The ATSB's final investigation report into an airspace incident
on 7 April involving a Boeing 737 and a Lancair aircraft has found
that while it was an 'airprox' it was not a 'serious incident'
because of timely action by the air traffic controller and both
crews.
The Boeing 737, operating under the instrument flight rules
(IFR), was en route from Townsville and descending for a landing at
Brisbane. A Neico Lancair IV-P aircraft, operating under the visual
flight rules (VFR), was en route from Maroochydore to St George, on
climb to flight level (FL) 165.
Both aircraft were operating in Class E airspace when the 737
crew observed a TCAS traffic symbol and received subsequent TCAS
alerts. This airspace was introduced as part of the National
Airspace System (NAS) phase 2b from 27 November 2003.
Despite the assistance of air traffic control to both crews, the
737 crew had observed the Lancair's traffic symbol on the TCAS
display but could not see the Lancair. They decreased the rate of
descent and after receiving TCAS traffic advisory (TA) and
resolution advisory (RA) alerts, climbed the 737 to FL166 and
turned about 15 degrees right of track. Recorded Air Traffic
Services (ATS) radar data indicated that the Lancair altered track
8 degrees to the right away from the 737 just before passing behind
and below the 737. The minimum distance between the two aircraft
was about 600 ft vertically at about 0.3 NM (about 556 metres)
laterally.
Information obtained from the crews of each aircraft, the ATS
controller, recorded flight data from the 737, ATS audio recordings
and radar data, was consistent. Based on all of the circumstances,
the incident was classified as an 'airprox' but not a 'serious
incident'.
The investigation found that the crews of both aircraft and the
air traffic controller complied with the published procedures for
Class E airspace under NAS 2b.
Airservices Australia advised it had subsequently issued a
national instruction and an information circular on safety alerts,
traffic avoidance advice, and traffic information. It had also
produced a computer-based training program for air traffic
controllers on duty of care, which provided advice on when a safety
alert is to be initiated.
The full investigation report (200401273) is available from the
website, or
from the Bureau on request.
Media Contact: 1800 020 616
