B767 first officer reported uncommanded left roll when extending speedbrakes.

Attributes
ACN	1612733
Time
Date	201901
Local Time Of Day	0001-0600
Place
Locale Reference	EWR.Airport
State Reference	NJ
Aircraft 1
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Component
Aircraft Component	Spoiler System
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Inflight Event / Encounter Weather / Turbulence

Narrative:

During descent on the ANJLL4 arrival; the captain (pilot flying) used the speedbrake lever. As the lever was extended; the aircraft started an abrupt roll to the left. It was confirmed via the synoptic display that the spoilers on the left and partially on the right were not extending. The crew extended the gear to slow the aircraft to the ATC requested speeds during approach as there was no way to slow without properly functioning spoilers. Aircraft malfunction. Heavy rain in ZZZ could have frozen the controls in cruise flight. Examine each aircraft to make sure water intrusion doesn't happen.

Original NASA ASRS Text

Title: B767 First Officer reported uncommanded left roll when extending speedbrakes.

Narrative: During descent on the ANJLL4 arrival; the Captain (Pilot Flying) used the speedbrake lever. As the lever was extended; the aircraft started an abrupt roll to the left. It was confirmed via the synoptic display that the spoilers on the left and partially on the right were not extending. The crew extended the gear to slow the aircraft to the ATC requested speeds during approach as there was no way to slow without properly functioning spoilers. Aircraft malfunction. Heavy rain in ZZZ could have frozen the controls in cruise flight. Examine each aircraft to make sure water intrusion doesn't happen.

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.