The Federal Aviation Administration issued the recommendation on Sunday involving main runways at the airport, saying in a statement that it took the action after noticing an increase in aborted landings by some foreign carriers flying visual approaches into the airport.
Pilots on Asiana Airlines Flight 214 had been cleared to make a visual approach when the plane crash-landed on July 6. Three people died, and 180 others were injured among the 307 aboard the flight that came in too low and too slow, slamming its landing gear into a seawall well before the actual runway.
Seconds before the accident, the pilots called for a go-around, meaning they wanted to abort the landing and circle for another approach. The FAA said such maneuvers are "routine, standardized procedures that can occur once a day or more at busy airports for various reasons."
Two weeks after the crash, another Asiana flight aborted its landing, San Francisco airport officials said. In addition, they said a Taiwanese EVA Air flight approached too low last week then aborted and began another approach.
The FAA said it was investigating the EVA flight. It did not say how many other such incidents have occurred.
Airport officials met with Asiana managers and FAA representatives after the July 19 aborted landing by the Asiana aircraft to see if any additional measures were necessary, airport spokesman Doug Yakel said.
Sen. Dianne Feinstein also has met with federal and local officials about improving airport safety. Spokesman Brian Weiss said Monday that Feinstein also spoke with the South Korea ambassador. Asiana is based in that country.
In clear weather, it's not unusual for pilots to make a visual approach, using the view through their windshield.
They also can use an instrument system called a glide slope indicator, although that has been out of service in San Francisco since June 1 because of ongoing runway improvements.
The FAA said all foreign carriers should continue to use alternate instrument approaches until the glide slopes return to service in late August.
The advice came from "an abundance of caution," the FAA said in its statement. However, it's not a requirement. Foreign pilots can choose to fly visual approaches, but they typically accept air traffic control assignments.