Narrative:

Zrh departure. ATC assigned the morok 1U RNAV departure. Adequate time at the gate to brief the SID. At runway end, runway symbol touched aircraft symbol which allows for use of LNAV after takeoff. When we were airborne a turn to the left was initiated at 1.1 DME klo VOR with heading select. After interception of magenta route line of the SID, LNAV was armed and then engaged. Climb airspeed was at 210 KIAS or less. I was PNF, and had progress page #2 displayed to check xtrack error. The initial deviation was 3H depiction is what the FMC depicts when airborne on course. With the command bars centered and still on the LNAV track, we both noticed that we were being commanded to fly away from the klo 255 degrees. At that time we changed roll modes to heading select and made a further cut to intercept the 255 degrees. Immediately thereafter, zrh departure asked for our heading and I said we are in a left turn to intercept the 255 degree radial. He said we were off course. We had no means to measure deviation from track. Rest of departure uneventful. Being an RNAV departure we used LNAV. However, the ground, the FMC map and legs page show a track from runway 16 to D163A, KLO163 at 1 NM to D360A, klo 360 degrees at 1 NM and a course of 255 degrees to the aarau waypoint. This would never work, that is a parallel track or heading. However, when one looks at the 10-3H, the SID track shows crossing the 360 degree radial at about 3 DME. If this is an RNAV departure, it is poorly drawn in the FMC computer. If we are to turn left after takeoff from runway 16 and intercept the 255 degree radial and disregard the RNAV course, then this should be stated, that is, do not use LNAV at the start. And then I question the purpose of this RNAV departure. Let's go back to the simple turn over the airport, klo VOR. In sum: this RNAV departure is really a manual dead-reckoning SID to intercept a VOR radial. This zrh RNAV departure does not give any guidance on how wide it may or may not be flown. Suggest we withdraw this particular SID until this matter is cleared up. Supplemental information from acn 370431: after leveling at ATC assigned altitude of 5000 ft and resetting qnh, it was noticed on raw data that the FMC was not following the proper ground track as depicted on the chart. Heading select was used to override LNAV and the raw data departure was re- intercepted. During the correction ATC questioned our heading and advised us that other traffic had to deviate.

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Original NASA ASRS Text

Title: A B767 DEPARTS OUT OF ZURICH, SWITZERLAND, AND HAS A COURSE DEV FROM THE ASSIGNED SID. PLT FEELS IT IS A COMPUTER OR LNAV PROB AND SUGGESTS NOT TO USE IT ANY MORE.

Narrative: ZRH DEP. ATC ASSIGNED THE MOROK 1U RNAV DEP. ADEQUATE TIME AT THE GATE TO BRIEF THE SID. AT RWY END, RWY SYMBOL TOUCHED ACFT SYMBOL WHICH ALLOWS FOR USE OF LNAV AFTER TKOF. WHEN WE WERE AIRBORNE A TURN TO THE L WAS INITIATED AT 1.1 DME KLO VOR WITH HEADING SELECT. AFTER INTERCEPTION OF MAGENTA RTE LINE OF THE SID, LNAV WAS ARMED AND THEN ENGAGED. CLB AIRSPD WAS AT 210 KIAS OR LESS. I WAS PNF, AND HAD PROGRESS PAGE #2 DISPLAYED TO CHK XTRACK ERROR. THE INITIAL DEV WAS 3H DEPICTION IS WHAT THE FMC DEPICTS WHEN AIRBORNE ON COURSE. WITH THE COMMAND BARS CTRED AND STILL ON THE LNAV TRACK, WE BOTH NOTICED THAT WE WERE BEING COMMANDED TO FLY AWAY FROM THE KLO 255 DEGS. AT THAT TIME WE CHANGED ROLL MODES TO HEADING SELECT AND MADE A FURTHER CUT TO INTERCEPT THE 255 DEGS. IMMEDIATELY THEREAFTER, ZRH DEP ASKED FOR OUR HEADING AND I SAID WE ARE IN A L TURN TO INTERCEPT THE 255 DEG RADIAL. HE SAID WE WERE OFF COURSE. WE HAD NO MEANS TO MEASURE DEV FROM TRACK. REST OF DEP UNEVENTFUL. BEING AN RNAV DEP WE USED LNAV. HOWEVER, THE GND, THE FMC MAP AND LEGS PAGE SHOW A TRACK FROM RWY 16 TO D163A, KLO163 AT 1 NM TO D360A, KLO 360 DEGS AT 1 NM AND A COURSE OF 255 DEGS TO THE AARAU WAYPOINT. THIS WOULD NEVER WORK, THAT IS A PARALLEL TRACK OR HDG. HOWEVER, WHEN ONE LOOKS AT THE 10-3H, THE SID TRACK SHOWS XING THE 360 DEG RADIAL AT ABOUT 3 DME. IF THIS IS AN RNAV DEP, IT IS POORLY DRAWN IN THE FMC COMPUTER. IF WE ARE TO TURN L AFTER TKOF FROM RWY 16 AND INTERCEPT THE 255 DEG RADIAL AND DISREGARD THE RNAV COURSE, THEN THIS SHOULD BE STATED, THAT IS, DO NOT USE LNAV AT THE START. AND THEN I QUESTION THE PURPOSE OF THIS RNAV DEP. LET'S GO BACK TO THE SIMPLE TURN OVER THE ARPT, KLO VOR. IN SUM: THIS RNAV DEP IS REALLY A MANUAL DEAD-RECKONING SID TO INTERCEPT A VOR RADIAL. THIS ZRH RNAV DEP DOES NOT GIVE ANY GUIDANCE ON HOW WIDE IT MAY OR MAY NOT BE FLOWN. SUGGEST WE WITHDRAW THIS PARTICULAR SID UNTIL THIS MATTER IS CLRED UP. SUPPLEMENTAL INFO FROM ACN 370431: AFTER LEVELING AT ATC ASSIGNED ALT OF 5000 FT AND RESETTING QNH, IT WAS NOTICED ON RAW DATA THAT THE FMC WAS NOT FOLLOWING THE PROPER GND TRACK AS DEPICTED ON THE CHART. HEADING SELECT WAS USED TO OVERRIDE LNAV AND THE RAW DATA DEP WAS RE- INTERCEPTED. DURING THE CORRECTION ATC QUESTIONED OUR HEADING AND ADVISED US THAT OTHER TFC HAD TO DEVIATE.

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.