Narrative:

The aircraft was being vectored by ATC to intercept the inbound course of the VOR approach to smo. An intercept angle of approximately 90 degrees to the inbound course was issued, as well as a clearance to commence the VOR approach (212 degrees inbound). At this time, the controller also issued a clearance to descend from 7000 ft and the aircraft was between darts (12.8 DME) and bevey (6.7 DME). The PF was initially using the autoplt and selected the 'approach mode' once cleared for the approach, to effect an inbound course intercept, instead of the 'navigation' function on the FMS. When the inbound course failed to capture, the PF disconnected the autoplt and hand-flew the aircraft to reintercept the inbound course. The aircraft descent was continued inside bevey towards culve (2.4 DME and 1120 ft minimum altitude). At this time, the CDI was centered and the aircraft was in VFR conditions at approximately 1600 ft. The PF inadvertently descended to about 1050 ft before reaching culve and the PNF called out 'low altitude.' the PF immediately commenced a recovery to the proper altitude of 1120 ft, at which time ATC radioed 'low altitude alert, minimum altitude to culve is 1120 ft, check your equipment.' PNF responded 'roger' as the aircraft had already recovered to the appropriate altitude of 1120 ft. The attention of the PF had been diverted from the normal sequences by not having properly armed the 'navigation' function of the FMS to facilitate the capture of the inbound course. Inattn to the altitude restr, while focusing on course correction, caused the slight altitude deviation. Additionally, the descent into VFR conditions may have contributed to the relaxation of altitude scan.

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Original NASA ASRS Text

Title: A CPR JET PIC DSNDS BELOW THE ASSIGNED ALT REQUIRED FOR CULVE INTXN DURING AN INST APCH NEAR SMO, CA.

Narrative: THE ACFT WAS BEING VECTORED BY ATC TO INTERCEPT THE INBOUND COURSE OF THE VOR APCH TO SMO. AN INTERCEPT ANGLE OF APPROX 90 DEGS TO THE INBOUND COURSE WAS ISSUED, AS WELL AS A CLRNC TO COMMENCE THE VOR APCH (212 DEGS INBOUND). AT THIS TIME, THE CTLR ALSO ISSUED A CLRNC TO DSND FROM 7000 FT AND THE ACFT WAS BTWN DARTS (12.8 DME) AND BEVEY (6.7 DME). THE PF WAS INITIALLY USING THE AUTOPLT AND SELECTED THE 'APCH MODE' ONCE CLRED FOR THE APCH, TO EFFECT AN INBOUND COURSE INTERCEPT, INSTEAD OF THE 'NAV' FUNCTION ON THE FMS. WHEN THE INBOUND COURSE FAILED TO CAPTURE, THE PF DISCONNECTED THE AUTOPLT AND HAND-FLEW THE ACFT TO REINTERCEPT THE INBOUND COURSE. THE ACFT DSCNT WAS CONTINUED INSIDE BEVEY TOWARDS CULVE (2.4 DME AND 1120 FT MINIMUM ALT). AT THIS TIME, THE CDI WAS CTRED AND THE ACFT WAS IN VFR CONDITIONS AT APPROX 1600 FT. THE PF INADVERTENTLY DSNDED TO ABOUT 1050 FT BEFORE REACHING CULVE AND THE PNF CALLED OUT 'LOW ALT.' THE PF IMMEDIATELY COMMENCED A RECOVERY TO THE PROPER ALT OF 1120 FT, AT WHICH TIME ATC RADIOED 'LOW ALT ALERT, MINIMUM ALT TO CULVE IS 1120 FT, CHK YOUR EQUIP.' PNF RESPONDED 'ROGER' AS THE ACFT HAD ALREADY RECOVERED TO THE APPROPRIATE ALT OF 1120 FT. THE ATTN OF THE PF HAD BEEN DIVERTED FROM THE NORMAL SEQUENCES BY NOT HAVING PROPERLY ARMED THE 'NAV' FUNCTION OF THE FMS TO FACILITATE THE CAPTURE OF THE INBOUND COURSE. INATTN TO THE ALT RESTR, WHILE FOCUSING ON COURSE CORRECTION, CAUSED THE SLIGHT ALTDEV. ADDITIONALLY, THE DSCNT INTO VFR CONDITIONS MAY HAVE CONTRIBUTED TO THE RELAXATION OF ALT SCAN.

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.