By David Alexander
WASHINGTON (Reuters) - The U.S. Navy's Blue Angels flight exhibition team has been ordered to stop using the so-called Split-S maneuver during its shows until further notice after an investigation into a crash that killed a top Marine Corps pilot this summer.
A Navy investigation report released on Thursday found that Captain Jeffrey Kuss performed the maneuver on June 2 in his F/A-18C aircraft during practice at Smyrna, Tennessee, at a lower-than-standard altitude, possibly because of low clouds.
The combat maneuver involves rolling upside down then diving in a half loop until the plane is flying in the opposite direction horizontally.
Blue Angels operating procedures call for the maneuver to be performed at a minimum altitude of 3,500 feet above the ground at a speed between 125 and 135 knots, the report said.
Kuss was no higher than 3,196 feet and was flying at up to 184 knots. Although he radioed that he was throttling out of afterburner during the mishap, he failed to do so, the report said.
"In layman's terms, he transitioned from the high performance climb to the Split S too low and too fast, and by not deselecting his afterburners during the maneuver, he continued to accelerate," the report said.
"The net effect of these deviations was that the aircraft was simply too low and too fast to avoid impacting the ground," it said.
Kuss ejected from his plane but it was too late, the report said.
The investigation concluded the cause of the crash was pilot error, with the weather and pilot fatigue seen as contributing factors. It concluded Kuss was fatigued because he failed to perform some routines he normally would have done out of habit.
Kuss was "universally recognized as one of the most meticulous and professional Blue Angel pilots by his teammates" and had 1,686.5 flight hours with no prior military mishaps or flight violations, the report said.
The commander in charge of the Blue Angels ordered a number of changes to the group's procedures, including directing that the Split S maneuver no longer be performed in the show until further notice.
The commander also directed that the Blue Angels' schedule of performances be adjusted in the future "to provide more regular breaks and better flow to allow rest and regularly assess the team's performance."
(Reporting by David Alexander; Editing by Michael Perry)