Night operations

General

Recognise the meaning of the definition of ‘night’ or other similar wording that is used for night flight.

Rationale: In Regulation (EU) No 1178/2011 (the ‘Aircrew Regulation’), ‘night’ for manned aviation ‘means the period between the end of evening civil twilight and the beginning of morning civil twilight or such other period between sunset and sunrise as may be prescribed by the appropriate authority’.

Some national laws use the sunset and sunrise times for the definition of a night flight. ‘Sunset’ is defined as the daily disappearance of the upper limb of the sun below the horizon. This time depends on the latitude and longitude of the viewpoint. There are many websites and apps to find out the sunset and sunrise times at a specific location.

Recognise the benefits of illuminating the operational area, especially during the critical phases of take-off and landing.

Recognise that during night flight it is hard to estimate the distance between the UA and other obstacles if visibility is only ensured by the lights of the UA.

Recognise that a visual obstacle avoidance system may be less accurate in night-time operations.

Understand that if the sight of the UA is lost at night, return-to-home (RTH) should be immediately followed.

Rationale: During daytime, it is sometimes difficult to see the position of the UA, which is even more difficult at night.

Recognise that an infrared radiation (IR) camera allows one to see enough at night. Turning off the front green flashing light might improve the view because there will be no reflection in the on-board camera.

Recognise that the IR camera does not help in case of rain/humidity, and that the IR visibility significantly decreases.

Explain the use of the green flashing light at night.

Explain the use of navigation lights, position lights, anti-collision lights, and other lights for UA controllability.

Explain the use of lights (e.g. navigation, position, or anti-collision lights) for recognising the presence of manned aircraft.

Rationale: Those lights show where the UA is positioned and the direction in which the UA is aligned.

For manned aircraft, a red navigation light is located on the leading edge of the left-wing tip and a green navigation light on the leading edge of the rightwing tip (for helicopters, on the left and right sides of the cockpit). A white navigation light is positioned on the tail as far aft as possible. High-intensity strobe lights are also located in those positions. They are used as anti-collision lights and flash twice after a short break. A red rotating beacon is also part of the anti-collision lights.

Degradation of visual acuity

Recognise that flying the UA at night degrades visual perception.

Recognise night myopia, caused by the increasing pupil size. At low-light levels, without distant objects to focus on, the focusing mechanism of the eye may go to a resting myopic position.

If night-vision goggles are used, know how they function.

Night illusions

Define the term ‘night illusion’.

Recognise and overcome visual illusions that are caused by darkness, and understand the physiological conditions that may degrade night vision.

State the limitations of night vision techniques at night and by day.

Altered visual-scanning techniques

State the limitations of the different visual-scanning techniques at night and by day.

Rationale: Despite the value of electronic means of conflict detection, physical lookout remains an important defence against the loss of visual separation for all types of aircraft.

To avoid collisions, the remote pilot should visually scan effectively from the moment the UA starts moving until it comes to a stop at the end of the flight. Collision threats are present everywhere.

Before take-off, the remote pilot should visually check the take-off area to ensure that there are no other objects. After take-off, the remote pilot should continue to visually scan to ensure a safe departure of the UA with no obstacles.

Altered identification of obstacles

Explain the effect of obstacles on the take-off distance that is required at night.

Rationale: The remote pilot should know the flight area where the UA will fly at night. Objects look different and power lines are nearly invisible at night. It is, therefore, advisable that the remote pilot conduct a test flight during the daytime.

Overflight (flight over known populated areas or over assemblies of people)

Identification of populated areas and assemblies of people

Explain the definition of ‘populated area’ and ‘assemblies of people’.

Optimising flight paths to reduce risk of exposure

Explain the effects of the following variables on the flight path and take-off distances:

—          take-off procedure;

—          obstacle clearances both laterally and vertically;

—          understand the lethality of a UAS including debris area through flying parts after a crash; and

—          recognise the importance of a defined emergency landing area.

Likely operating sites and alternative sites

Recognise the different operating sites and alternative sites on the route of the overflight.

Adequate clearance for wind effects, especially in urban environment

Explain how the wind changes at very low height due to its interaction with orography and buildings.

Obstructions (wires, masts, buildings, etc.)

Explain the effect of obstacles on the required takeoff distance.

Interpret all available procedures, data, and information regarding obstructions that could be encountered during overflight

Avoiding third-party interference with the UA

Explain how to avoid third-party interference with the UA.

