# NTSB BFO94LA159: Bell UH-1B, N204JB, Carrabasset, ME, August 31, 1994 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 31, 1994, 14:30 local (18:30 UTC) - Place: Carrabasset, ME - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 18, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 8979 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=BFO94LA159 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8979/pdf - Page: https://openairdocs.org/ntsb/BFO94LA159 ## Probable cause Fracture failure of the tail rotor drive intermediate gearbox. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, hover - rotor drive system,intermediate gearbox(42 deg) - fractured (cause) - Forced landing, emergency descent/landing - autorotation - performed, pilot in command - Hard landing, emergency landing - terrain condition - uphill ## Analysis THE PILOT REPORTED THAT HE WAS ENGAGED IN AN EXTERNAL LOAD OPERATION POURING CONCRETE FROM BUCKETS FOR A NEW SKI LIFT WHEN HE HEARD A LOUD 'BANG' NOISE FOLLOWED BY A GROWLING NOISE AND THE AIRCRAFT NOSE ATTEMPTING TO TURN RIGHT. HE STATED THAT HE ENTERED AUTOROTATION AND LANDED HARD ON UPSLOPING TERRAIN, COLLAPSING THE LANDING SKID. EXAMINATION OF THE AIRCRAFT REVEALED FRACTURE FAILURE OF THE TAIL ROTOR DRIVE SYSTEM INTERMEDIDATE GEAR BOX (42 DEGS). ## Factual narrative On August 31, 1994, at 1430 eastern daylight time, N204JB, a Bell UH-18, owned and operated by Joseph Brigham of Pembroke, New Hampshire, crashed during takeoff at Carrabasset, Maine. The certificated airline transport pilot, the sole occupant, was not injured. The helicopter was substantially damaged. Visual meteorological conditions prevailed and a flight plan was not filed. The helicopter was being operated under 14 CFR 133. According to an FAA Aviation Safety Inspector, this was an external load operation. The pilot reported that a foundation for the ski lift in Sugarloaf Mountain was being constructed, and the helicopter was being used to lift buckets of cement to pour into the foundation. The pilot stated that as the helicopter was lifting the bucket of cement, "...he heard a loud "bang" noise, followed by a growling noise and the aircraft nose attempting to turn right." He stated that he entered autorotation, flared hitting the tail stinger on the upslope, and landed hard with the aircraft still spinning, and broke off the skid landing gear. The helicopter was examined by an FAA Safety Inspector. The examination revealed the tail rotor gear box (42 deg) had separated from the tail boom due to overload. ## Aircraft - Registration: [N204JB](https://openairdocs.org/aircraft/N204JB), registered now, S/N 63-13088, built 1963 (OpenAirDocs) - Reported make and model: BELL UH-1B - Registry model: [Bell UH-1B](https://openairdocs.org/model/bell-uh-1b) (registry code 1181410) (OpenAirDocs) - Registry engine: [Lycoming T-53 series](https://openairdocs.org/engine/lycoming-t-53-series) (registry code 41549, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 63-13088 - Airframe hours: 8502 - Engines: LYCOMING T53-L-11D 1100 horsepower turbo shaft - Damage: Substantial damage - Flight: Business, Part 133 - Operator: Joseph Brigham - Registered owner: Joseph Brigham - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, August 26, 1994, 5 hours before - Departed: ME - Flight plan: VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 30,000 total, 2,500 in this make and model, 200 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 6 knots - Visibility: 15 statute miles - Lowest ceiling: 7,000 ft broken - Temperature: 63 °F, dew point 52 °F - Altimeter: 29.00 inHg - Observed at: AUG, 48 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19940831024429A](https://openairdocs.org/incident/19940831024429A), Aug 31, 1994: Bell UH1B, Carrabasset, ME, Substantial damage. External load ops crashed on takeoff. Autorotated prior impact. Tail rotor gear box separated due to overload. ## Other investigations on N204JB (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB CEN09LA565](https://openairdocs.org/ntsb/CEN09LA565), Sep 6, 2009: Bell UH-1B (N204JB), Arvilla, ND, substantial damage. Probable cause: The aircraft owner/mechanic/pilot's installation of an improper tail boom assembly and the resulting fatigue failure of the tail boom's attach fittings. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.