Narrative:

I was initially cleared to iad via lrp and the delro 1 arrival. I loaded the arrival into the garmin 530 and proceeded to lrp. A short while later the clearance was amended to 'direct lrp; direct mulrr; direct iad.' mulrr is on the arrival; and in an effort to simplify; instead of deleting all of the other waypoints on the arrival; I chose to add mulrr to the active flight plan; and delete the arrival from the flight plan; which I thought would be easier than deleting each of the other waypoints. Also; I wanted to show my copilot how to delete an arrival from the flight plan. I scrolled down on the active flight plan and entered mulrr; however I misspelled it 'mullr.' oddly enough; the incorrect 'mullr' appeared in the database; about 20 NM south of lrp. I thought it odd to have a dogleg; so I queried ATC twice; and each time they confirmed they needed me over mulrr. When I arrived at lrp; I made a hard left to the erroneous 'mullr and shortly thereafter; ATC was asking me where the heck I was going. They gave me a vector and all ended without incident. At that point I was quite puzzled by the fact that my mullr wasn't in the same place as their mulrr. On the ground; checked the database and found a user waypoint 'mullr' (N39 40.3 west 75 36.5); not too far from the real mulrr. I suspect a pilot on a flight sometime earlier was given direct mulrr; misspelled it as I did; and while punching the enter key without looking; (as I did) created a user waypoint at his present position. This chain of events could have been broken a number of ways: 1) always; always; always; verify the waypoint you are entering. Make sure it's in your geographical area; and not a user waypoint. Don't just look away and bang the enter key 3 times. 2) always have the paper version of the chart; arrival or departure open on your lap. Verify the paper matches the database. I usually do; but when I got the abbreviated clearance; I put the arrival away. If I had it in front of me; I would have seen the spelling/location was wrong. 3) if it doesn't look right; it probably isn't. If your route looks like an ekg; you did something wrong. Verify it; and verify it again. I did ask ATC about something that appeared abnormal; but I wasn't specific enough. We weren't talking about the same thing. I wonder how many user waypoints have been created this way in a typical garmin box that are close spellings to real waypoints. It might be worth a scroll through just to see how many times this has happened.

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Original NASA ASRS Text

Title: C550 CAPTAIN MISPROGRAMS FMC WAYPOINT ON ARRIVAL TO IAD.

Narrative: I WAS INITIALLY CLRED TO IAD VIA LRP AND THE DELRO 1 ARR. I LOADED THE ARR INTO THE GARMIN 530 AND PROCEEDED TO LRP. A SHORT WHILE LATER THE CLRNC WAS AMENDED TO 'DIRECT LRP; DIRECT MULRR; DIRECT IAD.' MULRR IS ON THE ARR; AND IN AN EFFORT TO SIMPLIFY; INSTEAD OF DELETING ALL OF THE OTHER WAYPOINTS ON THE ARR; I CHOSE TO ADD MULRR TO THE ACTIVE FLT PLAN; AND DELETE THE ARR FROM THE FLT PLAN; WHICH I THOUGHT WOULD BE EASIER THAN DELETING EACH OF THE OTHER WAYPOINTS. ALSO; I WANTED TO SHOW MY COPLT HOW TO DELETE AN ARR FROM THE FLT PLAN. I SCROLLED DOWN ON THE ACTIVE FLT PLAN AND ENTERED MULRR; HOWEVER I MISSPELLED IT 'MULLR.' ODDLY ENOUGH; THE INCORRECT 'MULLR' APPEARED IN THE DATABASE; ABOUT 20 NM S OF LRP. I THOUGHT IT ODD TO HAVE A DOGLEG; SO I QUERIED ATC TWICE; AND EACH TIME THEY CONFIRMED THEY NEEDED ME OVER MULRR. WHEN I ARRIVED AT LRP; I MADE A HARD L TO THE ERRONEOUS 'MULLR AND SHORTLY THEREAFTER; ATC WAS ASKING ME WHERE THE HECK I WAS GOING. THEY GAVE ME A VECTOR AND ALL ENDED WITHOUT INCIDENT. AT THAT POINT I WAS QUITE PUZZLED BY THE FACT THAT MY MULLR WASN'T IN THE SAME PLACE AS THEIR MULRR. ON THE GND; CHKED THE DATABASE AND FOUND A USER WAYPOINT 'MULLR' (N39 40.3 W 75 36.5); NOT TOO FAR FROM THE REAL MULRR. I SUSPECT A PLT ON A FLT SOMETIME EARLIER WAS GIVEN DIRECT MULRR; MISSPELLED IT AS I DID; AND WHILE PUNCHING THE ENTER KEY WITHOUT LOOKING; (AS I DID) CREATED A USER WAYPOINT AT HIS PRESENT POS. THIS CHAIN OF EVENTS COULD HAVE BEEN BROKEN A NUMBER OF WAYS: 1) ALWAYS; ALWAYS; ALWAYS; VERIFY THE WAYPOINT YOU ARE ENTERING. MAKE SURE IT'S IN YOUR GEOGRAPHICAL AREA; AND NOT A USER WAYPOINT. DON'T JUST LOOK AWAY AND BANG THE ENTER KEY 3 TIMES. 2) ALWAYS HAVE THE PAPER VERSION OF THE CHART; ARR OR DEP OPEN ON YOUR LAP. VERIFY THE PAPER MATCHES THE DATABASE. I USUALLY DO; BUT WHEN I GOT THE ABBREVIATED CLRNC; I PUT THE ARR AWAY. IF I HAD IT IN FRONT OF ME; I WOULD HAVE SEEN THE SPELLING/LOCATION WAS WRONG. 3) IF IT DOESN'T LOOK RIGHT; IT PROBABLY ISN'T. IF YOUR RTE LOOKS LIKE AN EKG; YOU DID SOMETHING WRONG. VERIFY IT; AND VERIFY IT AGAIN. I DID ASK ATC ABOUT SOMETHING THAT APPEARED ABNORMAL; BUT I WASN'T SPECIFIC ENOUGH. WE WEREN'T TALKING ABOUT THE SAME THING. I WONDER HOW MANY USER WAYPOINTS HAVE BEEN CREATED THIS WAY IN A TYPICAL GARMIN BOX THAT ARE CLOSE SPELLINGS TO REAL WAYPOINTS. IT MIGHT BE WORTH A SCROLL THROUGH JUST TO SEE HOW MANY TIMES THIS HAS HAPPENED.

Data retrieved from NASA's ASRS site as of January 2009 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.