# NTSB ATL99LA107: Continental Copters Tomcat MK5A, N9086T, Camden, AL, July 14, 1999 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 14, 1999, 19:30 local (23:30 UTC) - Place: Camden, AL - Coordinates: 31.989652, -87.289352 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=31.9897&lon=-87.2894&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report November 30, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 46797 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL99LA107 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/46797/pdf - Page: https://openairdocs.org/ntsb/ATL99LA107 ## Probable cause The failure of the cyclic control rod due to an overstress separation resulting from a material defect (inadequate quality of material) by the manufacturer. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, maneuvering - aerial application - rotorcraft flight control,cyclic control rod - overload (cause) - material defect(inadequate quality of material), manufacturer (cause) - Loss of control - in flight, maneuvering - aerial application - In flight collision with terrain/water, descent - emergency ## Analysis The pilot had completed a second pass over the field he was spraying when he lost cyclic control of the helicopter. He reduced power and the helicopter impacted the ground, coming to rest on its right side. The helicopter's cyclic control rod was metallurgically examined. One end of the cyclic control rod had separated at the thread relief radius and the failure appeared consistent with an overstress separation. Hardness readings taken during an ultrasonic inspection revealed the tensile strength was below the original rod design strength. ## Factual narrative On July 14, 1999, at 1930 eastern daylight time, a Continental Copters Inc. Tomcat MK5A helicopter, N9086T, collided with the ground following a loss of cyclic control during a low altitude aerial application maneuver in Camden, Alabama. The helicopter was operated by Farm Flying Service, Inc. under the provisions of Title 14 CFR Part 137, and visual flight rules. Visual meteorological conditions prevailed, and no flight plan was filed for the local agricultural flight. The commercial pilot received minor injuries, and the helicopter sustained substantial damage. The flight originated from Camden, Alabama, at an unknown time. According to the pilot, he had just completed a second pass over the field he was spraying when he lost cyclic control of the helicopter. He stated that he reduced power and the helicopter impacted the ground, coming to rest on its right side. The helicopter's cyclic control rod (P/N 074-140-843-11) was sent to the NTSB's Materials Laboratory for analysis. One end of the cyclic control rod had separated at the thread relief radius, and the other end was bent at the thread relief radius. The fractured end of the control rod was examined. The fractured face appeared perpendicular to the control rod axis for approximately 50 percent of the diameter. The fractured face then reversed direction, leaving a lip "typical of compressive bending." According to the report, the "surface features on the fracture face appeared to be consistent with an overstress separation." The separated end of the control rod was removed and ultrasonically inspected. The surface of the fracture face revealed "ductile dimples indicative of an overstress situation." Hardness readings taken from the flats of the separated end ranged from a tensile strength of 101,000 to 116,000 psi (pounds per square inch), to that of 99,000 to 117,000 psi on a different scale. According to the control rod drawing (074-140-843-9) supplied by the Texas Helicopter Company, both readings were below the original rod strength of 125,000 to 145,000 psi. ## Aircraft - Registration: [N9086T](https://openairdocs.org/deregistered/N9086T-2013-05-17), registration cancelled 2013-05-17, S/N CCI-78-1, built 1978 (OpenAirDocs) - Reported make and model: Continental Copters TOMCAT MK5A (TOMCAT MK5) - Registry model: [Continental Copters TOMCAT MK5A](https://openairdocs.org/model/continental-copters-tomcat-mk5a) (registry code 2390101) (OpenAirDocs) - Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: CCI-78-1 - Engines: Lycoming VO-435 260 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Ed W. Buford, doing business as Gulf Helicopters Inc. - Registered owner: Farm Flying Service, Inc. - Airworthiness certificate: Special, Restricted (Special) - Departed: PVT, AL ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 4,000 total, 300 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 40° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 9,500 ft overcast - Temperature: 81 °F, dew point 73 °F - Altimeter: 30.00 inHg - Observed at: GZH, 75 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 19990714009359A](https://openairdocs.org/incident/19990714009359A), Jul 14, 1999: Ccoptr TOMCATMK5A, Camden, AL, Substantial damage. Acft was involved in aerial application when the flight controls failed, the pilot lost control of the acft, and the acft crashed. (.4)the pilot had completed… ## Other investigations on N9086T (2) 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 MIA88LA250](https://openairdocs.org/ntsb/MIA88LA250), Aug 10, 1988: Continental Copters MK-5A (N9086T), Valley Park, MS, substantial damage - [NTSB MIA86LA228](https://openairdocs.org/ntsb/MIA86LA228), Aug 5, 1986: Continental Copters Tomcat MK5A (N9086T), Indiantown, FL, 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.