A B777 captain reports using the FMC to deviate left of track two miles for weather then forgetting ...

Attributes
ACN	1311168
Time
Date	201511
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	B777-200
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance Deviation - Track / Heading All Types Inflight Event / Encounter Weather / Turbulence

Narrative:

To avoid weather I slopped 2 miles left of track. Once clear of the weather I neglected to return to a strategic lateral offset procedure (slop) right of track. My relief first officer (rfo) noticed the error and we corrected back to a right of track slop. This occurred on a random route across the pacific for a period of approximately 45 minutes.this was my error. I thought a momentary deviation to the left of course to avoid weather would not be a problem. But then I forgot due to distraction with weather and turbulence and maybe a little fatigue. Rather than execute an offset just use heading select to momentary get around a build up. Pay more attention to detail.

Original NASA ASRS Text

Title: A B777 Captain reports using the FMC to deviate left of track two miles for weather then forgetting to return to a right offset for the oceanic crossing.

Narrative: To avoid weather I SLOPPED 2 miles left of track. Once clear of the weather I neglected to return to a Strategic Lateral Offset Procedure (SLOP) right of track. My Relief First Officer (RFO) noticed the error and we corrected back to a right of track SLOP. This occurred on a random route across the Pacific for a period of approximately 45 minutes.This was my error. I thought a momentary deviation to the left of course to avoid weather would not be a problem. But then I forgot due to distraction with weather and turbulence and maybe a little fatigue. Rather than Execute an offset just use heading select to momentary get around a build up. Pay more attention to detail.

Data retrieved from NASA's ASRS site 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.

A B777 captain reports using the FMC to deviate left of track two miles for weather then forgetting to return to a right offset for the oceanic crossing.