|Aircraft Overhauls from Tip to Tail|
|Written by Floyd Allen|
|Friday, 11 November 2011 16:25|
Interestingly enough, there may be some confusion as to what an “overhaul” is, and who can perform one.
“Well, technically,” stated Brad Power, a retired Arizona DPS aircraft mechanic supervisor, “I think what you are suggesting is that people will be inspecting and changing components, not actually doing an overhaul. I have found the FAA is quite adamant about what an overhaul is.”
According to Part VI of the April 2007 Civil Aviation Regulations published by the FAA in April, 2007, “overhaul” is defined as “The restoration of an aircraft/aeronautical product using methods, techniques, and practices acceptable to the Authority, including disassembly, cleaning, and inspection as permitted, repair as necessary, and reassembly...” On the other hand, maintenance is defined as “The performance of tasks required to ensure the continuing airworthiness of an aircraft, including any one or combination of overhaul, inspection, replacement, defect rectification, and the embodiment of a modification or repair.”
“Whatever you call it,” Jason Wolcott of GATTS in Manhattan, Kansas, said, “there are a number of things that can be attended to when you give an airplane close scrutiny with the intent of correcting any and all issues you encounter.”
As one of the premier training schools in the country, GATTS has a fleet of airplanes that need to be kept up to snuff, so Wolcott is well-versed in knowing what to look for. He shared that one of the places they always check are the windows.
“Jason’s right,” Phil Sanders of Triple S Repairs in Kingman, Arizona, agreed. “Occasionally, you may want to change the windshield, which, of course, may immediately force you to decide whether you want to put in a one-piece shield or keep the original two-piece style.”
“When you’re checking your windows,” Power added, “one of the main things to look for is the condition of the seals.”
“Problem is,” Wolcott interjected, “all too often we get used to the old glass and don’t even realize that it is deteriorating. Over a long period of time, 20 years or so, the problem takes place so gradually that we often neglect to detect it.”
All of the experts agreed that aesthetics is often an important part of an overhaul. As a result, the interior may be a good place to start when you are doing your overhaul. The first thing you may want to check is the plastic parts. Depending upon the climate you and your airplane spend most of your time in, cracking can be a real problem. Fortunately, it isn’t overly expensive to replace these parts.
“Because what you are basically doing is freshening up the craft,” Wolcott suggested, “I would strongly suggest you invest in a new carpet kit and new upholstery.”
“And,” Sanders said, “a new headliner can do a lot to improve how an airplane looks, as well.”
“Not everything you should check on the inside is aesthetics,” Power pointed out.
There were a number of suggestions that Power had concerning the “mechanics” of a craft. First, he suggested that you open all the panels in the fuselage. You will want to check the manufacturer’s manual and make sure everything is up to spec. Make sure that all structural elements are sound and that cables and pulleys are working properly.
“Another item you don’t want to forget,” Sanders said, “is the seat rail. You want to ensure that it is still properly locking into place so that you don’t find yourself in a situation where you are sliding back and forth all over the airplane.”
Though located on the inside of the craft, avionics is an entity all onto itself.
“One of the things we are considering,” Sanders opened, “is installing a new audio panel. We feel that this will give us better modulation. When we do, we will probably upgrade the radio, intercom, and headsets, as well.”
“Improvements in avionics are occurring so quickly that things are almost outmoded before you can get them installed,” Wolcott pointed out. Wolcott suggested that you probably should update really old avionics with a new GPS unit, which he said you should be able to pick up at a fairly reasonable price — particularly for a used 430 unit or equivalent. He further suggested that it is especially wise to get rid of anything that doesn’t work or that you don’t use, such as an old ADF.
“As well as the avionics themselves,” Wolcott said, “you may want to give some attention to the dash panel.” This is probably a good idea, inasmuch as it can get cracked and worn. A quick-and-easy fix is to put a cover on it. Or, you may want to paint the panel and re-label the instrumentation that is now part of it.
Another aspect of an interior overhaul is safety. An item you might want to attend here is safety straps. If your airplane still has a lap belt, it might be wise to update it with a shoulder harness. Also, you will want to check your door seals. Not only will they make your craft look better, they will cut down on wind noise, allowing you and your passengers to hear better in the craft, as well as just plain make your flight quieter and more enjoyable.
