# NTSB CHI90LA020: Bell 47G-2A-1, N500CD, Plymouth, IN, October 29, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: October 29, 1989, 08:05 local (13:05 UTC)
- Place: Plymouth, IN
- Coordinates: 41.34045, -86.309104 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.3404&lon=-86.3091&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report June 28, 1991
- Report: Approved by Office Director
- NTSB case key (mKey): 14586
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI90LA020
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14586/pdf
- Page: https://openairdocs.org/ntsb/CHI90LA020

## Probable cause

THE STUDENT'S IMPROPER USE OF THE CYCLIC CONTROL AND THE INSTRUCTOR'S (CFI'S) INADEQUATE SUPERVISION.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Miscellaneous/other, landing
  - autorotation - performed, dual student
  - cyclic - improper use of, dual student (cause)
  - supervision - inadequate, pilot in command(cfi) (cause)

## Analysis

DURING A BIENNIAL FLT REVIEW (BFR) FOR THE LEFT SEAT PLT, SVRL PRACTICE AUTOROTATIONS WERE PERFORMED.  THE CFI (RIGHT SEAT PLT) RPRTD THAT THE BFR WAS PROGRESSING VERY WELL UNTIL THE HELICOPTER TOUCHED DOWN ON A SOD TAXIWAY AFTER THE FINAL AUTOROTATION.  HE RPRTD THE TOUCHDOWN WAS SOFT, BUT IMMEDIATELY AFTER TOUCHDOWN, AFT CYCLIC WAS APPLIED . . .'  THE MAIN ROTOR BLADES CAME IN CONTACT WITH THE TAIL BOOM & SEVERED IT.  THE CFI RPRTD THE ACCIDENT WAS UNEXPECTED & OCCURRED SO QUICKLY THAT HE WAS UNABLE TO INTERVENE.  THE BFR PLT HAD A TOTAL FLT TIME OF 344 HRS WITH 310 HRS IN THIS MAKE & MODEL.  THE CFI STATED THE WX WAS CLEAR WITH CALM WINDS.

## Aircraft

- Registration: N500CD (not matched to a registry record)
- Reported make and model: BELL 47G-2A-1
- Category: Helicopter
- Serial number: 3458
- Airframe hours: 5453
- Engines: LYCOMING VO-435-A1F 260 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Registered owner: Marshall County Civil Defense
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, March 1, 1989, 103 hours before
- Departed: 52II, PLYMOUTH, IN
- Airport: C65, Plymouth Muni

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; airline transport, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: right; flight hours: 5,934 total, 200 in this make and model, 4,315 as pilot in command, 4 in the last 90 days, 2 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 5 statute miles
- Lowest ceiling: none
- Temperature: 46 °F, dew point 41 °F
- Altimeter: 30.00 inHg
- Observed at: SBN, 21 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 19891029043569A](https://openairdocs.org/incident/19891029043569A), Oct 29, 1989: Bell 47G2A1, Plymouth, IN, Substantial damage. Applied aft cylic immediately on touchdown by error. Main rotors severed tail boom. Biennial autorotation maneuver.

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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