Narrative:

Our flight was being vectored by baltimore approach for the RNAV runway 28 at fme. The approach utilizes 2 waypoints which were placed in our RNAV system during the en route phase of flight. As soon as I received vectors for the approach, I selected the RNAV function to identify the bolti intersection/waypoint and I also verified that the RNAV was programmed correctly. I was then told to proceed direct bolti and report crossing it. My partner, who is also instrument rated, was working the radios. While en route to bolti, my partner accidently switched off the RNAV mode and did not tell me what had happened. As a result, I missed bolti by 2 NM. When I realized the error, I switched back to the RNAV function and was informed by baltimore approach that I was indeed 2 mi off course. The result of this led to a missed approach and then we were vectored for the NDB 28 at fme. The rest of the flight was completed uneventfully. I believe the cause of this error was due to distrs in the cockpit during a critical phase of flight. My partner was also showing a passenger some landmarks on the ground which filled the cockpit with unnecessary chatter and caused me to look as well. This inattn to the flight instruments, RNAV indications, led to what could have been and was a major error on my part. I should have asked my partner and passenger to stop talking until we were on the ground. I now tell my passenger to stop talking prior to any approach to prevent any such distraction again.

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Original NASA ASRS Text

Title: PLT OF SMA WAS DOING FINE WITH HIS NAV TO FME AND APCH FOR LNDG UNTIL HE LOST R NAV.

Narrative: OUR FLT WAS BEING VECTORED BY BALTIMORE APCH FOR THE RNAV RWY 28 AT FME. THE APCH UTILIZES 2 WAYPOINTS WHICH WERE PLACED IN OUR RNAV SYS DURING THE ENRTE PHASE OF FLT. AS SOON AS I RECEIVED VECTORS FOR THE APCH, I SELECTED THE RNAV FUNCTION TO IDENT THE BOLTI INTXN/WAYPOINT AND I ALSO VERIFIED THAT THE RNAV WAS PROGRAMMED CORRECTLY. I WAS THEN TOLD TO PROCEED DIRECT BOLTI AND RPT XING IT. MY PARTNER, WHO IS ALSO INST RATED, WAS WORKING THE RADIOS. WHILE ENRTE TO BOLTI, MY PARTNER ACCIDENTLY SWITCHED OFF THE RNAV MODE AND DID NOT TELL ME WHAT HAD HAPPENED. AS A RESULT, I MISSED BOLTI BY 2 NM. WHEN I REALIZED THE ERROR, I SWITCHED BACK TO THE RNAV FUNCTION AND WAS INFORMED BY BALTIMORE APCH THAT I WAS INDEED 2 MI OFF COURSE. THE RESULT OF THIS LED TO A MISSED APCH AND THEN WE WERE VECTORED FOR THE NDB 28 AT FME. THE REST OF THE FLT WAS COMPLETED UNEVENTFULLY. I BELIEVE THE CAUSE OF THIS ERROR WAS DUE TO DISTRS IN THE COCKPIT DURING A CRITICAL PHASE OF FLT. MY PARTNER WAS ALSO SHOWING A PAX SOME LANDMARKS ON THE GND WHICH FILLED THE COCKPIT WITH UNNECESSARY CHATTER AND CAUSED ME TO LOOK AS WELL. THIS INATTN TO THE FLT INSTS, RNAV INDICATIONS, LED TO WHAT COULD HAVE BEEN AND WAS A MAJOR ERROR ON MY PART. I SHOULD HAVE ASKED MY PARTNER AND PAX TO STOP TALKING UNTIL WE WERE ON THE GND. I NOW TELL MY PAX TO STOP TALKING PRIOR TO ANY APCH TO PREVENT ANY SUCH DISTR AGAIN.

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.