Narrative:

We had just departed ZZZ on a northwest heading to intercept the transition route westbound 3-4nm northwest of ZZZ cruising at 80 knots indicated at 1300 feet msl. We were given a vector to turn left 260 for traffic avoidance. Just as the left turn was initiated; the helicopter began a series of lateral oscillations accompanied with a high frequency vibration.the low rotor light illuminated along with the low RPM horn sounding. The helicopter began a rapid yaw to the left (35 - 45 degrees) and pitched up slightly. The main rotor transmission temp/press light illuminated during this time. Collective was immediately lowered and full throttle applied with a great amount of aft cycle to try and help maintain rotor RPM.a left turn roughly 90 degrees was made toward a lighted area that appeared to be a parking lot. Upon very short final it was clear that the spot was actually a garbage truck storage area with fine gravel terrain. Due to the possibility of a run on into one of the trucks; an excessive flare was made to reduce all ground speed which resulted [in] the tail stinger contacting the ground. The helicopter came to a stop at a level attitude in a complete brown-out due to the dust on the ground. I reported no injuries and no assistance was needed. By the time I was done communicating the ordeal with tower my student had already pulled the mixture and fuel cut off along with turning off all switches except for comms.

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Original NASA ASRS Text

Title: Shortly after takeoff; at 80 knots and commencing a left turn; H269C helicopter instructor pilot encountered lateral oscillations; high frequency vibrations; and subsequent Low Rotor RPM warning and Main Rotor Transmission Temp/Press light. Pilot executed a successful forced landing in a gravel parking lot.

Narrative: We had just departed ZZZ on a NW heading to intercept the transition route westbound 3-4nm NW of ZZZ cruising at 80 knots indicated at 1300 feet msl. We were given a vector to turn left 260 for traffic avoidance. Just as the left turn was initiated; the helicopter began a series of lateral oscillations accompanied with a high frequency vibration.The Low Rotor Light illuminated along with the Low RPM horn sounding. The helicopter began a rapid yaw to the left (35 - 45 degrees) and pitched up slightly. The Main Rotor Transmission Temp/Press light illuminated during this time. Collective was immediately lowered and full throttle applied with a great amount of aft cycle to try and help maintain rotor RPM.A left turn roughly 90 degrees was made toward a lighted area that appeared to be a parking lot. Upon very short final it was clear that the spot was actually a garbage truck storage area with fine gravel terrain. Due to the possibility of a run on into one of the trucks; an excessive flare was made to reduce all ground speed which resulted [in] the tail stinger contacting the ground. The helicopter came to a stop at a level attitude in a complete brown-out due to the dust on the ground. I reported no injuries and no assistance was needed. By the time I was done communicating the ordeal with Tower my student had already pulled the mixture and fuel cut off along with turning off all switches except for comms.

Data retrieved from NASA's ASRS site 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.