Pilot Exceeded Limitation Speed, Entered Spin
A combination of human factors and aircraft anomalies caused a
spin during a July 30 crash of a two-seat F-15D Eagle during a Red
Flag exercise at Nellis Air Force Base, NV according to an Air
Combat Command accident investigation board report released this
The pilot in command, Lt. Col. Thomas Bouley, was killed in the
accident. An observer pilot, a Royal Air Force flight lieutenant,
sustained minor injuries and was treated and released.
According to the AIB report, the accident pilot momentarily
exceeded a technical order maneuvering limitation that is in place
when the F-15D has fuel in the external wing tanks. Additionally,
spatial disorientation resulting from the aircraft spin hampered
recovery and was also cited as a cause.
When the pilot momentarily exceeded limitations, the aircraft
departed from controlled flight due to the "left yaw/roll
phenomenon," an aerodynamic anomaly that affects some F-15D's with
two external fuel tanks. The departure, when coupled with an
external wing tank fuel imbalance, resulted in the F-15 going into
Through simulations, investigators concluded that once in this
spin, recovery was delayed by a radome, or nose cone, imperfection.
Although the nose cone was too damaged to analyze, simulations
provided substantial evidence that a radome anomaly aggravated the
aircraft's spin recovery.
The violent and prolonged spin left the pilot spatially
disoriented, which hampered the dive recovery, necessitating
ejection. The observer pilot, who was sitting in the F-15's
backseat, was ejected first, and he survived the crash. The mishap
pilot was ejected .4 seconds later and did not survive the
The aircraft, valued at $38 million, was assigned to the 57th
Wing at Nellis.