NYC94FA106 · Sikorsky S-76B
Sikorsky S-76B · Accident: airframe, component or system failure en route
From Goat Island Heliport (RI21) to EHT · East Hartford, CT
Event
- NTSB case
- NYC94FA106
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Sikorsky S-76B
- Aircraft type
- Sikorsky S-76
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N76UT
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Goat Island Heliport (RI21), GOAT ISLAND, RITo EHT · East Hartford, CT
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Airframe, component or system failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Manufacturer › Procedure inadequate
Approximate · Estimated position: the centre of Newport, RI, the place the record names. Not the accident site.
NTSB narrative
AFTER DISCHARGING PASSENGERS ON AN ISLAND, THE S-76 HELICOPTER DEPARTED FOR A RETURN FLIGHT TO THE MAINLAND. ONE MINUTE AFTER TAKEOFF, AT 500 FEET ABOVE THE WATER, A VIBRATION FOLLOWED BY A LOUD BANG OCCURRED. THE MAIN GEAR BOX (MGB) CHIP LIGHT ILLUMINATED AND THE NUMBER ONE ENG DROPPED OFF LINE. A FORCED LANDING WAS INITIATED, THE EMERGENCY FLOATS WERE INFLATED AND A DITCHING TO WATER WAS ACCOMPLISHED. THE NUMBER ONE ENG WAS SHUT DOWN, AND THE ACFT WAS WATER TAXIED ON THE SECOND ENG. AFTER A SECOND BANG WAS HEARD THE NUMBER TWO ENG WAS SHUT DOWN. EXAMINATION REVEALED THAT THE LEFT HAND (NUMBER ONE ENG) HELICAL GEAR IN THE MGB, FAILED FROM FATIGUE CRACKS ACROSS THE 12 ATTACHING BOLT HOLES. THE TORQUE REQUIRED ON THE 12 NUTS WAS 4OO INCH POUNDS. THREE NUTS HAD LESS THEN 60 INCH LBS, THE REMAINING NINE HAD NO TORQUE. BOTH MGB OIL PUMPS WERE SEIZED FROM FOD THAT ENTERED THE PUMPS THROUGH AN ALTERNATE OIL PATH, THAT BY-PASSED THE OIL SCREENS. THE NUMBER TWO ENG PINION GEAR IN THE MGB, FAILED DUE TO OVERHEATING FROM THE LACK OF LUBRICATION. ELAPSED TIME WAS LESS THAN 6 MINUTES FROM INITIAL FORCED LANDING TO SECOND ENGINE SHUT DOWN.
Probable cause
the failure of the left hand helical gear in the main gear box (MGB), due to undertorqued attaching bolts installed by the manufacturer, which resulted in a partial MGB failure. This failure resulted in the loss of the number one engine, illumination of the MGB chip light and a ditching to salt water on emergency floats.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record NYC94FA106
- Event ID
- 20001206X01604
- Case number
- NYC94FA106
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 83405eb7e19892c2f45437cd1de31a87954cf1dc49fcec03cc7c281c960d5061; retrieved 2026-09-23T00:58:37.146Z.