South-76 flight crew reported loss of tail rotor effectiveness on takeoff.

Attributes
ACN	1689954
Time
Date	201910
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	S-76/S-76 Mark II
Operating Under FAR Part	Part 135
Flight Phase	Takeoff
Route In Use	Direct Visual Approach
Flight Plan	VFR
Component
Aircraft Component	Tail Rotor
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Multiengine Flight Crew Rotorcraft Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 120 Flight Crew Total 2184 Flight Crew Type 55
Person 2
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine Flight Crew Rotorcraft Flight Crew Instrument
Experience	Flight Crew Last 90 Days 100 Flight Crew Total 15000 Flight Crew Type 8000
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy

Narrative:

Winds were out of the east at 10-15 kts in VFR conditions; and the aircraft was oriented directly into the wind. The helideck of the platform is located on the south side of the superstructure; with obstacles to the north. Upon departure from the platform; the aircraft began an unexpected right yaw and began to drift in a southwestern direction. Once the aircraft began to rotate; I as the first officer took control; believing the PIC (pilot in command) to be disoriented; as I had not heard a verbal acknowledgement after taking control. On the second or third spin; I was able to regain directional control through the application of left pedal and slight left cyclic while oriented to the east into the wind. I then lowered the nose in order to gain airspeed and was able to regain full control and recover the aircraft at roughly 50 feet AGL. After establishing a climb; I coupled the flight controls to the flight director; began a turn to the northwest; and relinquished controls back to the PIC.we then began an analysis of the aircraft; checking for any warning/cautions/advisories; any unusual vibrations in the flight controls; or any indications that an aircraft limit had been exceeded. None were present; and based on this information we continued our flight as planned. We made two more subsequent stops to drop off passengers and cargo; and terminated our flight. We conducted a normal shutdown; and then noticed we had used transient power; seven seconds into a two-minute power limit. Maintenance was notified; and we as a crew notified our supervisor of what had taken place.

Original NASA ASRS Text

Title: S-76 flight crew reported loss of tail rotor effectiveness on takeoff.

Narrative: Winds were out of the east at 10-15 kts in VFR conditions; and the aircraft was oriented directly into the wind. The helideck of the platform is located on the south side of the superstructure; with obstacles to the north. Upon departure from the platform; the aircraft began an unexpected right yaw and began to drift in a southwestern direction. Once the aircraft began to rotate; I as the First Officer took control; believing the PIC (Pilot in Command) to be disoriented; as I had not heard a verbal acknowledgement after taking control. On the second or third spin; I was able to regain directional control through the application of left pedal and slight left cyclic while oriented to the east into the wind. I then lowered the nose in order to gain airspeed and was able to regain full control and recover the aircraft at roughly 50 feet AGL. After establishing a climb; I coupled the flight controls to the flight director; began a turn to the northwest; and relinquished controls back to the PIC.We then began an analysis of the aircraft; checking for any warning/cautions/advisories; any unusual vibrations in the flight controls; or any indications that an aircraft limit had been exceeded. None were present; and based on this information we continued our flight as planned. We made two more subsequent stops to drop off passengers and cargo; and terminated our flight. We conducted a normal shutdown; and then noticed we had used transient power; seven seconds into a two-minute power limit. Maintenance was notified; and we as a crew notified our Supervisor of what had taken place.

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.