Collision Details
On the day of the accident, both helicopters were operating in the Gulf of Mexico offshore environment. A Bell 407 and an Aerospatiale AS-355-F1 collided while each was in cruise flight at an altitude of 1,000 feet above ground level over open ocean. Both aircraft were being flown by a single pilot and were conducting positioning flights between offshore platforms.
During the collision, the main rotor blades of the Aerospatiale struck the nose section of the Bell, removing the windshield, chin bubble, and anti-torque pedals. The Bell pilot initiated an autorotation to the water and was subsequently rescued. The Aerospatiale pilot was fatally injured during the collision and water impact sequence, and the helicopter impacted the water and sank.
Course and Separation
The Bell's direct flight course was approximately 265 degrees. The Aerospatiale's direct course was about 155 degrees. The Bell pilot reported that he did not see the Aerospatiale until just before the impact.
HSAC Recommendations
The Helicopter Safety Advisory Conference (HSAC) had published Recommended Practice (RP) No. 93.1 in 1993, which provided standardized vertical separation for helicopters flying in the offshore environment. The RP recommended enroute altitudes below 3,000 feet, weather permitting, based on magnetic heading: for headings of 0 to 179 degrees, altitudes of 750, 1,750, or 2,750 feet; for headings of 180 to 359 degrees, altitudes of 1,250 or 2,250 feet. These recommended altitudes, if used, would provide a minimum vertical clearance of 500 feet. Both operators of the accident helicopters were participating members of HSAC, but neither had included RP No. 93.1 in their respective operations manuals. The RP is recommended and not mandatory.