B767 flight crew reported landing at an airport not authorized in the company ops specs.

Attributes
ACN	1605119
Time
Date	201812
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Route In Use	Other Controlled
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Person 2
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Events
Anomaly	Deviation - Procedural FAR Deviation - Procedural Published Material / Policy

Narrative:

My schedule included flights into ZZZ on [multiple days.] although I had never operated into ZZZ myself before; I had seen the trip in our [dispatch package] many times. Yesterday; I was informed that ZZZ was designated as a regular airport for the B757 but only an alternate airport for the B767 in our ops specs. We operated the B767 into ZZZ for three flights before this oversight was found and [company] had the designation changed to right for the B767. I had always thought of the ops specs as something to refer to if the 'plan changed.' this was a great lesson for me to see the importance of referring to the ops specs for every flight even those built into [company's dispatch packages]. It would be helpful to include pertinent information in our [briefing] to save time.

Original NASA ASRS Text

Title: B767 flight crew reported landing at an airport not authorized in the company Ops Specs.

Narrative: My schedule included flights into ZZZ on [multiple days.] Although I had never operated into ZZZ myself before; I had seen the trip in our [dispatch package] many times. Yesterday; I was informed that ZZZ was designated as a Regular airport for the B757 but only an Alternate airport for the B767 in our Ops Specs. We operated the B767 into ZZZ for three flights before this oversight was found and [Company] had the designation changed to R for the B767. I had always thought of the Ops Specs as something to refer to if the 'plan changed.' This was a great lesson for me to see the importance of referring to the Ops Specs for every flight even those built into [Company's dispatch packages]. It would be helpful to include pertinent information in our [briefing] to save time.

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.