Bell Helicopter Textron Canada 206 L4 N435AE

Summary

On 25 April 2016 at about 23:45 local time, a Bell Helicopter Textron Canada 206 L4 registered N435AE, operated by Air Evac EMS Inc, was involved in an accident near Houston, Texas, United States. 3 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

25 April 2016 at 23:45

Classification

Accident

Location

Houston, Texas, United States

Nearest airport

Memorial City Hospital (8TS4)

Coordinates

29.7806, -95.5453

Aircraft

Bell Helicopter Textron Canada 206 L4

Registration

N435AE

Category

Helicopter

Year built

2012

Engines

1

Operator

Air Evac EMS Inc

Operating rule

Part 135: Air Taxi & Commuter

Phase of flight

Not recorded

Route

Houston → Victoria

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN16LA168

Nobody was injured.

The pilot's failure to maintain directional control during takeoff in varying wind conditions, which resulted in a hard landing.

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

Read the full NTSB narrative

The commercial pilot was departing for a positioning flight from a helipad bordered on three sides by buildings and parking structures. The pilot reported that, after lifting off, as he translated the helicopter from behind one of the buildings and into the prevailing wind, the nose began yawing right. He applied full left pedal, but the helicopter may have fully rotated once while moving back toward the helipad before the rotation stopped. The low rotor speed warning sounded, and the helicopter then began rotating rapidly right. The pilot lowered the collective and maneuvered toward the helipad. He subsequently raised the collective while at 25 ft above ground level, but the helicopter landed hard. A postaccident examination of the helicopter revealed no preimpact mechanical failures or malfunctions that would have precluded normal operation. A loss of tail rotor effectiveness can be encountered while hovering under certain wind conditions, which may be encountered unexpectedly near buildings due to rapidly changing wind conditions. However, the pilot's report that the low rotor speed warning sounded and engine data provided by the operator indicated that the main rotor speed decayed during the takeoff with a corresponding decrease in the tail rotor speed. A significant reduction in the tail rotor speed could result in an uncommanded yaw and a loss of directional control. The investigation was unable to determine if the pilot's loss of directional control was due solely to the decrease in rotor speed during takeoff, the varying wind conditions, or a combination of both.

Quoted verbatim from the NTSB record.