Last month, an Chatsworth helicopter crash involving an NBC4 news chopper that was covering a traffic accident and resulted in three fatalities was found to have emitted a warning sound indicating a mechanical anomaly just moments before the crash.
As a result, weight is being added to the possibility that the crash was caused by a mechanical defect rather than a simple pilot error.
According to a preliminary investigation report released on the 6th by the National Transportation Safety Board (NTSB), a warning sound was recorded during the final moments of a 4-minute and 21-second video filmed by a reporter aboard the helicopter at the time of the crash on the 15th of last month.
The report stated that the helicopter maintained normal noise levels throughout the flight, but during the final 29 seconds of the video, the noise frequency shifted and a warning sound began to ring. The NTSB explained that the warning sound matched alarms indicating overspeed or underspeed of the main rotor.
According to investigative authorities, the accident helicopter took off from Whiteman Airport at around 5:24 PM on the day of the incident to cover the traffic accident scene.
Analysis of Automatic Dependent Surveillance-Broadcast (ADS-B) data, which records aircraft position, altitude, and speed, showed that the accident helicopter flew about 9 miles to the accident scene while maintaining an average altitude of around 1,600 feet.
Upon arriving at the scene, the helicopter continued its news coverage flight at an altitude of approximately 1,700 feet above sea level (about 800 feet above ground level). Just before the crash, its ground speed reportedly dropped to about 7 miles per hour (6 knots).
At around 6:55 PM, the helicopter made a sharp right turn and began losing altitude. The final ADS-B records indicated that the helicopter descended steeply over the accident location, registering a ground speed of 38 knots (approx. 44 miles per hour).
Closed-circuit television (CCTV) footage near the accident site captured the helicopter diving sharply and colliding with a metal storage container, triggering a fire.
An on-site inspection revealed that the helicopter’s main rotor and tail rotor remained attached to their respective junctions, and most of the wreckage was found within a 30-foot radius. However, a significant portion of the fuselage was severely damaged by the post-collision fire.
Meanwhile, the NTSB has transported the wreckage of the accident helicopter to a separate investigation facility for precision analysis. The exact cause of the accident has not yet been determined.
