Engines are extremely reliable pieces of machinery. This reliability isn’t just luck though. It is a result of a robust testing and maintenance program. Prior to service entry, a jet engine undergoes an extensive testing to prove reliability. After service entry, an engine is sometimes tested to diagnose a fault, test an upgraded feature, or ensure proper function after an overhaul. Because of the raw power of a jet engine, great care in normally taken to secure the engine before a test.
Today, our focus is on the J-85 engine built by General Electric. The J-85 is a small but powerful engine with proven reliability. With up to 6,000lbs of thrust, the engine powers the T-38, F-5 and a non-afterburner powered version powered the A-37 Firefly. It can power jet aircraft to supersonic speeds. The jet engine is still tested on a regular basis. This is what a J-85 test is supposed to look like:
Unfortunately, mistakes occasionally occur. It appears someone forgot to bolt down the J-85 to the test rig properly in this video. Just 10 seconds into the testing, the engine is detached from its rig. Woosh! 6,000 lbs of thrust hurtle forward in an uncontrolled manner. That’ll leave a mark.