Section 5, Chapter 4 - Navigational Aids Flashcards
What are the ILS equipment specifications for Runway 25 and Runway 17?
Runway 25:
- Equipped with a CAT 3 ILS.
- Has associated DME facilities.
Runway 17:
- Equipped with a CAT 1 ILS.
- Has associated DME facilities.
Reference: For full details, refer to UK-AIP-AD2-EGAA.
Where can the designated operational coverage areas of the ILS Localiser and Glide Path signals be found?
The designated operational coverage areas of the ILS Localiser and Glide Path signals are shown in figures 1 and 2.
What are the definitions for ‘Fluctuations’ and ‘Guidance Error’ in the context of ILS faults or fluctuations?
- Fluctuations: Subjective assessment of an ILS signal variation that may or may not have been in or out of tolerance. Likely seen as a small deviation on the cockpit indicator display.
- Guidance Error: Objective assessment of autopilot activation or control motion direction from the aircraft systems. Likely to have affected the stability of the approach.
What actions should be taken when reports of ILS Guidance Errors or fluctuations are received?
Corroboration of Guidance Errors:
- Only corroborate reports when related to either localiser or glidepath of the ILS facility.
- Require two reports at the same part of the approach (within +/-50ft height and +/-0.2NM range).
- Query ‘DME’ reading to confirm position of errors.
Recording and Reporting:
- Record all ILS reports (fluctuations or guidance errors) in the watch log.
- Notify the Airport Operations Engineer (AOE).
- Contact NATS unit manager (including GM and GEM) for any downgrade or removal of ILS or glidepath component.
Pilot Communication:
- Obtain additional details about reports from the pilot after landing if safe to do so.
- Inform following aircraft of reported ILS variation and request they report any guidance error, specifying height and range.
Decision Process:
- Follow the decision process in figure 1.
- If required, withdraw the ILS from service.
- LOC/DME approaches may continue if only the glidepath is reported, provided the glidepath is switched off (consult Duty Engineering Officer).
Notes:
Cat I Airfields: Do not use ILS below Cat I decision height (200ft). If reports are received below 200ft, continue Cat I operations with a warning.
Glidepath Withdrawal: May be enabled depending on remote control configuration and ATC equipment. Procedural notification may be required before switching off.
Cat I Downgrade: Notify verbally (e.g., “ILS available on Runway xx CAT I only”), followed by ATIS/NOTAM and CSU switching.
What is the purpose of the RISDU in the context of ATC monitoring the ILS System, and where are they installed?
Purpose: The RISDU enables ATC to monitor the status of the 25 ILS System, with status changes indicated by audio and visual alarms.
Installation Locations:
* VCR (Visual Control Room)
* APR (Approach Room)
* Equipment Room
Additional Function: Indications on the RISDUs are available only when transferred from the Equipment Room to ATC. This transfer also allows ATC to switch off the relevant ILS Facility using the Emergency ILS shut down panel in the VCR.
What are the procedures for using the RISDU and handling alarms in ATC operations?
Initial Checks:
- The Duty Engineer switches on the RISDUs and checks indications.
- The Duty Engineer confirms the serviceability of the equipment with ATC before leaving the equipment room.
Controller Actions:
- Upon observing a change of status, controllers immediately advise pilots and take appropriate NOTAM action.
- The ATCO who cancels the alarm ensures other positions are aware of status changes.
Emergency Procedures:
- The Emergency ILS shut down panel is used to switch off the ILS System on receipt of a report of Faulty Guidance Signals. Detailed procedures are in Section 5, 4.2.5.
Unmanned Operation:
- Erroneous or spurious alarms may occur and can be cancelled if only the alarm LED is indicating.
What actions should controllers take based on RISDU and IRVR Display indications for the 25 ILS system?
Green Light:
- IRVR Display: 3
- Meaning: CAT 3 ILS Service Available
- Action Required: No action required
Amber Light:
- IRVR Displays:
- 3
- 2L3 (CAT 2 Glidepath, CAT 3 Localiser)
- IL3 (CAT 1 Glidepath, CAT 3 Localiser)
- 2 (CAT 3 Glidepath, CAT 2 Localiser)
- 1 (CAT 3 Glidepath, CAT 1 Localiser)
- Action Required: See below Section 4.2.4
Red Light:
- IRVR Displays:
- L3 (Glidepath Off, Localiser CAT 3)
- L2 (Glidepath Off, Localiser CAT 2)
- L1 (Glidepath Off, Localiser CAT 1)
- OFF (Glidepath state unknown, Localiser Off)
- Action Required: Switch off ILS immediately. For OFF indication, also contact Engineering and advise aircraft not to use the ILS.
Blank Light:
- IRVR Display: Blank
- Meaning: System Status unknown
- Action Required: Switch off ILS immediately, contact Engineering, and advise aircraft not to use the ILS.
What steps should be taken if an amber indication is displayed on the RISDU for the 25 ILS, and what are the conditions for system restoration?
- Advise aircraft using the ILS system of the current status.
- Wait until any aircraft already established on the ILS land.
- Switch the ILS OFF as per Section 4.2.5 (Emergency ILS Shutdown/Restore) and wait 1 minute.
- Switch the ILS ON as per Section 4.2.5 (Emergency ILS Shutdown/Restore).
- Check the ILS status on the RISDU:
- Green: No action required. The system may be used at the declared ILS CAT in the IRVR display.
