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Recommendation issued to: Civil Aviation Safety Authority

Recommendation details
Output No: R19980144
Date issued: 05 November 1998
Safety action status:



There is currently little or no guidance on effective methods that pilots can use to ensure that radio equipment is fully functional prior to flight. This is a particular hazard when aircraft are operating in mandatory broadcast zones (MBZ) or common traffic advisory frequency (CTAF) area, where alerted see-and-avoid procedures are intended to provide a higher level of safety. The Bureau continues to receive many reports of serious incidents in MBZs that involve poor usage of radio.


Occurrence summary

The pilot of a Beechcraft 200 King Air reported hearing a radio carrier wave on the mandatory broadcast zone (MBZ) frequency at the same time that he observed a Beechcraft Baron (Baron) taxiing. During its take-off roll, the Baron passed in front of a Fairchild Metroliner that was on final approach for the crossing runway.

Later that day, in heavy rain, the same Baron was on short final approach for a landing while a high capacity air transport aircraft was decelerating through about 80 kts on the reciprocal runway. Shortly before touch down, the pilot of the Baron initiated a go-around and commenced to climb. Witnesses estimated that the Baron passed some 100 m in front of, and 20 ft above, the other aircraft. Again, no radio transmissions were heard from the pilot of the Baron. Poor visibility, and the absence of two-way communication, resulted in a loss of awareness of each other's position and intentions, even though the crew of the airliner and the Baron pilot were aware of each other's presence.

The Baron pilot later reported that he had been making all the required radio calls and that he did not recognise that he had experienced a radio malfunction until he was approaching his final destination.

Related occurrences

The airline operator stated that company aircraft had been involved in 43 air safety occurrences in MBZs since 1 January 1995, in which other aircraft had experienced problems with radio communications, or problems with published procedures. In the same period, the Bureau has recorded approximately 65 reported occurrences relating to problems with communications in MBZs. In May 1998, a regional airline aircraft carrying fare-paying passengers was involved in a near head-on collision with a privately operated Cessna 172 (C172), also in an MBZ. No radio transmissions had been heard from the pilot of the C172. Investigation of this occurrence revealed that the effective range of the radio in the C172 was less than 2 NM.


Civil Aviation Regulation 242-Testing of radio apparatus, requires that a pilot check that the radio apparatus fitted to the aircraft and to be used in flight is functioning correctly, prior to taxiing for takeoff. The regulation does not specify how this is to be achieved. For specific details on correct procedures, pilots refer to a wide variety of other Civil Aviation Safety Authority (CASA) references including the Civil Aviation Orders, the Aeronautical Information Publication (AIP) and its supplement, the Civil Aviation Advisory Publications, and Aeronautical Information Circulars. Other sources of information that may be used by pilots are the documents specific to aircraft, such as Pilots Operating Handbooks, Flight Manuals, and relevant checklists. Pilots that have completed their training may also refer back to various other texts and notes that they had been supplied with or purchased as part of their flying training course. While some of these documents may contain suggested methods to check radio serviceability, the CASA publications that are regularly referred to, such as the AIP, do not contain any procedures, recommendations or guidelines regarding the conduct of such a check.


During the incident flight, the pilot received little direct evidence that the two radios were not functioning correctly. A transmit light was indicating that he was broadcasting He was also receiving radio transmissions satisfactorily and no radio transmissions were made by others to alert the pilot to his aircraft's radio problems.

The Baron pilot held a private pilot licence at the time of the incident, and had approximately 400 hours of flying experience. His training had been conducted at a variety of training organisations, and had begun prior to 1990. Since commencing this training, numerous airspace and procedural changes had taken place. As the pilot already possessed a licence, the operator of the Baron was not required to obtain the pilot's flying training records from his previous training organisation/s.

In order to obtain a private licence, pilots receive training based on the guidelines in the CASA publications, the Day Visual Flight Rules Syllabus, and the Flight Radio Operators Licence Syllabus. These documents do not detail specific methods that pilots can use to identify radio failures. In order to provide procedural training for pilots that will satisfy the requirements of the syllabus, training organisations also refer to a wide variety of commercially available texts and study guides.

