Bell 407 N445MT

Summary

On 3 January 2013 at about 02:57 local time, a Bell 407 registered N445MT, operated by Med-Trans Corporation, was involved in an accident near Clear Lake, Iowa, United States. 3 people were on board and 3 died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

3 January 2013 at 02:57

Classification

Accident

Location

Clear Lake, Iowa, United States

Nearest airport

Mason City Municipal (MCW)

Coordinates

43.1428, -93.4828

Aircraft

Bell 407

Registration

N445MT

Category

Helicopter

Year built

2009

Engines

1

Operator

Med-Trans Corporation

Operating rule

Part 91: General Aviation

Purpose of flight

Positioning

Phase of flight

Not recorded

Route

Mason City → Emmetsburg

Aircraft damage

Destroyed

Weather

VMC

Light

Night

NTSB number

CEN13FA122

3 people died.

The pilot’s inadvertent encounter with localized icing conditions and his subsequent in-flight loss of helicopter control.

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

Read the full NTSB narrative

GPS tracking data revealed that, after departure, the helicopter proceeded westbound about 600 ft above ground level (agl), following a roadway. About 6 minutes after liftoff, when the helicopter was about 3/4 mile south of the accident site, it turned right and became established on a northerly course. The helicopter subsequently turned left and appeared to be on a southerly heading at the final data point. Shortly before beginning the left turn, the helicopter entered a climb, reached an altitude of about 1,800 ft agl, and then entered a descent that continued until impact. Weather observations from the nearest Automated Surface Observing System, located about 7 miles east of the accident site, indicated that the ceilings and visibility appeared to be adequate for nighttime helicopter operations and did not detect any freezing precipitation. Although an airmen's meteorological information advisory for icing conditions was current for the route of flight, and several pilot reports of icing conditions had been filed, none of the reports were in the immediate vicinity of the intended route of flight. Witnesses and first responders reported mist, drizzle, and icy road conditions at the time of the accident. It is likely that the pilot inadvertently encountered localized icing conditions, which resulted in his subsequent in-flight loss of helicopter control. A postaccident examination of the helicopter revealed no preimpact failures or malfunctions. The engine control unit recorded engine torque, engine overspeed, and rotor overspeed events; however, due to their timing and nature, the events were likely a result of damage that occurred during the impact sequence. Evidence also indicated that the cyclic centering, engine overspeed, and hydraulic system warning lights illuminated; it is also likely that their illumination was associated with the impact sequence. Further, the engine anti-ice status light was illuminated, which was consistent with the activation of the anti-ice system at some point during the accident flight.

Quoted verbatim from the NTSB record.