Large Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors
On arrival into LIH the tower was closed. We listened to the ASOS and it reported that the visibility was missing. So we pulled up the weather via ACARS and it too was missing the visibility. I queried the Captain if we need a visibility report to land and he did not know. We were able to visually acquire the airport prior to the Instrument Approach Procedure (IAP) and did not have time to further research the question; so we both concluded that the safest course of action was to land. The next night on departure from LIH the ASOS was still reporting the visibility missing as well as the temperature missing. The Captain called dispatch and got the visibility and temperature. The visibility from the flight deck was unrestricted so we continued and took off. In flight I researched the situation further and believe we were in error in landing the first night and in taking off on the second night. [The Operations Manual] states that at an uncontrolled field an approved weather source is available and operational. [It also] states the required elements for a Surface Weather Report and includes visibility and temperature. [Another reference] gives the only approved weather source for LIH as the ASOS. I take full responsibility for not knowing this beforehand; but researching it took several hours and required me to gather knowledge from several different sources and is not something that could be figured out during the arrival segment of a flight. I believe this scenario should be more clearly spelled out somewhere in the [Operations Manual].
Air Carrier First Officer reported landing and departing LIH without weather information.