A U.S. Air Force F-15E Strike Eagle from the 335th Expeditionary Fighter Squadron returns to Bagram Air Field, Afghanistan on Nov. 28, 2011. (N.J. Air National Guard/DVIDS)
AVIANO AIR BASE, Italy — An Air Force investigation into what caused the crash of an F-15E Strike Eagle during a night combat operation over Libya last March has concluded that a weight imbalance was a major factor.
Col. Scott Shapiro, who led the accident investigation, said in a Wednesday phone interview from Ramstein Air Base, Germany, that the right wing of the jet was supporting at least 1,000 pounds more weight than the left side at the time of the March 21 crash.
The crew was conducting a night mission at 30,000 feet or higher with another F-15E against a target on the ground, Shapiro said.
Several factors created a severe imbalance, Shapiro said:
The F-15E's lone gun is located under the right wing, which creates an imbalance even without fuel or bombs loaded.The jet had four 500-pound bombs on the right side, and three under the left wing.A bomb had to be dropped from the left side, due to software anomalies.The crew also radioed that the external fuel tank on the right side didn't appear to be emptying into the engine properly.The situation deteriorated rapidly after the pilot dropped his bomb.
"He dropped it and was getting out of there," Shapiro said. "Halfway into the maneuver is when he went into the spin."
The pilot and weapons officer ejected before the jet crashed.
Shapiro, chief of strategic airlift capabilities for U.S. Air Forces in Europe, said he didn't believe the pilot was at fault.
"No. I don't think so. I didn't see that," he said.
Shapiro said his six-member investigative team repeatedly used a flight simulator programmed with the same conditions and got the same result — an uncontrollable aircraft.
But, following the service's flight guidance to pilots, the pilot believed his aircraft was capable of making a standard maneuver away from his bombing run, Shapiro said.
The executive summary of the investigation that was released Wednesday states the investigation board found "clear and convincing evidence" for its determination. Shapiro said most of that evidence came in the form of testimony from the crew, the pilot of the accompanying aircraft and maintenance personnel.
It wasn't possible to retrieve any information from the jet, Shapiro said, as its remains were destroyed on the ground so they couldn't be recovered by foreign forces. The Air Force estimates the loss of the F-15E, its munitions and fuel at nearly $48.2 million.
The F-15E was flying out of Aviano Air Base as part of the 492nd Expeditionary Fighter Squadron. It was the only aircraft lost by the United States during Operation Odyssey Dawn.
Shapiro said that, since he began his investigation, the Air Force has changed the guidance it issues to F-15E pilots about flying with weight imbalance at that altitude. He said he was told it was also addressing the software issue.
