Section 1, Chapter 6 - ATS Surveillance Systems Flashcards

Question

What methods can be used to identify aircraft using SSR Mode A?

Answer 1

**When using Mode A to identify aircraft, one of the following methods should be employed:** * Discrete Code Selection: Observing the pilot’s compliance with the instruction to select a discrete four-digit code. * Recognising Validated Code: Recognising a validated four-digit code previously assigned to an aircraft callsign. When code/callsign conversion procedures are in use and the code/callsign pairing can be confirmed, the callsign displayed in the data block may be used to establish and maintain identity. * IDENT Feature: Observing an IDENT feature when it has been requested.

Answer 2

* Caution: Simultaneous requests for SPI (Special Position Identification) transmissions within the same area may result in misidentification. * Restriction: Aircraft displaying a conspicuity or special purpose code are not to be identified using the IDENT feature, unless specified otherwise in MATS Pt 2.

Answer 3

**Controllers should assign Mode A codes according to the following categories within the Code Assignment Plan:** **Discrete Codes:** * Domestic Codes: Assigned to aircraft flying within the areas of responsibility of a unit. * ORCAM Codes: Assigned to international flights and normally retained beyond the area of responsibility of the assigning unit. **Special Purpose Codes:** Allocated internationally. **Conspicuity Codes:** Allocated nationally or to specific users/units.

Answer 4

* Allocate Discrete Code: Controllers at SSR-equipped units should allocate a discrete code to the flight in accordance with the SSR assignment plan. * Mode C Selection: Unless otherwise directed by an ATC unit, Mode C should be selected in conjunction with Mode A. * Verify Mode C: Controllers must verify the accuracy of the Mode C readout when assigning discrete codes to aircraft.

Answer 5

**Controllers must validate Mode A codes by:** * Checking: As soon as possible, either by direct reference to their display or with assistance from another controlling agency, to ensure the data displayed corresponds with the assigned code. * Procedures: At units with code callsign conversion equipment, procedures must be applied to ensure the correct correlation of the callsign with the assigned code.

Answer 6

**The code must be checked by one of the following methods:** **Squawk Observation:** * Instructing the aircraft to squawk the assigned code and observing that the correct numbers appear on the situation display. **Squawk IDENT:** * Instructing the aircraft to "squawk IDENT" and simultaneously checking the code numbers associated with the SSR response. **Matching Position Indication:** * Matching an already identified Position Indication with the assigned code for the flight.

Answer 7

* Reset Assigned Code: Instruct the pilot to reset the assigned code (SERA.13005(c)(1)). * Select Code 0000: If resetting fails to display the assigned code, instruct the pilot to select code 0000. * Switch Off Transponder: If a corrupt code still exists, normally instruct the pilot to switch off the transponder (SERA.13005(c)(2)). * Retention of Corrupt Code: The corrupt code may be retained to assist identification and tracking, provided Mode C has been verified. Inform associated ATC units of the retention of corrupt data.

Answer 8

**Controllers may deem Mode A codes to be validated when it can be ascertained from the Code Assignment Plan that an observed Mode A code has been assigned by a unit capable of validating the code, unless:** * The code is promulgated as being unvalidated. * The controller has been notified that the code is corrupt.

Answer 9

**Considerations: The Mode A code and associated Mode C data of special purpose codes must be considered unvalidated and unverified.** **Special Purpose Codes:** * Emergency Codes: 7500 (Hijack), 7600 (Radio failure), 7700 (General emergency). * Code 1000: Indicates an aircraft conducting IFR flight as General Air Traffic (GAT), where the downlinked aircraft identification matches the flight plan. * Code 2000: Selected by pilots of aircraft entering the UK from an adjacent FIR where transponder operation has not been required; also used for IFR conspicuity. * Code 7007: Selected by aircraft engaged in airborne observation flights under the Treaty on Open Skies. These flights have Flight Priority Category B status and details are published by NOTAM.

