The UK’s Air Accident Investigation Board (AAIB) has released its findings regarding a series of cabin heating duct failures aboard Leonardo AW189 helicopters. In a report released earlier this month, the AAIB examined a failure aboard a search-and-rescue-configured AW189 on a flight from its base at Lydd Airport in Kent on Jan. 7, 2022.
According to the AAIB, the duct “failed in flight, releasing fragments of duct insulation material into the cabin and cockpit, causing respiratory irritation to the occupants. The aircraft landed safely. Similar heating duct failures had previously occurred in several of the operator’s other AW189 aircraft.” Leonardo subsequently issued a service bulletin (SB) to make the installation of the existing duct “more robust” as an “interim solution.”
Leonardo told AIN it “is rapidly progressing to complete the new heating duct design to make it available soon. Meanwhile, an SB update will guarantee the necessary level of installation robustness before the new installation is available.” The SB requires duct inspection and modification.
An examination by Leonardo found the duct failure was due to “nonuniform adhesion on the bonding surfaces between the rigid and flexible duct sections. The collapse of the duct led to fragments of the duct insulation being discharged through the cabin in the cockpit heating vents.” In one case, it also resulted in smoke in the cockpit, triggering an emergency landing.