Risk Management Magazine

Search for Articles

Running on Empty

Running on Empty

116th Military Intelligence Brigade
Hunter Army Airfield
Fort Stewart, Georgia

We’ve all been there — that “will-I-make-it” moment. If you’re lucky enough to have avoided that experience, then you’ve heard it from the mouths of others — probably accompanied with a few nervous chuckles. For most, it’s the first time, and hopefully last, as well as a valuable learning point. I had one of those moments. Here is my story.

It was about a week since we arrived at our operating location. We had flown the route daily, some days with multiple turns, and had a good lay of the land. We were flying humanitarian relief missions and would launch from our airfield, fly up to 40 minutes to a remote staging area, pick up patients and fly them to a Navy hospital ship a few miles offshore for surgery. Given the remote area we were operating in and the distance to our airfield and refueling, our UH-60L was equipped with two full crashworthy external fuel system (CEFS) tanks. We were trained and familiar with CEFS and it was common knowledge that you could expect to get about 4.5 hours of continuous cruise flight from a full bag of gas. Our mission profile had us flying hops of seven to 10 minutes from our staging area with substantial ground time for passenger loading and unloading. This gave us significantly more station time.

We’d been conducting this mission for a week and routinely refueled and swapped out crews around the five-hour mark. Normally, by the time we landed (at the five-hour mark), we still had over an hour of fuel remaining and it was never an issue. This particular day, though, we had an early show. That made fuel, not time, our limiting factor. We departed as on any other day, but with an added eye on fuel checks. I did the routine fuel checks as we entered our mission profile, then closed out and continuously monitored our fuel during the mission.

As the five-hour mark drew near, our numbers indicated we had about an hour and 20 minutes of fuel remaining. We wondered, “Do we have time for one more load?” We decided we had enough time to take another load of passengers out to the ship and then head back to our airfield for refueling. According to our fuel checks, we’d still have about an hour’s fuel remaining after we dropped off the patients. Feeling confident, we decided we were good to go.

After dropping off the last patients, we proceeded back to the airfield. I started another fuel check for the flight back and closed it out after 15 minutes. This time, however, I noticed we were burning fuel at a slightly higher rate. No big deal, I thought; I’d just continue to monitor and we’d be fine. Ten minutes later, we were still burning more fuel than expected, further eroding our reserve. We were 10 minutes away from landing and down to 400 pounds of fuel. For anyone who’s ever flown with CEFS tanks, you know that’s enough to be nerve wracking.

We crested the last hills and entered the city limits. By then we were within five minutes of landing, but we also had less than 300 pounds of fuel and still needed to overfly the city to reach the airfield on the far side. Given our situation, we started looking for places where we could make a forced landing and also scanned for the best route around the city. We decided to skirt the city’s edge and follow the beach. If we had to put the Black Hawk down, that’s where we would do it.

With between 150 and 200 pounds of fuel remaining and both fuel-low caution lights flashing, we were cleared for landing. We flew the straight-in approach down the runway and proceeded to our ramp for shutdown. By that time, we had between 90 and 120 pounds fuel remaining on the fuel gauge. Once we landed, there was some nervous laughter and a few chuckles — but at least we were safe.

We talked about what went wrong during our crew after-action report. When we launched on that final mission, we had plenty of fuel, plus a reserve. We’d been continually doing fuel checks that day during our earlier flight legs and thought we knew what to expect. So why were things so different on that last leg?

As it turned out, we did our earlier fuel checks while flying short legs between the ship and shore or in holding patterns at maximum endurance airspeed waiting for the ship’s deck to be cleared. We didn’t think to note the fuel burn rate from our first long flight in the morning as a guide for the fuel required to get back.

What about our common knowledge of CEFS burn rates? We had hundreds of hours in CEFS aircraft, so we should have known what to expect. When I checked the fuel that day during our hops out to the ship and back, everything appeared normal. How could there have been such a big change in our burn rate on that last hop?

As it turned out, the answer was simple. On our earlier legs, we flew slower and, as a result, burned less fuel. However, on the last flight leg we were operating overwater with passengers onboard. As a safety egress precaution for overwater flight, we had opened the cargo doors on both sides of the aircraft and removed the cockpit doors. That created extra drag, which increased our fuel consumption. Our mission nearly ended in catastrophe because we didn’t take that into account. The only thing that saved us was operating by the book and ensuring we had the required reserve when we left the operating area.

What about you? When you plan your reserve, do you take into consideration that the flight profile for your return flight may be different than your mission profile? Remember, you might run out of fuel, but you’ll never run out of gravity.

  • 7 May 2023
  • Author: USACRC Editor
  • Number of views: 279
  • Comments: 0
Categories: On-DutyAviation