Air Combat Command Accident officials released the results of investigations August 27 for two incidents which happened in May.

F-15E Engine Put Together Wrong

The first incident involved engine damage on an F-15E Strike Eagle on May 29. Air Force investigators determined incorrect installation of compressor blade locks in the engine’s core module caused the damage.

The F-15E engine damage occurred during a test run at Nellis Air Force Base (NV), prior to the engine's being reinstalled in the aircraft. According to the report, there was "clear and convincing evidence" the mishap was caused by the incorrect installation of the ninth stage compressor blade locks in the engine’s core module. This allowed three stage blades to release during the test run, resulting in a severe compressor stall and subsequent damage to the engine prior to installation in the F-15E. It was also determined that the eighth, ninth and 11th stage blade locks and the seventh stage snap ring were incorrectly installed because technical order procedures were not followed. Because technical order procedures were not followed, the faulty installation went undetected.

The report also cited faulty maintenance procedures and deficient supervision as contributing to the incident. Damage to the engine was valued at more than $1.6 million. There was no other damage to government or private property, and there were no injuries.

Phantom Had a Mind of Its Own... For a While

In the second incident, an unmanned QF-4E Phantom II was intentionally destroyed in flight May 22 after ground-based controllers lost the capability to control the aircraft, according to ACC investigators.

The QF-4E aircraft was intentionally destroyed over White Sands Missile Range (NM), near Holloman AFB, by technicians remotely controlling the aircraft from a mobile ground station located within the range complex.

According to the report, after takeoff the drone detected a loss-of-connectivity signal. This happens when the ground portion of the drone control system is unable to send commands to or receive information from the drone. Eschewing a chance to practice a real-world emergency intercept situation, controllers used the ground-based UHF flight-termination system to destroy the drone.

The unmanned QF-4E, assigned to the 53rd Wing at Eglin AFB, Fla., was being flown by controllers from the 82nd Aerial Targets Squadron, Detachment 1, at Holloman AFB. The drone was supporting a live-fire mission and was slated to be shot down with an AIM-9 Sidewinder.

FMI: www.af.mil