The US National Transportation Safety Board (NTSB) is investigating an engine fire incident on a Horizon Air Bombardier Q400 that resulted in an emergency landing at San Jose International airport on 5 March.
No one was injured in the incident, which occurred on a flight from San Jose to Boise, Idaho, says a preliminary NTSB report. The aircraft, registration N417QX, was slightly damaged.
The aircraft, powered by twin Pratt & Whitney Canada PW150A engines, was climbing through 20,000ft when the crew was alerted to a fire on engine number two that was accompanied by a bang sound.
The engine was shut down and both of the powerplant's fire extinguishing bottles were activated, albeit unsuccessfully.
There was no visible fire but the aircraft's crew continued to receive a fire indication, leading to the flight's captain declaring an emergency and returning to San Jose.
The aircraft landed at 11:29 on runway 12L, says the NTSB. The aircraft's number one engine was shut down and the 47 passengers on board were evacuated.
An initial assessment showed that the fire damage to the Q400 was visible on only the aircraft's exterior. The NTSB says that the aircraft was moved to a hangar for further examination.
In response to queries, Pratt & Whitney Canada says it does not comment while an incident is under investigation.