Minimum separation distances from persons, vessels, vehicles, and structures

Explain the importance of minimum separation distances from persons, vessels, vehicles, and structures.

Impact of electromagnetic interference, i.e. high‑intensity radio transmissions

Describe the physical phenomenon ‘interference’.

Explain in which situations electromagnetic interference could occur, particularly with regard to electromagnetic emissions and signal reflections peculiar to an urban environment. Explain their impact on the UAS system (i.e. C2 link GNSS quality, etc.)

Crowd control strategies and public access

Explain the importance of ensuring that no one is endangered within the take-off and landing area.

Describe the different crowd control strategies.

Explain the importance of having knowledge of public access.

BVLOS operations

Operation planning: airspace, terrain, obstacles, expected air traffic, and restricted areas

Explain the operation planning for BVLOS operations:

—          check the flying conditions (e.g. geographical zone, NOTAM) and obstacles along the planned route;

—          secure the necessary documentation before the BVLOS operation;

—          know and comply with the local conditions in the area where the BVLOS operation takes place;

—          ensure communication with the air traffic controller (ATCO), depending on the type of airspace within which the BVLOS operation is planned to be conducted;

—          plan the BVLOS operation including flight route and response to contingency and emergency events;

—          in uncontrolled airspace, check the actual traffic level of manned traffic along the planned route, including low-level traffic such as paragliders, hang gliders, helicopters, model aircraft, seaplanes and other possible traffic;

—          in uncontrolled airspace, verify that the UAS operation has been notified to manned aviation using, e.g. NOTAM, or other means used by manned aviation;

—          how to employ airspace observers (AOs), when needed;

—          consider the C2 link limitations (e.g. maximum range and presence of obstacles); and

—          use of conspicuity devices or traffic information / detection of incoming aircraft / deconfliction and emergency manoeuvres.

Sensor systems and their limitations

State the limitations of the different sensor systems.

Rationale: UASs that are used for BVLOS operations should maintain precise positioning to avoid traffic conflict and to successfully carry out their mission. Environmental features, such as tunnels and urban canyons, can weaken GNSS signals or even cause them to be lost completely. To maintain accuracy in GNSS-denied environments, UA may use real-time kinematic (RTK) capable inertial navigation systems (INSs) that provide information from accelerometers and gyroscopes to accurately estimate position, velocity, heading, and attitude.

Cooperative and non‑cooperative aircraft (airspace surveillance)

Identify the cooperative and non-cooperative detect-and-avoid (DAA) sensor/system capabilities for UA, if applicable.

Rationale: Cooperative and non-cooperative DSAA capabilities are key enablers for UA to safely and routinely access all airspace classes.

Roles and responsibilities of the remote pilot to remain clear of collision

Explain the traffic alert system and traffic collision avoidance system (TCAS) phraseologies, and how these systems work.

Identify the roles and responsibilities of the remote pilot to remain clear of collision.

Explain the collision avoidance methodology that is used in the operation to keep the UA clear of other traffic.

Rationale: Collision avoidance is emerging as a key enabler for UAS operations in civil airspace. The operational and technical challenges of UAS collision avoidance are complicated by the wide variety of UA, of their associated missions, and of their ground control capabilities. Numerous technological solutions for collision avoidance are being explored in the UAS community.

Command, control and communication (C3) link performance and limitations

Know the definition of ‘C3’.

Understand the relation between communications and effective command and control (C2).

Understand the basic C3 structure.

Understand the use of true and relative motion displays.

Understand the problems inherent in C3.

Rationale: C3 cannot be accomplished without two‑way communications. C3 would be impossible unless the remote pilot can collect feedback in some form. Basic to any C3 system is the incorporation of a reliable communications network.

Signal or communications latency for the C2 link

Understand the impact of signal or communications latency on the C2 link.

Explain what can cause, and how to detect, a signal or communications latency.

Describe the actions that are required following a signal or communications latency.

Rationale: BVLOS control may require a satellite communications link that implies a level of signal delay, or signal latency, which may impact on the accuracy of the BVLOS operation.

Planning for the loss of C2 link or for system failure

Understand the impact of a loss of C2 link.

Explain what can cause, and how to detect, a system failure.

Describe the actions that are required following a loss of C2 link.

Describe how to plan the contingency routes in case of a loss of the C2 link.

