B767 flight crew reported having flown to destination that is not authorized per company ops specs.

Attributes
ACN	1605111
Time
Date	201812
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Flight Plan	IFR
Person 1
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Captain Pilot Flying
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument
Events
Anomaly	Deviation - Procedural FAR Deviation - Procedural Published Material / Policy

Narrative:

We were scheduled to operate to ZZZ as scheduled. While reviewing the departure papers we noticed a company NOTAM that restricted using ZZZ as an alternate for B767s. The captain called the dispatcher questioning our ability to operate a B767 into ZZZ. After a brief time on hold; the captain was assured this only applied to using ZZZ as an alternate we were okay to go to ZZZ. We operated as schedule and continued to operate this pairing the next two nights. We were later informed [company] discovered that [ops specs] only granted authorization for the B767 to use this airport as an alternate.

Original NASA ASRS Text

Title: B767 flight crew reported having flown to destination that is not authorized per company Ops Specs.

Narrative: We were scheduled to operate to ZZZ as scheduled. While reviewing the departure papers we noticed a company NOTAM that restricted using ZZZ as an alternate for B767s. The Captain called the Dispatcher questioning our ability to operate a B767 into ZZZ. After a brief time on hold; the Captain was assured this only applied to using ZZZ as an alternate we were okay to go to ZZZ. We operated as schedule and continued to operate this pairing the next two nights. We were later informed [Company] discovered that [Ops Specs] only granted authorization for the B767 to use this airport as an alternate.

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.