The US Federal Aviation Administration (FAA) is investigating an incident where a passenger was apparently granted unauthorised access to the cockpit of a United Airlines charter flight travelling from Denver to Toronto.

The moment, involving a man accompanying the Colorado Rockies baseball team on April 10, was caught on video that was posted online. Since the Sept 11, 2001 terrorist attacks, passengers have been strictly prohibited from entering the cockpit during flight.

United Airlines said in a statement that it’s “deeply disturbed” by the video, which has since been deleted from the individual’s social media account but remains visible elsewhere online. The airline said it has grounded the pilots involved in the flight while it conducts an investigation, calling the incident “a clear violation of our safety and operational policies”.

The case raises fresh concerns about operations at United Airlines, weeks after aviation regulators began a widespread safety review that was triggered by a series of mishaps at the carrier. The FAA has taken steps during the evaluation to temper United Airlines’ near-term growth by not allowing new planes or new cities to be added to its operating certificate.

While scrutiny across the US industry has been heightened since a fuselage panel broke off an Alaska Airlines plane mid-flight on Jan 5, the mishaps at United included a wheel falling off a plane shortly after take-off, an aircraft that veered off a Houston runway and an emergency landing after an engine began spewing flames.

The US aviation regulator said separately that federal rules “restrict flight deck access to specific individuals”, adding that it doesn’t comment on the details of open investigations. 

The probe was earlier reported by the Wall Street Journal. The Colorado Rockies did not immediately respond to a request for comment. BLOOMBERG