1.3.1   Radar and radio failure procedures

Aircraft Transmitter Failure
In the event of loss of radio contact with the aircraft due to failure of the aircraft Transmitter, the radar controller first determines whether the aircraft is receiving his transmissions by requesting the pilot to make a turn before attempting to establish contact on another frequency.

Radar Equipment Failure
In the event of radar equipment failure, the radar controller immediately takes action to establish standard IFR separation between aircraft under his control.

Ground Communication Failure
In the event of failure of ground radio communications used for Radar Control, aircraft should immediately establish radio contact with the appropriate ATS Unit, i.e. ACC, APP, TWR.

1.3.2   Procedures relating to air-ground communications failure in controlled airspace

Action by Air Traffic Control

1.3.3   Communications Failure - Departing Aircraft

1. A departing controlled IFR flight operating in instrument meteorological conditions, having acknowledged an initial or intermediate clearance to climb to a level other than the one specified in the current flight plan for the en-route phase of the flight, and experiencing two-way radio communication failure should, if no time limit or geographical limit was included in the climb clearance, maintain for a period of three minutes the level to which it was cleared and then continue its flight in accordance with the current flight plan.

   Note: The effect of this procedure is to introduce a uniform clearance limit for application in cases where the use of tactical control methods by the air traffic control makes it impracticable to include a time limit or a geographical limit in each climb clearance.

   Note: The level specified in the current flight plan means the level contained in the en-route air traffic control clearance acknowledged by the pilot.

2. A departing controlled IFR flight being vectored by radar away from the route specified in its current flight plan and experiencing two-way radio communication failure should proceed in the most direct manner to the route specified in the current flight plan.

2.2.1   Unlawful Interference Procedures

Pilots of aircraft in flight subjected to unlawful interference shall endeavour to set the transponder to Mode A Code 7500 to give indication of the situation, unless circumstances warrant the use of Code 7700.

Note: Mode A Code 7500 is permanently monitored in the Shannon FIR/UIR.

2.2.2   Radio Communication Failure Procedures

The pilot of an aircraft losing two way communications shall set the transponder to Mode A code 7600 and follow the procedures as detailed in EIDW AD 2.22.5.3, ENR 2.2 as appropriate; subsequent control of the aircraft will be based on these procedures.

Note: A controller observing a response on the radio communications failure code will ascertain the extent of the failure by instructing the pilot to operate the SPI feature or to change code. Where it is determined that the aircraft receiver is functioning, further control of the aircraft will be continued using code changes or SPI transmission to acknowledge receipt of clearances issued.

Note: Mode A code 7600 is permanently monitored in the Shannon FIR/UIR.

2.3.1   Conspicuity Code

1. Pilots of uncontrolled aircraft operating within the Shannon FIR shall activate their transponder on Modes A and C and select Code 7000 unless’
   1. a different code is assigned by ATC,
      or
   2. circumstances require the use of one of the Special Purpose Codes.
2. The fact that the transponder is set does not mean that the flight is being controlled
3. Pilots are warned of the need for caution when selecting Code 7000 due to the proximity of the International Special Purpose Emergency Codes.

2.3.2   Code Assignment Method

Since 2011 Ireland is part of the CCAMS area (Central Code Assignment & Management System).

This method of SSR code assignment is a pan-European solution to overcome the current and future shortages of the SSR codes used by Air Traffic Control for radar services.

CCAMS is a service based on a central server which is located in the CFMU Network Management Unit which provides a unique Mode 3/A SSR code to each flight operating in the European region. Assigning codes on a central basis is the most optimum code assignment that can be achieved which avoids code changes and code conflicts while coping with the increased traffic demand.

The result of this new SSR code assignment process is that all IFR aircraft in transit throughout the Shannon FIR/UIR, the Shannon Oceanic Transition Area (SOTA) and the Northern Oceanic Transition Area (NOTA) and aircraft departing from within the Shannon FIR will be assigned SSR Codes which Ireland receives on a dynamic basis from CCAMS, which will result in fewer SSR code changes for Pilots as the flight progresses across Europe.

In addition Westbound aircraft in transit through the Shannon FIR/UIR, the Shannon Oceanic Transition Area (SOTA) and the Northern Oceanic Transition Area (NOTA) or westbound aircraft destined for aerodromes within the Shannon FIR will retain the now CCAMS approved SSR Codes which are assigned by the adjacent ACC’s.

2.7.1   Pilots of aircraft having experienced transponder failure shall ensure that faulty transponders are restored to normal operation at the earliest possible time, i.e. if possible at the first landing after the event

2.7.2   ATC units will endeavour to provide for continuation of a flight with a faulty transponder in accordance with the original flight plan. However, in certain traffic situations, either in terminal areas or en-route, continuation of the flight may not be possible, particularly when failure is detected shortly after take-off. The aircraft may then be required to return to the departure aerodrome or to land at another aerodrome acceptable to the operator concerned and to ATC.

Note: At the present time, the temporary failure of SSR Mode C alone would not restrict the normal operation of the flight.

2.7.3   Transponder failure before intended Departure

1. At a particular aerodrome where it is not practicable to effect a repair to an unserviceable transponder before intended departure, the aircraft concerned will be permitted to proceed, as directly as possible o the nearest suitable aerodrome where repairs can be made.
2. Before submission of a flight plan, or as soon as possible thereafter pilots of such aircraft shall inform ATC of the defective state of their transponder. When granting clearance to such aircraft, ATS will take into consideration the existing or anticipated traffic situation and may have to modify the time of departure, flight level or route of the intended flight. Subsequent adjustments may become necessary during the course of the flight.
3. The defective state of the transponder shall be indicated in the ICAO flight plan form by inserting in item 10 under “SSR” the letter N for complete un-serviceability or, in case of partial transponder failure, the letter corresponding to the remaining transponder capability as specified in ICAO DOC 4444 - ATM 501/15 Appendix 2.

2.7.4   Transponder Failure after Departure

1. In case of a failure, which is detected after departure, pilots will act in accordance with the last received and acknowledged clearance, or in accordance with any amended clearance which may be issued by ATC.
2. Whenever an aircraft having experienced transponder failure, cannot obtain the required maintenance at the first aerodrome of landing after the event, the provisions contained under “Transponder failure before intended departure” apply.

2.8.1   SHANNON FIR

Traffic operating in class G airspace who have not filed a flight plan but who are monitoring or receiving a Flight Information Service on SHANNON Information frequency 127.500MHz are requested to squawk 2655.

2.8.2   DUBLIN CTA

Aircraft operating close to the Dublin Control Zone and not requiring an air traffic control service are strongly advised to monitor the Dublin Flight Information Frequency 118.500MHZ. Pilots monitoring this frequency should select the listening squawk 0401 to indicate that they are monitoring the frequency.