Narrative:

Our military DC9 was cited by ZLA for a pilot deviation near ipl while en route to njk. En route, ZLA issued us a descent clearance from FL330 down to 9000 ft MSL and changed our fpr by adding the ipl VORTAC along our planned route between gwire and njk. It was a beautiful VFR day in the southwest desert east of san diego, ca, and we were planning to request a visual approach since we could see the field from approximately 30 mi out. I was at the controls, autoplt engaged, using our universal FMS for navigation between pdz and gwire along J93. I drifted 1.2 mi left of course and was instructed to turn 15 degrees right to remain clear of restr airspace just north of njk. We were subsequently placed on a vector to keep us clear of the restr airspace. As these events were transpiring, we had been discussing our options to execute a visual to runway 26. Within 50 NM, we received ATIS and discovered runway 8 was in use. Our approach plates did not depict an approach to this runway, so we were definitely in for a visual approach. As we headed south, passing the field at 12000 ft MSL and approximately 15 mi to the west, talk of being high and close and our maneuver path to final elevated. Passing gwire, I asked the aircraft commander to verify the vector that would take us into mexican airspace. Our plan was to circle around to come in from the south over ipl as cleared to enter the downwind. The aircraft commander made a radio call to center stating we had the field in sight and reminded center we were on a vector. We were still in our descent passing 10500 ft at 250 KTS. The controller, who had apparently gotten busy with someone else on another frequency, then cleared us direct to njk without an altitude assignment. As center issued their clearance direct njk, I disconnected the autoplt and began a turn to the left to proceed as cleared. We received a call from the controller alerting us to traffic at 10-11 O'clock position, a helicopter at 8000 ft almost immediately after our clearance to the field, and went heads up for visual acquisition. A quick glance at TCASII verified the traffic we had in sight was not a factor, and the aircraft commander called the traffic to center as I continued my left turn with traffic holding steady on the left wing. Concentrating on my traffic separation while maneuvering to the field, I allowed the aircraft to descend below 9000 ft MSL. Out of habit, expectation and anticipation, both of us thought we were cleared for a visual approach. Over the course of planning on the long vector past the field in a high position, our perception of being out of a normal position to make a visual approach led us to anticipate the controller's instructions. The major problem was hearing the inflection of surprise in the controller's voice that he had forgotten us for a few moments, followed by his quick 'cleared direct el centro traffic 1O - 11 O'clock....' without a new altitude assignment on this amended clearance, we were both led down the path to an assumed clearance for a visual approach. Other contributing factors to the deviation were our situational awareness, heads out of the cockpit, looking down at traffic while in a turn with the autoplt off. Our situational awareness elevated the anticipation of a visual approach due to the proximity to the field, while the physical act of turning the aircraft left and looking down forced me into an unconscious gradual descent below our altitude restr. The simple solution is to verify altitudes and clrncs with controllers before deviating. We have checks and balances in our standard procedures to protect us from these incidents occurring such as altitude awareness programs, voice callouts and switch positioning to remind us of our clearance. Sticking to these basic fundamentals can virtually eliminate any deviation.

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Original NASA ASRS Text

Title: MIL DC9 CREW HAD ALTDEV IN ZLA CLASS E AIRSPACE.

