# NTSB FTW98LA144: Bell 47D1, N13012, Jeanerette, LA, March 11, 1998 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: March 11, 1998, 16:00 local (22:00 UTC) - Place: Jeanerette, LA - Coordinates: 29.910903, -91.6707 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.9109&lon=-91.6707&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report February 15, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 20551 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW98LA144 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20551/pdf - Page: https://openairdocs.org/ntsb/FTW98LA144 ## Probable cause The in-flight disconnect of the rotating scissors due to the separation of its hinge bolt. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - vfr pattern - final approach - rotorcraft flight control,rotating scissors - disconnected (cause) - miscellaneous,bolt/nut/fastener/clamp/spring - separation (cause) - Forced landing, descent - emergency - Roll over, landing - flare/touchdown - aircraft control - not possible, pilot in command(cfi) ## Analysis The dual student pilot was practicing landings in the local practice area, and had completed 4 to 5 landings. On the next landing, they were heading west, level at 350 feet agl, with an airspeed of 35 mph. As the student lowered the collective to initiate a steep approach, a severe vertical vibration was encountered. About 2 to 3 seconds later, a severe lateral vibration began. The flight instructor took the controls and continued the descent towards the landing area. At about 10 feet the instructor tried to reduce forward airspeed and descent rate by moving the cyclic aft and raising the collective. 'Neither of those inputs seemed to help a lot and we impacted hard.' The helicopter rolled over to the left before coming to rest heading to the east. There were no reported problems with tail rotor control. Examination of the helicopter by the FAA inspector revealed that the scissor hinge bolt which attaches the scissor to the swash plate was missing. He added that according to the maintenance records, the 5, 258 helicopter, underwent a 100 hour inspection on February 15, 1998, approximately 20 hours prior to the accident. ## Factual narrative On March 11, 1998, at 1600 central standard time, a Bell 47D1 helicopter, N13012, registered to and operated by Penn Tex Helicopters, Inc., was substantially damaged during a forced landing following a loss of control near Jeanerette, Louisiana. Visual meteorological conditions prevailed, and a flight plan was not filed for the Title 14 CFR Part 91 instructional flight. The flight instructor was not injured, and the commercial pilot receiving instruction sustained minor injuries. The flight originated from the Penn Tex Helicopters Heliport, Jeanerette, Louisiana, about 45 minutes prior to the accident. The flight instructor reported to the NTSB investigator-in-charge that his student was practicing landings in the local practice area, and they had completed 4 to 5 landings. On the next landing, they were heading west, level at 350 feet AGL, with an airspeed of 35 mph. As the student lowered the collective to initiate a steep approach, a severe vertical vibration was encountered. About 2 to 3 seconds later, a severe lateral vibration began. The flight instructor took the controls and continued the descent towards the landing area. "At about 100 feet I saw that we were in [a] direct collision course with a ditch and so I moved the cyclic to the left. This resulted in a slight left turn which turned us away from the ditch." At about 10 feet the instructor tried to reduce forward airspeed and descent rate by moving the cyclic aft and raising the collective. "Neither of those inputs seemed to help a lot and we impacted hard." The helicopter rolled over and came to rest heading east. The operator/instructor reported no problems with tail rotor control. Examination of the helicopter by the FAA inspector revealed that the left skid and tail boom were found separated from the fuselage, the main rotor and tail rotor sustained damage. Further examination of the main rotor system revealed that the scissor hinge bolt which attaches the scissor to the swash plate was missing. He added that according to the maintenance records, the 5, 258 hour helicopter, underwent a 100 hour inspection on February 15, 1998, approximately 20 hours prior to the accident. ## Aircraft - Registration: [N13012](https://openairdocs.org/deregistered/N13012-2018-02-08), registration cancelled 2018-02-08, S/N 648, built 1953 (OpenAirDocs) - Reported make and model: Bell 47D1 - Registry model: [Bell 47D1](https://openairdocs.org/model/bell-47d1) (registry code 1180802) (OpenAirDocs) - Registry engine: [Franklin 6V4 series](https://openairdocs.org/engine/franklin-6v4-series) (registry code 27033, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 648 - Airframe hours: 5258 - Engines: Lycoming VO-435-A1B 260 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Penn Tex Helicopters, Inc. - Airworthiness certificate: Special, Restricted (Special); Standard, Normal - Last inspection: 100 hour, February 15, 1998, 20 hours before - Departed: NONE ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 29; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 2,753 total, 335 in this make and model, 3,486 as pilot in command, 176 in the last 90 days, 36 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 5 knots - Visibility: 15 statute miles - Lowest ceiling: none - Temperature: 61 °F ## 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 19980311003149A](https://openairdocs.org/incident/19980311003149A), Mar 11, 1998: Bell 47D1, Jeanerette, LA, Substantial damage. Heli was practicing approaches when it started to vibrate vertically and laterally, landed hard. Jeanerette, LA (-23) on March 12, 1998, it was reported that… ## Other investigations on N13012 (3) 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 CHI84LA181](https://openairdocs.org/ntsb/CHI84LA181), May 6, 1984: Bell 47D-1 (N13012), Ridge Farm, IL, substantial damage - [NTSB FTW75DPG02](https://openairdocs.org/ntsb/FTW75DPG02), Jul 6, 1974: Bell 47D-1 (N13012), Almyra, AR, substantial damage - [NTSB NYCA3FKM14](https://openairdocs.org/ntsb/NYCA3FKM14), Oct 6, 1972: Bell 47D1 (N13012), Charlotte, NC, substantial damage 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.