Answer 10

**Considerations: The Mode A code and associated Mode C data of conspicuity codes must be considered unvalidated and unverified.** **Requirements for Pilots: Pilots are required to squawk a VFR or IFR conspicuity code when operating at and above FL100 and are advised to do so when below FL100, unless:** * They have been assigned a discrete code. * They are transponding on one of the special purpose codes, a frequency monitoring code, or one of the other specific conspicuity codes assigned according to the Code Assignment Plan. * They are flying below 3,000 ft in the aerodrome traffic pattern and have been instructed to select the aerodrome traffic pattern conspicuity code (7010). * On grounds of safety, the aircraft has been instructed to squawk standby. This is considered exceptional due to the associated reduction in protection from ACAS. ATSUs must log the circumstances and duration of such occurrences and make records available to the CAA on request.

Answer 11

**The SSR Code Assignment Plan provides a complete set of UK conspicuity codes, including those used at specific units or locations. Some of these codes are:** * 0024: Radar Flight Evaluation or Calibration. Used only for the duration of the radar evaluation or calibration. Not used while transiting to/from the trial. * 0033: Para Dropping. Selected by transponder-equipped aircraft five minutes before the drop commences until parachutists or loads are estimated to be on the ground. * 2000: IFR Conspicuity. Used when operating within UK airspace in accordance with IFR and have not received a specific instruction from ATS. * 7000: VFR Conspicuity. Used when operating within UK airspace in accordance with VFR and have not received a specific instruction from ATS. * 7001: Military Fixed Wing Low Level Conspicuity and Climbout. Used by military fixed-wing aircraft in the UK Low Flying System. Retained until an ATC unit gives alternative instructions. * 7002: Danger Areas General * 7003: Red Arrows Display/Transit. Used by the Red Arrows for display and transit. * 7004: Aerobatics and Display. Selected five minutes before aerobatic manoeuvres commence until normal operations resume. * 7005: High Energy Manoeuvres. Used by military fast-jet aircraft before engaging in sustained high-energy manoeuvres outside controlled airspace below FL 195 and outside the UK low-flying system. * 7006: Autonomous Operations within TRA and TRA (G) * 7010: Aerodrome Traffic Pattern Conspicuity Code. Facilitates ACAS collision avoidance. Selected when operating in or within approximately 2 NM of the aerodrome traffic pattern.

Answer 12

* Purpose: To prevent and mitigate the consequences of airspace infringements. * Pilot Actions: Pilots operating close to the peripheries of certain controlled airspace may select local SSR conspicuity codes and monitor the promulgated frequency. * Implication: Selection of these codes and frequency monitoring does not imply the provision of any form of ATS. * Controller Procedures: Detailed procedures for the use of monitoring codes and actions to be taken by controllers are specified in MATS Part 2.

Answer 13

**Levels of Mode S:** **Elementary Mode S:** * Provides selective interrogation of aircraft. * Includes aircraft identification Down-Linked Airborne Parameter (DAP). **Enhanced Mode S:** * Enables further DAPs from an aircraft’s flight management system. **Additional DAPs in Enhanced Mode S:** * Selected altitude * Indicated Airspeed (IAS) * Ground speed * Magnetic heading * Rate of climb/descent

Answer 14

* Additional Capability: Mode S transponder-equipped aircraft have an Aircraft Identification Feature (Flight Identity or Flight ID). * Flight Crew Action: The flight crew sets the aircraft identification in the transponder. * Difference from Aircraft Address: 1. Aircraft Identification Feature: Set by the flight crew and relates to the flight's identity. 2. Aircraft Address: A unique ICAO code specific to the airframe, over which crews have no control.

Answer 15

**Direct recognition of the Aircraft Identification Feature on the situation display can be used to establish surveillance identification, subject to:** * Correlation with Flight Plan: Correlating the Aircraft Identification Feature with the aircraft identification entered in the flight plan and displayed to controllers on flight progress strips. * Correlation with Callsign: Correlating the Aircraft Identification Feature with the aircraft’s callsign used in a directed RTF transmission to the controller. *Note: Controllers should exercise particular caution when there are aircraft with similar callsigns on the frequency and should use an alternative method if there is any doubt about the surveillance identification.*

Answer 16

* Action Required: The controller shall request the pilot to confirm the Aircraft Identification Feature. * Correction: If necessary, the pilot should re-enter the correct Aircraft Identification Feature.

