In a safety alert prompted by the July 7 incident at San Francisco International Airport (SFO) in which an Air Canada Airbus A320 nearly landed on a crowded taxiway, the U.S. Federal Aviation Administration is reiterating the importance of vigilant pilot monitoring and overall crew resource management (CRM) to maintain safe levels of situational awareness on the flight deck.

Approaching SFO at just before midnight, the pilots of the A320 received clearance to land on Runway 28 Right, but came within about 60 feet of touching down on the adjacent parallel taxiway. Four aircraft occupied the taxiway at the time: two United Airlines Boeing 787s, a United 737 and a Philippine Airlines Airbus A340.

"This incident is an extreme example of incorrect surface approaches and landings," the FAA said in the August 18 alert aimed at flight operations professionals. "This event highlights the importance of employing best practices for successful approaches and landings to the correct airport and runway."

On the night of the incident, Runway 28 Left remained closed for construction, and several indications of that fact included a lighted X and an Automatic Terminal Information Service (ATIS) message noting the runway's lights were not illuminated.

Preliminary NTSB reporting suggests the Air Canada pilots, who had lined up on the taxiway for at least 3 nautical miles, lost situational awareness. According to the NTSB, both the taxiway and the active runway were illuminated on "default settings," including green centerline and blue edge lights on the taxiway, as well as white centerline and touchdown zone lights and green threshold and edge lights on the runway's approach end.

At about 0.7 nautical miles out, the Air Canada crew queried ATC about "seeing lights on the runway," NTSB said, and requested a cleared-to-land confirmation. ATC re-confirmed the clearance. Moments later, the crew in the United 787 sitting first on the taxiway told ATC that the Air Canada aircraft was headed for the taxiway. The second aircraft, the Philippine A340, turned on its landing lights.

As the Air Canada aircraft passed over the taxiway end, at about 85 feet agl, the crew advanced the thrust levers and initiated a go-around.

"In post-incident interviews, both incident pilots stated that, during their first approach, they believed the lighted runway on their left was 28 Left and that they were lined up for 28 Right," the NTSB said in a factual update on the probe. "They also stated that they did not recall seeing aircraft on taxiway C but that something did not look right to them."

The FAA's alert emphasized using monitoring and CRM as risk-mitigation tools. The agency also underscored the importance of pre-flight briefings to cover topics such as notices to airmen and expected airfield configurations, and monitoring ATIS messages while approaching the airport.

"If something does not look correct, the observing crewmember bears the responsibility for communicating what they see," the FAA said. "The key behind successful CRM is being receptive, informative, proactive, and persistent. CRM also delineates job functions and the expectation of support."

The captain, who has accumulated about 20,000 total flight hours, served as the pilot flying. The first officer has flown about 10,000 hours.