- Amber: If the ‘amber’ fault persists, call out engineering. The service may continue at the declared ILS CAT in the IRVR display.
Note:
Restoration requirement is at the discretion of the Watch Manager/Deputy Watch Manager, considering weather, type of traffic, etc.
If further faults occur causing a change to red, switch off the ILS immediately.
When the ILS system’s serviceability changes, an engineer should be called if immediate restoration is required.
For the 17 ILS, shown on the RSI as separate LOC and G/P indications, switch off the complete 17 ILS if either indicates red. Restoration is at the discretion of the Watch Manager/Deputy Watch Manager.
What is the procedure for performing an emergency shutdown and restoration of the 25 ILS using the ‘EMERGENCY ILS SHUTDOWN’ panel?
To switch off the 25 ILS:
- Coordinate with APC and ensure no aircraft are using the ILS system.
- Insert the key into the lock beneath the 25 ILS label and turn it 90° anticlockwise to the ‘OFF’ position.
- The RISDU will alarm.
- The IRVR display will show ‘OFF’.
- Update ATIS.
- Issue NOTAM if required.
To switch on the 25 ILS:
- If switched off due to grass cutting inside critical areas, ensure all vehicles are clear.
- Insert the key into the lock beneath the 25 ILS label and turn it 90° clockwise to the ‘NORMAL’ position.
- Wait up to 1 minute for the ILS system to restore; do not keep turning the key from ‘OFF’ to ‘NORMAL’.
- The ILS system will restore and the RISDU will alarm.
- The ILS system can be brought back into service when ‘U3’ is displayed in the IRVR display.
- Advise APC of the ILS status and update ATIS.
What is the procedure for performing an emergency shutdown and restoration of the 17 ILS using the ‘EMERGENCY ILS SHUTDOWN’ panel?
To switch off the 17 ILS:
- Coordinate with APC and ensure no aircraft are using the ILS system.
- Insert the key into the lock beneath the 17 ILS label and turn it 90° anticlockwise to the ‘OFF’ position.
- The RSI will alarm and the 17 LOC, 17 GP will show red.
- Update ATIS.
- Issue NOTAM if required.
To switch on the 17 ILS:
- If switched off due to grass cutting inside critical areas, ensure all vehicles are clear.
- Insert the key into the lock beneath the 17 ILS label and turn it 90° clockwise to the ‘NORMAL’ position.
- Wait up to 1 minute for the ILS system to restore; do not keep turning the key from ‘OFF’ to ‘NORMAL’.
- The ILS system will restore and the RSI will alarm.
- The ILS system can be brought back into service when the RSI indicates ‘green’ on the 17 LOC and 17 GP.
- Advise APC of the ILS status and update ATIS.
What is the purpose of the Remote Status Indicator (RSI) in the ADC, and what are its key features and functions?
Purpose:
- The RSI is designed to display the status of various pieces of equipment to ATC.
Key Features and Functions:
Light Indications:
* ‘ON’ (Green)
* ‘OFF’ (Red)
* The unit does not consider whether connected equipment is in maintenance mode.
Alarm System:
* The RSI has an alarm that is triggered by any change of state in the displayed information.
* An associated silence button is included to mute the alarm.
Communication Requirement:
* The APR ATCO has no indication of the monitored services’ status, so the ADC ATCO must inform APR of any status changes.
What should be done if erroneous or spurious alarms occur during the unmanned operation of the RSI?
Erroneous or spurious alarms may be cancelled as long as the only other indication is the alarm LED.
What are the operational features of the RSI and the conditions for green indications for various pieces of equipment?
Operational Features:
- The front panel display shows the monitored pieces of equipment.
- Internal aural alarm with a front panel alarm cancel button.
- Alarm is triggered when:
- A change of state occurs on any connected equipment (green to red or red to green).
- The lamp test button is operated.
Conditions for Green Indications:
- DVOR: VOR serviceable (Note: Indications are shown on the RSI but are not monitored. Refer to Para. 3.2 Alarm Status Panel).
- BEL DME: BEL DME serviceable.
- RECORDER: At least one recorder deck serviceable and running.
- 17 DME: Serviceable.
- 25 DME: Serviceable.
- 17 LOC: Serviceable.
- 17 GP: Serviceable.
What are the procedures for operating the RSI and communicating status changes in ATC operations?
Procedures:
Initial Check:
- The Duty Engineer switches on the RSI and checks the indicators.
- The Duty Engineer confirms the serviceability of the equipment with ATC before leaving the Equipment Room unmanned.
Observing Status Changes:
- Controllers must pass information to pilots if any equipment status changes from green to red, until an Engineer returns to the Equipment Room.
- When ATC is informed that no ATC Engineer is present in the Engineering Equipment Room, Aerodrome Control must advise Approach Control of any status changes indicated on the RSI until the Engineer returns.
What steps should be taken if an ILS failure occurs or if synchronization between ILS ident and DME ident is lost?
ILS Failure:
- The associated DME will be switched off.
- If no engineer is on duty, the ATC Watch Manager/Deputy Watch Manager shall attempt to arrange a call-out if necessary.
- If no engineer is available, ATC shall inform pilots that the DME is not available for use.
Loss of Synchronization:
- If ATC is informed that synchronization between ILS ident and DME ident is lost, the DME is not to be used.