Answer 17

* Inform the Pilot: Notify the pilot of the persistent discrepancy. * Assign Discrete Mode A Code: Assign the aircraft a discrete Mode A code. * Notify Next Control Position: Inform the next control position or unit of the erroneous Aircraft Identification Feature transmitted by the aircraft.

Answer 18

* Requirement: Both units must have appropriate Mode S surveillance capability. * Condition: Transfer of identification using the Mode S Aircraft Identification Feature shall only be conducted in accordance with locally agreed arrangements. * Specification: Procedures must be specified in MATS Part 2.

Answer 19

* Generation: The Selected Altitude DAP is generated by flight crew inputs into the aircraft’s autopilot system. * Display Capability: Subject to appropriate surveillance system capability, the Selected Altitude DAP can be displayed to controllers on situational displays. * Presentation: Selected Altitude data will be presented as either a flight level or an altitude, depending on local surveillance system settings, detailed in MATS Part 2. * Terminology: For ATC and RTF purposes, the generic phrase ‘Selected Level’ is used to encompass data presented as either an altitude or a flight level. * Usage Limitation: Selected Levels display intent-based information only and shall not be used for the purposes of separation.

Answer 20

**Situations where the Selected Level may be at variance with the actual flight level include:** **SID/STARs with Vertical Restrictions:** * Pilots may select the final cleared level and use the aircraft flight management system to achieve vertical constraints. **Final Approach:** * Pilots may pre-select the missed approach procedure altitude. **Manual Flight:** * Particularly in response to vertical avoiding action manoeuvres, when the aircraft is being flown manually.

Answer 21

Units equipped with Enhanced Mode S surveillance systems that enable DAPs should display Selected Levels on the situation display to mitigate the risk of level busts. *Important Note: Checking of Selected Levels shall not be used as a substitute for RT readback of level clearances.*

Answer 22

* Do Not State Incorrect Level: Controllers shall not state on RT the incorrect level as observed on the situation display. * Query the Discrepancy: Controllers may query the discrepancy using the following phraseology: ***“(Callsign), check selected level. Cleared level is (correct cleared level).”***

Answer 23

* Query the Discrepancy: If a discrepancy is observed between the altimeter setting passed and that selected by the pilot, a controller should query the discrepancy using the following phraseology, as appropriate: ***“(Callsign), check altimeter setting QNH 1000” (where QNH 1000 hPa is the correct value).*** ***“(Callsign), check altimeter setting, confirm standard pressure is set?” (where 1013.25 hPa is the correct value).***

Answer 24

* Definition: A TMZ is airspace of defined dimensions within which aircraft are required to carry and operate a Mode S SSR transponder. * Alternative Provisions: Aircraft must comply with alternative provisions prescribed for that particular airspace by the ANSP, as referred to in SERA.6005(b).

Answer 25

Establishment Reason: A TMZ is established for overriding safety reasons where the airspace classification would not normally require the carriage of a transponder, but changing to a more restrictive classification of controlled airspace is not warranted. Purpose: * Creates a ‘recognised air traffic environment’. * Enhances the ability of ATS to provide safety. * Enables the operation of airborne and ground-based safety nets.

Answer 26

**Access to TMZ:** * Pilots of aircraft unable to comply with TMZ requirements may be granted access subject to specific approval by the ANSP. * Approval conditions depend on: * Types and density of air traffic operating or planned within the TMZ. * Actual or forecast meteorological conditions. **Procedures within TMZ:** * Standard ATS procedures and separation/deconfliction minima appropriate to the airspace classification are applied. * The existence of a TMZ does not confer or suggest any particular airspace classification.

