CHIEF WARRANT OFFICER 5 RANDY MILLER
1st Battalion, 351st Training Support Battalion
Fort Stewart, Georgia
As evening approached, the crews were preparing for their night vision goggle (NVG) training mission. The task was to conduct readiness level (RL) progression for hoist operations. As the crew adjusted their NVGs and cranked the UH-60, they had no idea a routine litter hoist training mission would result in something much more.
Performing RL progression tasks are standard procedures; yet crews often approach these tasks with anticipation and excitement, especially the new guys. On this night, a junior pilot (PI) was completing his aerial reconnaissance low-altitude progression tasks for hoist operations. The crew mix was right — an experienced pilot in command (PC) and a senior crew chief, both having conducted this mission on several occasions, were paired with an inexperienced PI. The flight plan was routine and the PI briefed the mission to the PC and crew chief. Neither crewmember had any serious questions about the mission. At the successful completion of this training, the PI was anticipating a progression to RL 1.
This training mission was a combination RL progression flight and training for ground crews to learn how to hook up a litter for aerial extraction. The PI brought the aircraft to a 50-foot above ground level hover, and the crew chief deployed the hoist, lowering a litter to the trainees on the ground. Some of them had eagerly discussed how awesome it would be to be winched up in the litter to the aircraft hovering overhead. This was the eventual plan; but first, a few practice winch down-and-up exercises were required to make sure everything worked as planned.
With the cable lowered to the ground and the simulated initial hookup, the Stokes litter basket began its ascent to the aircraft. During the ascent, the litter began to swing back and forth, with each oscillation more pronounced the closer it got to the aircraft. Ultimately, it rapidly swung out of control. The crew chief reached out with his gloved hand to control the back-and-forth movement; however, his attempt proved useless and the oscillations continued. The crew chief then used both hands to try and stop the rapid oscillations to no avail.
The crew chief’s leg dangled outside the aircraft’s door as he used his whole body in an attempt to stop the swinging litter. Suddenly, his leg became wedged between the hoist cable and cabin floor. The hoist continued to apply pressure to the cable until, without warning, the litter swung out, struck something on the aircraft and crashed to the ground with about 3 feet of steel cable hanging from the attachment point.
Fortunately, no one was injured, nor was any equipment damaged. The aircraft landed safely and the crew chief was treated for minor bruising to his leg. The UH-60 sustained minor cosmetic damage from the cable scraping the airframe.
As the aircraft crew joined the trainees on the ground, everyone silently said a prayer of thanks that no one was in the litter. Maintenance personnel inspected the aircraft immediately to determine why the cable suddenly snapped. Upon closer inspection, they found the cable had not snapped; rather, a protruding bolt from the aircraft wheel had cut it. This caused the cable to fail and the litter to fall 70 feet.
Lessons learned
The battalion safety officer immediately conducted an accident investigation and found additional failures that contributed to the mishap. The crew chief did not place his intercom switch to “hot mike” to allow crew coordination and he failed to lower the hoist cable without the litter attached to reduce oscillations. This, along with the failure to crew coordinate with the pilots, compounded the problems with handling the load.
Maintenance personnel tightened the protruding bolt that caused the cable failure. The battalion commander directed the company to inspect all aircraft for other bolts that might have backed out of their required positions, as well as determine if maintenance was performed by the book. Fortunately, no other aircraft had protruding bolts.
The next day, the battalion commander ordered a safety stand-down to discuss lessons learned and to remind all aviation crewmembers that flying helicopters is a dangerous business. He stressed that flight crews should plan their missions and preflight their aircraft with meticulous detail. Risk assessments are not just a check-the-box exercise, they take aviators one step closer to mishap prevention.
Thankfully, no one was injured in this incident. Nevertheless, the ground personnel recognized how close they came to death. Just thinking about joyriding in the litter on the hoist up to the aircraft was not using common sense. This incident was a good example of the dangerous jobs we perform every day. It was also a reminder how the addition of variables can affect mission risk. Use common sense when planning your next mission. One irrational decision can change everything.