by Jim Cavanagh
When you slide into an airplane new to you, what usually jumps out first isnt the radio stack or the new engine analyzer. Its the window trim that no longer covers the aluminum frame, or the uneven line of a cracked glareshield, or the multiple screw holes in the door post plastic trim, or the eroded beading applied to the edges of door trim.
As the age of the general fleet continues to advance, much of the 30-year-old plastic meant to last a decade or less is reaching the end of its practical life. But old and neglected are two different things and given the lively aftermarket in trim parts, theres no reason to live with unsightly or missing trim pieces.
At some point in an older airplanes life, interior plastic will have to be replaced. Over time, the old parts out gas solvents and become brittle, shrink due to heat or crack from the cold and harsh UV rays. Weve explored the interior replacement market before, but in the intervening years, the market has evolved. There are more suppliers offering more variety in plastic trim parts and more support, too, so you can do this job yourself, if you wish. This report will focus on who has what parts, how well theyre likely to fit and how much they cost.
Worth noting here is that its simple to change a plastic part and the FAA agrees that it falls well within the realm of approved owner-performed maintenance. The parts are usually fastened in place with screws or adhesive and are purely cosmetic. You can hire the job out to a shop charging whatever they charge, but really, any owner can unscrew a screw and save a few bucks. The trick is fine-point fitting and buying good parts in the first place.
A Good Part
A good interior part must meet certain criteria, the most important being proper fit. It has to be made of the correct material to withstand heat and cold and it has to have uniform thickness. Anything beyond these requirements-such as finished trim, beading, placards and pre-drilled holes-is pure gravy.
In the early days of the aftermarket parts business, replacements were made using the original part as a model. More often than not, the old parts had shrunken, distorted or cracked, leaving the fabricator with an imperfect replacement part. Any molds made from the bad part were bad molds and the fit was iffy. Most of the original molds were made from wood, plaster and bondo, which themselves eventually shrink. Parts that were too small to fit easily werent uncommon.
This is why the first generation of aftermarket parts were disappointing and turned many owners against PMA-supplied parts in general. But these days, aftermarket suppliers have gotten better and are building molds that reflect what the inside of the airplane is really like, thus you can expect better fit in general.
Using the correct material is important both for manufacturing and to ensure that the part remains temperature stable. The aftermarket shops use two materials. ABS sheet is excellent at higher temperatures, but becomes brittle in extreme cold. Kydex 100 is similar to ABS when it gets hot but retains more flexibility when the mercury drops into the teens and lower.Its also more expensive.
Regardless of the material used, the thickness of the sheet goods used to make the parts is critical to maintain a uniform thickness of the finished part. Older parts tend to be thin, both uniformly or at certain weak spots, particularly the older OEM stuff. This is the result of making the part out of too-thin material and overheating or overdrawing the plastic over the mold. Besides looking cheap and fragile, these parts will break prematurely.
Because there are so many older airplanes in need of plastic, the aftermarket segment has blossomed with companies that appear ever more cognizant of quality control. Gone are the days when you got a plastic part that needed major remedial trimming to fit.
The OEMs still support the plastic parts demand for most of their models, although prices are likely to be higher and service somewhat spotty. A quote from a factory dealer will probably reflect a discount, but OEM parts are generally more expensive. The aftermarket trim-part trade uses price, quick delivery and service as its selling points. Because of the expense of developing tooling and infrastructure, which pales in comparison to the STC/PMA certification process, the aftermarket houses tend to go for sales volume.
The plastic parts market is comprised of, in no particular order, Vantage Plane Plastics (formerly Kinzie Industries), Heinol and Associates, Texas Aeroplastics, Selkirk Aviation and Plane Parts. Of these, Heinol and Plane Parts specialize in Piper parts exclusively, Texas Aeroplastics makes a limited number of parts for Cessna 150s and even fewer parts for 172s and Selkirk Aviation specializes in Cessna singles from the 170 to C-185. Their parts are fiberglass, rather than plastic. Plane Plastics makes parts for virtually all modern certified aircraft.
All of these companies appear to strive for quality products. The plastics they use are virtually the same; sheet goods that will form under heat and vacuum, take a set without springing back and will remain stable at typical temperatures. Nearly all of the parts we examined were made of thicker material than the original-surprisingly thicker.
