{"id":41250,"date":"2026-05-21T12:24:10","date_gmt":"2026-05-21T11:24:10","guid":{"rendered":"https:\/\/aerospaceglobalnews.com\/?p=41250"},"modified":"2026-05-21T12:24:11","modified_gmt":"2026-05-21T11:24:11","slug":"aaib-leonardo-aw139-tail-rotor-bearings","status":"publish","type":"post","link":"https:\/\/aerospaceglobalnews.com\/news\/aaib-leonardo-aw139-tail-rotor-bearings\/","title":{"rendered":"AAIB: Leonardo AW139 narrowly avoided catastrophic tail rotor control failure"},"content":{"rendered":"\n

An offshore helicopter<\/a><\/span><\/strong> carrying passengers to North Sea oil rigs came close to a potentially catastrophic loss of tail rotor control after a critical bearing failure went undetected until a post-flight maintenance inspection, according to a newly released UK accident investigation report.<\/p>\n\n\n\n

The UK Air Accidents Investigation Branch (AAIB) <\/a><\/span><\/strong>said the extent of damage found inside the Leonardo AW139\u2019s<\/a><\/span><\/strong> tail rotor system indicated \u201ca loss of tail rotor control event would likely have occurred had the helicopter continued to operate.\u201d<\/p>\n\n\n\n

Leonardo AW139 tail rotor failure discovered after North Sea flights<\/h2>\n\n\n\n

The serious incident involved Leonardo<\/a><\/span><\/strong> AW139 helicopter G-CIMU, operated by CHC Helicopter, following a day of offshore passenger flights from Norwich Airport to North Sea oil rigs on 13 June 2022. The defect was discovered after the aircraft returned to base, and engineers noticed a hole worn through a protective cover over the tail rotor duplex bearing assembly.<\/p>\n\n\n\n

When the cover was removed, maintenance personnel found extensive internal damage, including exposed ball bearings, heavy wear and large amounts of carbon dust inside the assembly. The bearing deteriorated so severely that it disintegrated during removal attempts.<\/p>\n\n\n\n

\"Leonardo
Photo: AAIB<\/figcaption><\/figure>\n\n\n\n

Investigators warned the failure mechanism closely resembled the chain of events that caused the fatal 2018 Leicester City helicopter crash involving a Leonardo AW169<\/a><\/span><\/strong>, which killed five people, including club owner Vichai Srivaddhanaprabha.<\/p>\n\n\n\n

AAIB links AW139 failure to Leicester AW169 crash<\/h2>\n\n\n\n

The report explains that the failed component was a tail rotor duplex bearing, classified as a critical part, as its failure could have catastrophic consequences for the helicopter.<\/p>\n\n\n\n

The bearing connects the static tail rotor control actuator to the rotating tail rotor system, allowing pilots to control yaw through pedal inputs. Failure of the component can ultimately result in the loss of tail rotor pitch control.<\/p>\n\n\n\n

Investigators found the AW139 uses an almost identical tail rotor system design to the AW169 involved in the 2018 Leicester crash.<\/p>\n\n\n\n

\"Leonardo
Photo: AAIB<\/figcaption><\/figure>\n\n\n\n

In the Leicester accident, seizure of the duplex bearing triggered a sequence of failures that resulted in the uncontrollable loss of tail rotor pitch authority and the helicopter crashing shortly after takeoff from the King Power Stadium.<\/p>\n\n\n\n

The AAIB said a similar process occurred aboard G-CIMU, although in this case the helicopter landed safely before the full consequences developed.<\/p>\n\n\n

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