Rationale: It is of utmost importance to keep track of the UASs in civil airspace, and to know what happens if the C2 link between the remote pilot’s ground control station and the UAS is disrupted. In such a loss-of-the-C2-link situation, the UA usually flies on a pre-programmed contingency route based on its flight altitude, orientation, and bearing. The absence of situational awareness and direct communication from the UA makes it difficult or impossible for the ATCOs to discover the real position of the UA and identify if the pre‑programmed contingency route is properly followed impairing the possibility to clear the traffic along its intended route.

Interpreting separate data sources

Interpret different data sources to identify whether during flight the UA follows the planned route.

Crew resource management (CRM)

Explain the importance of CRM for BVLOS operations.

Low-altitude (below 500 ft) operations

Air traffic management (ATM) procedures

Describe the ATM procedures for low-altitude operations.

Radio communications and phraseology

Define the meaning of ‘standard words and phrases’.

Recognise, describe, and use the correct standard phraseology for each phase of a visual flight rules (VFR) flight.

Explain the selective calling (SelCal) system and aircraft communications addressing and reporting system (ACARS) phraseologies.

Explain the traffic alert and collision avoidance system (TCAS) phraseologies.

Situational awareness

Keep situational awareness, especially with low‑level manned aircraft and, if necessary, employ airspace observers (AOs).

Advanced aviation terminology

Explain the meaning of low-altitude operations related terminology.

Flight in non‑segregated airspace

Clear roles and responsibilities

Describe the relationship between the initiating causes (or threats), the hazard (top (main) event), the risk mitigations (the controls and barriers), and the potential consequential results (loss states) when conducting a flight in a non-segregated airspace.

Wake turbulence

State the wake turbulence categories for UA.

State the wake turbulence separation minima.

Transport and/or dropping of cargo

Weight and balance

Describe the relationship between UA mass and structural stress.

Describe why mass should be limited to ensure adequate margins of strength.

Describe the relationship between UA mass and aircraft performance.

Describe why UA mass should be limited to ensure adequate aircraft performance.

Depending on the type of operation, describe the relationship between centre-of-gravity (CG) position and stability/controllability of the UA.

Describe the consequences if the CG is in front of the forward limit.

Describe the consequences if the CG is behind the aft limit.

Describe the relationship between CG position and aircraft performance.

Describe the effects of the CG position on the performance parameters (speed, altitude, endurance, and range).

Be familiar with the abbreviations regarding mass and balance, e.g. (maximum) take-off mass ((M)TOM), (maximum) landing mass ((M)LM), basic empty mass (BEM), dry operating mass (DOM), operating mass (OM), and zero-fuel mass (ZFM).

Describe the effects of changes in the load when dropping an object.

Describe the effects of an unintended loss of the load.

Rationale: Mass and balance are extremely important for a UA. A UA that is not in balance may become difficult to control. Therefore, the overall balance should be considered when adding payloads, attaching gimbals, etc.

Load securing and awareness of dangerous goods

Calculate the MTOM and the MLM.

Explain the reasons for restraining or securing cargo loads.

Describe the basic methods of restraining or securing loads.

Explain why the transport of dangerous goods by air is subject to an additional training module.

State that certain articles and substances, which would otherwise be classified as dangerous goods, may be exempted if they are part of the UA equipment.

Rationale: The safe operation of the UAS requires to weigh all cargo in the UA (or provide an accurate estimate of weight using ‘standard’ values), load it correctly, and secure it to prevent loss or movement of the cargo during the flight.

Loading should be performed in accordance with the applicable regulations and limitations. The UAS operator’s loading procedures should be in accordance with the instructions given by the person that has the overall responsibility for the loading process for a particular UA flight. These loading instructions should match the requirements for cargo distribution that are included in the UA load and trim sheet.

Transport of dangerous goods

Safe transport of dangerous goods

Explain the terminology relevant to dangerous goods.

Be able to recognise dangerous goods and understand their labelling.

Be able to interpret the documentation related to dangerous goods.

Recognise dangerous goods by using ‘safety data sheets’ and the consumer labelling of the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

Explain that the provisions for the transport of dangerous goods by air are included in ICAO Doc 9284 ‘Technical Instructions for the Safe Transport of Dangerous Goods by Air’.

State the emergency/reporting procedures in case of an event with dangerous goods, including that in the event of a dangerous-goods-related emergency regarding the UA, the remote pilot should inform the ATC organisation of the transport of dangerous goods.

