B777 first officer reported a crew communications breakdown regarding dg documents.

Attributes
ACN	1553357
Time
Date	201806
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Parked
Person 1
Function	First Officer
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Procedural Hazardous Material Violation Deviation - Procedural Published Material / Policy Deviation - Procedural FAR

Narrative:

After hazmat inspection I placed the dangerous goods paperwork next to the captain on the pedestal. 10 minutes or so later; while a maintenance personnel was sitting in the cockpit discussing an oil leak; I saw what I thought was the captain's signature on the dg papers; and leaned into the cockpit to get them out of the way. The signature I had seen was that of the dg specialist. I did not double check the paperwork. I kept one; and gave the other to the dg specialist. It was about three hours into the flight that the captain said he didn't recall signing the paperwork. A quick check proved this to be correct. Captain then signed the paperwork. My mistake. I didn't double check the paperwork after I saw what I thought was signed paperwork. Don't make assumptions. Double check.

Original NASA ASRS Text

Title: B777 First Officer reported a crew communications breakdown regarding DG documents.

Narrative: After HAZMAT inspection I placed the dangerous goods paperwork next to the Captain on the pedestal. 10 minutes or so later; while a Maintenance Personnel was sitting in the cockpit discussing an oil leak; I saw what I thought was the Captain's signature on the DG papers; and leaned into the cockpit to get them out of the way. The signature I had seen was that of the DG specialist. I did not double check the paperwork. I kept one; and gave the other to the DG specialist. It was about three hours into the flight that the Captain said he didn't recall signing the paperwork. A quick check proved this to be correct. Captain then signed the paperwork. My mistake. I didn't double check the paperwork after I saw what I thought was signed paperwork. Don't make assumptions. Double check.

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.