A just-concluded probe into the crash involving a US Airforce F-16 jet that went down near Joint Base Andrews in Maryland early this year discovered the aircraft's engine was missing crucial parts, which led to the accident.

On April 5th this year, an F-16 fighter jet crashed shortly after take-off, from Joint Base Andrews on a routine training mission.

According to a press release from the US Airforce, investigators into the crash found the engine did not have two key parts. The investigators observed the components were left out during the jet engine's assembly.

Which led to the engine malfunctioning and causing the $22 million fighter jet to crash, CNN reported.

Assembly error

According to the investigation report, released on Thursday, the F-16 was not fitted with a rotation pin and a 600-degree training ring, as required in the jet's engine.

Lack of the two parts led to uncontrollable high amounts of fuel being pumped into the aircraft's engine. Consequently, it resulted in the F-16 accelerating abnormally, the engine overheating, bursting into flames and finally, engine failure.

Although the pilot was able to put out the fire, the damage it had already caused to the engine rendered the aircraft unusable and out of control, forcing the pilot to eject.

Airforce pilots are trained to eject after their attempts to save the aircraft have failed. The pilot also redirected the F-16 to a deserted area to avoid ground casualties. Apart from the loss of the fighter jet, there were no injuries or fatalities during the crash.

Cause of the assembly error

Investigators found the error occurred during assembly of the aircraft's engine, owing to procedural failures that took place at the Commodities Maintenance Squadron, Air Logistics Complex, based in Oklahoma.

The parts had been sent to Tinker Airforce Base for an overhaul by the Maintenance Squadron. The procedures used to keep track of the components at the facility's assembly line were found to be inadequate, causing the parts to be left out during the engine's final assembly.

Airforce spokesman Jerry Bryza told CNN that after the crash, the entire process of receiving, tracking and testing parts sent to the assembly line for an overhaul, was audited and improved, to avoid similar omissions from happening in the future.

The F-16 is a versatile aircraft which the US Airforce uses for airlifts, fighter roles and a wide range of other missions. Currently, the US Airforce has around 1000 F-16's in its possession.