Small aircraft descended below assigned altitude resulting in less than standard separation.

Attributes
ACN	137689
Time
Date	199001
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sli
State Reference	CA
Altitude	msl bound lower : 5500 msl bound upper : 6000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	descent other
Route In Use	enroute airway : sna
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument
Experience	flight time last 90 days : 40 flight time total : 800 flight time type : 300
ASRS Report	137689
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance
Consequence	faa : assigned or threatened penalties
Miss Distance	horizontal : 6000 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

WX en route to torrance called for isolated thunderstorms with mountain obscurement, light rime icing with the tops at 14000. I filed IFR at 12000'. Calexico was VFR and I departed as such and picked up my clearance and climbed to my assigned altitude. Sometime past oceanside VOR I was cleared to 6000'. I was at that altitude for some period of time and I was about 25 mi south of seal beach on V-273 and the coast approach controller told me to expect ILS runway 29R. Shortly thereafter the controller told me to descend at pilot's discretion. I answered and thought it a little strange that the airway was open from 6000 to the MEA which was 3000 to seal beach. I answered. I began a descent and reaching 5500 I got a call from the controller that I had deviated from assigned altitude, and gave me a vector to clear conflicting traffic. I had visual separation from the conflicting traffic, an small aircraft southbound at 5500. I informed the controller that I had been told to descend at pilot's discretion. Upon landing I was told to call coast TRACON. Upon reaching home I called coast and relayed the above to the operations manager. He informed me that he would have to review the tapes, and once that was done he would give me a call back to discuss the matter further. I never received a call back and assumed that the matter was taken care of. On 2/xx/90 I received a call from (name) of the FAA long beach FSDO. He stated that they had sent me a certified letter but it had been sent back because they had addressed the envelope incorrectly. He stated that his primary investigation of the matter including reviewing the tapes showed that I had not been given a clearance to descend at pilot's discretion. I asked him to please review the tapes again and call me back as I had a witness who had heard the clearance also. Later that day he called me back and stated that he had re-reviewed the tapes and had not found the clearance. I then asked him if I could review the tapes. The case is being sent to the FAA for prosecution and possible sanctions!

Original NASA ASRS Text

Title: SMA DESCENDED BELOW ASSIGNED ALT RESULTING IN LESS THAN STANDARD SEPARATION.

Narrative: WX ENRTE TO TORRANCE CALLED FOR ISOLATED TSTMS WITH MOUNTAIN OBSCUREMENT, LIGHT RIME ICING WITH THE TOPS AT 14000. I FILED IFR AT 12000'. CALEXICO WAS VFR AND I DEPARTED AS SUCH AND PICKED UP MY CLRNC AND CLIMBED TO MY ASSIGNED ALT. SOMETIME PAST OCEANSIDE VOR I WAS CLRED TO 6000'. I WAS AT THAT ALT FOR SOME PERIOD OF TIME AND I WAS ABOUT 25 MI S OF SEAL BEACH ON V-273 AND THE COAST APCH CTLR TOLD ME TO EXPECT ILS RWY 29R. SHORTLY THEREAFTER THE CTLR TOLD ME TO DSND AT PLT'S DISCRETION. I ANSWERED AND THOUGHT IT A LITTLE STRANGE THAT THE AIRWAY WAS OPEN FROM 6000 TO THE MEA WHICH WAS 3000 TO SEAL BEACH. I ANSWERED. I BEGAN A DSCNT AND REACHING 5500 I GOT A CALL FROM THE CTLR THAT I HAD DEVIATED FROM ASSIGNED ALT, AND GAVE ME A VECTOR TO CLEAR CONFLICTING TFC. I HAD VISUAL SEPARATION FROM THE CONFLICTING TFC, AN SMA SBND AT 5500. I INFORMED THE CTLR THAT I HAD BEEN TOLD TO DSND AT PLT'S DISCRETION. UPON LNDG I WAS TOLD TO CALL COAST TRACON. UPON REACHING HOME I CALLED COAST AND RELAYED THE ABOVE TO THE OPERATIONS MGR. HE INFORMED ME THAT HE WOULD HAVE TO REVIEW THE TAPES, AND ONCE THAT WAS DONE HE WOULD GIVE ME A CALL BACK TO DISCUSS THE MATTER FURTHER. I NEVER RECEIVED A CALL BACK AND ASSUMED THAT THE MATTER WAS TAKEN CARE OF. ON 2/XX/90 I RECEIVED A CALL FROM (NAME) OF THE FAA LONG BEACH FSDO. HE STATED THAT THEY HAD SENT ME A CERTIFIED LETTER BUT IT HAD BEEN SENT BACK BECAUSE THEY HAD ADDRESSED THE ENVELOPE INCORRECTLY. HE STATED THAT HIS PRIMARY INVESTIGATION OF THE MATTER INCLUDING REVIEWING THE TAPES SHOWED THAT I HAD NOT BEEN GIVEN A CLRNC TO DSND AT PLT'S DISCRETION. I ASKED HIM TO PLEASE REVIEW THE TAPES AGAIN AND CALL ME BACK AS I HAD A WITNESS WHO HAD HEARD THE CLRNC ALSO. LATER THAT DAY HE CALLED ME BACK AND STATED THAT HE HAD RE-REVIEWED THE TAPES AND HAD NOT FOUND THE CLRNC. I THEN ASKED HIM IF I COULD REVIEW THE TAPES. THE CASE IS BEING SENT TO THE FAA FOR PROSECUTION AND POSSIBLE SANCTIONS!

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.