Date: 201707
Local time of day: 1801-2400
Location: ALO.TRACON, IA
Weather elements / visibility: Rain
Aircraft: PA-32 Cherokee Six/Lance/Saratoga/6X
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class E ALO
ATC / advisory: TRACON ALO
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Confusion; Communication Breakdown; Situational Awareness; Troubleshooting
Anomaly: Deviation - Altitude Excursion From Assigned Altitude; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT; 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; Flight Crew Became Reoriented; Flight Crew Landed in Emergency Condition; Flight Crew Regained Aircraft Control; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Human Factors; Weather; Aircraft
Primary problem: Human Factors

Narrative: I was working Arrival position and was also Controller in Charge (CIC). There were some areas of weather in my airspace as well as the surrounding areas. I had just taken the position when Aircraft X checked on frequency entering my airspace as an overflight at 7000 feet. Our facility does not have weather radar so I advised the pilot of possible area of precipitation at 11 o'clock; 10 miles extending 15 miles northeast; type and intensity unknown. He acknowledged and said he would look out for it. The previous sector called to advise that Aircraft X was deviating south of course for weather.Approximately 10 minutes later I observed Aircraft X's altitude had dropped to 6500 feet very quickly. I asked him to say altitude. I received a garbled; unreadable response. I tried to contact him again and he responded with 'I need help air traffic'. His altitude was dropping rapidly during this time. I asked him how I could assist him but received no response. I told him that it appeared he was in a descent and asked if he was encountering weather. After no response again I transmitted to respond when able for assistance. His next transmission was to ask if air traffic was with him and I told him I was. He did not respond and was continuing to descend. I advised him that an airport was 20 miles southeast of his position if he needed to land. He still did not respond and at that point it appeared he would not recover from the spiral dive he seemed to be in.Another airport was 2 miles northwest of his position. As I was broadcasting the location of this airport to him the low altitude alert went off so I added that into the transmission. I only stated 'Low Altitude Alert; I'm showing you at one thousand niner hundred descending.' The Minimum Vectoring Altitude where he was at is 3000 feet and the lowest I saw him at was 1800 feet. He climbed to around 2000 feet so I suggested a 180 heading to avoid the weather in case that was the issue. I attempted contact again with no response. He finally reestablished contact and said he wanted to come in and land. I asked if he could climb and what his heading was. He said yes and that he was heading 114. I told him to climb to 3000 feet and remain on current heading for the airport. I asked if he needed assistance when he landed and he said no. I gave him to expect a Visual Approach and gave him the winds; runway and altimeter. When he reported airport in sight I cleared him for a Visual Approach and switched him to the tower. He landed without incident and was asked to call the facility. I didn't speak to him but he advised the Supervisor that he got disoriented in the clouds and that his headset cord came unplugged during the descent. I'm not sure there's anything that can be done by ATC to prevent this kind of situation. For pilots I would recommend avoiding flying if there is weather along your route of flight or deviate well away from it.




Synopsis: ALO TRACON Controller reported a temporary loss of contact with an aircraft which descended on its own to an altitude below the Minimum Vectoring Altitude.