Answer 27

**When only PSR is available, a controller can transfer the identity of an aircraft to another controller by the following methods:** **Direct Designation (Pointing):** * Pointing at the Position Indication where two situation displays are adjacent or a conference-type display is used. * Ensure blips on both displays correlate if the information is derived from separate PSR heads or beams. * Use an alternative method if parallax is likely to cause an error. * Direction and Distance from a Common **Reference Point:** * Designate the Position Indication in terms of direction and distance from a common reference point (geographical position or navigational facility) accurately indicated on both displays. * The Position Indication as seen by the accepting controller must be within 3 NM of the position stated. * The distance between the aircraft and the reference point must not exceed: 1. 30 NM if the aircraft is flying along a published ATS route or direction is given as a bearing in degrees. 2. 15 NM in other circumstances. **Electronic Marker or Symbol:** * Designate the Position Indication by positioning an electronic marker or symbol so that only one Position Indication is indicated and there is no possible doubt of correct identification.

Answer 28

**General Rule:** A pilot must be advised whenever identification is lost. **Exception:** * When using SSR, controllers may temporarily lose the ability to read data blocks due to overlapping or garbling (e.g., in holding areas). * If the controller anticipates that identification will be re-established immediately after the overlapping or garbling ceases, the pilot need not be advised of the lost identification.

Answer 29

* Outside Controlled Airspace: A pilot should be informed as soon as their aircraft has been identified. * Inside Controlled Airspace: The pilot needs to be informed only if the identification is achieved by the turn method.

Answer 30

**Pilots should be informed of their position in the following circumstances:** * Following identification of the aircraft using the turn method. * When the pilot requests the information. * When the aircraft is flying off the correct track. * When an aircraft estimate differs significantly from the controller’s estimate based on ATS surveillance system observation. * When the pilot is instructed to resume their own navigation following vectoring, if considered necessary by the controller.

Answer 31

**Table of Identification and Position Information:** * Additional Note: When providing a Basic Service, a controller may identify an aircraft to facilitate coordination or to assist in the provision of generic navigational assistance. However, the controller is not required to inform the pilot that identification has taken place or to pass a position report. * General Rule: Controllers may pass position information to aircraft whenever they consider it necessary.

Answer 32

Position information should be passed in one of the following forms: * A well-known geographical position. * Bearing (using points of the compass) and distance from a known position. * Magnetic track and distance to a location displayed on the situation display that is a reporting point, an en-route navigational aid, or an approach aid. * Latitude and Longitude (by specific units only when authorized in MATS Part 2). * Distance from touchdown if the aircraft is on final approach.

Answer 33

When using Mode C responses to assess vertical separation, controllers must continually monitor the Mode C responses to ensure that the vertical distance is never less than the prescribed minimum.

Answer 34

No, vertical separation using Mode C is not applied against aircraft transponding A0000.

Answer 35

Minimum vertical separation may be applied between verified Mode C transponding aircraft if the intentions of both aircraft are known to a controller because: * They are under the controller's control. * They have been coordinated. * They are operating in accordance with established agreements.

Answer 36

**If the intentions are not known, the minimum separation is:** **IFR Flights within Class A, C-E Airspace:** * Increased to 5,000 ft, or alternative approved minima within MATS Part 2. **VFR Flights within Class C Airspace:** * Increased to 5,000 ft, or alternative approved minima within MATS Part 2.

Answer 37

**Unverified Mode S altitude reporting or Mode C data may be used for separation within controlled airspace as follows:** **IFR Flights within Class A, C, and D Airspace, and VFR Flights within Class C Airspace:** * A minimum vertical separation of 5,000 ft, or an alternative approved minimum within MATS Part 2. * Surveillance returns, however presented, are not allowed to merge. **IFR Flights within Class E Airspace (Except Against Aircraft Displaying VFR Conspicuity or a Frequency Monitoring Code):** * A minimum vertical separation of 5,000 ft, or an alternative approved minimum within MATS Part 2. * Surveillance returns, however presented, are not allowed to merge. **IFR Flights within Class E Airspace (Against Aircraft Displaying VFR Conspicuity or a Frequency Monitoring Code):** * Whenever practicable, pass traffic information. * If requested by the pilot or deemed necessary by the controller, suggest traffic avoidance advice. *Note: The procedure in points (2) and (3) only applies to Frequency Monitoring codes notified for the purposes of VFR within Class E airspace.*

Answer 38

**Aircraft that do not meet the published operating requirements for a particular volume of TMZ may be deemed to be operating outside that TMZ unless:** * Information received indicates that an aircraft is lost or has experienced a radio failure. * The controller has approved such an aircraft to enter TMZ airspace without identifying the aircraft using an appropriate method

Answer 39

* Traffic Avoidance Advice: Controllers shall aim to prevent surveillance returns from merging when suggesting traffic avoidance advice. * Deconfliction Service: Refer to CAP 774, Chapter 4, Paragraph 4.10 for information on Deconfliction Service.

