Safety officials are investigating an unidentified issue with a Boeing 787’s General Electric GEnx-1B engine that occurred on July 28 at Charleston, S.C., which shut down a runway and forced flights to be diverted.

Few details of the incident, which occurred during a high speed run along the runway, are available. Local media reports indicate the runway was shut down shortly after 4 p.m. when fire broke out in grass beside the strip. The aircraft involved is thought to be the first 787 due for delivery to Air India (LN 54), and was conducting final ground runs before its upcoming first flight.

In a statement, GE says that “during a ground test run in North Charleston on July 28, a GEnx-1B engine on a non-revenue generating Boeing 787 aircraft experienced an issue. No one was injured.”

The incident marks one of the first known notable test events for the GEnx-1B, which is now in service on 787s operated by Japan Airlines. The GEnx-2B variant is also in service on 747-8s operated by several cargo airlines as well as on 747-8 passenger models flown by Lufthansa. GE adds that “about 100 GEnx engines are in service, and they have accumulated more than 125,000 flight hours.”

The engine-maker says that no known problems have so far surfaced that could account for the test failure, though the details of what damage occurred have yet to be revealed. The manufacturer says “GE continually monitors and analyzes the performance of the GEnx fleet in service, and we are not aware of operational issues that would hazard the continued safe flight of aircraft powered by these engines.”

Events during testing included the discovery of micro-cracks on a first stage high pressure turbine blade on a cyclic endurance engine in January 2011. Tests at the time indicated the event was a one-off anomaly.

The aircraft believed to be involved is the second 787 built at the Boeing Charleston facility. There are eight GE powered 787s that are either poised for delivery or in the final phases of preparation for handover. These are destined for Ethiopian Airlines, Qatar Airways, and Japan Airlines.