CAD's response to media enquiries on loss of standard separation
****************************************************************
There are media reports today which alleged that the new Air Traffic Management System (ATMS) did not issue timely alerts to air traffic controllers in January 2017. It is totally unfounded. The new ATMS issues the predictive conflict alert and/or conflict alert under different circumstances in a timely manner as per system design.
According to the CAD’s records, three loss of standard separation incidents took place within the Hong Kong Flight Information Region last month, on January 13, 24 and 26. In those three incidents, the minimum separation between the aircraft was less than the standard separation required by the International Civil Aviation Organization (ICAO), i.e. five nautical miles (horizontal separation standard) or 1 000 feet (vertical separation standard). The CAD has conducted comprehensive investigation into each incident and confirmed that all of them were minor in nature.
Investigation results of the three loss of standard separation incidents revealed that the new ATMS has issued predictive conflict alert and/or conflict alert in a timely manner as per system design. Upon receiving the alert, the Air Traffic Control Officer (ATCOs) concerned immediately took remedial measures in accordance with established procedures to safeguard aviation safety. The aircraft involved in the incidents operated in a safe and controlled manner at all time, and aviation safety was not undermined. All the aircraft concerned has no risk of collision.
The CAD conducts investigation on all loss of standard separation incidents in accordance with international practice and established procedures, follow up on the cases in a timely manner and make necessary improvement measures. The incidents and investigation results are regularly reported to and reviewed by the Air Traffic Safety Assessment Committee, and the flight and aviation safety experts from the airlines.
There are a number of factors contributing to loss of standard separation, including inclement weather, navigation operation, ground or flight operation procedures and human factors. In fact, other air navigation service providers around the world using different kinds of ATMS would occasionally encounter loss of standard separation incidents due to various reasons. In Hong Kong, one to two loss of standard separation incidents were recorded per month on average when the old ATMS was in use. There were five loss of standard separation incidents in the past three months (from November 2016 to January 2017) after the new ATMS was commissioned (i.e. less than two incidents per month on average), comparable to the average figure when the old ATMS was in use.
Reports claimed that there were six loss of standard separation incidents last month. In other words, there were three other incidents apart from January 13, 24 and 26. The CAD’s spokesman said that the ICAO allows individual civil aviation authority to establish different categorisation and procedures in handling loss of standard separation incidents to suit the individual circumstances , and the CAD has established a set of standard procedures. According to it, cases are classified as minor technical incidents if the infringement of standard separation between the aircraft was momentary and was less than 10 per cent of the standard separation, and even if the ATCO does not take any remedial action, the predicted flight tracks of the aircraft concerned would have no risk of collision. Nevertheless, the CAD will also follow up on this kind of incidents. The three other cases mentioned in the reports belonged to this category of minor technical incidents. The new ATMS has issued timely and appropriate alerts in those incidents according to the system design. Reference has been drawn from the UK-based National Air Traffic Services (NATS) in terms of the categorisation and handling of minor technical incidents. The same rule applied when the old ATMS was in use.
As mentioned above, there are a number of factors contributing to loss of standard separation. The new ATMS has more advanced features than the old one. Concerning its flight trajectory prediction functions, alert messages are issued to the ATCOs in a timely manner. According to the investigation results, no evidence showed that the loss of standard separation incidents, which took place last month, were related to the new ATMS. During the incidents, the new ATMS has been functioning normally, with no false targets observed. Besides, based on the system design, the new ATMS will calculate the time for issuing the predictive conflict alert with reference to the aircraft position and flight path trajectory. In other words, the predictive conflict alert, unlike some media reports suggested, may not be issued 60 seconds before the two aircraft collide in daily operation. The ATCOs are all conversant with the functionality and operations of the new ATMS.
The spokesman said that people in the know and are experienced in the field of air traffic management will understand “loss of standard separation” and “minor technical incidents” are incidents under two different categories and with different handling methods. Mixing the handling of one category with the other is not appropriate.
Ends/Wednesday, February 8, 2017
Issued at HKT 23:24
Issued at HKT 23:24
NNNN