted yawing motions, particularly during turns.
Flight envelope protection: Prevents the aircraft from entering unsafe flight conditions such as excessive bank angle or high angles of attack.

Autothrust: Automatic Thrust Control System

Autothrust systems automatically control engine power to maintain a specific speed or thrust setting, helping optimise fuel efficiency and reduce pilot workload.

Key points:

Speed control: The system adjusts engine thrust to maintain target airspeed.
Thrust settings: The system adjusts engine thrust to maintain target thrust setting.
Protection features: Limits thrust to avoid engine overboost or underperformance.

Communication Systems

Communication systems are essential for pilots to maintain contact with air traffic control (ATC) and other aircraft, ensuring safe and coordinated operations.

Key points:

VHF radio: The primary communication method for voice communication with ATC.
HF radio: Used for long-range communication when flying over oceans or remote areas.
ACARS: Aircraft Communications Addressing and Reporting System, kind of like texting!

Flight Management System (FMS)/Flight Management and Guidance System (FMGS)

The FMS and FMGS provide integrated flight planning and control, allowing the automation of navigation, performance optimisation, and system monitoring during flight.

Key points:

Flight planning: Enables pilots to input and modify flight routes, waypoints, and altitudes.
Navigation: Integrates data from GPS, inertial navigation, and other sources.
Guidance: Controls aircraft speed, altitude, and heading in line with the planned flight path.

Alerting Systems, Proximity Systems

Alerting systems provide pilots with critical safety information, while proximity systems help prevent accidents by alerting pilots to potential collisions or other hazards.

Key points:

Stick shaker: Warns pilots of an impending aerodynamic stall by vibrating the control columns.
GPWS (Ground Proximity Warning System): Alerts pilots if the aircraft is descending too rapidly toward the ground.
TCAS (Traffic Collision Avoidance System): Detects nearby aircraft and provides avoidance guidance.

Integrated Instruments: Electronic Displays

Modern aircraft use integrated electronic displays that combine multiple instrument readings into one cohesive system, improving situational awareness and reducing cockpit clutter.

Key points:

PFD (Primary Flight Display): Displays key flight information such as attitude, airspeed, and altitude.
ND (Navigation Display): Shows navigational data such as route, weather, and nearby traffic.
MFD (Multi-Function Display): Provides additional information like engine indications and other system information.

Digital Circuits and Computers

Digital circuits and onboard computers play a central role in processing data from sensors and controlling various systems within the aircraft.

Key points:

Microprocessors: Handle complex computations for things like flight control and navigation.
Data buses: Enable communication between the aircraft’s various digital systems.
Redundancy: Critical systems often include backup computers or circuits to ensure reliability.

Maintenance, Monitoring, and Recording Systems

These systems continuously monitor the aircraft’s performance, recording data for maintenance, crew performance, and investigative purposes.

Key points:

Aircraft monitoring systems: Continuously track the health of the aircraft's systems (e.g., engines, hydraulics).
Flight data recorders (FDR): Record flight parameters for post-flight analysis or accident investigation.
Cockpit voice recorders (CVR): Records aural sounds in the cockpit and communication between crew members and ATC.