Answer 40

**Verification Process:** * Once the aircraft has been identified and the Mode A validated, verify that the Mode C readout indicates 200 ft or less from the level reported by the pilot. * If the aircraft is climbing or descending, instruct the pilot to give a precise report as the aircraft passes through a level. **Assistance:** * Verification may be achieved with the assistance of an ATSU with which the aircraft is in contact.

Answer 41

A Mode C readout can be assumed to have been verified if it is associated with a deemed validated Mode A code (SERA.13010(b)).

Answer 42

* Confirm Altimeter Setting and Level: Ask the pilot to confirm their altimeter setting and level. * Persistent Discrepancy: If the discrepancy remains: 1. Instruct the pilot to switch off Mode C. 2. If independent switching of Mode C is not possible, instruct the pilot to select A0000.

Answer 43

* At Assigned Level: An aircraft may be considered to be at an assigned level if the Mode C readout indicates 200 ft or less from that level. * Leaving a Level: An aircraft instructed to climb or descend may be considered to have left a level when the Mode C readout indicates a change of 400 ft or more from that level and is continuing in the anticipated direction. * Passing Through a Level: An aircraft climbing or descending may be considered to have passed through a level when the Mode C readout indicates that the level has been passed by 400 ft or more and is continuing in the required direction. * Reaching an Assigned Level: An aircraft may be considered to have reached an assigned level when three successive Mode C readouts indicate 200 ft or less from that level.

Answer 44

* Normal Display: Mode C information is typically displayed as a Flight Level. * Exception: On some ground equipment, the vertical position of an aircraft flying below a pre-determined datum is displayed as an altitude.

Answer 45

**Conditions for Transfer:** * Satisfactory two-way speech communication is available between the controllers. * The identity of the aircraft has been transferred to, or established by, the accepting controller. * The accepting controller is informed of any level, speed, or vectoring instructions applicable to the aircraft at the stage of transfer. **Additional Information:** * If the route of the aircraft is not known, the offering controller must pass the observed track or reported aircraft heading to the accepting controller.

Answer 46

**Control of arriving aircraft may be transferred to Approach Radar Control under the following conditions:** * The transfer of control message is prefixed with "radar release." * Details of all conflicting aircraft are passed to the approach radar controller. * Conflicting aircraft are either transferred to Approach Radar Control or identified according to the accepting controller’s decision. * Neither the track nor the level of the conflicting aircraft is altered without coordination.

Answer 47

* Controller Authority: A controller may instruct an aircraft to turn in any direction as dictated by circumstances. * Avoidance of Unknown Aircraft: When avoiding unknown aircraft, the Rules of the Air (RoA) Regulations should be observed if practicable.

Answer 48

**An aircraft can be vectored outside the horizontal or vertical limits of controlled airspace under the following conditions:** * Emergency Situation: When an emergency situation arises requiring the aircraft to be vectored outside controlled airspace. * Severe Weather: When avoiding severe weather; the circumstances must be explained to the pilot before the aircraft leaves controlled airspace. * Pilot Request: When specifically requested by the pilot.

Answer 49

* Outside Controlled Airspace and VFR within Class E Airspace: Aircraft are not obliged to follow instructions given by ATC. * Traffic Service or Deconfliction Service: If the pilot accepts a Traffic Service or Deconfliction Service, the controller can expect that their instructions will be followed.

