Date: 201712
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: IMC
Weather elements / visibility: Snow
Light: Daylight
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Time Pressure; Situational Awareness
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Diverted; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Weather
Primary problem: Weather

Narrative: ZZZ weather was forecast to be 300/05KT P6SM SCT050 BKN100 at +/- one hour from planned time of arrival. An alternate was not required at the time of dispatch; however it was added enroute when snow conditions began earlier than anticipated. Upon communicating with my dispatcher; he added ZZZ1 as our alternate being that it was the closest acceptable airport with the best weather and we had very little contingency fuel. At that time ZZZ1 reported calm winds; 1-3/4 SM visibility -SN BR BKN024 OVC033 M08/M11. After a few vectors from ATC and when the weather became acceptable we approached ZZZ for the ILS (to the only runway open at the time). The approach controller informed us shortly before the final approach fix that Runway XX was reporting 4500 RVR. As a Restricted Captain I was required to add 1/2SM to visibility in order to be in compliance with FM-1. *Note: The [reporting] system does not allow fractions to be added under the Cause/Weather section of this report; however it was 3/4 SM as reported in the ATIS.* The charted minima for ZZZ ILS XX requires 1/2SM and the weather was above that minima for CAT 1 at; however below the 1 SM/5000 RVR requirement that my restricted status imposed. We therefore abandoned the approach before the final approach fix and notified the approach controller immediately that we would have to divert to ZZZ1. Enroute to our diversion airport; ZZZ1 weather deteriorated to approximately the same conditions we found in ZZZ (4500 RVR for the only runway in use; Runway XY). As we had little other options with the fuel onboard; [ATC was advised] on approach to ZZZ1 Runway XY when the fuel level reached approximately 2100 pounds (near 30 minutes remaining). It was clear that [Captain's] authority was required to land below Restricted Captain Minima and that a go-around would be ill-advised.The cause of this event is attributed to the lack of fuel due to the early onset of snow conditions at the destination. As no alternate was filed or required at the time of dispatch; an alternate had to be added enroute when weather deteriorated at the destination. The situation became more constricted when the alternate weather also dropped below Restricted Captain Minima; directly driving the need to deviate from the higher minima to safely land the aircraft. At the time of planning; the flight was dispatched with adequate fuel; however preemptively adding an alternate - while not required initially - would have been prudent and given the crew more options for alternate airfields with better conditions.




Synopsis: EMB-175 Captain reported that because of weather conditions and low fuel on board the crew landed below restricted captain minima.