Cargolux 747-400F Main-Gear Bogie Separation: Faulty Parts Identified

In the aftermath of a significant incident involving a Cargolux Boeing 747-400F, investigators have uncovered crucial details about the failure of the aircraft’s main landing-gear assembly.

The aircraft, which was en route to Chicago O’Hare from Luxembourg, experienced a critical failure of its right-hand body main-gear assembly during takeoff on May 14, 2023.

According to the report from Flight Global. The failure occurred when the aircraft was lifting off from runway 06. The right-hand main-gear strut over-extended, causing the wheel bogie to tilt downward rather than the usual slight tilt-up that precedes gear retraction.

This malfunction triggered landing-gear alerts in the cockpit, and the pilots were unable to select the gear-up position. Faced with these issues, the crew decided to dump fuel and return to the departure airport.

Upon landing back at Luxembourg, the right-hand main-gear bogie separated from the aircraft, along with a portion of the inner shock-strut cylinder. The separation led to the bogie striking the underside of the aft fuselage multiple times, as well as the right-hand horizontal stabilizer. Fortunately, the crew managed to land the aircraft safely, but the incident highlighted serious issues with the landing-gear assembly.

Preliminary findings from Luxembourg’s investigation authority, AET, indicate that the tilt-down of the bogie on takeoff was a sign of over-extension of the shock strut. However, it was noted that the maximum over-extension condition was not reached. Components of the landing-gear assembly were sent for analysis under the oversight of the NTSB.

Boeing’s analysis revealed a significant issue: the upper bearing carrier had failed, with the bearing and piston ring retention lands sheared off. Further investigation into the failure of an inner cylinder segment is ongoing. The findings from this investigation are expected to provide deeper insights into the root causes of the malfunction.

Additionally , Boeing has announced plans to redesign the door-plug mechanism on its 737 MAX aircraft. This move comes in the wake of a troubling incident involving an Alaska Airlines 737 MAX 9, which experienced a mid-air cabin panel blowout in January.

The incident has been a major blow to Boeing, marking its second significant crisis in recent years and prompting a rigorous investigation by the US National Transportation Safety Board (NTSB).