The French accident investigation organization BEA has released its findings on an Airbus A380 that lost an engine (as in it “fell off”) over a remote part of Greenland on September 30, 2017. There were no injuries of anyone on board the jumbo jet or on the ground—it’s a very remote area.
The investigation itself was fascinating. The results, less so. It’s hard to believe that BEA even tried to find the engine, let alone succeed in recovering it. But in a matter of days investigators did all of that, in large part because it was an urgent matter. After all, no one knew why the fan and inlet cowling had failed and separated in flight. Was it a problem that would recur on other A380s?
The crews were just changing over as they cruised along over Greenland with 497 passengers and 24 crewmembers on board, heading to Los Angeles from Paris when the number-four engine stalled, as indicated by a warning in the cockpit, and then failed altogether. The flight diverted to Goose Bay, Canada, where it landed without incident.
The quick response is impressive. But how does one find an engine fan and inlet cowling separated in flight? How do you find a big part of a giant engine in a vast wilderness of ice? Well, you use the flight data recorder and go from there.
For starters, Denmark, which has jurisdiction over Greenland where the engine failed, designated French BEA team to take charge of the investigation. They did so with help from Airbus, the Alliance GP7200 engine manufacturers (GE and Pratt & Whitney are 50/50 partners on the engine), the NTSB and others.
Amazingly, within days of the accident—it’s classified as such—investigators located the area in Greenland where the engine had failed and fallen off, and dispatched teams to find it. And it’s a good thing they hurried, because the fan was already buried in more than 10 feet of snow, and it was hard enough to dig it out from that depth. No doubt, but people got some exercise.
Despite the sterling effort from all involved, the report, issued this week, is less than reassuring. Investigators, who were looking for a smoking gun as to why the engine failed and the fan separated, wanted something reassuring to say to the world. The report does anything but. While it’s very technical in nature about the metallurgy involved in the manufacture of such engines, the report’s authors essentially said that it found nothing to show why the engine failed.
It did conclude that there were several areas of concern that were “likely to have contributed to the accident.” These are all associated with the properties of the titanium alloy, Ti-6-4, used in the components that failed and the risk that the material is more susceptible to failure in larger structures. The Alliance GP7200-series engine is one of the largest turbofans in the world. It’s outfitted on just under half of A380s in the fleet, with the Roll-Royce Trent 900, the original A380 engine, comprising the slight majority.
There have been, thank goodness, no recurrences of the issue, though the thought of what might have happened if things had gone slightly differently should be enough to motivate those scientists and engineers looking for an answer.
