Medium large transport drifts off course while computing fuel accuracy.

Attributes
ACN	289276
Time
Date	199411
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mkc
State Reference	KS
Altitude	msl bound lower : 24000 msl bound upper : 24000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 250 flight time total : 17000 flight time type : 12000
ASRS Report	289276
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	non adherence : clearance other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : became reoriented other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

En route from stl to slc -- planned fuel burn 17K -- 25K on board. Winds at altitude 265/115 -- after takeoff FMC said landing fuel would be 2.3. My immediate concern was accuracy of FMC information or where to go for fuel. While checking different cruise altitude and adding wind to see what optimum altitude should be the aircraft drifted off course. Course was from hallsville VOR to mke. I ended up south of course. After realizing position and correcting back, ZKC, who never realized the navigation error either, suddenly saw a conflict. A turn was commenced to avoid an airliner. TCASII never showed a target. In retrospect, I should have given the first officer the responsibility of flying, navigating, etc while I studied the computer. We both had our heads in and down. Unhealthy.

Original NASA ASRS Text

Title: MLG DRIFTS OFF COURSE WHILE COMPUTING FUEL ACCURACY.

Narrative: ENRTE FROM STL TO SLC -- PLANNED FUEL BURN 17K -- 25K ON BOARD. WINDS AT ALT 265/115 -- AFTER TKOF FMC SAID LNDG FUEL WOULD BE 2.3. MY IMMEDIATE CONCERN WAS ACCURACY OF FMC INFO OR WHERE TO GO FOR FUEL. WHILE CHKING DIFFERENT CRUISE ALT AND ADDING WIND TO SEE WHAT OPTIMUM ALT SHOULD BE THE ACFT DRIFTED OFF COURSE. COURSE WAS FROM HALLSVILLE VOR TO MKE. I ENDED UP S OF COURSE. AFTER REALIZING POS AND CORRECTING BACK, ZKC, WHO NEVER REALIZED THE NAV ERROR EITHER, SUDDENLY SAW A CONFLICT. A TURN WAS COMMENCED TO AVOID AN AIRLINER. TCASII NEVER SHOWED A TARGET. IN RETROSPECT, I SHOULD HAVE GIVEN THE FO THE RESPONSIBILITY OF FLYING, NAVIGATING, ETC WHILE I STUDIED THE COMPUTER. WE BOTH HAD OUR HEADS IN AND DOWN. UNHEALTHY.

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.