Manufacturing plastic parts requires a vacuum table and a bridge that holds a plastic sheet. This sheet is heated thoroughly and uniformly by electric elements and when soft enough-determined either by gauges or a trained eye-its lowered onto a table loaded with the mold. Vacuum is applied through holes drilled into the table to draw the heat-softened plastic around the mold. After cooling , parts are cut out of the sheet and trimmed. Some companies use computerized robotic arms to trim and drill holes, others trim by hand using rotary tools with different attachments, sanders and files.
All of the companies depend heavily on e-commerce, with online catalogs.Some catalogs are easier to use than others. Plane Plastics, for example, offers more parts, but their catalog is a series of isometric drawings, similar to the aircraft parts catalog. It takes a careful look to get the right part. Plane Plastics numbers are basically the original part number, with a K in front. Plane Parts, one of the two Piper-exclusive companies, has photos of some of their products but not all, and their part numbers are their own, not referenced to the original manufacturer. Heinols Web catalog has beautifully clear photos of each part they sell and seems to generally use Piper part numbers.
Each of the companies we interviewed told us that they based their prices on the expense of making the part, not on a percentage of OEM price. In the old days, the factory list and a multiplier were used to price a part and this would change regularly as the factory prices went up. This is still done in the aircraft salvage industry. Owners, however, dont like paying for something based on an inflated price and are much more comfortable buying a product priced on its cost, with reasonable profit built in.
Interestingly, prices among the companies vary quite a bit, with Plane Plastics generally cheaper than Selkirk for Cessna parts, although not always. Plane Plastics and Selkirk parts are almost always less expensive than Cessnas OEM parts, sometimes by as much as several hundred dollars. On Piper parts, Heinol is the high-priced vendor but, again, this appears to vary from part to part. If you need parts for a model supported by two or more manufacturers, by all means shop on price. The OEM part might be price competitive, but in most cases, it wont be.
In most market segments we cover, we rarely see such wide swings in price.For example, Cessna wants $797.53 for a Skyhawk glareshield while Plane Plastics will sell you one for $131.25 and Selkirks price is $265.00. Whats going on here?
We think the OEM price is marked up to generate some sort of return on investment that isnt necessarily sensitive to volume or customer pushback.Selkirk and Plane Plastics are clearly closer to the ground in terms of customer reaction to pricing and they also compete with each other.
Otherwise, we surmise price differences are largely due to volume. Companies able to buy materials in larger quantities have a cost-of-goods advantage which generates more sales which generates more volume discounting.Plane Plastics even has a machine that converts scrap plastic into pellets that get shipped back to the manufacturer for credit. Its a large, expensive machine whose payoff presumably accrues only at a certain production level.
All of the companies offer discounts of some sort. Plane Plastics discounts if youre a previous customer. They also have discounts for large orders and the occasional special that they announce via e-mail bulletins.Jerry Evans, at Texas Aeroplastics, occasionally discounts to type clubs, but feels he has pared his prices as low as he can. Al Heinol told us he offers discounts on multiple parts.
And thats a good way to buy plastic parts, when possible. Brian Powers, sales manager of Plane Plastics, told us that shipping and handling is based on bulk and a maximum weight per package. Once a large piece is crated, a number of other parts can usually be included with no increase in shipping. A door panel might cost $20 to package and ship, but in most cases, this same $20 will cover a second panel, an armrest, panel overlay, glove box door and a baggage door. So, if youre replacing plastic in your airplane, order all the parts at once.
Fit is the proof in the plastic-parts pudding. No matter how well its made and how good the deal, if it doesnt fit, the part is junk and the expense in both time and money goes up exponentially. This is why all of the shops we interviewed stress that their parts fit better than the other guys. But do they?
Most parts will be close, if not absolutely perfect. How they get this accuracy is different with each company and certainly, the longer theyve been in business, the more accurate their parts should be. A couple of the companies, Vantage Plane Plastics and Heinol and Associates, have a number of pieces of original Piper tooling. This may or may not be a good selling point. It certainly sounds good, but the condition of the tooling is the real question. Was the original tooling well made? Has it been damaged and repaired? Has it remained dimensionally stable over the years? Did the original parts pulled off of this tooling fit exactly? Important questions when a buyer is counting on a perfect part.
