Aircraft Accident/Incident Report

Main Pass 61A, --
Thursday, March 24, 2011 16:55 CDT

NTSB Narrative Summary Released at Completion of Accident

After the helicopter was refueled with the engine running, the pilot departed from an offshore oil platform. The pilot and the two passengers reported a loud bang just after the turboshaft-powered helicopter lifted off. The pilot immediately lowered the helicopter’s nose and entered an autorotation to the water below; as the helicopter descended, the pilot activated the helicopter’s float system. The floats inflated; however, the helicopter impacted the water and rolled inverted. Examination of the helicopter’s engine found no preaccident mechanical malfunctions or failures that would have precluded normal operation. A review of data downloaded from the engine’s data monitoring system revealed a “spike” in the engine’s turbine outlet temperature and torque readings. The oil platform was venting un-ignited methane gas at the time the helicopter departed the platform. It is likely that the helicopter’s engine experienced a compressor stall due to ingesting the methane gas, and the pilot immediately reacted by initiating an autorotation.

NTSB Probable Cause Narrative

The loss of engine power due to an engine compressor stall as a result of ingesting methane gas during takeoff.

Event Information

Type of Event Accident
Event Date 3/24/2011
Event Day of the Week Thursday
Time of Event 1655
Event Time Zone Central Daylight Time
Event City Main Pass 61A
Event State GULF OF MEXICO
Event Country --
Zipcode of the event site --
Event Date Year 2011
Event Date Month 3
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude --
Event Location Longitude --
Event Location Airport --
Event Location Nearest Airport ID --
Indicates whether the acc/inc occurred off or on an airport --
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness --
Investigator's weather source Pilot
Time of the weather observation 2211 Coordinated Universal Time? Same as GMT
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID KMIS
Elevation of weather observation facility --
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation UTC
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 22
Dew Point at event time (in degress fahrenheit) 21
Wind Direction (degrees magnetic) 40
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 5
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 29.97
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor 3
Injury Total None --
Injury Total Serious --
Injury Total All 3
Investigating Agency NTSB
NTSB Docket Number (internal use) 30034
NTSB Notification Source --
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Aug 6 2012 4:51PM
User who most recently changed record snyg
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N32041
NTSB Number CEN11LA252
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 135: Air Taxi & Commuter
Type of Flight Plan filed Company VFR
Flight plan Was Activated? Yes
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name BELL
Aircraft Model 206L-3
Aircraft Series Identifier --
Aircraft Serial Number 51539
Certified Max Gross Weight --
Aircraft Category Helicopter
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 7
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection AAIP
Date of Last Inspection Mar 18 2011 12:00AM
Airframe hours since last inspection --
Airframe Hours 11510
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site No
ELT Type C126
Aircraft Owner Name PHI INC
Aircraft Owner Street Address 2001 SE EVANGELINE TRWY
Aircraft Owner City LAFAYETTE
Aircraft Owner State LA
Aircraft Owner Country USA
Aircraft Owner Zipcode 70508-2156
Operator is an individual? No
Operator Name PHI INC
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address 2001 SE EVANGELINE TRWY
Operator City LAFAYETTE
Operator State LA
Operator Country USA
Operator Zip code 70508-2156
Operator Code --
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation --
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Non-scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Passenger Only
Type of Flying (Per_Bus / Primary) --
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code --
Departure City Main Pass 61A
Departure State GM
Departure Country USA
Departure Time --
Departure Time Zone CDT
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code --
Destination City Main Pass 61A
Destination State GM
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record May 9 2012 1:03PM
User who most recently changed record hatc
Since inspection or accident --
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --