CC Log: The Dangers Of Airplane Corrosion

Corrosion is an insidious problem if you live in a humid climate. Case in point’€¦

Airplane Corrosion

As I turned the key and dropped the airstair door of the Cessna 421, it was like shaking hands with an old friend. I was in Subic Bay, Philippines, on the west side of the island of Luzon, staring across the bay at the low mountains of the coast, remembering the trip I had made in 2003 from Kansas City to Subic.

I've never been a big fan of 421s, but this one was a jewel---or so I thought at the time. It was equipped with everything you could ask for in Cessna's top-of-the-line piston twin. The Golden Eagle was owned by a company that administers VA hospitals, primarily in Indonesia but all over the Far East, including Japan, Korea and other places where American G.I.s are hospitalized. The company generally planned flights all over the region, but most hops were within 800 nm of Subic Bay or Manila.

The westbound flight had gone without a hitch. The weather was good, everything in the airplane worked as it was supposed to, and I made the 7,500 nm trip in only six days: Kansas City to California; Santa Barbara to Honolulu; to Majuro, Marshall Islands; to Guam to Subic.

There was a minor glitch when I arrived over Subic. It seems the runway was being resurfaced at the former Navy base, and what had been a 2,500-meter strip of asphalt had been reduced to only 550 meters, a little sporty, but still manageable at light weight.

Shortly after I turned over the logbooks and keys, I learned that 100LL avgas was becoming scarce in the area. The pilot who would be operating the airplane for the owners was concerned, but he felt he had a decent line on where to find 100 octane. He commuted back to Manila with me. I wished him luck and jumped on the first flight back to California. 

Three years later, the pilot called again and told me avgas was drying up in that part of the world and everyone was converting to turbine equipment. Avgas was becoming scarce all over the Far East, and the corporate pilot who flew and maintained the airplane in Subic Bay often had to do some clever route planning to get his passengers where they needed to go.

He asked if I'd come get the 421 and fly it back to Kansas City. The company was in the process of buying a King Air and was planning to put its Golden Eagle back on the market when it reached the U.S.

I arrived in Subic Bay just in time for a huge typhoon to block the route between the Philippines and Guam, my first stop on the trip back to Kansas City. After a two-day delay to let the typhoon blow through, I was finally able to make the short 800 nm hop to Guam.

Unfortunately, Guam wasn't quite ready for me. The typhoon had slammed into the U.S. island territory and done considerable damage at the main airport. One-hundred-octane fuel was still available, theoretically, but a fire had damaged the storage rack, and the FAA wasn't sure the fuel was safe to pump.

After several days of waiting for FAA approval of the tank, and no resolution in sight, I decided to wait at home. The client agreed, so Air Micronesia flew me back to California to wait for fuel availability at Guam.

The delay turned out to be two months long while "my" 421 sat on the ramp at what was then known as Agana Airport, unhappily rusting away. When I returned to Guam a full two months later, corrosion had welded the brakes together, and there were a number of other squawks related to rust.

It turns out that Guam is infamous for rain, high humidity and corrosion, so much so that the military tests its new jungle equipment at bases on the island.

Finally, three months after I had left Subic Bay, I was able to launch from Guam for Majuro, Marshall Islands. It seemed that at last, I might be able to get this trip over with.

By then, I was paranoid about the airplane and had the FBO do a VERY comprehensive inspection. The mechanic came back with a list of things that "should be done," but he needed to order parts from Cessna in Wichita, and that could take another month.

This time, the owners in Kansas City said they'd do whatever I recommended. I took a test flight around Guam for an hour, and everything seemed tight and happy, so I agreed to go.

The 800-nm trip eastbound to Majuro went well. The 421 seemed happy, everything worked as it should, and I was eager to get this trip over with. The weather had improved dramatically, and I was even gifted with tailwinds on the leg to the middle Pacific island. Majuro was welcoming, and I took an extra day to double-check everything before the 2,000-nm leg up to Honolulu.

That leg is always a headwind stretch, so all tanks were refueled from the barrels of 100 octane I'd had shipped down from Honolulu.

The following morning, I was ready, or so I thought. I did a comprehensive preflight, started engines and taxied to the threshold. Only one more 2,150-nm leg after this one.

Majuro airport is built on a short, straight section of a typical Pacific ring atoll. The runway is plenty long enough to handle 737s, so length isn't a problem. The ocean laps at both sides of the asphalt, however, so if you lose directional control for any reason, the airplane is liable to get wet.

In my case, both engines spooled up without problems, though acceleration was slugging at 1,000 pounds over gross. All gauges remained in the green as the airplane accelerated through rotation speed and lifted off normally.

Well, almost, anyway. Just as I was reaching for the gear handle, the right engine lost power, and the Cessna tried to make a hard-right turn toward the beach.

I slapped both throttles to idle, slid sideways back to the asphalt and slammed the 421 back on to the runway somewhere near the centerline.

I had already used up most of the asphalt, and I could only pray that the new brakes installed in Guam were able to stop the airplane before it ran out of runway and charged into the small terminal building at the end of the strip.

As I turned off the active into the ramp, I noticed that the right engine that I assumed had quit cold was still running but was unresponsive to throttle commands. The right throttle obviously was no longer connected to anything.

Somehow, I managed to make a succession of right turns onto the left ramp and met the airport manager at a parking space.

After I explained my problem to the manager, we went in search of the only mechanic on the island capable of wiring on a Cessna 421. It turned out he was on holiday in Europe, so once again, I called the client with bad news, boarded the next Air Micronesia flight (operated by Continental) back to Honolulu and on to Los Angeles the next day. I called a friend in Las Vegas, an airline captain with Southwest and an A&P mechanic who also did ferry flying in his spare time, and he agreed to hop out to Majuro, fix the throttle linkage (and anything else that had rusted away in Guam) and fly the airplane back to Kansas City.

Fred later reported that there was corrosion practically everywhere he looked, and it took him a week's work to prepare the airplane for the flight back to the mainland.

Bill CoxWriter
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