Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Commercial
Flight Crew Last 90 Days 150; Flight Crew Total 850; Flight Crew Type 850
Aircraft Equipment Problem Critical; Ground Event / Encounter Ground Strike - Aircraft
Flight Crew Landed in Emergency Condition; Flight Crew Took Evasive Action
Aircraft
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.
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.