# NTSB MIA94LA144: Bell 206B, N72Z, St. Petersburg, FL, May 19, 1994 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: May 19, 1994, 15:42 local (20:42 UTC) - Place: St. Petersburg, FL - Coordinates: 27.849601, -82.630844 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=27.8496&lon=-82.6308&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report January 12, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 37548 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA94LA144 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/37548/pdf - Page: https://openairdocs.org/ntsb/MIA94LA144 ## Probable cause THE FAILURE OF THE NUMBER FIVE BEARING, SHAFT, OR THOMAS COUPLING FOR UNDETERMINED REASONS. CONTRIBUTING TO THE ACCIDENT WAS THE PILOT-IN-COMMAND'S DELAYED RESPONSE IN CONDUCTING THE EMERGENCY PROCEDURE BY NOT REDUCING THE THROTTLE TO IDLE POSITION, AND IMMEDIATELY ENTERING AUTOROTATION. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, takeoff - initial climb - rotor drive system,tail rotor drive shaft bearing - failure,total - rotor drive system,tail rotor drive shaft bearing - undetermined (cause) - rotor drive system,tail rotor drive shaft - failure,total - rotor drive system,tail rotor drive shaft - undetermined (cause) - rotor drive system,tail rotor drive shaft coupling - failure,total - rotor drive system,tail rotor drive shaft coupling - undetermined (cause) - Forced landing, descent - emergency - emergency procedure - delayed, pilot in command (contributing factor) - In flight collision with terrain/water, descent - emergency - terrain condition - water ## Analysis The pilot was on initial takeoff climb at about 60 knots and 200 feet agl when he heard a loud noise from the vicinity of the tail section, followed by an immediate nose heavy condition. A right turn was initiated away from mangrove trees and the collective pitch was lowered. The helicopter started to turn to the right and collided with water and terrain in a nose down, right skid low attitude. Examination of the helicopter by an FAA inspector revealed the number five bearing, thomas coupling, and about 2 feet of the tail rotor driveshaft had separated and were not recovered. ## Factual narrative On May 19, 1994, about 1542 eastern standard time, a Bell 206B, N72Z, registered to Helicopter Inc., operating as a 14 CFR Part 91 aerial observation flight, crashed on initial takeoff climb into the bay near St. Petersburg, Florida. The helicopter sustained substantial damage. The commercial pilot and one passenger received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed. The flight originated from the Channel 10 television helipad about 2 minutes before the accident. The pilot-in-command stated he was in a climb at 60 knots and 200 feet agl when he heard a loud noise from the tail section, and experienced an immediate nose-heavy condition. He initiated a right turn away from the mangrove trees and lowered the collective pitch. The helicopter started to turn to the right and collided with the water. The on-scene investigation was conducted by the FAA. The helicopter was located in Tampa Bay, sitting upright on the skids, adjacent to the 12200 block of Gandy Boulevard. According to the FAA, the helicopter collided with the water and terrain in a nose-down right skid low attitude. A main rotor blade slapped the top of the tail rotor driveshaft cover. The main rotor system separated from the helicopter. The tailboom was bent down aft of the intermediate section of the fuselage. The fuel system was not ruptured. The landing gear was attached with evidence of lateral shift. Examination of the airframe revealed evidence to indicate a mechanical failure of the tail rotor drive system. The No. 5 bearing, thomas coupling, and about 2 feet of the driveshaft had separated, and were not located. Examination of the flight control system, engine assembly and accessories revealed no evidence of a precrash failure or malfunction. Continuity of the flight control system was confirmed for pitch, roll, and yaw with the fracture in the tail rotor pitch tube exhibiting failures consistent with overload. Selected parts were shipped to the Bell Helicopter Textron Field Investigations Laboratory for examination. The laboratory concluded, all of the fractures and damage that occurred on the cover assembly, 90-degree gearbox upper and lower fairings, driveshaft hanger assembly, driveshaft segment, tail rotor pitch change tube, tailboom, and the main rotor blades resulted in overload. The 90-degree tail rotor gearbox was operational. The tailboom was fractured forward of the 90-degree gearbox, and the aft end of the tailboom was bent upward, and forward indicating it had received loads from below. The tail rotor driveshaft bearing hanger had fractured due to overload. Rubbing was present on the tailboom adjacent to the hanger where the Thomas coupling had been spinning, and the driveshaft hanger bracket where the bearing hanger and the Thomas coupling were mounted showed evidence of rubbing. (For additional information see, Bell Helicopter Report No. 20694R-006). The Bell Long Ranger Rotorcraft Flight Manual, Section 3, EMERGENCY AND MALFUNCTION PROCEDURES, PAGE 3-10, 3-14. COMPLETE LOSS OF TAIL ROTOR THRUST states, "IN-FLIGHT reduce throttle to idle, immediately enter autorotation, and maintain a minimum AIRSPEED of 52 KIAS (60 MPH) during descent." The helicopter parts were returned to Mr. William E. Roach Jr., Oldsmar, Florida, by Bell Helicopter on October 12, 1994. The parts were signed for by Mr. Joel Robinson, Oldsmar, Florida, on October 13, 1994. ## Aircraft - Registration: [N72Z](https://openairdocs.org/deregistered/N72Z-2012-04-12), registration cancelled 2012-04-12, S/N 3537, built 1981 (OpenAirDocs) - Reported make and model: BELL 206B - Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs) - Registry engine: [Allison 250-C20 series](https://openairdocs.org/engine/allison-250-c20-series) (registry code 03020, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 3537 - Engines: ALLISON 250-C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial observation, Part 91 - Registered owner: Helicopter Inc. - Airworthiness certificate: Standard, Normal ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 58; commercial; airplane ratings: single-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 11,000 total, 6,000 in this make and model, 10,800 as pilot in command, 120 in the last 90 days, 40 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 15 statute miles - Lowest ceiling: none - Temperature: 88 °F, dew point 64 °F - Altimeter: 29.00 inHg - Observed at: TPA, 8 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 19940519011809A](https://openairdocs.org/incident/19940519011809A), May 19, 1994: Bell 206B, St Petersburg, FL, Substantial damage. Loud noise on climb over bay. Lost tailrotor control. Ditched. Tail rotor drive shaft bearing and hangar failed. 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.