Cargolux Boeing 747-400 Forced to Return to Luxembourg After Landing Gear Failure

Luxembourg City, Luxembourg – On May 14th, 2023, a Cargolux Boeing 747-400, registered LX-OCV, was forced to return to Luxembourg shortly after takeoff due to a significant landing gear malfunction. The aircraft, operating flight CV-6857 from Luxembourg to Chicago O’Hare, experienced a failure to retract its landing gear, prompting the crew to abort the transatlantic flight and make an emergency landing back at Luxembourg Airport.

Incident Overview

The flight had just departed from Luxembourg’s runway 06 at 16:08 local time when the crew encountered issues with the landing gear. Despite attempting to retract the gear, the crew received a “GEAR TILT” message followed by a “GEAR DISAGREE” warning on the EICAS (Engine Indicating and Crew Alerting System), signaling a problem with the gear alignment and retraction mechanism. Unable to resolve the issue in-flight, the crew decided to level off at FL100 and enter a holding pattern near DIK VOR to perform the necessary checklists.

Given the severity of the situation, the crew declared an emergency to obtain clearance for fuel dumping over land, which was necessary to reduce the aircraft’s weight for a safe landing. Approximately 40 tons of fuel were jettisoned over a designated area in Belgium before the aircraft was vectored back to Luxembourg for an Instrument Landing System (ILS) approach to runway 06.

Landing Gear Separation on Touchdown

At 17:00 local time, the aircraft touched down on runway 06. However, during the landing, the right-hand center body landing gear (BLG) bogey separated from the aircraft, causing significant damage. The wheel bogey, which included part of the inner cylinder, detached from the aircraft, skidding across the runway and coming to rest in front of the Cargolux hangar. The separated gear assembly struck the lower aft fuselage multiple times and also impacted the right-hand horizontal stabilizer before coming to a stop.

Airport surveillance footage revealed that the BLG had exhibited abnormal behavior shortly after takeoff, with the wheel truck initially pitching up before over-extending and releasing vapor—an indication of hydraulic or mechanical failure. During the climb out, the bogey was observed in a pitch-down position, which persisted throughout the flight until its separation upon landing.

Damage Assessment and Investigation

The aircraft sustained extensive damage, particularly to the right-hand BLG, the lower aft fuselage, and the right-hand horizontal stabilizer. The runway surface also suffered significant abrasions from the separated gear, necessitating immediate repairs before the airport could reopen.

Following the incident, Luxembourg’s AET (Accidents and Incidents Investigation Agency) initiated a detailed investigation, supported by Germany’s BFU (Federal Bureau of Aircraft Accident Investigation) due to the German origin of the aircraft’s engines. Preliminary findings indicate that the over-extension of the right-hand BLG strut and subsequent failure were central to the gear separation. The punctured fuselage was classified as substantial damage, preventing the aircraft from being pressurized, which led to the classification of the event as an accident.

Safety and Operational Implications

This incident underscores the critical importance of proper maintenance and inspection of landing gear systems, particularly in large, heavy aircraft such as the Boeing 747-400. Landing gear failures not only compromise the aircraft’s structural integrity but also pose significant risks during takeoff and landing phases, which are already the most critical phases of flight.

The AET’s investigation is ongoing, with a focus on determining the precise cause of the gear malfunction and over-extension. No safety recommendations have been issued yet, but the final report will likely offer crucial insights into preventing similar occurrences in the future.

The aviation industry will closely monitor the findings of this investigation, particularly as they relate to the mechanical integrity of aging aircraft like the Boeing 747-400. The incident serves as a potent reminder of the complexities and challenges of maintaining the aging fleet of large cargo aircraft still in active service across the globe.

Cargolux, known for its high safety standards, will undoubtedly take the necessary steps to address the issues highlighted by this accident, ensuring the continued safety of its operations and the well-being of its crew and cargo.