CHIEF WARRANT OFFICER 3 BRIAN FITZGERALD
Eastern Army National Guard Aviation Training Site
Fort Indiantown Gap, Pa.
To prevent accidents, we need to take a link out of the chain of events that lead to the mishap. The accident I discuss in this article could have easily ended differently. And while luck is not part of the Army Safety Program, this event happened to have some good fortune.
The event was an engine replacement on a UH-60A Black Hawk. After a test flight, the engine needed adjustment, and the mechanics found hardware that presented a foreign object damage threat lying under the engine inlet cowling. The FOD could have been ingested into the engine if a hard left bank had been initiated. Let’s go over the series of events that led to this incident.
Originally, the engine was to be replaced. During the removal maintenance process, hardware that could be reused was supposed to be tagged to stay with the equipment it supported. Evidently, one bag of hardware was not properly attached to its part. Due to the number of new, inexperienced mechanics, this maintenance process was overlooked. Is it possible that the remaining senior mechanics got overloaded with work and did not shadow the new mechanics?
The next series of events occurred during the installation process. After the engine was replaced, the outer components and covers were installed. A seasoned mechanic would have questioned the engine inlet cover hardware not being attached to it. However, a less experienced mechanic did not question this and looked up the hardware in the parts manual. He then installed the cover with the new hardware.
The next link in the series of events took place when the mechanic’s completed work was examined by a technical inspector. If a technical inspector looked at the work and saw all new hardware on a component being reinstalled, this should have caught their attention. However, it was not noticed during the process. The technical inspector then signed off the final inspection on the work completed. Was the technical inspector in a hurry or overloaded?
Then the final link in the chain of events happened. After the maintenance is completed, the pilots receive the log book with the maintenance records and complete the preflight process. The only problem with this incident was the inlet cover concealed the bag of hardware sitting on the upper pylon area. It would be difficult to see unless the cover was removed. The test flight was performed and the aircraft went to the next phase.
After the maintenance test flight was completed, other items needed adjusting. When the mechanics removed the covers, they discovered the hardware lying under the engine inlet cowling. This halted the maintenance process and grounded the aircraft. A FOD check was conducted on the entire aircraft before anything else was completed. This caused a work stoppage to account for all tools and hardware to ensure nothing else was overlooked. The deadline for the engine maintenance was pushed back until a safety check was completed, which caused problems in scheduling the aircraft. If the job had been performed correctly the first time, it would not need to be done a second time.
Let’s review the items that led to this event: The new mechanic overlooked steps during the teardown process. Then, during the installation process, another mechanic overlooked the hardware not being attached to the part for reinstallation. The technical inspector did not question the new hardware on the component during inspection. The technical inspector did not look at the area before the part was installed. The pilots did not complete a thorough preflight.
If the engine did not need adjustments, how long would the hardware have remained on the deck? Since luck was a part of this chain of events, we won’t have to wait and see. With this example, be sure you take the link out of the events and don’t make your safety depend on luck.