A Robinson R22 that ditched in floodwater near Adavale in south-west QLD had insufficient power to climb away because it was overweight, according to an ATSB investigation report released this week.
VH-KNG was one of three R22s deployed in March this year to help evacuate people from flooded areas. The pilot of KNG spotted a person stranded on a roof of a building that was surrounded by fast-moving floodwater. After assessing the situation as critical, the pilot landed on the roof and loaded the person on the helicopter.
However, when the pilot attempted to depart, but the aircraft struggled to climb away or maintain altitude once it was out of ground effect, resulting in a ditching from which both the pilot and the passenger needed to be rescued.
ATSB investigators determined that the Robinson was 46 kg overweight given that the person recovered was wearing wet clothing and carrying medical equipment.
ATSB Chief Commissioner Angus Mitchell noted that the pilot had not been trained for missions such as this one and was under pressure from the urgent situation.
“This was an unfamiliar and demanding rescue operation for the pilot, who, under time pressure due to the perceived imminent risk of a roof collapse, did not assess available performance after boarding a heavier than expected passenger and committed to the rescue with an immediate take-off,” he said.
“The operator and pilot felt an understandable and commendable moral obligation to conduct a rescue operation, but they were neither trained nor equipped for such scenarios, and the pilot attempted a take-off with the helicopter significantly overweight.”
ATSB investigators found the passenger weighed 130 kg and estimated an extra 10 kg for the wet clothes and medical equipment. This was loaded into the R22, which was only 94 kg below the 622 kg MTOW at the time.
Robinson performance data revealed that the R22 should be able to hover out of ground effect up to a pressure altitude of 3400 feet at 24oC, but the data doesn't take into account the humidity on the day of the accident and provides no figures for the aircraft when operated over MTOW.
Mitchell acknowledged the important role volunteers play in emergency response in Australia, including through mercy flights, which by definition are outside the scope of normal operations for pilots and operators.
“Mercy flights can save lives when dedicated, trained assistance is not available,” he said. “This investigation should not deter pilots and operators from conducting mercy flights, but rather highlight that when responding to an emergency it is important to stop and take a moment to assess risk to the rescuers before assisting others.”
The ATSB has produced a You Tube video detailing the accident sequence and the full investigation report is on the ATSB website.