Sunday, January 10, 2021

Dynamic Rollover: Aerospatiale AS 350B2 Ecureuil, N346AE; accident occurred January 11, 2019 at Ponca City Regional Airport (KPNC), Oklahoma



Aviation Accident Final Report - National Transportation Safety Board

The National Transportation Safety Board not travel to the scene of this accident.

Additional Participating Entity: 

Federal Aviation Administration / Flight Standards District Office; Oklahoma City, Oklahoma

Investigation Docket - National Transportation Safety Board:


Location: Ponca City, Oklahoma
Accident Number: CEN19LA068
Date & Time: January 11, 2019, 11:45 Local
Registration: N346AE
Aircraft: Aerospatiale AS350
Aircraft Damage: Substantial
Defining Event: Dynamic rollover
Injuries: 2 None
Flight Conducted Under: Part 91: General aviation - Positioning

Analysis

The pilot and an air ambulance crewmember were repositioning the helicopter due to incoming inclement weather. About halfway into the flight, the front windshields were fogging over, and the pilot increased the demister. Upon reaching the destination, the pilot hovered near the company hangar; by this time, the windshields had completely fogged over. The crewmember warned the pilot that he was getting close to the hangar, which was on the helicopter's left side. The pilot felt that he was high enough off the ground to move the helicopter several feet to the right, but the right skid was too low and contacted the ground, which resulted in a dynamic rollover. The helicopter sustained substantial damage to the rotor blades, fuselage, and tailboom.

Based on the available information, the dynamic rollover was a result of the pilot's failure to maintain altitude during the hover operation with a fogged-over windshield.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot's failure to maintain altitude during the hover operation while his view was obstructed due to the fogged-over windshield.

Findings

Aircraft Altitude - Not attained/maintained
Personnel issues Monitoring environment - Pilot
Aircraft Flight compartment windows - Not specified

Factual Information

On January 11, 2019, about 1145 central standard time, an Airbus Helicopters AS350B2 helicopter, N346AE, sustained substantial damage during a dynamic rollover during landing at the Ponca City Regional Airport (PNC), Ponca City, Oklahoma. The airline transport pilot and helicopter air ambulance crewmember were not injured. The helicopter was registered to and operated by Air Evac EMS, Inc. under the provisions of Title 14 Code of Federal Regulations Part 91 as a positioning flight. Day instrument meteorological conditions prevailed for the flight, which operated on company visual flight rules flight plan. The flight originated from the Ponca City Hospital about 1141.

The pilot was a repositioning the helicopter due to incoming inclement weather. The weather conditions at the time included light rain and a temperature of about 38° F. He contacted the company Operations Control Center (OCC) and he and the OCC staff agreed that the flight could be conducted within the company safety requirements.

The flight was initiated and about halfway into the flight the front windshields were fogging over and the pilot increased the demister. Upon reaching the destination, the pilot hovered near the company hangar by which time the windshields had completely fogged over. The passenger warned the pilot that he was getting close to the hangar which was on the helicopter's left side. The pilot noted that he was looking out of the left chin bubble windshield while attempting to move the helicopter laterally to the right. He felt that he was high enough off the ground to move the helicopter several feet to the right, but the right skid was too low and contacted the ground resulting in a dynamic rollover.

Examination of the helicopter revealed substantial damage to the rotor blades, fuselage, and tail boom.

History of Flight

Landing-flare/touchdown Dynamic rollover (Defining event)

Pilot Information

Certificate: Airline transport; Commercial Age: 75,Male
Airplane Rating(s): Single-engine land; Multi-engine land
Seat Occupied: Right
Other Aircraft Rating(s): Helicopter
Restraint Used: 5-point
Instrument Rating(s): Airplane; Helicopter
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 2 With waivers/limitations
Last FAA Medical Exam: November 6, 2018
Occupational Pilot: Yes
Last Flight Review or Equivalent:
Flight Time: 6617 hours (Total, all aircraft), 2522 hours (Total, this make and model), 4720 hours (Pilot In Command, all aircraft), 23 hours (Last 90 days, all aircraft), 8 hours (Last 30 days, all aircraft), 0 hours (Last 24 hours, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: Aerospatiale 
Registration: N346AE
Model/Series: AS350 B2 
Aircraft Category: Helicopter
Year of Manufacture: 1996
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 2946
Landing Gear Type: High skid
Seats: 4
Date/Type of Last Inspection: January 8, 2019 100 hour 
Certified Max Gross Wt.: 4961 lbs
Time Since Last Inspection: 
Engines: 1 Turbo shaft
Airframe Total Time: 11499 Hrs as of last inspection
Engine Manufacturer: Honeywell
ELT: C126 installed, not activated 
Engine Model/Series: LTS-101-700D
Registered Owner: 
Rated Power: 732 Horsepower
Operator: 
Operating Certificate(s) Held: On-demand air taxi (135)
Operator Does Business As: 
Operator Designator Code: EVCA

Meteorological Information and Flight Plan

Conditions at Accident Site: Instrument (IMC)
Condition of Light: Day
Observation Facility, Elevation: PNC,1008 ft msl
Distance from Accident Site: 0 Nautical Miles
Observation Time: 17:42 Local 
Direction from Accident Site: 0°
Lowest Cloud Condition: Unknown
Visibility 4 miles
Lowest Ceiling: Broken / 900 ft AGL 
Visibility (RVR):
Wind Speed/Gusts: 12 knots / 
Turbulence Type Forecast/Actual:  /
Wind Direction: 130° 
Turbulence Severity Forecast/Actual:  /
Altimeter Setting: 30.01 inches Hg 
Temperature/Dew Point: 4°C / 2°C
Precipitation and Obscuration: Moderate - None - Mist
Departure Point: Ponca City, OK 
Type of Flight Plan Filed: Company VFR
Destination: Ponca City, OK (PNC)
Type of Clearance: None
Departure Time: 11:41 Local 
Type of Airspace: Class E

Airport Information

Airport: Ponca City Regional Airport PNC
Runway Surface Type:
Airport Elevation: 1008 ft msl 
Runway Surface Condition: Unknown
Runway Used: 
IFR Approach: None
Runway Length/Width:
VFR Approach/Landing: Unknown

Wreckage and Impact Information

Crew Injuries: 2 None 
Aircraft Damage: Substantial
Passenger Injuries:
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 None
Latitude, Longitude: 36.725276,-97.101943

2 comments:

  1. Firstly, I'm glad nobody was injured in this accident; secondly - and I'm no expert on helicopters - I would think that if there's one place in the world you would like to have a defogger/defroster that is 100% effective every time its use is needed, it would be the windscreen of a helicopter. Maybe I'm missing something here ? Perhaps someone can explain how the defrost/defog works on one of these machines.

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