Narrative:

Using FMC for navigation, I attempted to enter a leg/waypoint on flight plan near current position. By the time the computer had calculated fix, we were passing it. Aircraft began turn off course to reverse direction. We corrected with heading select, however, aircraft did drift toward prohibited airspace. We corrected before entering it, however, ATC did ask our heading reference this airspace. No further problems noted. Supplemental information from acn 436228: ATC asked our heading and advised that our track was approaching a restr area and gave us a heading to ensure that we didn't enter the restr airspace. Prevention: it may not be necessary to put a fix in the box if it can be idented and naved to by an alternate method. Especially if the aircraft is approaching the waypoint in question.

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Original NASA ASRS Text

Title: AN ACR PIC EXPERIENCES A HDG TRACK DEV WHEN ATTEMPTING SOME UNORTHODOX FMC PROGRAMMING NEAR DAG, CA.

Narrative: USING FMC FOR NAV, I ATTEMPTED TO ENTER A LEG/WAYPOINT ON FLT PLAN NEAR CURRENT POS. BY THE TIME THE COMPUTER HAD CALCULATED FIX, WE WERE PASSING IT. ACFT BEGAN TURN OFF COURSE TO REVERSE DIRECTION. WE CORRECTED WITH HDG SELECT, HOWEVER, ACFT DID DRIFT TOWARD PROHIBITED AIRSPACE. WE CORRECTED BEFORE ENTERING IT, HOWEVER, ATC DID ASK OUR HDG REF THIS AIRSPACE. NO FURTHER PROBS NOTED. SUPPLEMENTAL INFO FROM ACN 436228: ATC ASKED OUR HDG AND ADVISED THAT OUR TRACK WAS APCHING A RESTR AREA AND GAVE US A HDG TO ENSURE THAT WE DIDN'T ENTER THE RESTR AIRSPACE. PREVENTION: IT MAY NOT BE NECESSARY TO PUT A FIX IN THE BOX IF IT CAN BE IDENTED AND NAVED TO BY AN ALTERNATE METHOD. ESPECIALLY IF THE ACFT IS APCHING THE WAYPOINT IN QUESTION.

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.