The concern related to the communication problems between crews operating on the ground at Broome airport outside tower hours.
The reporter expressed a safety concern regarding the safety of aircraft on the ground at Broome airport during CTAF hours.
The reporter advised that there have been a number of occurrences at Broome where aircraft taxiing to the runway cannot communicate with aircraft using the opposite runway. This has resulted in aircraft taking off towards each other and avoiding action being taken by flight crew on previous occasions. On other occasions this has been circumvented by other flight crew members giving timely warning or controllers starting their shift giving timely warnings.
The reporter advised that the hump in the runway is so large that an aircraft taxiing on one end of the runway would not be able to see a Boeing 737 taxiing on the other.
This concern was reported previously to CASA in REPCON AR201300097, but no changes have been made to the procedures at the airport.
CASA has reviewed the REPCON and in regards to the hump in the runway surface at Broome Aerodrome, and examined compliance of the runway with the line of sight requirements in the Manual of Standards (MOS) Part 139. Analysis of a longitudinal engineering plan confirms compliance with MOS 139 minimum unobstructed line of sight requirements. The plan identifies an unobstructed line of sight along the runway, from a point three metres above the runway, of 1,270 metres. This distance is greater than half the length of the runway. MOS 139 section 6.2.7 – Runway Sight Distance refers.
I am advised that the En-Route Supplement Australia will be updated to highlight the possible degradation of communications between ground stations during CTAF operations due to terrain shielding, and the visibility issues associated with the runway slope.
CASA were advised that the En-route section of the ERSA already has a section warning users of the potential issues with communication on the ground at Broome, but this alone has not resolved this known problem at the airport. CASA were also advised that after another separation-related issue on the ground at Broome, the ATSB were informed that there is a rush of VFR traffic just after 6AM as they are not permitted to depart before this time. A suggestion was made that a duty runway should be defined when wind conditions do not naturally favour one direction.
CASA comments:
CASA has reviewed your further query about the REPCON and notes that additional information has been added to the En-Route Supplement Australia, providing pilots with information on the possibility of poor radio propagation in the CTAF area on the ground or operating at low level.
I am advised that the issue was not raised during the Post Implementation Review of Broome and Karratha conducted earlier this year.
CASA will write to the operator of Broome Aerodrome requesting the operator to review the wording in ERSA to make it clearer that there is a problem with the radio coverage. CASA will also ask the operator to ensure that drivers of ground vehicles are aware of this problem.