A Different Kind of Aircraft Recovery

Submitted by: Doug Cahill

The following story is from Doug Cahill and relayed to me, the webmaster, as part of an email message:

Although I recovered dozens of downed aircraft that year, my most memorial was when the Boeing Maintenance Rep and my crew replaced a Combining Box Transmission ("C" Box) in the field. The ship took a 50 caliber in the "C" Box. The crew made a running landing on a road along side of a canal and slid off the road. The low hanging (front) main rotor blade was within inches of the water. The aft drive train shafts going to the aft vertical shaft were burn black, the drive shaft to number one was black and four forward shafts were black also. I took our Boeing Rep out to the site with me. We were extremely short of maintenance pilots and flew most recoveries single pilot. The Battalion Commander was already there and the word was given to destroy the aircraft as there was no way to get any equipment to the site. I said to our Rep, his name was "Bob" and I don't remember his last name, "Bob, have you ever had a "C" Box apart?" If anyone knows his name and if he is still with us, please let me know. He said "Yes, once, back in school." I then asked if we could take it apart, piece by piece, making a map as we go, gaining practice and then reverse the process and install the new box after we assemble it on the aircraft?

There was just no way to take out the old one and put in a new one, due to size and weight with the equipment that we had available in the field. He said, "Doug, I think we can." I said, "Fine, we are going to do it." We sent the ship we flew out on, back to Maintenance with the parts list and the crew that had just put the bird down. Thankfully we were scroungers and had all the parts we needed. A spare C. Box was not on our authorized stockage list, but, we had one. The top of this Ch-47 was like ice from all the oil that had spilled out of the bullet hole. The "Box" took the hit about half way down the casing and there was sure no oil in there, thus creating the burnt shafts. Since the "C" Box integraty had been lost by the bullet damage it could no longer hold its' considerable supply of oil.

Well Bob and I and our crew went to work. The crew removed the No 1. EMT and all the drive shafts and related items. Bob and I took the "C" Box apart, piece by piece and threw it overboard. Bob, made a map of each piece as we dissembled it. Once the case was empty of gears and other internal parts we unbolted it and muscled the case up and out and overboard. Our spare parts had already arrived. We reversed the process with the new "C" Box. We took it all apart, laid it out on a tarp and hauled the case up the side and set it in place. Then we reassembled the guts of the "C" Box. I said to Bob, "You know this is crazy?" He said, something like, "Yea, I know." We kept looking at the slope of the Ch-47 forward blade hanging within a foot of the water. I said, "Bob, do you think it will come out of this hole? What did the manual say? One inch of cyclic movement left and right. Yea, OK.” Well we patched and repaired as much as we could given that we were running out of daylight. I said to Bob and the Crew, “If the "C" box holds together, there is no guarantee both engines will fire and there is no way to fly out of this hole on one engine. In addition, there is a great possibility the blade will hit the water, if not at crank, or idle, but in transit to flight. That would cause the blades to mesh, or turn the aircraft over or worse.” I said to the crew, there is no sense in more than one dying today, you guys get in the maintenance aircraft and I will attempt to fly it out of here. Bob said, no way, I am going with you. The flight engineer and crew chief said, “It’s our bird, we are going with you.” I told them they were nuts.

I remember all of this as if it was yesterday. I said to Bob, “Bob, get in right seat.” Strapped in the left seat, I was having second thoughts. I then said to the flight engineer, “APU to flight.” As I said earlier I was having real second thoughts, and I was looking at the blade near the water. I then said, “One to ground,” we cranked, and I let it run on number one for about five minutes. The blades were really close to the water. We were still in one piece. I took a deep breath and said, “Two to ground.” We were soon running on both engines. This was no normal run up. I said Bob, “When I tell you throw both condition levers to flight.” I got a firm grip on the controls. I told the crew to hang on and told Bob to throw both condition levers to flight. When Bob advanced the condition levers to flight, I jerked that machine to a hover, probably using full left cyclic. Next thing I knew, we were at a hover and still alive. I hovered for a minute after sliding left to have some solid ground under us. I thought about shutting down and checking things over; but then I thought, “How long will this "C" box (combining transmission)l stay together or any of the other transmissions or shafts for that matter.” I then pushed the stick forward, pulled power and flew her home.

Once home, we tore the machine apart, replaced everything, forward transmission, aft vertical shaft, the field installed “C” box, and everything that may have been affected by this incident. In other words, we rebuilt it. Our actions saved this aircraft from destruction. To the best of my knowledge the actions we took to save the day had never been done, or even thought off, by anybody else before we did it. It was definitely one for the books!

Combining box transmissionn picture.