# NTSB DEN93LA091: Continental Copters Tomcat MK5A, N9014T, Duson, LA, July 30, 1993

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 30, 1993, 09:30 local (14:30 UTC)
- Place: Duson, LA
- Coordinates: 30.229238, -92.190147 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=30.2292&lon=-92.1901&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report November 19, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 18305
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN93LA091
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18305/pdf
- Page: https://openairdocs.org/ntsb/DEN93LA091

## Probable cause

FAILURE OF THE TRANSMISSION MAST BEARING, RESULTING IN OIL CONTAMINATION AND SUBSEQUENT BLOCKAGE OF THE INTERNAL OIL PORTS AND PASSAGES.  FACTORS WERE: TOTAL LOSS OF COLLECTIVE CONTROL AND PARTIAL LOSS OF CYCLIC CONTROL.

## 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
  - rotor drive system,main gearbox/transmission - failure,total (cause)
  - fluid,oil - contamination (cause)
  - lubricating system,oil port/passage,internal - blocked(total) (cause)
- Forced landing, descent - emergency
- Hard landing, landing - flare/touchdown

## Analysis

WHILE ENGAGED IN AN AERIAL APPLICATION OPERATION, THE PILOT HEARD BANGING NOISES AND THE ENGINE BEGAN TO OVERSPEED. ALTHOUGH COLLECTIVE CONTROL WAS INEFFECTIVE, THE PILOT WAS ABLE TO MANEUVER THE HELICOPTER TO A HARD LANDING USING THROTTLE AND PARTIAL CYCLIC CONTROL.  POST ACCIDENT INVESTIGATION DISCLOSED THE TRANSMISSION MAST BEARING HAD FAILED, CONTAMINATING THE OIL WITH STEEL PARTICLES THAT OBSTRUCTED THE INTERNAL OIL PASSAGES.

## Aircraft

- Registration: [N9014T](https://openairdocs.org/deregistered/N9014T-2018-03-09), registration cancelled 2018-03-09, S/N CCI74-5, built 1974 (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: CC174-5
- Airframe hours: 3786
- Engines: LYCOMING VO-435-A1F 260 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Penn-Tex Helicopters, Inc.
- Registered owner: Penn-Tex Helicopters, Inc.
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, March 9, 1993, 358 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 9,150 total, 5,000 in this make and model, 9,000 as pilot in command, 100 in the last 90 days, 40 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 20° at 6 knots
- Visibility: 7 statute miles
- Lowest ceiling: 25,000 ft overcast
- Temperature: 82 °F, dew point 73 °F
- Altimeter: 30.00 inHg

## 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 19930730027229A](https://openairdocs.org/incident/19930730027229A), Jul 30, 1993: Ccoptr TOMCATMK5A, Duson, LA, Substantial damage. Loud bumping sound on spray run. Lost collective. Hard landing chopped tail. Mast bearing had failed.

## Other investigations on N9014T (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 MIA77FKG51](https://openairdocs.org/ntsb/MIA77FKG51), Jul 12, 1977: EL Tomcat MK5A (N9014T), Colquitt, GA, destroyed
- [NTSB OAK75FJA10](https://openairdocs.org/ntsb/OAK75FJA10), May 9, 1975: Tomcat MK-5 (N9014T), Ewa, HI, 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.

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