Narrative:

Prior to this leg of the mission; I checked weather with the local metars; xm weather; and also called the oncoming duty pilot to check for any significant weather on the radar and other reports. Only thing significant was sct 4;900 ft at ZZZ1 and 7;000 sct or few at ZZZ2. A company aircraft took off in the same general direction to a scene flight about 10 minutes before me from the same location. We talked about the weather enroute and had nothing significant to report except for the 40 KT winds out of the south. Enroute; I climbed to an altitude of approximately 3;900 ft MSL on a direct flight to the scene. We talked to a plane in the pattern at ZZZ3 and said the winds were strong but nothing else would be an issue. We flew about 30 minutes and then encountered a small cloud (less than a second). We had a normal visible horizon for flying over the mountains in that area which I have done numerous times over the last 7 years. I had contacted approach for flight following back to the base. When the next one went by; we started looking to fly in a direction where we had a clear horizon of ground lights. Mostly straight ahead. We then descended to a lower altitude of about 3;500 ft MSL. This did not help either as we then tried to turn left and noticed no horizon/ground lights. Since we still had ground lights to the right; we began to turn back to the right toward better visibility. At this point we began picking up clouds on the right side as well so we turn back to our original heading. At this point; we still had a visible reference straight ahead but the clouds were getting thicker and I decided that descending was not an option due to the uneven terrain that had points as high as 2;420 ft MSL in the area. At this point we decided to not risk turning around and turned to a heading south and contacted approach and declared an emergency and climbed to 4;500 ft MSL. A controller offered assistance and we asked for vectors to the south. We flew in IMC for at least 15 minutes until approach was able to lower us to 4;000 ft MSL which was the MVA for that area and said in 4 miles they would be able to give us lower to 2;500 ft MSL. At this point; we began to pick up ground lights and started to descend at the same time we lost communication with approach. We relayed information through another plane and continued to the scene for an uneventful landing. The problem occurred due to inadequate weather reporting sights along the route and the inability to detect the low lying clouds. Nighttime was a major contributor in that we could not see the clouds coming so we believed the weather report. One thing that occurred during the flight was that I experienced the leans due to radios being mounted on the lower center pedestal. I reached down twice during one point to increase the volume on a radio and also change a setting in the GPS. When I returned to the instruments; I was in an approximate 15 degree bank and had turned 90 degrees off my heading. When I was level again; I looked back down to make another adjustment and it felt like I was level but was turning again. At this point; I focused completely on the attitude indicator to ensure that it was straight and level regardless of how I felt. Bottom line on this event was that I was not going to risk flying the helicopter into a mountain trying to get beneath the clouds. The weather forecast was not correct in the fact that the clouds were not reported in the areas where I was flying.

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Original NASA ASRS Text

Title: Helicopter pilot reports inadvertently entering IMC during VFR night mission. Reporter contacts ATC and declared an emergency. With ATC help mission is completed successfully.

Narrative: Prior to this leg of the mission; I checked weather with the local METARS; XM weather; and also called the oncoming Duty Pilot to check for any significant weather on the radar and other reports. Only thing significant was SCT 4;900 FT at ZZZ1 and 7;000 SCT or FEW at ZZZ2. A company aircraft took off in the same general direction to a scene flight about 10 minutes before me from the same location. We talked about the weather enroute and had nothing significant to report except for the 40 KT winds out of the south. Enroute; I climbed to an altitude of approximately 3;900 FT MSL on a direct flight to the scene. We talked to a plane in the pattern at ZZZ3 and said the winds were strong but nothing else would be an issue. We flew about 30 minutes and then encountered a small cloud (less than a second). We had a normal visible horizon for flying over the mountains in that area which I have done numerous times over the last 7 years. I had contacted Approach for flight following back to the base. When the next one went by; we started looking to fly in a direction where we had a clear horizon of ground lights. Mostly straight ahead. We then descended to a lower altitude of about 3;500 FT MSL. This did not help either as we then tried to turn left and noticed no horizon/ground lights. Since we still had ground lights to the right; we began to turn back to the right toward better visibility. At this point we began picking up clouds on the right side as well so we turn back to our original heading. At this point; we still had a visible reference straight ahead but the clouds were getting thicker and I decided that descending was not an option due to the uneven terrain that had points as high as 2;420 FT MSL in the area. At this point we decided to not risk turning around and turned to a heading south and contacted Approach and declared an emergency and climbed to 4;500 FT MSL. A controller offered assistance and we asked for vectors to the south. We flew in IMC for at least 15 minutes until Approach was able to lower us to 4;000 FT MSL which was the MVA for that area and said in 4 miles they would be able to give us lower to 2;500 FT MSL. At this point; we began to pick up ground lights and started to descend at the same time we lost communication with Approach. We relayed information through another plane and continued to the scene for an uneventful landing. The problem occurred due to inadequate weather reporting sights along the route and the inability to detect the low lying clouds. Nighttime was a major contributor in that we could not see the clouds coming so we believed the weather report. One thing that occurred during the flight was that I experienced the leans due to radios being mounted on the lower center pedestal. I reached down twice during one point to increase the volume on a radio and also change a setting in the GPS. When I returned to the instruments; I was in an approximate 15 degree bank and had turned 90 degrees off my heading. When I was level again; I looked back down to make another adjustment and it felt like I was level but was turning again. At this point; I focused completely on the attitude indicator to ensure that it was straight and level regardless of how I felt. Bottom line on this event was that I was not going to risk flying the helicopter into a mountain trying to get beneath the clouds. The weather forecast was not correct in the fact that the clouds were not reported in the areas where I was flying.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.