Instrument rated private pilot of a C182 descended below assigned altitude prior to established on f...

Attributes
ACN	414220
Time
Date	199809
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : smo
State Reference	CA
Altitude	msl bound lower : 2400 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : lax artcc : mem
Operator	general aviation : personal
Make Model Name	Skylane 182/RG Turbo Skylane/RG
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 47 flight time total : 250 flight time type : 16
ASRS Report	414220
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was on an IFR flight plan from the bay area to santa monica (smo). I experienced intermittent problems with the transponder and #1 navigation radio. The flight was fairly uneventful until approach into smo. While being vectored for the VOR approach to runway 21, radar contact was temporarily lost resulting in a late vector to intercept the final approach course. I was cleared for the approach and told to remain at 3000 ft MSL until on course. I turned right to intercept the course. The needle on the #1 navigation remained pegged to the right even after I was certain I had flown through the final approach course. I began a slow turn to the left hoping to reintercept the approach and commented to my passenger that the radio appeared to be malfunctioning. The needle moved toward the center and I began a descent. Before the needle had completely centered, the 'navigation off' flag sporadically appeared on the #1 navigation. I dialed the frequency and course into the #2 navigation but, during the process, deviated to the left of course and was at 2400 ft MSL without actually being established on the final approach course. The controller asked if I had the airport in sight, to which I replied affirmative. However, it was very hazy and I was unfamiliar with the area. I became less certain that I was actually looking at the airport and asked the controller for a vector. By this time, I had traveled closer to the airport and determined that I actually did have the airport in sight. I was cleared to land and did so without incident. In retrospect, I should have had the #2 navigation also set to the approach course which would have allowed for an easy switch to the #2 once it appeared the #1 navigation was not functioning properly. Also, after a late vector to the final approach course, I let my desire to 'catch up' influence my decision to begin my descent prior to being fully established on course. I was also too anxious to confirm having the airport in sight.

Original NASA ASRS Text

Title: INST RATED PVT PLT OF A C182 DSNDED BELOW ASSIGNED ALT PRIOR TO ESTABLISHED ON FINAL VOR COURSE DUE TO DISTR OF THE FAULTY INDICATION OF THE #1 VOR NAV COURSE INDICATOR AND DIALING IN THE #2 VOR NAV RECEIVER. RPTR WAS ABLE TO SALVAGE THE APCH AND LAND UNEVENTFULLY.

Narrative: I WAS ON AN IFR FLT PLAN FROM THE BAY AREA TO SANTA MONICA (SMO). I EXPERIENCED INTERMITTENT PROBS WITH THE XPONDER AND #1 NAV RADIO. THE FLT WAS FAIRLY UNEVENTFUL UNTIL APCH INTO SMO. WHILE BEING VECTORED FOR THE VOR APCH TO RWY 21, RADAR CONTACT WAS TEMPORARILY LOST RESULTING IN A LATE VECTOR TO INTERCEPT THE FINAL APCH COURSE. I WAS CLRED FOR THE APCH AND TOLD TO REMAIN AT 3000 FT MSL UNTIL ON COURSE. I TURNED R TO INTERCEPT THE COURSE. THE NEEDLE ON THE #1 NAV REMAINED PEGGED TO THE R EVEN AFTER I WAS CERTAIN I HAD FLOWN THROUGH THE FINAL APCH COURSE. I BEGAN A SLOW TURN TO THE L HOPING TO REINTERCEPT THE APCH AND COMMENTED TO MY PAX THAT THE RADIO APPEARED TO BE MALFUNCTIONING. THE NEEDLE MOVED TOWARD THE CTR AND I BEGAN A DSCNT. BEFORE THE NEEDLE HAD COMPLETELY CTRED, THE 'NAV OFF' FLAG SPORADICALLY APPEARED ON THE #1 NAV. I DIALED THE FREQ AND COURSE INTO THE #2 NAV BUT, DURING THE PROCESS, DEVIATED TO THE L OF COURSE AND WAS AT 2400 FT MSL WITHOUT ACTUALLY BEING ESTABLISHED ON THE FINAL APCH COURSE. THE CTLR ASKED IF I HAD THE ARPT IN SIGHT, TO WHICH I REPLIED AFFIRMATIVE. HOWEVER, IT WAS VERY HAZY AND I WAS UNFAMILIAR WITH THE AREA. I BECAME LESS CERTAIN THAT I WAS ACTUALLY LOOKING AT THE ARPT AND ASKED THE CTLR FOR A VECTOR. BY THIS TIME, I HAD TRAVELED CLOSER TO THE ARPT AND DETERMINED THAT I ACTUALLY DID HAVE THE ARPT IN SIGHT. I WAS CLRED TO LAND AND DID SO WITHOUT INCIDENT. IN RETROSPECT, I SHOULD HAVE HAD THE #2 NAV ALSO SET TO THE APCH COURSE WHICH WOULD HAVE ALLOWED FOR AN EASY SWITCH TO THE #2 ONCE IT APPEARED THE #1 NAV WAS NOT FUNCTIONING PROPERLY. ALSO, AFTER A LATE VECTOR TO THE FINAL APCH COURSE, I LET MY DESIRE TO 'CATCH UP' INFLUENCE MY DECISION TO BEGIN MY DSCNT PRIOR TO BEING FULLY ESTABLISHED ON COURSE. I WAS ALSO TOO ANXIOUS TO CONFIRM HAVING THE ARPT IN SIGHT.

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.