Narrative: OUR MIL DC9 WAS CITED BY ZLA FOR A PLTDEV NEAR IPL WHILE ENRTE TO NJK. ENRTE, ZLA ISSUED US A DSCNT CLRNC FROM FL330 DOWN TO 9000 FT MSL AND CHANGED OUR FPR BY ADDING THE IPL VORTAC ALONG OUR PLANNED RTE BTWN GWIRE AND NJK. IT WAS A BEAUTIFUL VFR DAY IN THE SW DESERT E OF SAN DIEGO, CA, AND WE WERE PLANNING TO REQUEST A VISUAL APCH SINCE WE COULD SEE THE FIELD FROM APPROX 30 MI OUT. I WAS AT THE CTLS, AUTOPLT ENGAGED, USING OUR UNIVERSAL FMS FOR NAV BTWN PDZ AND GWIRE ALONG J93. I DRIFTED 1.2 MI L OF COURSE AND WAS INSTRUCTED TO TURN 15 DEGS R TO REMAIN CLR OF RESTR AIRSPACE JUST N OF NJK. WE WERE SUBSEQUENTLY PLACED ON A VECTOR TO KEEP US CLR OF THE RESTR AIRSPACE. AS THESE EVENTS WERE TRANSPIRING, WE HAD BEEN DISCUSSING OUR OPTIONS TO EXECUTE A VISUAL TO RWY 26. WITHIN 50 NM, WE RECEIVED ATIS AND DISCOVERED RWY 8 WAS IN USE. OUR APCH PLATES DID NOT DEPICT AN APCH TO THIS RWY, SO WE WERE DEFINITELY IN FOR A VISUAL APCH. AS WE HEADED S, PASSING THE FIELD AT 12000 FT MSL AND APPROX 15 MI TO THE W, TALK OF BEING HIGH AND CLOSE AND OUR MANEUVER PATH TO FINAL ELEVATED. PASSING GWIRE, I ASKED THE ACFT COMMANDER TO VERIFY THE VECTOR THAT WOULD TAKE US INTO MEXICAN AIRSPACE. OUR PLAN WAS TO CIRCLE AROUND TO COME IN FROM THE S OVER IPL AS CLRED TO ENTER THE DOWNWIND. THE ACFT COMMANDER MADE A RADIO CALL TO CTR STATING WE HAD THE FIELD IN SIGHT AND REMINDED CTR WE WERE ON A VECTOR. WE WERE STILL IN OUR DSCNT PASSING 10500 FT AT 250 KTS. THE CTLR, WHO HAD APPARENTLY GOTTEN BUSY WITH SOMEONE ELSE ON ANOTHER FREQ, THEN CLRED US DIRECT TO NJK WITHOUT AN ALT ASSIGNMENT. AS CTR ISSUED THEIR CLRNC DIRECT NJK, I DISCONNECTED THE AUTOPLT AND BEGAN A TURN TO THE L TO PROCEED AS CLRED. WE RECEIVED A CALL FROM THE CTLR ALERTING US TO TFC AT 10-11 O'CLOCK POS, A HELI AT 8000 FT ALMOST IMMEDIATELY AFTER OUR CLRNC TO THE FIELD, AND WENT HEADS UP FOR VISUAL ACQUISITION. A QUICK GLANCE AT TCASII VERIFIED THE TFC WE HAD IN SIGHT WAS NOT A FACTOR, AND THE ACFT COMMANDER CALLED THE TFC TO CTR AS I CONTINUED MY L TURN WITH TFC HOLDING STEADY ON THE L WING. CONCENTRATING ON MY TFC SEPARATION WHILE MANEUVERING TO THE FIELD, I ALLOWED THE ACFT TO DSND BELOW 9000 FT MSL. OUT OF HABIT, EXPECTATION AND ANTICIPATION, BOTH OF US THOUGHT WE WERE CLRED FOR A VISUAL APCH. OVER THE COURSE OF PLANNING ON THE LONG VECTOR PAST THE FIELD IN A HIGH POS, OUR PERCEPTION OF BEING OUT OF A NORMAL POS TO MAKE A VISUAL APCH LED US TO ANTICIPATE THE CTLR'S INSTRUCTIONS. THE MAJOR PROB WAS HEARING THE INFLECTION OF SURPRISE IN THE CTLR'S VOICE THAT HE HAD FORGOTTEN US FOR A FEW MOMENTS, FOLLOWED BY HIS QUICK 'CLRED DIRECT EL CENTRO TFC 1O - 11 O'CLOCK....' WITHOUT A NEW ALT ASSIGNMENT ON THIS AMENDED CLRNC, WE WERE BOTH LED DOWN THE PATH TO AN ASSUMED CLRNC FOR A VISUAL APCH. OTHER CONTRIBUTING FACTORS TO THE DEV WERE OUR SITUATIONAL AWARENESS, HEADS OUT OF THE COCKPIT, LOOKING DOWN AT TFC WHILE IN A TURN WITH THE AUTOPLT OFF. OUR SITUATIONAL AWARENESS ELEVATED THE ANTICIPATION OF A VISUAL APCH DUE TO THE PROX TO THE FIELD, WHILE THE PHYSICAL ACT OF TURNING THE ACFT L AND LOOKING DOWN FORCED ME INTO AN UNCONSCIOUS GRADUAL DSCNT BELOW OUR ALT RESTR. THE SIMPLE SOLUTION IS TO VERIFY ALTS AND CLRNCS WITH CTLRS BEFORE DEVIATING. WE HAVE CHKS AND BALS IN OUR STANDARD PROCS TO PROTECT US FROM THESE INCIDENTS OCCURRING SUCH AS ALT AWARENESS PROGRAMS, VOICE CALLOUTS AND SWITCH POSITIONING TO REMIND US OF OUR CLRNC. STICKING TO THESE BASIC FUNDAMENTALS CAN VIRTUALLY ELIMINATE ANY DEV.

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.