SUBJECT - ESTABLISHMENT OF TWO-WAY COMMUNICATIONS AT MBZs AND
CTAFs.
SAFETY DEFICIENCY
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) areas, 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.
FACTUAL INFORMATION
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.
Publications
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.
Training
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.
ANALYSIS
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.
