Page 17 - 2017-Issue2

17 GETTING CLOSE WITH ATS

procedures.
• Ground based automation utilized to CONFIRM ROUTE However, due to poor training for both Pilots and Controllers
minimizing potential for error. In other words, the only there have often been misunderstandings as to which message set
person that can’t see that they are going off course is the to use and what the message set actually means. There are also
pilot! issues with datalink connectivity and interoperability worldwide.
For voice communications, every pilot and controller has been
trained to use Standard Phraseology. Phraseology is a code, and by
Phase 2 of the trial will expand RLatSM to all Oceanic Tracks using this code everyone should understand what is required of
and Phase 3 will see the expansion across the entire NAT airspace. them. When using standard phraseology, instructions should be
These two phases have been delayed indefinitely, mainly due to easier to understand and misunderstandings reduced to a
Datalink Connectivity. minimum.
Out of 1500 daily flights there are 300 datalink connectivity Everyone is guilty of deviating from standard phraseology. All
issues. The Air Navigation Service Providers (ANSPs) experience manner of changes are added, which means the code becomes lost.
the loss of datalink contact with aircraft from 30 seconds to 15 In the international arena, not everyone has a good command of
minutes or longer, and this includes being unable to re-establish the English despite the Aviation Language Tests, and the use of
connection. This has resulted in a safety review process where two everyday language instead of standard phraseology has led to
of the ANSPs have identified an increase in the controller workload countless misunderstandings and misinterpretations.
issues and this in turn has warranted the delay in any trial There are several examples of this, one such is the phraseology
expansion. for SID/STAR.
These issues existed prior to the introduction of RLatSM, The use of SID/STAR phraseology brings significant benefits. It
however, separation was not based on the connection and was enables efficient and concise communication. It allows ATC to
therefore of minimal industry concern. issue, and aircrew to understand, detailed clearance information
What causes these connectivity issues? There are a wide variety that would otherwise require long and complex transmissions.
of causes ranging from aircraft avionics software to ground based Over time these benefits have been eroded. The development of
systems. non-harmonised practices resulted in different meanings becoming
Should the loss of the connection be considered as a loss of attached to certain elements of SID/STAR phraseology. Confusion
separation? The aircraft remains RNP4, so in the lateral plane no continued to creep in and pilots became uncertain of what air
off course event should occur; but the separation minima relies traffic controllers meant. This resulted in additional questions and
solely on timely ADS/CPDLC actions to correct unintended off requests for clarification on already cluttered frequencies. The
course events, and without the connection the only safety nets are increased safety risk, where possible ill-conceived assumptions and
compliance with pilot procedures and ACAS/TCAS. guesswork were everyday occurrences, called for a renewed effort
The constant reduction in separation has led to concerns as to to strengthen and harmonize the SID/STAR phraseology.
how to handle a situation where the aircraft needs to come off the The ATS Committee worked with IFATCA and ICAO over a
route or track to divert or turnback. The NAT has developed period of 10 years to provide core phraseology that would:
procedures just for that airspace whereby:
“Before commencing any diversion across the flow of • Positively reinforce when the lateral, vertical and speed
adjacent traffic or before initiating any turn-back (180°), aircraft requirements embedded in a SID or STAR apply;
should, while subsequently maintaining a same direction 15 NM • Explain how to explicitly cancel or amend those
offset track, expedite climb above or descent below the vast requirements and provide additional phraseology that
majority of NAT traffic (i.e. to a level above FL410 or below enabled the cancelling of any level or speed restrictions, as
FL280), and then maintain a flight level which differs from those local circumstances, practice or procedures permit; and
normally used: by 1000 ft if above FL410, or by 500 ft if below • Harmonise the phraseology to bypass waypoints or amend
FL410. However, if the pilot is unable or unwilling to carry out the lateral profile of a SID or STAR.
a major climb or descent, then any diversion or turn-back Despite these new and improved provisions being
manoeuvre should be carried out at a level 500 ft different from recommended by ICAO, the use of this phraseology has not yet
those in use within the NAT HLA, until a new ATC clearance is been applied globally, so in some cases the confusion will remain
obtained.” 17SAB02-Turnback Procedures in the NAT as will the safety risk.
These are not comfortable procedures to follow and there are Maybe, it is time for the end users to take a stand and make a
risks to activating TCAS/ACAS warnings. determined effort for all aviation professionals to return to using
In describing the issues related to the reduction of separation the standard phraseology they were trained on. In doing this our
the use of communications has been mentioned. global voice should be easily understood and contribute to
The application of Controller Pilot Data Link Communications ensuring a high standard of safety.
(CPDLC) in areas of poor voice communication has certainly
improved communications in areas which have been reliant on HF.

ISSUE 2 | 2017 InterPilot | The Safety and Technical Journal of IFALPA