December 1, 2010 - The National Transportation Safety Board released a final report on a fatal crash involving a transport-category helicopter caused by a bird strike. The Board said the lack of requirements for bird strike-resistant windshields contributed to the crash, and called on the FAA to develop such requirements. 

On January 4, 2009, a dual-engine Sikorsky S-76C++ helicopter (N748P), registered to and operated by PHI, Inc., crashed into marshy terrain near Morgan City, Louisiana approximately 7 minutes after takeoff from Amelie, Louisiana, on a charter flight to an oil rig in the Gulf of Mexico. Both pilots and 6 of the 7 passengers were killed in the crash. 

The aircraft had reached level cruise flight at 850 feet mean sea level and 135 knots when the cockpit voice recorder recorded a loud bang, followed by sounds consistent with rushing wind and a power reduction on both engines. The aircraft crashed several seconds later.

About 4 months after this accident, Sikorsky issued a safety advisory to all operators of the S-76C++ regarding the reduced safety of acrylic windshields (both cast and stretched) compared to the helicopter?s original windshield. According to the advisory, the S-76C++?s laminated glass windshield demonstrated more tolerance to penetrating damage from in-flight impacts (such as bird strikes) compared to acrylic windshields.  

Sikorsky expressed concern in the safety advisory that the presence of a hole through the windshield, whether created directly by object penetration or indirectly through crack intersections, may cause additional damage to the helicopter, cause disorientation or injury to the flight crew, increase pilot workload, or create additional crew-coordination challenges. The investigation revealed that, following this accident, PHI is replacing all of the windshields in its S 76 helicopters with windshields that meet European bird-strike standards. 

Based on main rotor speed decay information provided by Sikorsky, the accident flight crew had, at most, about 6 seconds to react to the decaying rotor speed condition. Had they quickly recognized the cause of the power reduction and reacted very rapidly, they would likely have had enough time to restore power to the engines by moving the ECLs back into position. However, the flight crewmembers were likely disoriented from the bird strike and the rush of air through the fractured windshield; thus, they did not have time to identify the cause of the power reduction and take action to move the ECLs back into position. 

The accident helicopter was not equipped with an audible alarm or a master warning light to alert the flight crew of a low-rotor-speed condition. An enhanced warning could have helped the accident flight crew quickly identify the decaying rotor speed condition and provided the flight crew with more opportunity to initiate the necessary corrective emergency actions before impact. The NTSB determined that the helicopter crashed because of the sudden loss of power to both engines following the bird strike and the subsequent disorientation of the crewmembers.