It was a clear, crisp day in New Hampshire's White Mountains as we flew visual flight rules in our UH-60A. Chief Warrant Officer 2 Gray, the pilot in command for this flight, and I had departed the Army National Guard Concord Army Aviation Support Facility for some mountain training. The winds were light enough that we practiced mountain approaches to the helipad atop Mount Washington, not far from an observatory.
We were flying without a crew in the back, and the sun coming through the windows kept us from needing to run the heater. As a result, however, we had very little air circulation in the aircraft. As we hovered over the pad on one of the approaches, the small vent on my pilot-side window popped open and Gray thought he smelled something. I closed the vent, commenting that I hadn't noticed anything unusual.
We decided to land nearby at Twin Mountain Airport to check the aircraft. As we slowed to land and entered effective translational lift, we both immediately noticed something that smelled like burning plastic. Up to this point, nothing in the cockpit suggested any problems and our engine indications were all within limits.
Once we were on the ground, I told Gray that, because of the odor, I suspected we had an electrical problem. He did a walk-around of the aircraft, looking to find the cause. Just as he was finishing, smoke began billowing into the aircraft from the right-rear part of the cabin near the rescue hoist. He immediately reentered the co-pilot's seat and we preformed a dual emergency engine shutdown and exited the aircraft.
Fortunately, we had another aircraft in the vicinity. Once the smoke and fumes cleared out of the cockpit, we used our high-frequency radio -- which operated on battery power -- to contact them.
While the other aircraft was en route, we inspected the No. 2 engine cowling. We discovered the V band clamp connecting the engine to the hover infrared suppressor system baffle deswirler had failed. Looking closely, we could see a one-inch gap between the sections. The smell we noticed was gaskets melting in the No. 2 engine cowling.
The second Black Hawk landed behind us and shut down. Its pilot, CW2 Barnes, walked to our aircraft, stopping to pick up a metal fin lying on the tarmac. We soon identified it as a missing fin from the deswirler. Fortunately, the PC in the other aircraft was our facility maintenance officer, CW5 Gokey. He assessed the damage and took pictures of the area. We then secured the aircraft and left it under the supervision of the local sheriff's department. The UH-60 was recovered two days later.
Upon examination, maintainers found damage to the aircraft's No. 2 engine cowling and HIRSS baffle deswirler. High temperatures also damaged sheet metal in the engine compartment.
What I took away from this incident was that, especially in a peacetime environment, it definitely pays to play it safe. Choosing to land the aircraft at a suitable site and give it an once-over paid huge dividends in this case. I'd hate to think about what could've happened had we headed home fat, dumb and happy and something major failed.
How About You?
Did you ever follow a hunch something was wrong with your aircraft and later discovered you'd dodged a bullet? That's a story worth telling, especially if it keeps another crew from biting the bullet. Please take a few moments to write down what happened and email it to firstname.lastname@example.org. I'll be glad to read your story and even more glad to share it.