The Boeing 737 (B737) was in cloud overhead Hamilton Island at 3,000 ft and the crew were cleared to track outbound on the 325 radial for a VOR/DME approach to runway 14 by the aerodrome controller. The 325 radial was the outbound leg of a "teardrop pattern" approach. The crew were instructed to report when commencing the turn inbound. The co-pilot was the flying pilot and the pilot in command was monitoring the approach and making the radio calls.
The pilot of a Cessna 182M Skylane departed Shute Harbour (12 NM west-north-west of Hamilton Island) and requested an air traffic control clearance for a parachute dropping operation. The aerodrome controller told the pilot that he would "have one for you in a moment" but did not instruct the pilot to remain outside controlled airspace. The controller was required to obtain an airspace release from the Tabletop controller, who was located in the Brisbane Centre. An airspace release was subsequently obtained from the Tabletop controller for an area encompassing a 5 NM radius of Shute Harbour up to and including 10,000 ft.
The B737 crew reported turning inbound and that they were visual. The aerodrome controller told them to continue approach to runway 14. The profile of the runway 14 VOR/DME approach restricted the descent of aircraft to not below 2,300 ft until inside 8 NM from Hamilton Island.
Less than 1 minute later, the Skylane pilot was issued with a clearance by the aerodrome controller to operate within a 5 NM radius of Shute Harbour not above 10,000 ft and to report ready for the drop. Since first contact with the aerodrome controller, the pilot had been steadily climbing and was established inside controlled airspace at about 2,100 ft when the clearance was issued. Seconds later, the pilot and parachutists in the Skylane sighted the B737 in a left banking turn, in their relative 2 o'clock position and at the same level. The Skylane pilot estimated the B737 passed alongside them with less than 100 m of lateral separation.
The B737 crew were unaware of the near mid-air collision with the Skylane. Their traffic alerting and collision avoidance system (TCAS) did not alert them to the proximity of the Skylane because the Skylane's transponder, although fitted, was not switched on and operating. The pilot of the Skylane was required to have the transponder activated and selected to code 1200 in accordance with Aeronautical Information Publication (AIP) Australia ENR 1.6-8.
At the time of the occurrence, the Skylane was about 10 NM north-west of Hamilton Island, where the 9-12 DME control area step had a Class D airspace lower limit of 1,500 ft. Analysis of the radar data showed that the B737 was below 2,300 ft beyond 8 NM of Hamilton Island, which was below the altitude profile for the approach. The recorded radar altitude of the B737 was consistent with the altitude reported by the pilot of the Skylane.
The control tower did not have a Local Instruction or any lateral separation diagrams that plotted separation points between the final approach path of the runway 14 VOR/DME approach and the Shute Harbour parachuting area.
The Skylane pilot was inside controlled airspace before the air traffic control clearance was issued. Had the controller made a positive instruction for the pilot to remain outside controlled airspace, or told the pilot to standby for a clearance, the pilot may have levelled at 1,500 ft while awaiting the clearance. Such an action would have provided greater than the minimum separation of 500 ft that was required between an aircraft in controlled airspace and an aircraft outside controlled airspace.
Although the Skylane was fitted with a transponder, the pilot did not have the transponder operating. If the transponder had been operating on code 1200 or any other code, the TCAS in the B737 would have alerted the crew to the proximity of the Skylane. Also, the Tabletop controller, although not controlling the two aircraft, may have received a short-term conflict alert on the radar display, which could have been relayed to the aerodrome controller alerting him to their close proximity.
The aerodrome controller was required to set up a separation standard between the two aircraft before issuing the Skylane pilot with an air traffic control clearance, unless the clearance incorporated a requirement that ensured separation. Because vertical separation was not available due to the B737 being on an instrument approach, some form of lateral separation was required.
The arc of the 5 NM radius of Shute Harbour and the inbound radial of the runway 14 VOR/DME approach overlapped each other. As a result, there was no form of lateral separation between the aircraft when the clearance was issued.
- The aerodrome controller did not issue a positive instruction when the pilot of the Skylane asked for a clearance.
- The pilot of the Skylane entered controlled airspace before receiving an air traffic control clearance.
- The pilot of the Skylane did not select and operate code 1200, or any other code on the aircraft's transponder.
- The non-flying pilot of the B737 did not adequately monitor the aircraft's altitude and allowed the flying pilot to descend the aircraft below the profile of the VOR/DME approach.
- The aerodrome controller did not establish a separation standard between the B737 and the Skylane, when the Skylane was cleared to enter controlled airspace.
- The control tower at Hamilton Island did not have a Local Instruction or lateral separation diagrams that may have helped the controller in working out a lateral separation standard between the possible positions of the two aircraft.
Local safety action
As a result of this investigation, Airservices Australia issued a Terminal Operations - Request for Change (RFC). The RFC requested that the following be inserted in Hamilton Island Local Instructions, within the section titled Lateral Separation as follows:
Parachuting Operations at Shute Harbour (YSHR)
Lateral separation exists between an aircraft cleared on the HM RWY 14 VOR/DME IAL and a PJE aircraft up to A100 with a clearance to: "OPERATE OVER THE MAINLAND WEST OF PIONEER POINT AND SHUTEHAVEN".
The change was implemented on 23 September 1999.
|Date:||25 May 1999||Investigation status:||Completed|
|Time:||1400 hours EST|
|Location:||6 km NE Shute Harbour, (ALA)|
|State:||Queensland||Occurrence type:||Near collision|
|Release date:||20 November 2000||Occurrence category:||Incident|
|Report status:||Final||Highest injury level:||None|
Aircraft 1 details
|Aircraft manufacturer||The Boeing Company|
|Type of operation||Air Transport High Capacity|
|Damage to aircraft||Nil|
|Departure point||Sydney, NSW|
|Destination||Hamilton Island, QLD|
Aircraft 2 details
|Aircraft manufacturer||Cessna Aircraft Company|
|Type of operation||Sports Aviation|
|Damage to aircraft||Nil|
|Departure point||Shute Harbour, QLD|
|Destination||Shute Harbour, QLD|