Narrative:

Sfo-lax, followed the 24/25 profile descent over santa monica VOR for vectors to a visibility approach to runway 24R. The ATIS stated high cloudiness, 7 mi visibility. While on a high right downwind, we could see the airport and the assigned runway, but were hesitant to declare 'runway in sight' because of some low clouds to the north and east of lax. When we mentioned this concern to the approach controller, he responded that 'everyone' could complete the visibility approach. I then accepted the clearance for a visibility. Almost immediately, we were turned to a southerly heading and cleared for this visibility and to switch over to tower frequency. We were, at this point, close in and high; all radios and instruments were set, tuned and idented to receive and use the LOM and 24R ILS and we were intercepting from above and from the north. At the time of change over to 'tower' and just inside romen LOM, a low cloud deck obscured view of runways. I instructed the first officer to check in with 'tower' with the statement that we needed to use the ILS. The response came in two consecutive, and somewhat confusing, instructions; 'maintain (intercept) heading and 2000'', followed almost immediately by 'continue the approach'. With this, I continued my intercept of the ILS and descended to +/- 1400' before we received the instruction to fly 250 degree and maintain 2000'. After we stated that this would not get us to the runway, 'tower' mentioned that these instructions were for a missed approach. Approach control may not have been aware of the low cloud deck and was 'pushing' visuals. I accepted because I felt ill-equipped to doubt the controller's expertise. Time and our position pushed both the tower controller and me into a corner and I, in retrospect, should have initiated a miss at first observation of the obstruction. Instead, and as a result of instructions that were not fully clear, I descended below the earlier stated 2000', possibly in violation of the controller's intentions.

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Original NASA ASRS Text

Title: ACR LGT ALT DEVIATE EXCURSION FROM CLRNC ALT ON VISUAL APCH TO LAX.

Narrative: SFO-LAX, FOLLOWED THE 24/25 PROFILE DSNT OVER SANTA MONICA VOR FOR VECTORS TO A VIS APCH TO RWY 24R. THE ATIS STATED HIGH CLOUDINESS, 7 MI VISIBILITY. WHILE ON A HIGH R DOWNWIND, WE COULD SEE THE ARPT AND THE ASSIGNED RWY, BUT WERE HESITANT TO DECLARE 'RWY IN SIGHT' BECAUSE OF SOME LOW CLOUDS TO THE N AND E OF LAX. WHEN WE MENTIONED THIS CONCERN TO THE APCH CTLR, HE RESPONDED THAT 'EVERYONE' COULD COMPLETE THE VIS APCH. I THEN ACCEPTED THE CLRNC FOR A VIS. ALMOST IMMEDIATELY, WE WERE TURNED TO A SOUTHERLY HDG AND CLRED FOR THIS VIS AND TO SWITCH OVER TO TWR FREQ. WE WERE, AT THIS POINT, CLOSE IN AND HIGH; ALL RADIOS AND INSTRUMENTS WERE SET, TUNED AND IDENTED TO RECEIVE AND USE THE LOM AND 24R ILS AND WE WERE INTERCEPTING FROM ABOVE AND FROM THE N. AT THE TIME OF CHANGE OVER TO 'TWR' AND JUST INSIDE ROMEN LOM, A LOW CLOUD DECK OBSCURED VIEW OF RWYS. I INSTRUCTED THE F/O TO CHK IN WITH 'TWR' WITH THE STATEMENT THAT WE NEEDED TO USE THE ILS. THE RESPONSE CAME IN TWO CONSECUTIVE, AND SOMEWHAT CONFUSING, INSTRUCTIONS; 'MAINTAIN (INTERCEPT) HDG AND 2000'', FOLLOWED ALMOST IMMEDIATELY BY 'CONTINUE THE APCH'. WITH THIS, I CONTINUED MY INTERCEPT OF THE ILS AND DSNDED TO +/- 1400' BEFORE WE RECEIVED THE INSTRUCTION TO FLY 250 DEG AND MAINTAIN 2000'. AFTER WE STATED THAT THIS WOULD NOT GET US TO THE RWY, 'TWR' MENTIONED THAT THESE INSTRUCTIONS WERE FOR A MISSED APCH. APCH CTL MAY NOT HAVE BEEN AWARE OF THE LOW CLOUD DECK AND WAS 'PUSHING' VISUALS. I ACCEPTED BECAUSE I FELT ILL-EQUIPPED TO DOUBT THE CTLR'S EXPERTISE. TIME AND OUR POS PUSHED BOTH THE TWR CTLR AND ME INTO A CORNER AND I, IN RETROSPECT, SHOULD HAVE INITIATED A MISS AT FIRST OBSERVATION OF THE OBSTRUCTION. INSTEAD, AND AS A RESULT OF INSTRUCTIONS THAT WERE NOT FULLY CLR, I DSNDED BELOW THE EARLIER STATED 2000', POSSIBLY IN VIOLATION OF THE CTLR'S INTENTIONS.

Data retrieved from NASA's ASRS site as of July 2007 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.