TCA had three Mallards. J18, J19, and J42 which was N51151. J18 was, at the time N36DF and J19 was N95DF. I don't remember which one had the de-icing boots, but I do remember that we wanted to get rid of them but never did. J42 was about 400 lbs. lighter than the other two and we never figured out why. It was the favorite of pilots, had the best props (least eroded by water impact damage), and was the best of the three by far. Of course it was the one that crashed. The crash, even though the airplane was inverted when it hit the water after the engine departed from the airframe, was a non-injury accident with 10 passengers and two pilots getting out unhurt.
J42 has 12:1 blowers in it's R-1340s, while the other two aircraft had 10:1 blowers. One day, J42 had a throttle lever break off inside the overhead quadrant, which would require a major overhead disassembly to change-out the lever/pulley assembly to properly fix. It happened on the ramp at Avalon, so I had to go over there with a piece of aluminum to somehow lash to what ever was left of the throttle in an attempt to ferry the aircraft back to Long Beach Airport. I got to the Pebbly Beach ramp and did my best to lash the aluminum handle to the remains of the throttle lever/pulley, but it didn't work very well.The piece was too loosely attached, no matter how tight I twisted the safety wire we used. I opened the interior headliner behind the wing spar and used two pairs of safety wire pliers, one on each side of the throttle cable loop so I could control the #1 engine while the pilot controlled the #2 engine. He gripped the real #2 throttle and the "fake" #1 throttle (which was not connected anymore). I demonstrated to the pilot how I could precisely control the #1 engine to match the manifold pressure needles as he commanded the #2 engine. I would keep the needles matched by following his #2 manifold pressure needle with my #1 needle. All he had to do was pretend to be controlling the #1 engine with the "repaired" throttle lever that wasn't working very well.
I braced myself to keep from being jarred out of position during the rough ocean water take-off and gripped the two pairs of safety wire pliers to control the #1 engine. We left the seaplane ramp and into the ocean we went. The take-off was uneventful, but I could see that the pilot could advance #1 engine with the repaired throttle arm but the engine could not be retarded by him...... I had to do that with my safety wire pliers that were clamped to both sides of the cable loop. After we were airborne, I practiced a couple of throttle transitions with the pilot and told him that it would be a piece of cake.
The only major transition we made was during approach to Long Beach Airport, when the pilot brought it back to idle, I had to match that, which I did with a perfect MAP needle match all the way down to idle. We touched down on the long runway at LGB and taxied in to TCA's hangar.
After getting to the home barn, we talked over how we were going to get one of our two grounded aircraft back in service by the morning. It was now 7:00PM and we needed to be up and running by 9:00am the next morning. One aircraft, J19 had an engine removed and was awaiting a replacement engine and J42 (N51151) had a broken throttle arm. We decided that it would be faster to take an engine off of N51151 and install it on to N95DF, J19. The three of us stayed all night, removing the engine from N51151 and installing it on N95DF. After the rest of the crew came in the next morning, one of them said "What about the 12:1 blowers on the engine that was removed from N51151 and the other engine with 10:1 blowers that was already on the airplane." None of us thought about that when we made the decision to take the engine from J42 and put it on J19. We had a meeting with the pilots and they reluctantly decided to try it out. After several take-offs and landings on land and on the water, the pilots told us that the difference in boost was unnoticeable, except for a 1.5in/hg higher manifold pressure reading in the engine with 12:1 blower.
We operated J19 that way, successfully until the FAA busted us and fined Trans Catalina. After this, we changed everything back to the way it was supposed to be when we received the correct 10:1 blower engine replacement. Shortly after this was when J42/N51151 had the accident when the pilot attempted a take-off in seas that were too rough for a safe take-off. The severe hull pounding caused an engine to leave the aircraft. The engine went about 100 yards out in front of the aircraft before it hit the water. The aircraft climbed slightly, rolled over inverted and nosed into the water. The departed engine was never recovered because it sank into water that was over 1200 feet deep. The rest of the aircraft was perched on an underwater cliff 100 feet below the surface near the edge of a 1000 foot dropoff. After the barge came into Long Beach with the salvaged aircraft, we took all of the instruments and radios out and placed them in distilled water. They ended up being scrapped anyway. About a week after the aircraft was delivered to the hangar, the remaining engine was drained of the water that was in the oiling system. Then we discovered that the whole magnesium case was destroyed by the salt water. We could actually punch holes through the case with our fingers after just one week out of the water. The rest of the aircraft was in perfect except for a broken off left wing. Chalks bought it from the insurance company for about $15,000.