Answer 50

* Separation Goal: Controllers should aim to keep the aircraft under their control at least 2 NM within the boundary of controlled airspace. * Monitoring: Controllers should monitor the operation of aircraft in adjacent uncontrolled airspace, especially if circumstances necessitate vectoring an aircraft to be less than 2 NM from the boundary. * Coordination: Consider coordinating with the appropriate controlling agency if applicable. * Safety Action: Regardless of airspace divisions and classifications, controllers should take appropriate action for the safety of aircraft if unknown aircraft appear to present a risk of collision.

Answer 51

* Instruction to Resume Navigation: When vectoring is complete, pilots will be instructed to resume their own navigation. * Direct Route: If a direct route is required, the controller shall specify this in the instruction.

Answer 52

**The controller must either:** * Provide Magnetic Track and Distance Information: When instructing the aircraft to resume own navigation. * Issue Vectoring Instructions: To intercept the appropriate radial to the holding or routing fix.

Answer 53

Controllers must ensure that levels assigned to IFR flights in receipt of a Radar Control Service provide adequate terrain clearance for the phase of flight.

Answer 54

**Controller Responsibilities:** * Controllers ensure levels assigned to IFR flights in receipt of a Radar Control Service provide adequate terrain clearance. * Controllers have no responsibility for terrain clearance of, and shall not assign levels to, aircraft operating Special VFR or VFR within controlled airspace which accept vectors. **Minimum Terrain Clearances:** **Within the defined final approach area:** * Achieved if levels are assigned in accordance with a procedure approved by the CAA. **Within the Surveillance Minimum Altitude Area:** * Levels allocated must be in accordance with the information published on the SMAC. **Within 30 NM of the radar antenna associated with the unit providing the service:** * 1,000 ft above any fixed obstacle within: 1. 5 NM of the aircraft. 2. 15 NM ahead and 20° either side of the aircraft’s track. * When the aircraft is within 15 NM of the antenna, provided a SMAC or approved procedure has been notified, the 5 NM and 15 NM distances may be reduced to 3 NM and 10 NM, respectively. **Outside the above phases:** * 1,000 ft above any fixed obstacle: 1. Within 15 NM of the centerline of the ATS route. 2. Within 30 NM of the aircraft (for all other flights). * In sections of control areas where the base is defined as a flight level, the lowest useable level normally provides not less than 1,500 ft terrain clearance.

Answer 55

* Pilot Responsibility: Within Class G airspace, regardless of the service being provided, pilots are ultimately responsible for terrain clearance. * Specific Terrain Requirements: Terrain requirements pertaining to level allocations and the provision of vectors are specified within the conditions of the services as detailed in CAP 774 – UK Flight Information Services.

Answer 56

Unknown Aircraft: A position symbol that cannot be associated with an aircraft known by the controller to be operating within the airspace concerned shall be considered to represent an unknown aircraft.

Answer 57

**Class A:** * If the aircraft is making an unauthorized penetration, is lost, or has experienced radio failure: * Provide traffic avoidance advice. * Pass traffic information. **Class C:** * If the aircraft is making an unauthorized penetration, is lost, or has experienced radio failure: * IFR flights: Provide traffic avoidance advice and pass traffic information. * VFR flights: Pass traffic information and suggest traffic avoidance advice if requested by the pilot or deemed necessary by the controller. **Class D:** * If the aircraft is making an unauthorized penetration, is lost, or has experienced radio failure: * IFR flights: Provide traffic avoidance advice and pass traffic information. * VFR and SVFR flights: Pass traffic information and suggest traffic avoidance advice if requested by the pilot or deemed necessary by the controller (remind pilots to remain clear of cloud with the surface in sight). **Class E:** * Pass traffic information unless sequencing and separating IFR flights is compromised. * IFR flights: * Provide traffic avoidance advice if the aircraft is lost, has experienced radio failure, or infringes Class E airspace. * Pass traffic information whenever practicable and suggest traffic avoidance advice if requested by the pilot or deemed necessary by the controller. * Participating VFR flights: Pass traffic information according to CAP 774 – UK Flight Information Services. **Class G:** * Flights receiving Deconfliction Service or Procedural Service: Pass traffic information and deconfliction advice according to CAP 774 – UK Flight Information Services. * Flights receiving Traffic Service or Basic Service: Pass traffic information according to CAP 774 – UK Flight Information Services. * If more immediate action is required, pass traffic avoidance advice before traffic information. *Notes: * When providing traffic avoidance advice, remind pilots of their responsibility to remain clear of cloud with the surface in sight. * If more immediate action is required, traffic avoidance advice may be passed before traffic information. * If the flight rules of unknown aircraft cannot be determined, apply the procedure in Section 1, Chapter 6, Paragraph 10A.5(2).*

