# NTSB NYC90MA009: Agusta A109A Mkii, N21FL, Lacey Township, NJ, October 10, 1989

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Major investigation · Final report
- Date: October 10, 1989, 13:29 local (17:29 UTC)
- Place: Lacey Township, NJ
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 5 fatal
- Status: Completed, report May 18, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 36745
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC90MA009
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/36745/pdf
- Page: https://openairdocs.org/ntsb/NYC90MA009

## Probable cause

IN-FLIGHT SEPARATION OF A MAIN ROTOR BLADE DUE TO FATIGUE FAILURE OF THE MAIN ROTOR BLADE SPAR, WHICH ORIGINATED AT A MANUFACTURING INDUCED SCRATCH (TOOL MARK) THAT WAS THE RESULT OF INADEQUATE QUALITY CONTROL.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - rotor system,main rotor blade spar - fatigue (cause)
  - inadequate quality control, manufacturer (cause)
  - rotor system,main rotor blade - separation (cause)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

AS THE HELICOPTER WAS IN CRUISE FLT AT AN ALT OF 2200' MSL, A PORTION OF ONE OF THE MAIN ROTOR BLADES SEPARATED. THE SUBSEQUENT IMBALANCE RESULTED IN SEPARATION OF THE TRANSMISSION & MAIN ROTOR ASSEMBLY FROM THE HELICOPTER.  THE HELICOPTER THEN CRASHED IN AN UNCONTROLLED DESCENT.  A METALLURGICAL EXAM OF THE SEPARATED BLADE REVEALED THAT IT HAD FAILED FROM FATIGUE.  THE FRACTURE HAD INITIATED AT A MANUFACTURING INDUCED SCRATCH IN THE SPAR OF THE BLADE. THE SCRATCH WAS ON THE INNER SURFACE OF THE SPAR AT BLADE STATION 2825 (IN MILLIMETERS), NEAR THE LEAD BALANCE WT. IT WAS IN LINE WITH THE EDGE OF THE ADHESIVE FILET.  THERE WAS EVIDENCE THAT THE CRACK ORIGINATED WHERE A SHARP TOOL WAS USED TO TRIM THE EDGE OF THE ADHESIVE FILET.  THE BLADE FRACTURED AFTER 922 HRS OF OPERATION.

## Aircraft

- Registration: [N21FL](https://openairdocs.org/deregistered/N21FL-1990-05-14), registration cancelled 1990-05-14, S/N 7309 (OpenAirDocs)
- Reported make and model: AGUSTA A109A MKII
- Registry model: [Agusta AGUSTA A109](https://openairdocs.org/model/agusta-agusta-a109) (registry code 0260109) (OpenAirDocs)
- Category: Helicopter
- Serial number: 7309
- Airframe hours: 911
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Destroyed
- Flight: Part 135
- Operator: Paramount Aviation
- Registered owner: Fsq Air Charter Corp.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, September 3, 1989, 47 hours before
- Departed: 6N4, NEW YORK CITY, NY
- Destination: ACY, ATLANTIC CITY, NJ
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 27; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; toxicology performed; flight hours: 2,900 total, 100 in this make and model, 2,900 as pilot in command, 100 in the last 90 days, 40 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 190° at 8 knots
- Visibility: 7 statute miles
- Lowest ceiling: 4,000 ft broken
- Temperature: 61 °F, dew point 37 °F
- Altimeter: 30.00 inHg
- Observed at: WRI, 22 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 19891010039549A](https://openairdocs.org/incident/19891010039549A), Oct 10, 1989: Agusta A109A, Lacey Township, NJ, Destroyed, 5 fatal. Main rotor blade separated in flight. Helicopter came apart and crashed.

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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