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B777 first officer reported returning from break and being questioned by shanwick as to why they were offset 3 NM to the right of track. The international relief officer stated that the offset was initiated to avoid wake turbulence from the preceding aircraft without requesting a clearance to do so.
| Attributes | |
| ACN | 1367834 |
| Time | |
| Date | 201606 |
| Local Time Of Day | 0001-0600 |
| Place | |
| Locale Reference | EGGX.ARTCC |
| State Reference | FO |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Make Model Name | B777 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | FMS/FMC |
| Person 1 | |
| Function | First Officer Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 129 Flight Crew Total 10531 Flight Crew Type 129 |
| Events | |
| Anomaly | Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types |
Narrative:
I had just returned to the cockpit from my break/rest period. I was given a quick brief of our flights progress. We had been cleared as filed on a random route at FL370. The flight log was in order and filled out properly; HF frequencies were tuned; and a SELCAL check with shanwick oceanic had already been performed. Ten minutes later we received a SELCAL from shanwick. Upon contacting them via HF; we were asked why our last position report showed us on a 3 mile right offset. I quickly checked the route to confirm our position/strategic lateral offset procedure (slop). It did indeed show R3. I asked the other first officer the reason for the 3 mile offset. He said it was entered because of unusually strong wake turbulence from the aircraft 20 miles ahead and 1;000 feet above. He relayed that to shanwick and stated that we would return to an offset of 0 or 1R. We returned to a slop of R1. I asked the first officer if they sent a request for a right deviation via cpdlc. He said no. The rest of the crossing and flight were uneventful.
Original NASA ASRS Text
Title: B777 First Officer reported returning from break and being questioned by Shanwick as to why they were offset 3 NM to the right of track. The IRO stated that the offset was initiated to avoid wake turbulence from the preceding aircraft without requesting a clearance to do so.
Narrative: I had just returned to the cockpit from my break/rest period. I was given a quick brief of our flights progress. We had been cleared as filed on a random route at FL370. The flight log was in order and filled out properly; HF frequencies were tuned; and a SELCAL check with Shanwick Oceanic had already been performed. Ten minutes later we received a SELCAL from Shanwick. Upon contacting them via HF; we were asked why our last position report showed us on a 3 mile right offset. I quickly checked the route to confirm our position/Strategic Lateral Offset Procedure (SLOP). It did indeed show R3. I asked the other First Officer the reason for the 3 mile offset. He said it was entered because of unusually strong wake turbulence from the aircraft 20 miles ahead and 1;000 feet above. He relayed that to Shanwick and stated that we would return to an offset of 0 or 1R. We returned to a SLOP of R1. I asked the First Officer if they sent a request for a right deviation via CPDLC. He said no. The rest of the crossing and flight were uneventful.
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.