Answer 58

**General Rule:** * Controllers must seek to achieve the required minima. * Pilots must comply with the instructions given. **Exception in Class D or E Airspace:** * If the pilot reports having the unknown aircraft in sight and positively states that they will maintain their own separation from it: * Further controller action may be limited to passing traffic information. **Consideration:** * It may not always be possible to achieve the required separation minima against unknown traffic infringing controlled airspace due to their sudden appearance and/or unpredictable maneuvers. * Controllers shall apply all reasonable endeavors to achieve separation (SERA.7002(a)).

Answer 59

* Separation Minima: Controllers are not required to achieve separation minima. * Avoiding Action Instructions: * Aimed at reducing the risk of collision as far as possible. * Must consider aircraft proximity and constraints. * Pilot Compliance: Subject to prevailing meteorological conditions (SERA.7002(a)).

Answer 60

Controllers shall advise pilots when the conflict no longer exists (SERA.7002(b)).

Answer 61

Controllers should attempt to contact the relevant agency to identify the aircraft and agree on a course of action.

Answer 62

**Contact London FISO:** * Controllers should contact the appropriate London FISO for assistance in identifying the aircraft. * Example instruction: "G-ABCD, at (unit) request - contact (unit) (frequency) immediately." **Achieve Identification:** * Once the subject aircraft is on the controller's frequency, ensure that identification of the aircraft is achieved. **Relay Instructions:** * Simple transfers of communication are part of the London FISOs’ standard operating procedures. * FISOs are not permitted to issue control instructions to aircraft. * Controllers must not request FISOs to relay any instructions other than for the aircraft to transfer directly to their control frequency. **Royal Flights:** * Procedures for Royal Flights in fixed-wing aircraft are detailed in Chapter 9.

Answer 63

**Traffic information to aircraft shall include the following elements:** **Bearing from the Aircraft:** * Given in terms of the 12-hour clock. * If the aircraft is turning, direction is given by compass points. **Distance from the Aircraft:** * Provided in nautical miles. **Direction of the Unknown Aircraft:** * Described as, for example, “traffic is opposite direction/crossing left to right,” etc. **Height Information:** * When available, includes the unverified Mode C of the unknown aircraft.

Answer 64

* Controllers should avoid referencing the actual level of the other aircraft. * If necessary, inform the pilot that the other aircraft is "(number) thousand feet above/below."

Answer 65

**Space Weather Overview:** * The Earth is subjected to electromagnetic and high-energy particle radiation from galactic sources and the Sun, known as space weather. * Most space weather variability is of solar origin, with minor events being more common than major ones. * Several times in each 11-year solar cycle, space weather can have an operational impact. **Effects of Severe Space Weather:** * Increased solar radiation is typically detected at higher altitudes. * Severe space weather events can affect both aircraft at altitude and ground level. * These events can degrade or cause loss of satellite-based and/or ground-based navigation and communications systems. * Aircraft occupants, especially those in high-level flight, can be exposed to increased levels of solar radiation. **Space Weather Forecasts and Alerts:** * Available from the Met Office and ICAO. * Aircraft operators should consider space weather impacts when filing a flight plan. * Severe space weather can occur without warning, and flights above 49,000 ft AMSL must carry equipment to monitor radiation dose rates. **Pilot Requests and Emergency Procedures:** * Pilots may request a descent to a lower level during severe space weather events. * Controllers should accommodate such requests whenever possible. * Pilots may initiate an emergency descent without clearance, using transponder code A7700 and informing ATC as soon as possible. * During an emergency descent, pilots are responsible for separation and collision avoidance.

