Date: 201404
Local time of day: 0601-1200
Location: SFO.Airport, CA
Flight conditions: VMC
Light: Daylight
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B SFO
ATC / advisory: Tower SFO
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Other / Unknown
Second reporter function: Pilot Flying; First Officer
Anomaly: ATC Issue All Types
Detector: Person Air Traffic Control
Result: Air Traffic Control Issued Advisory / Alert
Contributing factors: Human Factors; Procedure
Primary problem: Ambiguous

Narrative: We had been cleared for the FMS Bridge Visual Runway 28R. On the FMS Bridge Visual (RNAV-F) Runway 28R SFO; just after passing SAMUL prior to F101D ATC issued us an 'altitude alert'; he said we were supposed to cross the 'Bridge' at 1;800 FT and said we were low. We were in the APR mode with aircraft having crossed SAMUL at 1;500 FT and descending towards F101D at 1;200 FT. We reconfirmed we were in APR mode with the glide path indicator centered (yes). We had the airport and runway visually and confirmed we were at an appropriate altitude for our position and leveled off at 1;200 FT. We confirmed our altitude and position check with the proper PAPI indications from Runway 28R. Pilot flying disconnected autopilot and we continued our approach to landing Runway 28R. Recalling the Controller's statement of 'required to cross the Bridge at 1;800 FT'; I believe he may have thought us to be on the Quiet Bridge Visual Runway 28R; instead of the FMS Bridge Visual Runway 28R as we were cleared. The crossing altitude for the Quiet Bridge Visual is indeed 1;800 FT at the bridge causing the altitude alert from the Controller. On the FMS Bridge Visual SAMUL is prior to the bridge and crossing altitude is lower at 1;500 FT; so by the time we crossed the bridge we were descending towards the crossing altitude of 1;200 FT at F101D; so of course our altitude was required to be lower than 1;800 FT at the bridge. We had visual contact with the airport; ground and all traffic advised the entire approach; and the procedure was followed both laterally and vertically. Looking back I can see the controllers concern and the different minimum crossing altitudes on the two visual approaches that initiated his alert. We as a crew; verified our position and altitude relative to the airport and the charted approach; the aircrafts status; configuration; and ensured the proper MODE was engaged for the approach. We verbalized to each other proper position and configuration and proceeded with the approach and landing.


Second narrative: Was cleared 'FMS Bridge Visual 28R' and handed off to Tower. Autopilot was engaged and was in 'Final APP' mode. Tower reported 'check altitude ....you were to cross the bridge at 1;800'. We showed we were on profile and following the approach path both by electronic and visual means. No other comments by ATC.


Synopsis: A320 flight crew reports being told they are low passing the bridge on the FMS Bridge Visual 28R approach. The crew does not agree; believing the Controller is confusing the FMS Bridge Visual 28R with the Quiet Bridge Visual Runway 28R; which uses different fixes and crossing altitudes.