Competency-based training provides specific guidance for training schools in order for them to impart the knowledge and skills that a pilot must demonstrate before being granted a license. Such a system consists of a number of key competencies, such as "Solve Problems", each of which is divided into units such as "Operate Radio". The units would be further divided into specific tasks and skills. To be issued a license, a pilot would be required to demonstrate competency in all the units, and thus fulfil the requirements of the key competencies. As pilots demonstrated each skill a record would be produced of the completed training. As the acceptable standard for the issuing of a license would be detailed, a competency-based training system would provide consistency in training standards across all flying schools.

Aerodrome Frequency Response Unit

Following a serious breakdown of communications in the Bundaberg MBZ in 1997, BASI issued IR970110, which in part, prompted the introduction of aerodrome frequency response units, or beep-back units, at some locations. This is an automated system that responds to a radio transmission on its frequency with either a tone or a read-back of the location. A beep-back unit is effective in informing pilots that they are on the correct frequency, and that they are transmitting and receiving normally. However, the unit cannot distinguish between a carrier wave only transmission and a modulated (voice carrying) transmission. Consequently, the unit responds normally to both types of transmission.


Operating at busy uncontrolled airports requires pilots to utilise alerted see-and-avoid procedures wherever possible in order to decrease the risk of collisions with other aircraft. Pilots, therefore, need to conduct an effective radio serviceability test and be able to recognise a possible radio failure. There is currently no specific mention of these matters in the Day Visual Flight Rules syllabus, nor is there any suitable procedure documented in CASA publications. In addition, knowledge and use of a recommended radio serviceability test procedure may not be receiving sufficient emphasis during initial and ongoing flying training.

Flying training organisations employ a variety of methods to train students. Subsequently, the content and depth of knowledge imparted to students, and the standard procedures taught, is likely to vary considerably. In addition, when students undertake flying training at a variety of organisations, there is an increased possibility that they will not acquire the required knowledge and skills to enable them to conduct their flying with a high level of proficiency and thus safety. Without an industry-wide, comprehensive and detailed syllabus, student pilots are also more likely to receive incomplete training. A competency-based training system, such as that which is currently being developed by CASA, may address the above deficiency and contribute to reducing the hazard of incomplete training. The system would produce a detailed record of all the training that a pilot has completed and would allow a pilot to transfer from one flying school to another without repeating or missing important aspects of training. As the competency-based training system would require a pilot to demonstrate each skill and procedure that is required, it would ensure that a student pilot learns both the theory and the application of these skills and procedures. Consideration also needs to be given to implementing a system whereby a pilot's flying training record is an accountable record of his/her flying training experience, in the same way that a logbook is intended to be an accountable record of a pilot's flying experience. This incident may have been prevented if the pilot had been required to demonstrate both an effective procedure to check the radio, and the ability to detect partial or complete radio failures, as part of his training.

While aerodrome frequency response units have made a positive contribution toward safe and effective communications in MBZs, this incident would not have been prevented had a unit been installed. Such a unit would have responded normally to the pilot's carrier wave only transmission and would have reinforced the pilot's perception that his radios were functioning correctly. Further defences are needed to reduce the likelihood and consequences of communication breakdowns to an acceptable level.

Output text

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority consider the need to ensure that knowledge and use of a recommended radio serviceability test procedure forms part of initial and ongoing flying training.

In addition, the Bureau has also issued the following recommendation:


The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority develop and publish an effective procedure by which pilots can ensure radio equipment is fully functional prior to flight.

Initial response
Date issued: 16 April 1999
Response from: Civil Aviation Safety Authority
Action status: Open
Response text:

CASA recognises the nature of the problem outlined in the report but does not agree with the BASI recommendation. CASA does not agree that specific serviceability checks overcome the problem because such checks cannot provide the solution in the airspace most affected. This is because there is no radio communication serviceability check which can be carried out which positively establishes that the radio is serviceable, other than establishing two way communication. The problem is that at aerodromes with CTAF or MBZ, that there is often no other station within range with which two way communication can be established by an aircraft preparing for takeoff.

