Most of the errors have happened at night and in the winter when aircraft must descend through clouds on final approach.
In daylight, it's fairly easy to spot the differences between Mineta San Jose and Moffett Field. The large hangars at Moffett are distinctive. But at night, landmarks on the ground are difficult to spot, and pilots are focusing on landing approach lights.
"You're coming in here, and there are two airports fairly close together with similar approaches, and if you're in a fast-moving aircraft, the difference between being here and being here is only a matter of a minute," Hilller Aviation Museum CEO Jeffrey Bass said.
Commercial aircraft have made that mistake, preparing to land at Moffett instead of San Jose, six times in the past dozen years or so, according to online data. But not all errors of this nature are reported. And the Federal Aviation Administration would not confirm that number.
The FAA pointed out there were no injuries or damage to the aircraft. It further said, "The FAA's new pilot qualifications and training rules will continue to help ensure that the best qualified and trained pilots are operating the flight decks of U.S. commercial airplanes."
Pilots do have to guard against distractions, caused by lights on the ground -- called illusions.
"Even a string of lights down a road can actually be momentarily confusing for a pilot," Bass said. "Any time there's a string of lights is anywhere, it pops up in your mind -- is that an airport? Is that a runway?"
Retired commercial airline Capt. Dick Deeds says familiarity with an airport makes a difference.
"Being familiar with the route is a big thing, I think," he said. "These kinds of errors made under visual conditions are generally by somebody unfamiliar with the area."
