Date: 201603
Local time of day: 1201-1800
Location: ZZZ.TRACON, US
Flight conditions: IMC
Light: Daylight
Aircraft: EC135
Operator: Air Taxi
Operating under: Part 135
Mission: Ambulance
Flight phase: Cruise
ATC / advisory: TRACON ZZZ
Reporter organization: Air Taxi
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Commercial
Human factors: Situational Awareness
Anomaly: Inflight Event / Encounter VFR In IMC; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Air Traffic Control Issued New Clearance; Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Human Factors; Weather
Primary problem: Weather

Narrative: We accepted a flight for a hospital transfer [between two hospitals]. When we accepted the flight and launched to the hospital; they did not have an accepting or a bed at [the destination hospital]. Once we arrived at the hospital; the hospital asked if we could change the destination. I pulled the weather up on my phone at the hospital; and the TAF was reporting: Winds 120(ESE) at 4 knots; 6 or more miles vis; and clouds broken at 3;500; OVC at 10;000. When I checked the Helicopter Emergency Medical Services (HEMS) tool; it was clear [along the route]; with only some slight snow trace showing on the radar about mid way along our route of flight. I briefed the crew that we would encounter this snow enroute; but that it was only trace amounts and destination was reporting good weather.We departed the hospital; and there were some trace snow squalls visible to the South West; so I adjusted our flight path to the north slightly to ensure we went along a flight path with the lowest terrain clearance. As we continued along the route; we started to encounter some sparse snow flurries; which corresponded with what I had seen on radar. As we continued along the route; snow continued to increase in intensity. I pulled up ATIS to get the information before contacting approach and the nearby airport was reporting 2.5 miles and 2;900 foot ceilings. We continued based off of that weather report; with the understanding that weather conditions would get better as we got over the higher elevations into the area with lower elevations. Conditions continued to deteriorate; so I prompted approach about the current observations at the airport. Approach informed me that visibility had come down to one mile. At this time; we were struggling to maintain VFR conditions; and we were starting to lose ground references; so I committed to the procedure for Inadvertent Instrument Meteorological Conditions (IIMC). I responded to Approach that I was IMC; and that I needed radar vectors to an approach at the airport. I changed the transponder from assigned squawk to 7700. The auto pilot was already engaged; so I adjusted the auto pilot to initiate a climb. Approach gave us an assigned altitude of 3;000 and started vectoring us for the ILS. The Medcrew contacted Medbase and alerted them that we would be diverting to the airport instead of the hospital. We conducted the ILS without further incident; and as we broke out over the runway; the Paramedic was the first one to see the runway. He called out that he had visual with the runway; and at that moment neither myself; nor the nurse could see it out the right side of the aircraft due to us being positioned slightly right of center line. Once I looked further down out the right side; I observed the runway and continued VFR. We taxied down the taxiway and into parking in front of the FBO. The ambulance was waiting at the FBO to transport the patient and the Medcrew to the hospital.After I landed; four military helicopters cycled into the ramp one at a time as they completed a recovery as well. This flight of four experienced the same deteriorating weather conditions that I experienced and chose the same course of action. They were briefed by military forecasters that had a very similar TAF that I had received from the civilian side. I feel that the un-forecasted weather events led to both myself and the military crews to commit to an IFR solution. I say this because I am not sure that better forecasting would have helped in this situation. I felt comfortable committing to the IIMC procedure due to the extensive training that I received both in the Military and the training I received when doing an aircraft transition into the EC135. I felt comfortable using the autopilot to fly the vectors; and the approach under IMC conditions because I had already done it in the simulator; in training. Now that this event is behind me; the one thing that I would change; if these particular set of circumstances were to happen again is: I would have committed to IIMC recovery sooner and spent less time trying to maintain VFR.




Synopsis: A helicopter pilot reported inadvertently entering IMC; and requesting an IFR clearance and vectors to the city airport from ATC for an ILS approach.