Small Transport; Low Wing; 2 Recip Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 7.5
Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued Advisory / Alert
Airspace Structure; Procedure; Weather; Airport
Aircraft X was cleared Rnav-A approach into MDM with instructions to cancel IFR with FSS. During this time frame there were three other situations within our airspace that added complexity to the situation. Opposite direction climbing and descending IFR traffic at OME; IFR departure at GAL climbing through VFR traffic same direction; and three approaches at ANI with bad frequency static heard only by the pilots. We observed Aircraft X west of MDM airport flashing MSAW (Minimum Safe Altitude Warning) and appeared to be on the published missed approach until his route of flight and altitude was cross checked with the published missed approach. The Radar Controller advised my trainee to call FSS to see if Aircraft X canceled IFR. FSS had no contact with Aircraft X so I then told the Radar Controller to issue a MSAW alert. I also had my trainee call FSS back to issue a MSAW alert. During this whole time Aircraft X continued to fly west to 0AK (Pilot Station). I told my trainee to call the high sector to have one of their aircraft try to get a hold of Aircraft X on CTAF and guard frequency. At this point it appeared that they broke off the approach at MDM and was proceeding to 0AK visually; which is not uncommon for pilots in Alaska to do. They will start an approach at an adjacent airport to get below the weather and then proceed to their destination.Knowing that did not take any importance from the severity of the situation. Aircraft X eventually started flying circles around 0AK possibly looking for hole in the clouds to land. We told the supervisor to call airport management at 0AK and MDM; also to call BET tower to see if they had anyway to contact someone at 0AK. We had the high sector begin to monitor for an ELT. An ALNOT (Alert Notice) was issued and I made the decision to 'Lock Down' KSM; 0AK and MDM because all three airports are within very close proximity and we were unsure if Aircraft X landed at 0AK or went to adjacent airport. Eventually ENA FSS called and had confirmation that Aircraft X had arrived at 0AKIt is critical IFR cancellation be received before breaking off an approach.  Until cancellation has been received the pilot has two options; land per the approach plate or execute the published missed approach. If no response is heard from FSS or ATC over frequency they need to use a satellite phone to report cancellation. If they don't have a satellite phone they should buy one before their next flight. The Radar Controller and myself were very concerned that they crashed while circling 0AK looking for a hole in the clouds.
ZAN Center Controller observed an IFR aircraft break off the approach and circle to an adjacent airport. The aircraft had not reported cancelling its IFR clearance.