Submitted by: the ole gunny

In the last issue of “The Flight Line“ , we introduced the “Duece” as the fore runner to the CH-53 Sea Stallion. I can't just drop the intro there because there were a number of events that I remember when I was flying them that I feel should be documented somewhere and I' ve chosen here. Now, this is going back to the early 1960's when I was in HMH-461 at New River N.C. In the second paragraph of the preceding issue we mentioned the fact that this particular Helicopter had automatic Blade Folding capabilities and when it worked it made life a lot easier for everyone and when it didn't it was naturally as you would expect “a pain in the main drain”. I recall one incident on the flight line where a crew came back after flying and went to blade fold mode and nothing worked. It was determined later to be a rotor head positioning problem and that the slip ring would require replacing. This, at that time, was normally done by an electrician so, after some more troubleshooting it was etched in stone that the slip ring would have to be changed. A new or rebuilt slip ring was ordered and brought out to the aircraft and the electrician completed the replacement in a short period of time and then it was into the test phase of the newly installed part. The APU or Auxiliary Power Unit was started and the switch placed in the Rotor Head Fold position. When the rotor Head positioning switch was placed in Blade Fold Position the # 1 and #5 blades would position themselves over either side of the aft pylon. The Rotor brake would automatically go from a “hard brake” to a “soft brake” during this process. Once the rotor blades were in position for folding the brake would go back to the hard setting, there by not allowing the rotor head to inadvertently turn causing damage to the system and the A/C..

What the crew and observers see during this process is the rotor head and all five blades slowing turning until the slip ring tells them to stop because the head is in the fold position. At least that's what's supposed to happen. Normally at that point the Fold Blades light comes on and the switch is moved to fold the blades. Everything was going as planned up to that point except the blades were folding out over the front of the Helicopter and not over the back as is designed and was planned. The process could not be stopped until the cycle was completed. This minor cliche caused major concern amongst all watching because the added weight forward of the Center Of Gravity caused the parked Helo to rock forward on the main Landing gear thereby causing the tail wheel assembly to lift off the ground.. Thankful, for all concerned that it was not far. Now, Folks we got a problem. Word got from the flight line back to the Maintenance Office faster then I've ever seen. It wasn't very long before we had 20 or 30 guy's standing around and trying their best to appraise the situation without laughing at the dilemma. Finally, some of the old hands figured out the best way to recover from this mishap was to attach a Jeep winch to the tail and pull it back down and then Flip the unfold switch and hopefully everything would reverse itself without too much damage. Everything worked as planned. The only damage was some minor scratches on the under side of the rotor blades. Needles to say the next few days found all the electricians getting educated on the proper orientation of the slip ring in the Aircraft. If I remember correctly, there was even a Maintenance Directive that came down from the big Maint. Chief in the sky and all slip rings were marked in a manner that they could not be installed backwards. What a way to learn a lesson !!