A320 first officer reported several autoflight anomalies on a night visual approach to sfo that; if ...

Narrative:

We contacted norcal approach descending into sfo. We were assigned the quiet bridge visual to 28L. Since this approach is not in the database we asked for the FMS RNAV approach. Norcal said we could fly this but it would have to be to 28L since 28R was closed. We were high at the start of the approach but quickly got closer to the lowest altitudes on the RNAV approach. After descending to the lowest altitude on the approach; about 1;200 ft over the bridge; the captain switched our approach to the 28L ILS to give me backup navigation since it was night time VFR. At that point the FD kept showing a descent as I was trying to level off at 1;200 ft until the last point on the RNAV (approximately over the bridge). The autothrottles were not adding power even though I was pulling back on the stick trying to level off. This resulted in us descending slightly below the last altitude of 1180 as I was trying to move over to the 28L. At that point I got a 'glideslope' alarm from the aircraft (GPWS). The FD was trying to get me to go lower even though the VASI was showing that I was below the glideslope already. I leveled off and caught both the localizer and glideslope. We landed with no further incident.

Original NASA ASRS Text

Title: A320 First Officer reported several autoflight anomalies on a night visual approach to SFO that; if uncorrected; would have taken the flight into a CFIT situation.

Narrative: We contacted NorCal Approach descending into SFO. We were assigned the Quiet Bridge Visual to 28L. Since this approach is not in the database we asked for the FMS RNAV approach. NorCal said we could fly this but it would have to be to 28L since 28R was closed. We were high at the start of the approach but quickly got closer to the lowest altitudes on the RNAV approach. After descending to the lowest altitude on the approach; about 1;200 FT over the bridge; the Captain switched our approach to the 28L ILS to give me backup navigation since it was night time VFR. At that point the FD kept showing a descent as I was trying to level off at 1;200 FT until the last point on the RNAV (approximately over the bridge). The autothrottles were not adding power even though I was pulling back on the stick trying to level off. This resulted in us descending slightly below the last altitude of 1180 as I was trying to move over to the 28L. At that point I got a 'glideslope' alarm from the aircraft (GPWS). The FD was trying to get me to go lower even though the VASI was showing that I was below the glideslope already. I leveled off and caught both the localizer and glideslope. We landed with no further incident.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1122804
Time
Date	201310
Place
Locale Reference	SFO.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Person 1
Function	First Officer Pilot Flying
Experience	Flight Crew Last 90 Days 270 Flight Crew Total 16600 Flight Crew Type 11000
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

A320 first officer reported several autoflight anomalies on a night visual approach to sfo that; if uncorrected; would have taken the flight into a CFIT situation.