Narrative:

Simply put, we made a mistake. Our flight was en route fll-lga at FL330, autoplt was on, and VNAV/LNAV functions were engaged. Route being flown was 'nanci 4 STAR' into lga. ZDC gave us holding instructions: ott 052 degree radial, 20 DME/left turns/10 mi legs/efc XY00 Z. Both captain and I wrote down our holding instructions. Apparently, however, we were over, or just past (northeast) of ott when we received our holding instructions, because looking at the 'legs page' of the FMC the next VOR displayed was dqo. Using the 'hold page' of the FMC I entered all the information given in the holding clearance but used dqo versus ott VOR. I read what I'd entered into the FMC to the captain who agreed that it was correct. I then entered the holding fix into the 'legs page' between dqo and stefe intersection (stefe intersection was 24 DME northeast of dqo and our holding fix was 20 DME). At XX34Z ZDC told us to make 'a right left turn to 240 degrees to enter the hold.' we were 5 mi southwest of kerno intersection at this time -- 44 DME northeast of ott. After turning, I used raw data from ott VOR and subsequently entered the correct hold. ATC made no further comments, and we weren't aware of any traffic conflicts. Our flight continued to lga without incident. In retrospect, I think this incident could've been prevented. Had the captain (as PNF) been backing up our route with raw data rather than being in 'navigation' (FMC generated route information) like me. Though not required, that way is the company recommended way to operate en route. Also, as is true with all computers, 'garbage in, garbage out.' the FMC will not perform correctly if not programmed correctly. We both copied our holding clearance correctly (and read it back correctly) but entered it into the FMC incorrectly. Supplemental information from acn 235109: shortly after the FMC update, I left the primary VHF frequency to advise our company of our holding and an efc. The lesson learned from this was to pay closer attention to detail. Although altitude, direction of turn, leg distance, course, and distance were entered, we transposed the next downline NAVAID on the arrival into the holding fix. Regrettably, after entering this information into the FMC, I failed to monitor flight progress while communicating on the backup VHF radio to our company. Perhaps closer monitoring by both the PNF, myself, as well as the PF could have prevented this error.

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Original NASA ASRS Text

Title: HDG TRACK POS DEV AFTER CLRNC AMENDED TO HOLD ENRTE. HOLDING PROC HOLDING PATTERN LOCATION CONFUSED.

Narrative: SIMPLY PUT, WE MADE A MISTAKE. OUR FLT WAS ENRTE FLL-LGA AT FL330, AUTOPLT WAS ON, AND VNAV/LNAV FUNCTIONS WERE ENGAGED. RTE BEING FLOWN WAS 'NANCI 4 STAR' INTO LGA. ZDC GAVE US HOLDING INSTRUCTIONS: OTT 052 DEG RADIAL, 20 DME/L TURNS/10 MI LEGS/EFC XY00 Z. BOTH CAPT AND I WROTE DOWN OUR HOLDING INSTRUCTIONS. APPARENTLY, HOWEVER, WE WERE OVER, OR JUST PAST (NE) OF OTT WHEN WE RECEIVED OUR HOLDING INSTRUCTIONS, BECAUSE LOOKING AT THE 'LEGS PAGE' OF THE FMC THE NEXT VOR DISPLAYED WAS DQO. USING THE 'HOLD PAGE' OF THE FMC I ENTERED ALL THE INFO GIVEN IN THE HOLDING CLRNC BUT USED DQO VERSUS OTT VOR. I READ WHAT I'D ENTERED INTO THE FMC TO THE CAPT WHO AGREED THAT IT WAS CORRECT. I THEN ENTERED THE HOLDING FIX INTO THE 'LEGS PAGE' BTWN DQO AND STEFE INTXN (STEFE INTXN WAS 24 DME NE OF DQO AND OUR HOLDING FIX WAS 20 DME). AT XX34Z ZDC TOLD US TO MAKE 'A RIGHT L TURN TO 240 DEGS TO ENTER THE HOLD.' WE WERE 5 MI SW OF KERNO INTXN AT THIS TIME -- 44 DME NE OF OTT. AFTER TURNING, I USED RAW DATA FROM OTT VOR AND SUBSEQUENTLY ENTERED THE CORRECT HOLD. ATC MADE NO FURTHER COMMENTS, AND WE WEREN'T AWARE OF ANY TFC CONFLICTS. OUR FLT CONTINUED TO LGA WITHOUT INCIDENT. IN RETROSPECT, I THINK THIS INCIDENT COULD'VE BEEN PREVENTED. HAD THE CAPT (AS PNF) BEEN BACKING UP OUR RTE WITH RAW DATA RATHER THAN BEING IN 'NAV' (FMC GENERATED RTE INFO) LIKE ME. THOUGH NOT REQUIRED, THAT WAY IS THE COMPANY RECOMMENDED WAY TO OPERATE ENRTE. ALSO, AS IS TRUE WITH ALL COMPUTERS, 'GARBAGE IN, GARBAGE OUT.' THE FMC WILL NOT PERFORM CORRECTLY IF NOT PROGRAMMED CORRECTLY. WE BOTH COPIED OUR HOLDING CLRNC CORRECTLY (AND READ IT BACK CORRECTLY) BUT ENTERED IT INTO THE FMC INCORRECTLY. SUPPLEMENTAL INFO FROM ACN 235109: SHORTLY AFTER THE FMC UPDATE, I LEFT THE PRIMARY VHF FREQ TO ADVISE OUR COMPANY OF OUR HOLDING AND AN EFC. THE LESSON LEARNED FROM THIS WAS TO PAY CLOSER ATTN TO DETAIL. ALTHOUGH ALT, DIRECTION OF TURN, LEG DISTANCE, COURSE, AND DISTANCE WERE ENTERED, WE TRANSPOSED THE NEXT DOWNLINE NAVAID ON THE ARR INTO THE HOLDING FIX. REGRETTABLY, AFTER ENTERING THIS INFO INTO THE FMC, I FAILED TO MONITOR FLT PROGRESS WHILE COMMUNICATING ON THE BACKUP VHF RADIO TO OUR COMPANY. PERHAPS CLOSER MONITORING BY BOTH THE PNF, MYSELF, AS WELL AS THE PF COULD HAVE PREVENTED THIS ERROR.

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.