FORT RUCKER, Ala. (February 5, 2019) - Foreign object damage on a military aircraft is a serious issue. Before every mission, the entire flight crew, which is five personnel on a CH-47, checks for FOD and ensures the aircraft is ready for flight. Depending on the crew, preflight can take anywhere from 30 minutes to an hour and a half. It is supposed to be a thorough process. During deployments, however, you get into a battle rhythm and things can go unnoticed due to the monotony of day-after-day operations. In any military aviation setting, that can be devastating.Eight years ago, I was deployed to Jalalabad, Afghanistan, in Regional Command - East. It was a typical day; we woke up, went to chow and received the brief for our mission. After our brief, we headed out to the aircraft, where the flight engineer, crew chief and door gunner were already getting it ready for the mission. I climbed up and began conducting the preflight/FOD check on the upper half of the aircraft, which took about a half hour. By the time I climbed back down, the others were finished with the rest of the aircraft.I grabbed my checklist and started my pre-mission brief to the rest of the crew. Everyone was confident about the mission and we put on our gear. The CE then climbed on top of the aircraft to ensure everything was secure as I did a walk-around on the bottom to make sure it was ready for startup and takeoff. Everything was going as planned. There were no surprises - as it should be since we had been doing this mission set for several months and there wasn't anything that was outside the norm.After my walk-around and confirmation from the CE that the aircraft was ready to go up-top, we climbed in to the cockpit. I took the right seat and adjusted my mirror so I had a good view of the back of the aircraft. Once on battery power, we continued with the checklist and there were still no issues. Then everything went awry.The left-seat pilot cleared the auxiliary power unit, which is very loud, and the CE stated it was clear to start. When the APU came to life with a thunderous scream, something darted out from underneath the front-right seat of the cabin area. I saw it out of the corner of my eye but wasn't sure what it was. "What the hell was that," I asked the CE. Once he finished laughing, he said a cat had been hiding under the seat. The APU had startled the cat, causing him to run off the aircraft. The rest of the crew also found this to be extremely funny. However, the realization that we'd missed a cat during our preflight checks made us wonder what else we could have overlooked.As a crew, we collectively decided to shut down the APU and take another look at the aircraft. Fortunately, we didn't find another cat or any other types of FOD that could have caused a disaster on a typically mundane mission. That cat ended up becoming our mascot for the rest of the deployment. He visited us in the crew shed every couple of days, but he never set foot on another aircraft. Having him around served as a reminder to always conduct thorough FOD checks before every mission.Do you have a story to share? Risk Management is always looking for contributors to provide ground, aviation, driving (both private motor vehicle and motorcycle) and off-duty safety articles. Don't worry if you've never written an article for publication. Just write about what you know and our editorial staff will take care of the rest. Your story might just save another Soldier's life. To learn more, visit https://safety.army.mil/MEDIA/Risk-Management-Magazine.