As pointed out in the report, aerodrome frequency response units do not distinguish between carrier wave only and normal transmissions so are not suitable for the purpose. Another alternative would be to use external radio test equipment but this would be completely impractical for the vast majority of aerodromes and operators.

CASA is of the view that the solution is to alert pilots to the fact that they cannot assume that radio communication equipment is serviceable until two way communications have been established. Hopefully this awareness would have led to more determined efforts to communicate and greater vigilance on the part of the pilot concerned in the incident highlighted in the report. Many pilots will already be well aware of this problem, however it seems there may be a considerable number who are not.

CASA will examine what can be done to ensure that all pilots are aware that establishment of two way communication is the only means by which full radio serviceability can be established and that extra vigilance is required for traffic avoidance until such communication has been established. There may also be a need to include material on the limitations in the use aerodrome frequency response units to determine radio serviceability.

CASA does agree with the suggestion in the report that competency standards are an effective means of ensuring training is accomplished and has already moved in the direction indicated.

The requirement to conduct a radio serviceability check before flight is included as an element of the new national competency standards soon to be approved for the Private and Commercial Pilot licences for aeroplanes. The standards are in a format which requires the pilot under training to demonstrate competence in each element.

It will also be a requirement that each student maintain a record of competencies achieved, certified by the appropriate instructor, which will be a portable document held by the student. This record will be in addition to the current requirement for flying schools to maintain flying training records and will be used to ensure that a pilot has received training and achieved the required standard in all competencies listed before undergoing a flight test for license issue. CASA is confident that this system will cover off the concerns raised in the report regarding pilot training.


Further correspondence
Date issued: 07 June 1999
Response from: Civil Aviation Safety Authority
Response status: Closed - Accepted
Response text:

The recently released assessment guide forming part of the day VFR syllabus for Private and Commercial Pilot Licence provides the following checks and actions for the training element of "Use R/T Equipment":

Preflight checks are completed in accordance with Flight Manual/P0H. Serviceability of all required R/T equipment is checked.
All radio control switches are used.
The responsibilities of a radiotelephone operator are carried out. Standard air traffic radio transmissions are performed.
Received -instructions are complied with.
Pilot transmitted information and phraseology is applicable to the flight phase. Traffic and alerting transmissions are recorded.
Transmission "in the blind" is demonstrated.
Listening watch is maintained.
Simulated transmission of urgency and distress messages is demonstrated. HF radio is tuned if applicable.
Awareness of international distress frequencies is demonstrated. Radio silence is maintained when required.
Ability is demonstrated to recognise 'carrier wave only' transmissions as a transmitting or receiving pilot and react to rectify the abnormal situation.
Loss of radio transmission/reception procedure are performed.
Comprehension of and reaction to light signals is demonstrated.
The ability to communicate with Air Traffic Services and other aircraft, using the RIT is demonstrated.

In addition, the training element "maintain R/T Equipment" requires the following checks and actions:

Fault finding procedures not involving special tools or instruments are employed.
Minor faults are rectified.
Meters and other means are used to indicate normal operation of equipment equipped with monitoring devices.
Aeroplane R/T antenna systems are identified.
Aeroplane battery positions and charging methods are described.
Trailing aerial is tuned.
Emergency communications equipment is operated.
Knowledge of fuse positions, circuit breakers and emergency power switches is demonstrated.
Procedures for conduct of routine pre-flight test of aeroplane R/T installation is followed.

The Achievement Record which details the competencies completed is certified by the instructor and retained by the student as a permanent record. It is readily accessible when students transfer between training schools.

The Authority believes that these new competency based standards will ensure a satisfactory knowledge of radio procedures is achieved during pilot training.



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Last update 01 April 2011