III. COMMUNICATION FAILURE

Communication systems are complex. A communication failure may have various causes, which in turn may be simple or complex. They are usually caused by electrical / electronic or hardware problems.

Simple causes:

Communication failure may be caused by a simple technical problem such as a defect in the pilot’s or controller’s headset or microphone, or blocked frequency.

Complex cause:

The causes of communication failure may be more complex, for example:

· a broken wire

· a malfunction of the radio equipment

· a power failure

Originating with ATC:

Remember, communication problems do not always originate with the ACFT.

They may also originate with ATC. A sector or unit frequency may be lost. ATC would quickly become aware of this problem. It would be solved by a change of frequency.

Communication failure may affect the pilot’s ability to communicate in various ways:

The pilot may be able to:

Transmit but not receive messages

Receive but not transmit messages

send carrier waves only. This is called NON-VERBAL or SPEECHLESS communication.

Whenever possible, the ACFT will squawk A 7600.

Smaller ACFT may be more affected by communication failure than larger ACFT as they have fewer back-up systems.

A controlled flight experiencing communication failure in Visual Meteorological Conditions shall:

· set transponder to A7600

· continue to fly in VMC

· land at the nearest suitable aerodrome

· report its arrival time by the most expeditious means to the appropriate ATS unit

Instrument meteorological conditions (IMC)

· Communication failure occurs. ACFT sets transponder to A7600.

· Maintain last assigned speed and level for a period of 7 minutes, OR, if the minimum flight altitude is higher than the last assigned level, maintain the minimum flight altitude for a period of 7 minutes.

· Thereafter, adjust level and speed in accordance with the filed flight plan.

· If being radar vectored, or proceeding offset according to RNAV without a specified limit, proceed in the most direct manner possible to rejoin the current flight plan route no later than the next significant point, taking into consideration the applicable min. flight altitude.

Instrument meteorological conditions (IMC)

Arriving aircraft with communication failure

The ACFT will proceed according to the current flight plan to the designated navigational aid serving the destination aerodrome and hold until commencement of descent.

Commence descent at, or as close as possible to, the EAT last received and acknowledged.

OR

If no EAT received and acknowledged, commence descent at, or as close as possible to, the ETA resulting from the CPL.

Complete a normal instrument approach procedure as specified for the designated navigation aid.

Land, if possible, within 30 minutes after the ETA specified,

OR

Within 30 minutes of the last acknowledged expected approach time, whichever is later.

ATC

In the event of communication failure, REMEMBER:

· Following the ASSIST code of practice

· Inform your Supervisor

· As soon as the failure becomes known, maintain separation between the affected ACFT and other ACFT based on the assumption that the ACFT will operate in accordance with the (ICAO) rules define for VMC or for IMC

· Recognize that this is an unusual situation which could become an emergency

· Establish whether the aircraft has:

· functioning transmitter

· functioning receiver

· neither

· if blocked frequency, establish the source:

· ground

· airborne

· inform all units concerned

· try to make contact with the aircraft on other available frequencies – 121.5 Mhz; 243.0 MHz; company frequency, or by any other available means, eg SELCAL; VOR: mobile phone etc.

· if control has to be transferred to another ATC station, radar hand-off procedure should be followed

CREW