Narrative:

I was piloting a law enforcement eurocopter AS350BA responding to assist looking for a missing person. I was flying with an experienced tactical flight officer (tfo) who is rated in airplanes only. When we arrived over the incident location we were at 500 ft AGL and approximately 100 KTS. I lowered the collective to decelerate and also began a shallow left hand turn. I noticed the ng passing below 90% but the bleed valve light was not illuminated; as it usually is below 96%. At the same time I heard the sound of compressor stalls from above and behind me. The stalls were continuous and were later reported being heard by deputies on the ground working the same call. I raised the collective per the emergency procedure; but the compressor stalls continued. I continued to manipulate the collective to try and find a position where the condition would stop; but was unable to find one. At that point I noticed the rotor RPM was lowering to the bottom of the yellow arc and I heard the low rotor RPM horn sound. I fully lowered the collective; made a 90 degree turn to the right towards a four lane road and broadcast a 'mayday' over the police radio. My tfo assisted with transmitting our location and asking for additional units while looking out for obstacles and pointing out possible alternative landing locations. When I started the flare to land I found the aircraft to be unstable in the yaw axis as the compressor stalls continued so I elected to do a run-on landing. The engine was still running upon landing and I shut it down immediately with my tfo reading off the checklist to confirm all systems were shut down. There was no damage to the aircraft or property on the ground. The entire event; from first compressor stall to touchdown was approximately 20 seconds.

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Original NASA ASRS Text

Title: An AS350 police helicopter developed compressor stalls at 500 FT AGL. After declaring an emergency they landed uneventfully on a four lane road.

Narrative: I was piloting a law enforcement Eurocopter AS350BA responding to assist looking for a missing person. I was flying with an experienced Tactical Flight Officer (TFO) who is rated in airplanes only. When we arrived over the incident location we were at 500 FT AGL and approximately 100 KTS. I lowered the collective to decelerate and also began a shallow left hand turn. I noticed the Ng passing below 90% but the bleed valve light was not illuminated; as it usually is below 96%. At the same time I heard the sound of compressor stalls from above and behind me. The stalls were continuous and were later reported being heard by deputies on the ground working the same call. I raised the collective per the emergency procedure; but the compressor stalls continued. I continued to manipulate the collective to try and find a position where the condition would stop; but was unable to find one. At that point I noticed the rotor RPM was lowering to the bottom of the yellow arc and I heard the low rotor RPM horn sound. I fully lowered the collective; made a 90 degree turn to the right towards a four lane road and broadcast a 'Mayday' over the police radio. My TFO assisted with transmitting our location and asking for additional units while looking out for obstacles and pointing out possible alternative landing locations. When I started the flare to land I found the aircraft to be unstable in the yaw axis as the compressor stalls continued so I elected to do a run-on landing. The engine was still running upon landing and I shut it down immediately with my TFO reading off the checklist to confirm all systems were shut down. There was no damage to the aircraft or property on the ground. The entire event; from first compressor stall to touchdown was approximately 20 seconds.

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.