1. 6. COMMUNICATIONS Radio Telephone (R/T) and Radio Navigation (R/N) services
R/T Communications
English is the standard language for all commercial flights, worldwide. This means it is an option at all international airports i.e.those with ATC, but uncontrolled aerodromes will generally use the national language.
Transmissions should be as concise – kept to essential information only
All R/T frequencies in the Shannon FIR are listed in the AIP (ENR section)
R/N Aids currently in use
DVOR VHF Omnidirectional Radio Range
DME Distance Measuring Equipment (slant distance)
NDB Non-Directional Beacon
ILS Instrument Landing System
Details of all R/N equipment and identifiers (VOR and NDB station identifiers use Morse Code
signals) . Aerodrome identifiers are listed in the AD section of the AIP.

2. 6. COMMUNICATIONS Controlled Airspace
All aircraft must be capable of two-way radio communications with ATC in controlled airspace
A pilot must FILE a flight plan with ATC if he intends entering controlled airspace
He then needs to REQUEST ATC clearance before entering the airspace, and ATC will often give a conditional clearance e.g. not above 2000 ft or proceed to Bunratty (a common holding point before clearing a plane to land on Shannon runway 24)
A pilot can refuse any unreasonable clearance e.g. which will involve flying into cloud or below 500ft agl.
If the flight ends in controlled airspace, ATC will automatically close the flight plan. Otherwise the pilot must close it him/herself
e.g. landing at Shannon – ATC closes flight plan.
leaving Shannon CTR for Coonagh – pilot must close flight plan
Failure to close a flight plan may lead to launching an unnecessary SAR operation – closure should be within 30 mins of the ETA stated on the flight plan unless ATC is informed otherwise.

3. 6. COMMUNICATIONS Communications failure - 1
If you cannot make radio contact with an ATC, there may be several reasons for this
Check the frequency – you may have set the wrong one
Try contacting other aircraft on the same frequency
Try a different one to the same or nearby station e.g. Shannon Information on if no response from Shannon Tower on 118.7
If still no contact, pass your message twice on the original frequency starting with “Transmitting Blind”
If you need to change frequency anyway e.g. from Shannon Information to Shannon Tower, again start your message with “Transmitting Blind” before changing frequency.
Set the transponder to the code for radio failure 7600
If already in a CTR, proceed to one of the holding areas and wait for light signals from the Tower
You MUST NOT enter a CTR without radio contact with its ATC unit first
In this situation make for the nearest uncontrolled aerodrome . Use a standard join to enter the circuit land normally, then contact ATC at the destination airport.

4. 6. COMMUNICATIONS Communications failure - 2
In controlled airspace, if you are flying IFR or cannot complete your flight in VMC :
continue to the next reporting point
return to the flight level you should be on according to the flight plan
fly to the VOR for the destination airport
hold there until the latest ETA is reached, or the ETA stated on the flight plan
land within 30 mins of the later of the above

5. 6. COMMUNICATIONS Transponder
A transponder is a radar receiver/transmitter used for communications with ATC. It is know as Secondary Surveillance Radar (SSR).
There are three types of Transponder:
MODE A. Can be given a specific code (“squawk”) by ATC for a controlled flight. A squawk is four-figure number.
There are four standard squawks:
“Conspicuity” . Shows ATC that there is a plane up there when no flight plan has been filed
“Hijack”. Lets ATC know the aircraft has been hijacked
“Radio failure”. Lets ATC know the aircrafts radio is u/s
“Emergency” Lets ATC know the aircraft is in serious trouble
MODE C. Fitted with an altitude encoder – will automatically transmit altitude information as well as aircraft squawk
MODE S. Transmits information about the aircraft (type, Reg. No, pilot’s birthday etc.) as well as the above.
When setting a squawk, turn the transponder to ” standby” first – enter the code, then switch to “A”. This is to avoid inadvertently transmitting one of the emergency squawks.
All aircraft operating in controlled airspace MUST have a transponder

6. 6. COMMUNICATIONS ATC R/T Services
Air Traffic Control Service
“Provides a service for the orderly flow of traffic and an alerting service” to all traffic in controlled airspace. Provides traffic separation, especially for IFR traffic. VFR traffic is responsible for keeping separation from other VFR traffic. Shannon (Tower) ATC frequency is 118.7
Flight Information Service
A branch of ATC providing information on request about other traffic when outside controlled airspace. May advise a heading to avoid conflicting traffic on request but does not give orders. Will also give information on request about aerodromes, weather and will accept flight plan changes. R/T frequency of Shannon Information is 127.5
Alerting Service
Alerts Search and Rescue if an aircraft is overdue or transmits a distress signal or is otherwise thought to be in trouble. It does NOT advise of danger due to other traffic or terrain.

7. 6. COMMUNICATIONS Restricted Airspace
Defined airspace (red hatched areas on the 1:500,000 chart) with restrictions on the flight of aircraft (see AIP Section 5.1.1):- Prohibited (P). Volume of airspace in which all flight is prohibited. Usually sensitive areas such as prisons or other high-security installations e.g P9 – prohibited area around Limerick Prison Danger (D) areas. Flight permitted when not active (see AIP or phone contact no. or ask ATC) Restricted (R) areas. Usually near military installations, contact with military controlling authority essential when active (ask ATC) but access usually allowed if no conflict with military traffic. Military Operating Areas (MOAs). Used for military flight training. The airspace may be shared with civilian traffic. Contact with military controller essential if crossing an MOA – but often they can be flown under or over. Bird Migration. In various parts of the country, especially close to estuaries, wetlands and inland waterways ( e.g. the Shannon Lakes) , there may be bird concentrations. The main Areas affected are shown in Section ENR5.6-1 of the AIP. Although not defined as Restricted Airspace, they are potentially dangerous and should be avoided. The AIP recommends that if flying close to them, fly as high as possible and with the landing lights on.