Date: 202009
Local time of day: 1201-1800
Location: C90.TRACON, IL
Flight conditions: Marginal
Aircraft: Small Aircraft; Low Wing; 1 Eng; Fixed Gear
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Final Approach
Airspace: Class B ORD
ATC / advisory: TRACON C90
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Distraction; Physiological - Other; Communication Breakdown
Anomaly: ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Track / Heading All Types; Flight Deck / Cabin / Aircraft Event Illness / Injury; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance; Flight Crew Regained Aircraft Control
Contributing factors: Aircraft; Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: I took over the position after the previous controller had cleared the aircraft for an ILS Approach. Shortly thereafter; I noticed that the aircraft was drifting left of course. I asked the pilot if he was correcting. He replied something unintelligible and 'ILS'. I watched him for a few more seconds at which point he seemed to start zigzagging across the localizer. I asked him if he was okay; and I believe I received no reply. I then told the pilot to climb and maintain 3;000 feet and fly heading 360. I don't believe he replied to that either. After a few more seconds; it became obvious to me that the pilot had vertigo and was spiraling the aircraft in a left turn. I told the pilot that he probably doesn't realize it; but he was in a tight left turn and he needed to level his wings. During this whole process; I believe he transmitted a few times; but usually it was what sounded like a grunting noise. Shortly after the tight turns; he lost control of his altitude; and began climbing rapidly upwards a few thousand feet; and then stalled out and plunged back to within a few hundred feet of the ground; repeatedly.During the entire time I continued to encourage him to level his wings and try to level out his altitude; and fly any heading of his choosing. The controllers around me assisted in trying to locate a nearby VFR airport (there were none); and controlling airplanes that normally would have been controlled on my frequency. After about 10 minutes of terror; he finally gained control of the aircraft and flew on a 190 heading at 3;000 feet. I left him flying that course and altitude for several miles to try to clear his vertigo. During this time; he requested the RNAV approach. To keep him from getting vertigo again; I turned him no more than 90 degrees at a time and did not change his altitude; and then left him on the new heading for a minute or two before turning additional degrees to get him setup for the RNAV approach. Once he was nearly straight-in with the runway; I cleared him for the RNAV approach and he landed without further incident.After speaking to people familiar with the [aircraft]; it seems apparent to me that this pilot was not only unprepared for the weather he was flying in; but also unfamiliar with all of the systems of his aircraft. Apparently; he could have just pressed a button and the aircraft would have leveled off on it's own. Although it is probably beyond the scope of the FAA; but my recommendation would be that [aircraft's] pilots receive more training on the proper handling of their aircraft in IMC conditions.For controllers; perhaps more information on what we can or should suggest to pilots who encounter this type of situation. As a flight instructor; I had some ideas of what to say to him; but I don't know if all other controllers would know this. Also; it was suggested to me to tell the pilot to pull his parachute. I do not know the legality of saying that to the pilot would be; especially if it resulted in a worse outcome. On the other hand; if he had crashed the aircraft; would the FAA had preferred that I suggest pulling the parachute? I don't know.




Synopsis: A TRACON Controller reported a pilot on his frequency lost control of their aircraft due to vertigo but with the Controller's assistance was able to regain control and land safely.