Date: 201702
Local time of day: 1201-1800
Location: ZBW.ARTCC, NH
Flight conditions: IMC
Weather elements / visibility: Icing
Aircraft: Light Transport
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Ambulance
Flight phase: Descent
Airspace: Class E ZBW
ATC / advisory: Center ZBW
Reporter organization: Government
Reporter function: Approach; Departure; Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Distraction; Situational Awareness
Second reporter function: Handoff / Assist
Anomaly: ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Air Traffic Control Provided Assistance
Contributing factors: Airspace Structure; Airport; Human Factors; Weather; Procedure
Primary problem: Weather

Narrative: Aircraft X was trying to land at CYES (an uncontrolled airport without an instrument approach). I descended him to 050 for arrival. I advised him of moderate rime icing in the vicinity from a PQI departure with the altitudes and temperature. I advised him that no weather was available for CYES and offered him the FVE weather since it was the closest airport. I provided him the FVE special observation and advised him to contact FSS for the current NOTAMS. He advised that his intentions were to land at CYES visually and advised that his plan was to fly the RNAV approach into FVE via the IAF if he was unable to get the field in sight. He asked for a lower altitude to get ground contact.I descended him to 031 which is the Minimum IFR Altitude (MIA) around PQI. Montreal center called to get an updated departure time for Aircraft X and advised that they were blocking the airspace for him. By this time the complexity of the sectors was rapidly increasing due to weather and increased traffic. I provided Aircraft X with the updated weather at FVE and asked his intentions. He wanted to continue and try to get the field in sight. The PQI departure that had reported moderate rime icing was now reporting severe icing and requesting a climb to avoid.I called the Controller in Charge (CIC) over to report the severe icing while getting further reports from [the PQI departure]. A D side was provided at this time and while they were being briefed; I noticed that Aircraft X had entered the 035 MIA. I told Aircraft X that if he didn't have the field in sight that he needed to climb to 035. He advised that he did not have the field and was climbing. He stated that he couldn't get the field in sight and wanted to fly the RNAV for FVE. He was issued a right turn to 110 to avoid a higher MVA. While this was occurring; a BGR departure (which I leveled at 100 due to a BGR arrival at 110) reported moderate rime icing at 100. This report was passed to an ALTRAV that was entering the sector that was also landing BGR. I asked the CIC to split the sectors due to complexity and Surry Sector was split off. Any time that an aircraft is going to enter uncontrolled airspace an MSAW alert goes off due to the fact that the MIA is listed as 128. An MSAW alert would be expected and would be looked over. I recommend that there be an instrument approach into CYES.


Second narrative: I was returning from my break and began running the list to see which Certified Professional Controller (CPC) was ready for a break. The CIC at the time asked me to open up 15/16 D-Side; to assist the radar controller; because there was weather and icing in the Surry sector. As I was opening up the D-side; and getting myself caught up on the traffic situation; the radar controller announced to me that he had mistakenly descended an aircraft below the MIA at 031 in a 035 feet shelf. The aircraft call sign was Aircraft X and it was inbound to CYES; which is an airport in uncontrolled airspace just outside our airspace. The weather conditions were very IFR at CYES. I am not sure why the radar controller descended the aircraft below the MIA; since it happened right as I was sitting down. I am thinking that he was trying to use the TAA [Terminal Arrival Area] for the RNAV 32 approach into the neighboring airport FVE in hopes that the aircraft would get CYES in sight and be able to proceed visually. Unfortunately; I do not know further details about how or why the aircraft was below the MIA. The radar controller was actively working with the CIC to remedy the situation at the time; and then the CIC quickly split the sectors as the next controller was walking into the control room right at that time. There is a lot of ambiguity surrounding aircraft landing at CYES; since it is in uncontrolled airspace and is in Canada. There are no instrument approaches going into that airport; so many times controllers are able to successfully use the approach into FVE to get the aircraft to get CYES in sight. Unfortunately; there is no other way to allow the aircraft to descend below 035 without using that to be able to get low enough to get the airport in sight. It would be very helpful to have an airway that went from PQI to YYY VOR that would allow an aircraft to descend below the 035 MIA; or better yet; an instrument approach going into CYES airport.


Synopsis: ZBW Controllers reported that an aircraft was descended below the Minimum IFR Altitude in error to get it below clouds to see the airport.