What happened
On August 10, 2019, at 14:46 local time, a Boeing 787-8, registration LN-LND, experienced a serious technical malfunction shortly after departing from Rome Fiumicino “Leonardo da Vinci” International Airport. During the initial climb, the aircraft's left engine began exhibiting excessive vibrations. Simultaneously, the engine began ejecting fragments of turbine blades. These high-energy fragments struck the aircraft's wing, fuselage, and horizontal stabilizer. Some of the ejected material, which was at a high temperature, fell to the ground in the nearby city of Fiumicino.
The investigation
The ANSV investigation examined the mechanical failure of the engine components and the subsequent impact of the debris on the airframe. The inquiry involved international cooperation with the NTSB (USA), UK AAIB (UK), and BFU (Germany) to analyze the engine's design and manufacturing processes. Investigators focused on the structural integrity of the Intermediate Pressure Turbine (IPT) blades and the containment capabilities of the engine casing during an axial release event.
Findings
- The primary cause of the event was corrosion fatigue within the Intermediate Pressure Turbine (IPT) blades.
- The failure was attributed to a design deficiency regarding the alloy composition and the protective coating used on the IPT blades.
- While the engine's design successfully contained the radial projection of the fragments, the engine failed to contain the axial projection of the debris.
- The investigation noted that current certification standards for the maximum allowable probability of such negative events are based on criteria established over 40 years ago, which may not reflect modern technological capabilities or the increased risk to populations living near airports due to higher-energy debris projections.