B737-300 flight crew experienced difficulty when loading the departure into the FMC. A 'direct to' s...

Attributes
ACN	742496
Time
Date	200706
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	ground : preflight
Route In Use	departure sid : n/s
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 187
ASRS Report	742496
Events
Anomaly	other spatial deviation
Resolutory Action	flight crew : returned to intended or assigned course
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Aircraft

Narrative:

During preflight and upon loading company route; the FMC did not allow me to activate or execute the route. A message came up that said 'altitude constraint at roppr.' we called maintenance to help out with the problem and he immediately knew that we needed to remove the fix with the constraint (roppr) and then re-insert it into the legs page. Apparently; a known or recurring problem that in our case caused a late turn. Upon reaching the first fix (rbell; I believe) the FMC did not direct the proper turn and a 'direct to' roppr was performed manually. ATC informed us that our turn was late. We indicated to him that we had had a glitch with the LNAV and that it was now working fine and we could continue with the LNAV SID. The '7000B' constraint problem at the second fix should be either fixed in the FMC code/route; or there should be some guidance on how to get rid of the problem during preflight.

Original NASA ASRS Text

Title: B737-300 FLT CREW EXPERIENCED DIFFICULTY WHEN LOADING THE DEP INTO THE FMC. A 'DIRECT TO' SOLUTION WAS UTILIZED; BUT WHEN FLYING THE DEP; THE FMC DID NOT COMMAND A LEAD TURN AND THE FLT CREW OVERSHOT THE DESIRED COURSE.

Narrative: DURING PREFLT AND UPON LOADING COMPANY RTE; THE FMC DID NOT ALLOW ME TO ACTIVATE OR EXECUTE THE RTE. A MESSAGE CAME UP THAT SAID 'ALT CONSTRAINT AT ROPPR.' WE CALLED MAINT TO HELP OUT WITH THE PROB AND HE IMMEDIATELY KNEW THAT WE NEEDED TO REMOVE THE FIX WITH THE CONSTRAINT (ROPPR) AND THEN RE-INSERT IT INTO THE LEGS PAGE. APPARENTLY; A KNOWN OR RECURRING PROB THAT IN OUR CASE CAUSED A LATE TURN. UPON REACHING THE FIRST FIX (RBELL; I BELIEVE) THE FMC DID NOT DIRECT THE PROPER TURN AND A 'DIRECT TO' ROPPR WAS PERFORMED MANUALLY. ATC INFORMED US THAT OUR TURN WAS LATE. WE INDICATED TO HIM THAT WE HAD HAD A GLITCH WITH THE LNAV AND THAT IT WAS NOW WORKING FINE AND WE COULD CONTINUE WITH THE LNAV SID. THE '7000B' CONSTRAINT PROB AT THE SECOND FIX SHOULD BE EITHER FIXED IN THE FMC CODE/RTE; OR THERE SHOULD BE SOME GUIDANCE ON HOW TO GET RID OF THE PROB DURING PREFLT.

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.

B737-300 flight crew experienced difficulty when loading the departure into the FMC. A 'direct to' solution was utilized; but when flying the departure; the FMC did not command a lead turn and the flight crew overshot the desired course.