Narrative:

This situation happened twice on 2 consecutive days. The first day resulted in ATC asking us our altitude (which was 400' low). Our flight was being radar vectored for a visual approach to runway 25R at lax. The lax approach (north) controller was trying to vector us direct to the airport and close in and high. (This situation will not work for a non-pressurized aircraft.) I was the PNF. ATC instructed us to fly heading 210 we were already cleared to maintain 4000'. We were descending. Traffic was pointed out as 2 O'clock, 10 mi, eastbound. Medium large transport for runway 24R. I reported that aircraft in sight and was instructed to maintain visual separation and pass behind him. My copilot was concerned about our high altitude and closeness to the airport and did not stop descending. I was totally outside the aircraft watching the situation developing. ATC asked us our altitude, at which point, I said 'we're climbing back to 4'. ATC then instructed us to maintain 3500 (we descended to approximately 3600 when asked our altitude). We were then vectored to a 3 mi right base at 3500 and cleared for the visual and advised that a long landing was approved. I advised them we needed a 270. That was approved and a normal landing followed.

Related reports:

Google
 

Original NASA ASRS Text

Title: FLT CREW OF SMT DEVIATED FROM ASSIGNED ALT ON APCH TO LAX CLEARED VISUAL APCH.

Narrative: THIS SITUATION HAPPENED TWICE ON 2 CONSECUTIVE DAYS. THE FIRST DAY RESULTED IN ATC ASKING US OUR ALT (WHICH WAS 400' LOW). OUR FLT WAS BEING RADAR VECTORED FOR A VISUAL APCH TO RWY 25R AT LAX. THE LAX APCH (NORTH) CTLR WAS TRYING TO VECTOR US DIRECT TO THE ARPT AND CLOSE IN AND HIGH. (THIS SITUATION WILL NOT WORK FOR A NON-PRESSURIZED ACFT.) I WAS THE PNF. ATC INSTRUCTED US TO FLY HDG 210 WE WERE ALREADY CLRED TO MAINTAIN 4000'. WE WERE DESCENDING. TFC WAS POINTED OUT AS 2 O'CLOCK, 10 MI, EBND. MLG FOR RWY 24R. I REPORTED THAT ACFT IN SIGHT AND WAS INSTRUCTED TO MAINTAIN VISUAL SEPARATION AND PASS BEHIND HIM. MY COPLT WAS CONCERNED ABOUT OUR HIGH ALT AND CLOSENESS TO THE ARPT AND DID NOT STOP DESCENDING. I WAS TOTALLY OUTSIDE THE ACFT WATCHING THE SITUATION DEVELOPING. ATC ASKED US OUR ALT, AT WHICH POINT, I SAID 'WE'RE CLIMBING BACK TO 4'. ATC THEN INSTRUCTED US TO MAINTAIN 3500 (WE DESCENDED TO APPROX 3600 WHEN ASKED OUR ALT). WE WERE THEN VECTORED TO A 3 MI RIGHT BASE AT 3500 AND CLRED FOR THE VISUAL AND ADVISED THAT A LONG LNDG WAS APPROVED. I ADVISED THEM WE NEEDED A 270. THAT WAS APPROVED AND A NORMAL LNDG FOLLOWED.

Data retrieved from NASA's ASRS site as of August 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.