Narrative:

Traffic was moderate but complex with a recently certified controller working the 28/28 shoreline configuration. There were closely spaced parallel approaches to both 28L and 28R. In the middle of the traffic; a B737 got a low altitude alert and without hesitation the local controller issued a low altitude alert and advised the pilot to check their altitude immediately. I assumed it was an anomaly since they had the field in sight below about 1;400 feet at the time. The B737 crew immediately came back and said they were correcting. This surprised me. Their altitude was not far off of the expected altitude for the segment of flight. I still wonder if they were low or our equipment was faulty.

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Original NASA ASRS Text

Title: A Tower Controller describes a low altitude alert issued by a newly certified Local Controller to a B737 on short final. The altitude did not seem far off and the reporter wondered if the equipment may have been faulty; but the crew acknowledged the deviation.

Narrative: Traffic was moderate but complex with a recently certified controller working the 28/28 shoreline configuration. There were closely spaced parallel approaches to both 28L and 28R. In the middle of the traffic; a B737 got a low altitude alert and without hesitation the local controller issued a low altitude alert and advised the pilot to check their altitude immediately. I assumed it was an anomaly since they had the field in sight below about 1;400 feet at the time. The B737 crew immediately came back and said they were correcting. This surprised me. Their altitude was not far off of the expected altitude for the segment of flight. I still wonder if they were low or our equipment was faulty.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.