Narrative:

Flying right seat as flight instrument, transitioning a private pilot to a retractable aircraft. After 1 hour airwork over san joaquin valley, decided to practice lndgs at tracy airport (an uncontrolled field). Monitored unicom, overflew field at 1500' AGL to observe tetrahedron, when voice on radio said, 'tracy traffic, contact tracy tower on 121.2.' 'what tower?', my student and I asked each other. Complying, we were informed of temporary tower staffed by national guard. I asked if an air traffic area was in effect, and was told it was. I reported position (well within air traffic area) and intentions and was cleared to land. Since tracy was not an intended destination, just a spur of the moment training decision, neither student nor instrument had checked NOTAMS. I've been using this uncontrolled field for almost 10 yrs for just such activities, and was shocked to find it suddenly a controled field. National guard temporary activities were unknown to student or instrument. (Afterwards, I checked NOTAMS and sure enough, the information was there!) military controller showed good judgement in making announcement over unicom frequency. He didn't seem perturbed by our appearance in his airspace--I imagine it happened often. I wonder if any local or itinerant pilots actually bothered to check NOTAMS under like circumstances. Seems to me instrs have 2 options: 1) check NOTAMS for every field within 100 mi of the training area, just in case an unscheduled landing takes place, or 2) do what I did--occasionally bust an air traffic area, and file an ASRS report at the earliest opportunity.

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Original NASA ASRS Text

Title: SMA ENTERED THE TRACY, CA, ATA WITHOUT CLRNC.

Narrative: FLYING RIGHT SEAT AS FLT INSTR, TRANSITIONING A PVT PLT TO A RETRACTABLE ACFT. AFTER 1 HR AIRWORK OVER SAN JOAQUIN VALLEY, DECIDED TO PRACTICE LNDGS AT TRACY ARPT (AN UNCONTROLLED FIELD). MONITORED UNICOM, OVERFLEW FIELD AT 1500' AGL TO OBSERVE TETRAHEDRON, WHEN VOICE ON RADIO SAID, 'TRACY TFC, CONTACT TRACY TWR ON 121.2.' 'WHAT TWR?', MY STUDENT AND I ASKED EACH OTHER. COMPLYING, WE WERE INFORMED OF TEMPORARY TWR STAFFED BY NATL GUARD. I ASKED IF AN ATA WAS IN EFFECT, AND WAS TOLD IT WAS. I RPTED POS (WELL WITHIN ATA) AND INTENTIONS AND WAS CLRED TO LAND. SINCE TRACY WAS NOT AN INTENDED DEST, JUST A SPUR OF THE MOMENT TRNING DECISION, NEITHER STUDENT NOR INSTR HAD CHKED NOTAMS. I'VE BEEN USING THIS UNCONTROLLED FIELD FOR ALMOST 10 YRS FOR JUST SUCH ACTIVITIES, AND WAS SHOCKED TO FIND IT SUDDENLY A CTLED FIELD. NATIONAL GUARD TEMPORARY ACTIVITIES WERE UNKNOWN TO STUDENT OR INSTR. (AFTERWARDS, I CHKED NOTAMS AND SURE ENOUGH, THE INFO WAS THERE!) MIL CTLR SHOWED GOOD JUDGEMENT IN MAKING ANNOUNCEMENT OVER UNICOM FREQ. HE DIDN'T SEEM PERTURBED BY OUR APPEARANCE IN HIS AIRSPACE--I IMAGINE IT HAPPENED OFTEN. I WONDER IF ANY LCL OR ITINERANT PLTS ACTUALLY BOTHERED TO CHK NOTAMS UNDER LIKE CIRCUMSTANCES. SEEMS TO ME INSTRS HAVE 2 OPTIONS: 1) CHK NOTAMS FOR EVERY FIELD WITHIN 100 MI OF THE TRNING AREA, JUST IN CASE AN UNSCHEDULED LNDG TAKES PLACE, OR 2) DO WHAT I DID--OCCASIONALLY BUST AN ATA, AND FILE AN ASRS RPT AT THE EARLIEST OPPORTUNITY.

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.