Agusta A109A MKII N21FL

Summary

On 10 October 1989 at about 17:29 local time, a Agusta A109A MKII registered N21FL, operated by Paramount Aviation, was involved in an accident near Lacey Township, New Jersey, United States. 5 people were on board and 5 died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

10 October 1989 at 17:29

Classification

Accident

Location

Lacey Township, New Jersey, United States

Coordinates

Not recorded

Aircraft

Agusta A109A MKII

Registration

N21FL

Category

Helicopter

Engines

2

Operator

Paramount Aviation

Operating rule

Part 135: Air Taxi & Commuter

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

New York City → Atlantic City

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

NYC90MA009

5 people died.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.