I was designated as the pilot in command (PC) for the flight of Pilot 2 and myself. Our tasking was to launch an OH-58A/C from our facility; fly an hour north, where we would perform a range sweep; refuel; and then return to home station. Sounded easy, and we had done it many times before. However, the following factors caused us to have a not so routine flight that day:
1. The mission was assigned the day prior, and I decided to do the preflight the evening before.
2. The facility standing operating procedures stated that fuel samples could not be taken while aircraft were in the hangar.
3. For the next morning's mission, I coordinated a time to arrive at the airfield and a proposed takeoff time.
4. Pilot 2 showed up early and had the aircraft moved out to the launch pad.
5. I arrived later and Pilot 2 gave me the "ready-to-go" sign.

Here was the start of my failure to do my PC duties. I started the aircraft, everything was going fine and we were on schedule. As we cleared the airfield, I asked Pilot 2 to start a fuel check. As he wrote the numbers down, we both looked at each other and said, "Those numbers can't be right." I told Pilot 2 I was turning back; something was obviously wrong. Our fuel gauge was reading 600 to 650 pounds of fuel, which is not where it should have been. We landed back at our facility without incident.
Pilot 2 asked me if I had checked the fuel sample. I told him I hadn't because I assumed he'd done it after pushing the aircraft outside the hangar. As it turned out, he hadn't checked the fuel sample either.
Our maintenance personnel pulled a sample and found water in the fuel. After further inspection, they found water had just made it to the fuel pump and filter. We had, at most, only seconds before the engine would have stalled due to lack of fuel.
Going a step further, we examined the maintenance records and asked the crew chiefs why there was so much water in the fuel. We found out the engine had been washed just prior to the flight. The crew chief, attempting to unclog the engine deck drain, had sprayed water up the fuel vent tube instead of the engine deck drain tube. Both tubes come out next to each other on the pilot's side of the aircraft.
I should have paid attention during the preflight and asked the right questions. If I had, we could've identified the problem, avoided the incident and performed our mission with another aircraft. Also, had I properly checked the fuel sample and not assumed the other pilot had accomplished that, we would've completed this mission successfully.