BELL 407 near Delray Beach, FL — 2012-03-23

Probable cause

The pilot’s improper response to a simulated engine failure and the instructor’s delayed and improper remedial action.

NTSB narrative

While in cruise flight during the law enforcement aerial surveillance and evaluation flight, the instructor induced a simulated engine failure. The pilot being evaluated rolled the throttle from the idle position back to the flight position instead of lowering the collective to maintain rotor rpm. The instructor then took control of the helicopter, but he did not lower the collective either, and the main rotor rpm subsequently decayed to well below the lower limit of the normal operating range. The low-rotor condition resulted in a loss of helicopter control and glide capability and a subsequent hard landing in trees. Examination of the flight department's training program revealed that the conditions and standards for the performance of a simulated engine failure were not outlined as a separate task within the manual and that the manual did not provide information regarding entry altitudes, callouts, recovery altitudes and procedures, or maneuver termination protocols. The instructor reported no mechanical deficiencies with the helicopter that would have precluded normal operation.

Analysis

Primary failure mode

Human factors

First missed decision gate

Instructor could have chosen not to induce simulated engine failure.

NTSB coding

• Loss of lift · Other
• Delayed Action

Evidence available

• 7 docket documents

Docket documents7

• Evidence Control Form - GPS496 - Return to Ownerform
• Evidence Control Form - Return of Rolls Royce ECU to Ownerform
• Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1form
• Miscellaneous (Pilot Statement)interview
• Witness Statementinterview
• Electronic Devices 17 - Attachment 1 - DECU Tabular Data (CSV)other
• Electronic Devices 17 - Specialist's Factual Report (GPS and DECU)report