Once you finish your interior overhaul, you will want to proceed to the exterior.
“One of the things I would do,” Sanders offered, “is simply clean the oil off the belly from the blowback. That in itself does a world of good.”
“Obviously,” Power said, “one of the major elements of the outside is the skin. You certainly want to examine it for cracks, and then may want to strip and paint it.”
Wolcott agreed that the skin of the craft often needs attention. He suggested that you may be able to buff it out rather than strip and paint it, however. Or, if one or two individual panels need the extra attention, you can tend to them individually rather than paint the entire craft. The prop spinner is another exterior area that lends itself to aesthetics attention. This can either be repainted or stripped and polished, depending on which look you prefer.
The next exterior item you will probably want to check is the wheel pants. At the very least, Sanders suggested that you check to make sure they haven’t filled up with mud and debris.
“You actually have two options here,” Wolcott advised, “you can either repair the wheel pants or replace them. I would suggest,” he went on, “if you fly into unimproved airstrips very often, you may just want to remove them.”
While you’re checking your wheel pants, you should probably check the tires, as well. Verify they have the proper pressure. Keep in mind that the “proper” pressure may vary, depending on the type of airstrip you most often land on. Too, this would probably be a good time to inspect the brakes and make sure that they are in good working order.
As you examine your airplane, you will want to check out the fuel tank drains, making sure they are not leaking. A telltale sign you can look for is a blue, yellow, or green streak. This can be corrected with a quick, cheap fix. While there, you should also check your fuel cap seals.
“An item that is frequently overlooked,” Sanders offered, “is the crossover tubes that connect the tanks to the fuel selector valve. Especially in the heat where we live, that can deteriorate fairly quickly, and if you don’t spot it in time, it can raise all kinds of havoc.”
The final thing that may need “overhauling” is your engine.
“That,” Power shared with a smile, “is an item that can be overhauled. Typically, if an overhaul is needed, you will want to ship it off to an approved facility to have the work done.”
One of the better facilities that accomplish such tasks is Poplar Grove Airmotive in Poplar Grove, Illinois. “When we get an engine in, we are extremely comprehensive in its overhaul,” Dave Allen of Poplar Grove Airmotive shared.
According to Allen, they go over the engine with a fine-toothed comb. This includes all hardware such as washers, nuts, bolts, etc. They check housings for damage and inspect and make sure that all dimensional fits are in accordance with specifications. They proceed with the understanding that anything that comes with the engine is considered part of the engine, such as the starter and accessory housings.
Engines aside, the time needed to overhaul an airplane will vary dramatically from pilot to pilot. If you are a hands-on type of person, Wolcott suggested that an overhaul my take a month of weekends. Also, he pointed out that some of the work could be done without taking your craft out of service. If you prefer to send your airplane out to be worked on, you might expect an upholstery job to take up to two weeks or more.
“When we do an engine similar to the one found in a Cessna 172,” Allen shared, “we advise owners to count on us putting between 60 and 65 hours in on the project.”
Cost can vary even more than the time frames involved. Factors affecting the cost include quality of materials used and self repair vs. skilled labor. While it can, in most instances, be accomplished relatively inexpensively, it can also run into thousands of dollars. Factor in engine overhaul, and you might actually find yourself in a position of having to decide whether to do the overhaul or simply buy a different airplane.
“Personally,” Sanders shared, “we have what we consider to be a diamond in the rough, so I can’t imagine us seriously considering replacing our airplane under any circumstances.”
“I understand Phil’s position,” Wolcott said, “but, typically, the decision is more pragmatic than sentimental in nature. Bottom line is bottom line, and the decision is, for the most part, made from a ‘dollars and cents’ perspective.”Whether you want to undertake a work of love or farm out the job to mechanics and other professionals, overhauling your aircraft can be both an aesthetically pleasing endeavor and one that results with improved safety. Regardless of your initial goal, knowing that both will be improved should be more than enough to make you think about overhauling your airplane at your earliest convenience!
|Last Updated ( Friday, 11 November 2011 16:31 )|