Chock-Full of Trouble

By CHIEF WARRANT OFFICER 3 NATE MARSHALL, Detachment 4, Operational Support Airlift Command District of Columbia Army National Guard, Fort Belvoir, VAAugust 4, 2011

My co-pilot and I had departed Guantanamo Bay Naval Air Station several hours earlier with a load of 11 passengers, including a one-star general. Our final destination for that day was Rhode Island. We had planned a stop at West Palm Beach (Fla.) International to clear customs and refuel, followed by another refuel stop at Myrtle Beach International. The weather was easily doable, with scattered thunderstorms, moderate turbulence and light icing forecast along the route. We would be at 20,000 feet the majority of the time. Overall, it looked like a normal day for us.

The flight through the Caribbean was uneventful, and we landed at West Palm Beach just as a few thunderstorm cells were starting to build in the area. It took 20 minutes to clear customs " just long enough for one of the cells to turn violent and start dumping copious amounts of rain and lightning onto the airfield. A fuel delay turned a planned one hour ground time into two hours.

We departed West Palm uneventfully. As we were vectored for the approach at Myrtle Beach International, we saw several thunderstorm cells painted on our weather radar and NEXRAD weather uplink display. The cells were in all directions from the airport, but still far enough apart that we were easily vectored around them. Once we had the airport in sight, we accepted a clearance for a visual approach. The landing was uneventful, as was taxi and parking, which was directed by a lineman from the FBO.

After we shut down the engines, the lineman gave us the signal that he’d put the wheel chocks in place. We released the parking brake, which is standard procedure on our airplane for two main reasons. First, the linemen may need to tow the airplane to a different parking spot to facilitate ramp operations. Second, the brakes on the C-26 have been notorious for overheating if used extensively during the landing rollout or subsequent taxi. If left engaged after parking, the heat will not dissipate as quickly and can actually build to a point that damage occurs.

We helped our passengers deplane and directed them into the FBO. My co-pilot and I did our postflight checks, including ensuring chocks were installed on at least one of the three sets of landing gear wheels. I observed that chocks were installed on the nose wheel. I placed our fuel order with the lineman and we walked into the FBO, as we had done so many times on other missions.

A few minutes later, the lady behind the desk waved me over and said lightning had been observed in close proximity to the airport, so the fuelers were on a weather delay. I explained this to the general and the rest of the passengers. A few minutes later, there I was, where this story began, watching the rain and wind. I was horrified when our aircraft spun 140 degrees to the left, where it came to a stop. Originally, it had been parked on the line with a ground power unit (GPU) just off the right wing tip and a King Air parked near the left wing tip. I was sure my airplane had hit the King Air or GPU. There was too much speed and movement involved for it to have missed hitting something.

I called to the co-pilot and we both ran outside into the storm. There was a tug with a couple of sets of chocks parked just outside the FBO door. We each grabbed a set of chocks and ran toward the airplane, ignoring the torrential downpour and lightning. I’m sure the same thought was running through both our minds " “Save the airplane!” I remember thinking I had never been in rain this hard. I could feel water in my socks before I was 20 feet from the FBO door. As I installed the wheel chocks on one main landing gear, my co-pilot installed chocks on the other. I crouched under the fuselage for a moment and conducted a 360-degree scan, examining each section of the airplane. To my relief, I could see it had not collided with anything. I could hardly believe it!

The chocks that were installed before the storm were still in the same place, but the forward-most chock had been pushed out of the way. It didn’t take long to figure out what happened. The wind had pushed on the left side of the vertical stabilizer, causing the aircraft’s tail to rotate to the right and the nose to the left. The nose wheel free castered, which allowed the airplane to rotate counterclockwise free of the chocks until it weathervaned completely into the wind. As I looked around the ramp at other airplanes, I saw several light airplanes had been bent and mangled in their tie-down ropes. Some had literally twisted in their parking spaces as they pulled against the ropes. One Cessna 152 even had a bent fuselage. All had been pulled in the same direction.

It was then I realized my error. The chocks installed by the FBO lineman were the small wooden chocks often used on light general aviation aircraft like a Cessna 172 or other light airplane. Yet these same chocks were used so many other times on our airplane in the past. After all, we park on completely level surfaces and it would take a huge amount of force to roll over any wheel chock, right? Wrong!

I made a huge mistake. I was complacent. I did not take the time to think about what could possibly go wrong. We do have larger, heavier (30 pounds) wheel chocks onboard that we could have used. On this day, however, the weather was nice, so we weren’t expecting any surprise monsoon-like winds. Plus, we were only stopping long enough to refuel … what could possibly go wrong?

From this experience, I learned to ensure two sets of chocks suitable for our C-26 are installed whenever we park. As part of my postflight checks, I now check the size and weight of any chocks installed by FBO linemen before I walk away from the airplane. The FBOs do have the heavier chocks, but sometimes you have to ask for them. If they only have one set, I retrieve ours from the cargo compartment and install them as well. I learned a huge lesson and will never make that mistake again.