Explain the principles of compatibility and segregation of dangerous goods.

Explain the special requirements for loading radioactive materials.

Explain the use of the dangerous goods list.

Explain the procedures for collecting safety data, e.g. reporting accidents, incidents, and occurrences with dangerous goods.

Note: The learning objectives should be derived from the Technical Instructions and should be commensurate with the personnel responsibilities.

Operations with multiple UASs and swarms

Limitations related to human factors

Understand the human performance limitations in an operation with multiple UASs, including UAS swarms.

List the vital actions that the remote pilot and the persons who assist the remote pilot should perform in case of an emergency descent of the multiple/swarming UASs.

CRM

Explain the importance of CRM for operations with multiple UASs and swarms.

Navigating multiple platforms

Describe how to navigate multiple platforms.

Recognising system failures

Describe the different failures that may potentially occur during multiple/swarming UAS operations.

Explain what to do in the event of a failure.

Recognise that the remote pilot can override the system in the event of a failure.

Emergency containment procedures

List the different emergency containment procedures and describe the basic conditions for each kind of emergency.

Describe the recovery techniques in the event of engine or battery failure during multiple/swarming UAS operations.

UAS launch and recovery using special equipment

Operating procedures

Explain the specific procedures for launch and recovery operations.

Explain the impact on the UA’s behaviour when the systems for launch and recovery are operated from a moving vehicle, including ships.

Recognising failures

Describe the different failures that may occur during launch and recovery operations.

Explain what to do in the event of a failure.

Describe the cases where the remote pilot can override the system in the event of a failure.

Flying over hilly environment

Temperature inversions

Describe the following:

—       the effect of thermic-induced turbulence near the Earth’s surface;

—       surface effects;

—       diurnal and seasonal variations;

—       the effect of clouds; and

—       the effect of wind.

Rationale: The temperature can affect the density altitude. If the UA flies on a hot and humid day, the remote pilot will experience poor UA performance: as the temperature increases, the air molecules spread out. As a result, the propellers or motors of the UA do not have much air to grab on to.

Orographic lifting

Describe the effect of exploiting orographic lifting (i.e. slope or ridge) and the actions required.

Describe the vertical movements, wind shear, and turbulence, which are typical of hilly environment.

Rationale: Orographic lifting occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude, it quickly cools down adiabatically, which can raise the relative humidity to 100 %, create clouds and, under the right conditions, cause precipitation[100].

Higher winds through passes

Describe the effects of wind shear and the actions required when wind shear is encountered at take-off and approach.

Describe the precautions to be taken when wind shear is suspected at take-off and approach.

Describe the effects of wind shear and the actions required following entry into strong downdraught wind shear.

Describe the influence of a mountainous area on a frontal passage.

Rationale: In mountainous environment, the wind blows smoothly on the windward side of the mountain. On the leeward side, the wind follows the contours of the terrain and can be quite turbulent: this is called a katabatic wind. The stronger the wind, the higher the downward pressure. Such a wind will push the UA down towards the surface of the mountain. If the remote pilot does not know how to recognise a downdraft, which is downward moving air, the situation can become quite challenging.

Mountain waves

Explain the origin and formation of mountain waves.

State the conditions necessary for the formation of mountain waves.

Describe the structure and properties of mountain waves.

Explain how mountain waves may be identified through their associated meteorological phenomena.

Explain that mountain wave effects may exceed the performance or structural capability of the UA.

Explain that mountain wave effects may be propagated from low to high levels.

Indicate the turbulent zones (mountain waves, rotors) on a drawing of a mountain chain.

High- and low-pressure patterns

Describe the movements of fronts and pressure systems, and the life cycle of a midlatitude depression.

State the rules for predicting the direction and the speed of movement of fronts.

State the difference in the speed of cold and warm fronts.

State the rules for predicting the direction and the speed of frontal depressions.

Density altitude effects

Define pressure altitude and air density altitude.

Explain the effects of all-up mass (AUM), pressure, temperature, density altitude, and humidity.

Explain the influence of density altitude on the equilibrium of forces and moments in a stable hover, if applicable.

Rationale: Higher-density altitude means thinner air, and thinner air means that the remote pilot will experience poor UA performance. The propellers or motors of the UA do not have much air to grab on to. Lower-density altitude means thicker, denser air, and higher UA performance.

This knowledge is very important when the remote pilot flies in a mountainous or other high-elevation environment.