Pilot of light twin engine aircraft descends below clearance altitude and MEA.

Attributes
ACN	121377
Time
Date	198908
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : hdf airport : sna
State Reference	CA
Altitude	msl bound lower : 7600 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : ont
Operator	general aviation : instructional
Make Model Name	Small Aircraft, Low Wing, 2 Eng, Retractable Gear
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : cfi pilot : instrument
Experience	flight time last 90 days : 250 flight time total : 780 flight time type : 30
ASRS Report	121377
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	non adherence : clearance non adherence : published procedure other anomaly
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

En route from north las vegas to santa ana, I was radar vectored from V283 north of homeland VOR to V283 west of homeland, and being stepped-down from 12,000 MSL. Accustomed to a rapid descent in this area, when I was advised to 'turn right...intercept the 075 radial of sli...caution traffic...at 7000...', I acknowledged, turned right, adjusted the obs, and continued my descent out of 10,000. I had the traffic in sight and determined it was not a factor. But, at 7600 MSL, the controller reminded me that my last assigned altitude was 8000. I advised the controller that I understood my new assigned altitude to be 7000, but complied with her request for 8000. After landing, I realized that the MEA for that area is, indeed, 8000, and that I must have mistaken the reported altitude of my traffic for my assigned altitude. I had my area chart in front of me at the time of the occurrence, but evidently, in the dark, did not notice the charted MEA. I was, instead, relying on the vectors received from the controller which, in this case, I misunderstood.

Original NASA ASRS Text

Title: PLT OF LIGHT TWIN ENGINE ACFT DESCENDS BELOW CLRNC ALT AND MEA.

Narrative: ENRTE FROM NORTH LAS VEGAS TO SANTA ANA, I WAS RADAR VECTORED FROM V283 N OF HOMELAND VOR TO V283 W OF HOMELAND, AND BEING STEPPED-DOWN FROM 12,000 MSL. ACCUSTOMED TO A RAPID DSCNT IN THIS AREA, WHEN I WAS ADVISED TO 'TURN RIGHT...INTERCEPT THE 075 RADIAL OF SLI...CAUTION TFC...AT 7000...', I ACKNOWLEDGED, TURNED RIGHT, ADJUSTED THE OBS, AND CONTINUED MY DSCNT OUT OF 10,000. I HAD THE TFC IN SIGHT AND DETERMINED IT WAS NOT A FACTOR. BUT, AT 7600 MSL, THE CTLR REMINDED ME THAT MY LAST ASSIGNED ALT WAS 8000. I ADVISED THE CTLR THAT I UNDERSTOOD MY NEW ASSIGNED ALT TO BE 7000, BUT COMPLIED WITH HER REQUEST FOR 8000. AFTER LNDG, I REALIZED THAT THE MEA FOR THAT AREA IS, INDEED, 8000, AND THAT I MUST HAVE MISTAKEN THE REPORTED ALT OF MY TFC FOR MY ASSIGNED ALT. I HAD MY AREA CHART IN FRONT OF ME AT THE TIME OF THE OCCURRENCE, BUT EVIDENTLY, IN THE DARK, DID NOT NOTICE THE CHARTED MEA. I WAS, INSTEAD, RELYING ON THE VECTORS RECEIVED FROM THE CTLR WHICH, IN THIS CASE, I MISUNDERSTOOD.

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.