A320
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 7
Other / Unknown
Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Overshoot; Deviation - Track / Heading All Types; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Returned To Clearance
Aircraft; ATC Equipment / Nav Facility / Buildings; Human Factors
I was working the Mulford/Grove combined sector for the Oakland final on an odd configuration. No aircraft could land on our long runway; Runway 30; and we were forced to land air carriers on our shorter runways; runways 28 left and right. An A320 was cleared for the RNAV Runway 28L approach into OAK; about 7 miles from JUPAP; told to cross JUPAP at or above 3;700 as published. About a mile prior to JUPAP the A320 started a right turn about 10-20 degrees right of course but continued to descend as if on the profile. I told the A320 he appeared right of course and to say intentions. The A320 indicated he was turning back to course; I observed him descend below the MVA and still heading right of course not correcting. I issued a Low Altitude Alert; climbed the A320 to the MVA and then resequenced him for the ILS Runway 28R. The A320 landed without incident. I was later informed that a pilot deviation was filed against the pilot; which I do not think is necessary. Also to note is that I believe this was during a period where we had NOTAMs out for GPS unreliable; but I cannot confirm because accurate records are not kept for when NOTAMs are canceled. I do not have a fix recommendation as I still do not know why the error occurred.
NCT Controller reports an A320 crew descending early and deviating from the RNAV (GPS) Y Runway 28L course during approach to OAK. The crew is queried then issued a low altitude alert and the approach is continued to landing. A NOTAM for GPS unreliable may have been in effect at the time of the incident.