Unprecedented corrosion caused fatal helicopter crash in January, IDF finds
Extremely rare corrosion inside an engine component ultimately caused an otherwise mechanically sound helicopter to crash into icy seas earlier this year, killing two pilots on board, the military said on Sunday as she was finishing her investigation into the mysterious accident.
The AS565 Panther helicopter – known in the IAF as “Atalef” or bat – slammed into the water just off the northern city of Haifa on January 3. Both pilots, Lt. Col. Erez Sachyani and Major Chen Fogel, were killed but a third officer on board, Cpt. Ron Birman, managed to jump and was rescued with relatively minor injuries.
The final report largely confirmed the tentative findings released by the military just a month after the crash.
According to the investigation, the malfunction was the result of corrosion that maintenance did not identify, the component in question being well located inside the engine and therefore not part of the routine checks recommended by the French manufacturer Airbus. Helicopters.
The Army said the malfunction, the first of its kind, was not known to either the manufacturer or the Air Force.
In its final report, the IDF said the corrosion was likely due to the aircraft’s constant proximity to the sea. The “Atalef” fleet is capable of landing on Israeli Navy missile ships and is mainly used for missions at sea.
The report adds that the “flushing process” of the engine, which aims to prevent corrosion, was “not optimal” and was not carried out “exactly” according to the manufacturer’s instructions.
According to the report, the helicopter was to undergo a more thorough inspection by the manufacturer after an additional 250 hours of flight. It received a final full inspection, which is supposed to be scheduled every 1,650 flight hours, in 2017.
Instead, the corroded part caused the turbine blade to fracture, starting a fire in the left engine that quickly spread to the right, filling the cabin with smoke. The military blamed engine components that were not flame retardant at the “required temperature”, such as aluminum, for allowing the fire to spread.
“This is due to a manufacturer design issue. Following this, the helicopter manufacturer will release safety information regarding the engine’s aluminum components,” the IDF said.
There was no immediate comment from Airbus Helicopter or its parent company Airbus.
Sachyani and Fogel maintained control of the aircraft and attempted to extinguish the fire with an on-board extinguisher system while lowering it for a water landing using a flotation system built into the helicopter.
The probe determined that the force of the impact with the water either knocked Sachyani and Fogel out completely or at least disoriented them enough that they were unable to unbuckle their seat belts or use the fuel tanks. oxygen in the cabin when the helicopter began to sink.
Both are believed to have drowned shortly after impact. Rescuers, who arrived within eight minutes of the crash, were unable to get them out alive, according to the inquest.
The final findings of the investigation have been presented to the families of Sachyani and Fogel, the army said.
The investigation determined that the pilots were calm and in control during the malfunction and behaved relatively well. But he also found that the pilots had not turned off the engines before turning on the fire suppression system, which prevented it from operating at full capacity.
“We emphasize that the crew was competent, qualified and faced a sequence of difficult malfunctions … under complex flight conditions in the dark of night over the sea,” the military said Sunday.
After the crash, former IAF chief Amikam Norkin grounded the Air Force’s fleet of AS565 Panther helicopters. They remained out of service due to initial difficulties in determining the cause of the malfunction. After discovering that a corroded blade was responsible, the Air Force sent all remaining helicopters for a check to make sure they didn’t have a similar problem, and began to phase them back in. in normal service.
“A thorough, professional and thorough investigation has been carried out here,” IDF chief Aviv Kohavi said. “We lost two of our best drivers in this accident. Our task now is to study the findings and lessons learned, and prevent the next accident.
Judah Ari Gross contributed to this report.