Final Report: What Caused Norwegian’s Uncontained 787 Engine Failure

Italy’s Agenzia Nazionale per la Sicurezza del Volo has released its final report from the investigation of a Norwegian 787 Dreamliner uncontained engine failure in August 2019. The incident, which caused glowing hot debris to crash into cars and houses outside of Rome’s Fiumicino Airport, occurred due to corrosive fatigue to the Rolls-Royce Trent 1000 fan blades.

Final Report: What Caused Norwegian’s Uncontained 787 Engine Failure
Italian investigators have released the final report on what caused the uncontained failure of a Boeing 787-9 in August 2019. Photo: Vincenzo Pace | Simple Flying

Uncontained failure heading out of Rome

We are almost at the anniversary of the spectacular engine failure of United Airlines Flight 328 over Colorado. It is hard to forget the images of the engine burning in mid-air or the large cowling debris in people’s driveways. Thankfully, there were no injuries and no major damage to property.

However, not that long before, another widebody jet also suffered an uncontained engine failure, with incandescent parts falling from the sky, hitting one person, 25 vehicles, and 12 houses in an Italian town a little way from Rome’s Fiumicino Airport.

The incident occurred on August 10th, 2019. It involved a five-year-old Boeing 787 registered as LN-LND belonging to Norwegian Air, powered by Rolls-Royce Trent 1000 engines.

The aircraft was operating flight DY-7115 from Rome to Los Angeles. However, at 3,000 feet, the pilots declared an emergency and returned to Fiumicino. There were 298 passengers and 12 crew on board, none of whom sustained any injuries.

An initial investigation was conducted immediately, resulting in a service bulletin for Trent 1000 engines. However, just yesterday, the Italian aircraft accident investigation agency, the Agenzia Nazionale per la Sicurezza del Volo (ANSV), released its final report on the incident.

Norwegian 787 Dreamliner
The aircraft in question was LN-LND, powered by Rolls-Royce Trent 1000 engines and five and half years old at the time of the incident. Photo: Steven Byles via Wikimedia Commons

Corrosion fatigue faster than expected

When examining the left-hand engine, the ANSV investigators have found that progressive corrosion fatigue resulted in a six-millimeter crack in an intermediate pressure turbine blade. This caused the fan blade to separate during take-off from Rome.

Furthermore, investigators discovered cracks in additional fan blades, in both the left-hand and the right-hand engines. The turbine blade that caused the incident failed at cycle 1,210, still 200 cycles away from the limit imposed by the European Safety Agency (EASA). The full report can be found here.

Boeing 787
Rolls-Royce has suffered massive financial burdens due to issues with the Trent 1000 engines. Photo: Boeing

Are the Trent 1000 issues finally resolved?

Issues with the Trent 1000 engines have been a massive headache for Rolls-Royce, in particular the faster-than-expected deterioration of the fan blades. Through this year, they will have cost the company over £2 billion (approximately $2.7 billion).

As a result, Rolls-Royce has also lost a lot of ground to General Electric, which also supplies engines for the Dreamliner. However, the engine-maker’s leadership is optimistic that the problems may finally have been resolved.

“After a difficult three or four years, I feel confident about the durability of the engines and the future. We have learned a lot,” Rolls-Royce engineering and technology director Simon Burr told Bloomberg during an interview in July last year.

At the time, Rolls-Royce was still testing the high-pressure turbine, focusing on replicating the sustained stress and high temperatures of the aircraft’s climb to cruising altitude, which is a more strenuous moment than the take-off itself.

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