# NTSB MKC87IA070: Agusta A109, N4GH, Lincoln, NE, March 30, 1987

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: March 30, 1987, 15:00 local (21:00 UTC)
- Place: Lincoln, NE
- Coordinates: 40.909877, -96.790458 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.9099&lon=-96.7905&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report July 10, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 34308
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC87IA070
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/34308/pdf
- Page: https://openairdocs.org/ntsb/MKC87IA070

## Sequence of events

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

- Airframe/component/system failure/malfunction, taxi - from landing
  - rotor drive system,tail rotor drive shaft - overtorque (cause)
  - rotor drive system,tail rotor drive shaft - failure,total (cause)

## Analysis

THE PIC STATED THAT HE WAS GROUND TAXIING THE HELO TO THE RAMP AREA AT DUNCAN AVIATION TO SHUTDOWN FOR REFUELING. DURING THE TAXI, THE PIC HEARD A LOUD 'BANG' EMINATING FM THE REAR OF THE HELO. THE PIC LOWERED COLLECTIVE PITCH AND NO FURTHER NOISE WAS HEARD AND NO VIBRATION WAS FELT. THE PIC RE-APPLIED COLLECTIVE PITCH TO MOVE FORWARD WHEN THE HELO BEGAN TO YAW AND VIBRATE. AT THIS POINT THE PIC LOWERED COLLECTIVE TO FLAT PITCH AND SHUTDOWN THE ENG. REMOVAL REVEALED A BROKEN PORTION OF THE T/R DRIVESHAFT ABOUT 1 FT FORWARD OF THE GEARBOX. METALLURGICAL EXAMINATION BY THE NTSB LAB AND AN INDEPENDENT METALLURGIST CONCLUDED THAT THE DRIVESHAFT FAILED IN A MANNER CHARACTERISTIC OF TORSIONAL OVERLOAD. THE PIC STATED THAT NO CONTACT WITH THE GRND OR STATIONARY OBJECT HAD OCCURRED.

## Aircraft

- Registration: [N4GH](https://openairdocs.org/deregistered/N4GH-2013-11-07), registration cancelled 2013-11-07, S/N 7151, built 1978 (OpenAirDocs)
- Reported make and model: Agusta A109
- Registry model: [Agusta AGUSTA A109](https://openairdocs.org/model/agusta-agusta-a109) (registry code 0260109) (OpenAirDocs)
- Registry engine: [Allison 250 SER 400HP](https://openairdocs.org/engine/allison-250-ser-400hp) (registry code 03013, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 7151
- Airframe hours: 2023
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Minor damage
- Flight: Part 91
- Registered owner: Rodgers Helicopter Service
- Airworthiness certificate: Standard, Utility
- Last inspection: 100 hour, December 14, 1986, 11 hours before
- Departed: OMAHA, NE
- Destination: LNK, LINCOLN, NE
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 8,334 total, 68 in this make and model, 8,012 as pilot in command, 58 in the last 90 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 240° at 9 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 43 °F

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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