Narrative:

I had approximately 1 hour flight time before accepting delivery during which I checked the operation of the various instruments and radios in the aircraft. Before this, I had not flown for 45 days. The aircraft was equipped with a different autoplt and some different avionics from my previous plane. The most significant was a LORAN, with which I was not familiar, which could be coupled to both the HSI (horizontal situation indicator) and the ap (autoplt). Consequently, I elected to fly the former owner back to atlanta from gaithersburg, md, for a familiarization flight. The aircraft seemed straight forward enough, but the ap and LORAN were completely new to me. At our destination, bear creek (henry county airport), we refueled and prepared to return home. Before takeoff I checked the slaved dg (directional gyroscope) against the magnetic compass. I pressed the 'slave' button during the check. There was sufficient daylight to accomplish this check without the aid of panel lighting. Having learned how to use it, I tuned the LORAN to athens and left the LORAN coupled to the ap/HSI; however the ap was not engaged. During the preflight we had sought to connect an intercom unit to our headphones. I was accompanied by another pilot. I elected to use the hand microphones and cabin speaker as we had during the familiarization flight down to bear creek. I contacted atlanta approach and advised them of our intention. We were assigned a transponder frequency and advised to remain on the atlanta approach radio frequency and to stay clear of the TCA. I asked my passenger (a pilot occupying the right seat) to take a flashlight from my flight bag so that we would be prepared in the event of an electrical failure. He found the light, but in the process of trying to place the batteries in it dropped some elements of the flashlight on the floor. I sought to help by reaching for another light. Neither of us noticed that 1) there was no light illuminating the magnetic compass and 2) we were hearing nothing on the atlanta approach frequency on the speaker. My 'copilot' noticed that we were flying almost directly over atlanta's hartsfield airport. After switching radios, I did make contact with atlanta approach which informed me that I had just flown right over hartsfield airport, and gave me another heading to navigation. Over the next few mins, our radio contact with atlanta approach was intermittent. For the remainder of the flight we had intermittent failure of the cabin speaker. Use of an earphone solved the problem. We also discovered that the slaved HSI/dg had been disengaged during the preflight check when I pressed the slave button to test it. The design of the slave button was different from those in my experience and when pushed, the dg is disengaged unless the button is pushed again. Consequently, the effect of my preflight check was to disengage the slaved dg. The fact of the disengagement was not evident, and the magnetic compass did not disclose the error because the magnetic compass was not illuminated.

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Original NASA ASRS Text

Title: GA SMT UNAUTH PENETRATION OF ATL TCA.

Narrative: I HAD APPROX 1 HR FLT TIME BEFORE ACCEPTING DELIVERY DURING WHICH I CHKED THE OP OF THE VARIOUS INSTS AND RADIOS IN THE ACFT. BEFORE THIS, I HAD NOT FLOWN FOR 45 DAYS. THE ACFT WAS EQUIPPED WITH A DIFFERENT AUTOPLT AND SOME DIFFERENT AVIONICS FROM MY PREVIOUS PLANE. THE MOST SIGNIFICANT WAS A LORAN, WITH WHICH I WAS NOT FAMILIAR, WHICH COULD BE COUPLED TO BOTH THE HSI (HORIZ SITUATION INDICATOR) AND THE AP (AUTOPLT). CONSEQUENTLY, I ELECTED TO FLY THE FORMER OWNER BACK TO ATLANTA FROM GAITHERSBURG, MD, FOR A FAMILIARIZATION FLT. THE ACFT SEEMED STRAIGHT FORWARD ENOUGH, BUT THE AP AND LORAN WERE COMPLETELY NEW TO ME. AT OUR DEST, BEAR CREEK (HENRY COUNTY ARPT), WE REFUELED AND PREPARED TO RETURN HOME. BEFORE TKOF I CHKED THE SLAVED DG (DIRECTIONAL GYROSCOPE) AGAINST THE MAGNETIC COMPASS. I PRESSED THE 'SLAVE' BUTTON DURING THE CHK. THERE WAS SUFFICIENT DAYLIGHT TO ACCOMPLISH THIS CHK WITHOUT THE AID OF PANEL LIGHTING. HAVING LEARNED HOW TO USE IT, I TUNED THE LORAN TO ATHENS AND LEFT THE LORAN COUPLED TO THE AP/HSI; HOWEVER THE AP WAS NOT ENGAGED. DURING THE PREFLT WE HAD SOUGHT TO CONNECT AN INTERCOM UNIT TO OUR HEADPHONES. I WAS ACCOMPANIED BY ANOTHER PLT. I ELECTED TO USE THE HAND MICROPHONES AND CABIN SPEAKER AS WE HAD DURING THE FAMILIARIZATION FLT DOWN TO BEAR CREEK. I CONTACTED ATLANTA APCH AND ADVISED THEM OF OUR INTENTION. WE WERE ASSIGNED A TRANSPONDER FREQ AND ADVISED TO REMAIN ON THE ATLANTA APCH RADIO FREQ AND TO STAY CLR OF THE TCA. I ASKED MY PAX (A PLT OCCUPYING THE R SEAT) TO TAKE A FLASHLIGHT FROM MY FLT BAG SO THAT WE WOULD BE PREPARED IN THE EVENT OF AN ELECTRICAL FAILURE. HE FOUND THE LIGHT, BUT IN THE PROCESS OF TRYING TO PLACE THE BATTERIES IN IT DROPPED SOME ELEMENTS OF THE FLASHLIGHT ON THE FLOOR. I SOUGHT TO HELP BY REACHING FOR ANOTHER LIGHT. NEITHER OF US NOTICED THAT 1) THERE WAS NO LIGHT ILLUMINATING THE MAGNETIC COMPASS AND 2) WE WERE HEARING NOTHING ON THE ATLANTA APCH FREQ ON THE SPEAKER. MY 'COPLT' NOTICED THAT WE WERE FLYING ALMOST DIRECTLY OVER ATLANTA'S HARTSFIELD ARPT. AFTER SWITCHING RADIOS, I DID MAKE CONTACT WITH ATLANTA APCH WHICH INFORMED ME THAT I HAD JUST FLOWN RIGHT OVER HARTSFIELD ARPT, AND GAVE ME ANOTHER HDG TO NAV. OVER THE NEXT FEW MINS, OUR RADIO CONTACT WITH ATLANTA APCH WAS INTERMITTENT. FOR THE REMAINDER OF THE FLT WE HAD INTERMITTENT FAILURE OF THE CABIN SPEAKER. USE OF AN EARPHONE SOLVED THE PROBLEM. WE ALSO DISCOVERED THAT THE SLAVED HSI/DG HAD BEEN DISENGAGED DURING THE PREFLT CHK WHEN I PRESSED THE SLAVE BUTTON TO TEST IT. THE DESIGN OF THE SLAVE BUTTON WAS DIFFERENT FROM THOSE IN MY EXPERIENCE AND WHEN PUSHED, THE DG IS DISENGAGED UNLESS THE BUTTON IS PUSHED AGAIN. CONSEQUENTLY, THE EFFECT OF MY PREFLT CHK WAS TO DISENGAGE THE SLAVED DG. THE FACT OF THE DISENGAGEMENT WAS NOT EVIDENT, AND THE MAGNETIC COMPASS DID NOT DISCLOSE THE ERROR BECAUSE THE MAGNETIC COMPASS WAS NOT ILLUMINATED.

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.