The F-16C that crashed on April 5, 2017, shortly after departure from Joint Base Andrews, was brought down by faulty reassembly of the main engine control (MEC) unit during overhaul, according to the Air Force Accident Investigation Board assigned to the mishap. The absence of a retaining ring and associated anti-rotation pin led to malfunction of a pilot valve, which caused a massive excess of fuel to be delivered to the engine.
Source: avwebF-16 Crash Caused By Bad Maintenance