The ATSB this week issued a warning about situational awareness in confined spaces after the tail of an AW139 struck foliage in 2021.
Toll Helicopters' AW139 VH-TJK was tasked to conduct a medevac near Shelly Beach, NSW, in May 2021, making an attempt to land at an unimproved landing site at night. Whilst checking the ground below the aircraft, an undetected yaw caused the tail to contact surrounding trees.
The tail rotor did not hit the trees and no-one was injured in the incident, but the aircraft was grounded.
“This incident highlights the need for flight crew to have a heightened situational awareness when operating into a confined area and unfamiliar location in the vicinity of obstacles,” Director Transport Safety Stuart Macleod said.
“There is little to no margin to recover from any unexpected events in these conditions.”
Investigations revealed that the pilot hovered the helicopter 100-130 feet AGL whilst an aircrew officer (ACO) described the intended landing site including size, obstacles (advising that there were no power lines and that the trees were small), and available access.
The crew planned to continue the landing based on the description, but at about 13 feet AGL, the ACO told the pilot that they were drifting right before determining that the tail was clear. However, the drift right continued, leading the ACO to believe that the helicopter was closer to the trees than expected, calling "climb, climb, climb" twice.
Given the proximity of the trees, the ACO thought contact may have happened, but there was no other indication. At no time did the ACO tell the flight crew of the contact potential.
After further assessment at 100 feet AGL, the crew diverted to land at nearby Bear Cottage, where a walkaround revealed foliage staining on the vertical stabliser below the tail rotor.
The ATSB’s report notes the role crew coordination plays in HEMS flights, as it assures improved situational awareness, reduces errors, and fosters effective teamwork.
“Effective coordination and communication (including of concerns) minimises the risk of misinterpretation, ensures accurate transmission of information, and reduces the likelihood of mistakes,” Macleod said.
The full report is on the ATSB website.