Answer 66

**Potential causes of spurious primary returns (clutter) include:** * Weather: Adverse weather conditions affecting radar returns. * Anomalous Propagation: Unusual atmospheric conditions causing false returns. * Ground/Sea Returns: Reflections from the ground or sea surface. * Birds: Birds causing radar returns. * Wind Turbine Effects: Interference from wind turbines. * Radar Countermeasures: Use of chaff or other countermeasures. *Note: Distinguishing clutter from actual aircraft surveillance returns may be difficult, especially with processed surveillance systems.*

Answer 67

**Clutter on the situation display can impact ATS provision in the following ways:** * Increased Risk: The controller may not detect conflicting traffic. * Obscured Information: Aircraft position symbols, track histories, and data blocks may be hidden or obscured. * Spurious Tracks: Spurious tracks may be generated, which can be indistinguishable from genuine aircraft returns. * Identification Delays: There may be a delay in identifying aircraft and placing them under an ATS. * Increased Workload: Controller workload may increase.

Answer 68

**Potential Effects of Clutter:** * Reduced degree, accuracy, and timeliness of instructions, advice, and information provided by controllers. * Impacts on safety and expedition of flight operations. **Possible Necessities Due to Clutter:** * Aircraft may need to be rerouted. * Air traffic services may be reduced below the level requested by the pilot. **Procedures:** * Specific tactical procedures to be applied by controllers in response to observed clutter are provided below (in the document).

Answer 69

Wind turbines can generate various negative effects on ATS systems, which should be considered during the wind turbine application planning process. CAP 764 provides specific information on these impacts. Long-term or permanent clutter impacts should be assessed locally, with procedures documented in MATS Part 2.

Answer 70

Controllers should consider the nature and extent of the clutter and take the following actions: * Inform pilots under Deconfliction Service or Traffic Service about the clutter extent and offer a reroute if possible. * Inform pilots about the reduction in traffic information/deconfliction advice if rerouting is not feasible, as detailed in CAP 774. * For all surveillance services, maintain aircraft identity; if rerouting is impracticable, consider an alternative type of approach. If identity cannot be maintained, terminate the service.

Answer 71

Controllers should consider the extent of the clutter and take the following actions: * Vector the aircraft around the clutter, if practicable. * If clutter intensity obscures the aircraft’s PSR or SSR position symbol, avoid using radar separation for that aircraft. * Provide IFR traffic in Class E airspace with reduced traffic information if necessary. Radar Control Service and air traffic service shall not be terminated.

Answer 72

Controllers should manage VFR flights receiving a Traffic Service within Class E airspace by following the procedures in 18B.1(1) and 18B.1(2): * Inform pilots about the extent of the clutter and offer a reroute if possible. * Inform pilots about the reduction in traffic information if rerouting is not feasible. Additionally, controllers remain responsible for providing advice on aircraft infringing controlled airspace and should consider the clutter’s nature, consistency, observed movement, relative speed, and track to identify unknown aircraft.

Answer 73

Controllers should assess the nature and extent of the clutter and decide whether: * A radar approach is not possible due to clutter and inform the aircraft. * A radar approach could be carried out, but radar contact may be lost. Inform the aircraft early about the clutter and provide missed approach instructions in advance if necessary.

Answer 74

During a surveillance system failure, controllers should: * Inform aircraft under control of the failure. * Apply local contingency procedures detailed in MATS Part 2. * Employ reduced vertical separation temporarily (e.g., 500 ft instead of 1,000 ft or 1,000 ft instead of 2,000 ft) if standard separation cannot be provided immediately. Inform pilots and pass essential traffic information as necessary. * When the surveillance system is notified as serviceable again, re-identify all aircraft by an approved method before providing any ATS surveillance service. * Follow MATS Part 2 procedures that obviate the need for notification of the system’s return to serviceable state, if approved by the CAA.

Answer 75

When an STCA is generated, the controller should: * Immediately assess the situation. * Take necessary action to ensure that the applicable separation minimum is not infringed. * Follow specific local STCA procedures detailed in MATS Part 2. * Refer to CAP 670 for STCA requirements.

Section 1, Chapter 6 - ATS Surveillance Systems Flashcards

(100 cards)