The Agenzia nazionale per la sicurezza del volo (ANSV, Italian Civil Aviation Safety Investigation Authority) published on its website the investigation final report about the serious incident involving the Boeing B787-8 registration marks LN-LND occurred on August the 10th 2019, in Fiumicino.
The planned destination of the flight was Los Angeles; the aircraft took off from runway 16R of Rome-Fiumicino international airport at 4.45 pm local time.
Shortly after, while the aircraft was flying over the city of Fiumicino, the crew felt strong vibrations, followed by malfunction messages related to the left engine, which was then shut down in accordance to the procedures.
The crew declared emergency and decided to return to the departure airport.
Due to the malfunction a large number metallic fragments were ejected from the aforementioned engine; these hot fragments, after having produced superficial damage to the aircraft, fell down onto the streets of the city of Fiumicino, causing damage to vehicles and houses.
The aircraft landed in overweight and OEI (One Engine Inoperative) conditions, then leaving autonomously the runway and stopping at the taxiway “H”. As a consequence of the landing the left main landing gear overheated; thus, a fire started from there. This was quickly suppressed by means of portable powder fire extinguishers used by the Fire Brigade that was already deployed on site, waiting for the aircraft. At the end of this activity, the passenger disembarkation procedure took place without further inconvenience.
The ANSV investigation ascertained that the serious incident was caused by a technical factor. Specifically, the engine failure was due to the detachment of one of the Intermediate Pressure Turbine (IPT) blades that was induced by a corrosion-fatigue progressive fracture. This was made possible by an improvable design of the blade; it is worth to note that at the time of the event it was already available a more reliable modified blade standard, the introduction of which was in progress.
The detachment of the aforementioned blade induced damage to other parts of the engine. In relation to the technical factor, during the investigation the ANSV addressed three safety recommendations to EASA (European Union Aviation Safety Agency), aimed at:
- re-evaluate service management rationale that was used to calculate the life of pre-modification IPT blades, thus applying more stringent time limits;
- to avoid two engines of the same pre-modification standard being installed on the same aircraft.
In addition to the technical factor, extensively discussed in the investigation report, organizational factor related to regulatory aspects probably contributed to the event to occur. In more detail, the ANSV, at the end of the investigation, addressed to EASA and to the US FAA (Federal Aviation Administration) two further safety recommendations, aimed at the revision/integration of the current certification and continuous airworthiness regulations about aircraft engines. A third recommendation was addressed to EASA regarding the assessment of the risk of being hit by parts detached from the aircraft for the population on the ground
The report is available in Italian and English at the ANSV website (www.ansv.it), page “Le Relazioni d’inchiesta”.
Attached, 2 photos of the event.