Heinol is so confident that its parts are perfect that they arrive predrilled; all an owner has to do is pull the old part and install the new one. Heinol is the only supplier to do this. Heinol boasts the latest in vacuum forming technology, uses Kydex 100 and believes that by focusing on Piper parts exclusively, he has perfected his line over the years.
Scott Brown, of Vantage Plane Plastics, told us that when they bought Kinzie, the parts had acres of excess material that needed to be trimmed by the installer. Having installed a few of these panels in a Mooney a few years ago, we can confirm this. In the intervening years, Vantage has put effort into eliminating this excess material, although they concede some parts still need the extra trim material. On a recent visit to their shop, Brown showed us a new Cessna part and how much needed material would have to be trimmed before it could be installed.
Out in California, Bob Atkins of Plane Parts, told us that all of his parts were engineered from scratch, using both an old part and an actual airframe to compute dimensional requirements for a perfect fit. He makes a mold for each part, then changes the mold as necessary to get a perfect part.This is an excellent way to create parts, but in 15 years, he has PMAd a hundred or so parts using this method. So if he doesnt have what you need, it could take a while to get it.
I obtained a selection of parts from each supplier and examined them carefully. I noticed one thing right away: All of them, including the OEM versions, are thicker than the parts they replace and they are more uniform in thickness throughout. From what I could tell by installing a few parts, they fit as advertised.
As he claims they are, Al Heinols parts were drilled and matched the holes in the airframe. When I installed these parts in a friends Archer, I found that, as Heinol claimed, they fit perfectly. I did have to pick a slightly larger bit, but the holes were still under the screw head. Parts from Plane Plastics and Texas Aeroplastics fit in the right space, but were undrilled and this is probably the most difficult aspect of installation.
There are a couple of tricks to locating screw holes: First, make a tool to locate the holes. Variations of this tool can easily be made for odd fitting parts. The other trick is to nest the new part with the old and drill the holes. Sometimes you have to cut the old part to get it to nest. Drill the smallest hole you can in the new part and feel through this hole with thin wire or a small jewelers screwdriver to determine the direction to enlarge the hole for final fit.
If you mislocate the hole or get it too large, use a finish washer under the screw head. Upholstery shops have various assortments of screws and washers, but stainless screws and washer or countersunk screws and tinnerman washers work fine.
While all of the companies claimed that their parts were easy to install, all of them also confirmed that an experienced installer will usually do a better job of getting the fit right. But to be realistic, these companies would probably rather deal with the occasional installation pro than having to teach Installation 101 to nimrod customers. Nonetheless, they do provide advice and customer service. About 80 percent of sales go directly to owners and if they want repeat business, they have to be prepared to help owners install the parts. A few years ago, I got some parts from Plane Plastics for a Tomahawk I was restoring and only about half fit. Shortly thereafter, they apparently improved the molds and next batch fit perfectly.
In this competitive market, buying strictly on price makes sense. That all but eliminates the OEM parts. From my examination and trial of these parts, they seem to be of comparable quality across the board so I dont see the sense of paying a lot more money to get the same quality part.
If you own other than a Piper or a Cessna, Plane Plastics is the top pick, simply because theyre the only aftermarket supplier. If youre a Piper owner, you have three companies to choose from. Again, price rules. Plane Plastics generally has the lowest prices, but not always. Youll have to shop the particular part you need, then compare.
Heinol generally has the highest prices but, again, that varies. Heinol pre-drills the parts, which is a plus, and uses Kydex 100, which we think is a better material. Further, Heinol also supplies many parts with plascards and decals and on some parts, that will be worth the premium. But overall, we think Plane Plastics has the best price/value equation, if you dont mind fussing with the fit and drilling holes yourself.
Also With This Article
“Sample Piper and Cessna Parts”
Heinol and Associates, 866-865-1262, www.piper-plastic.com
Vantage Plane Plastics, 866-307-5263, www.planeplastics.com
Texas Aeroplastics, 817-491-4735, www.buyplaneparts.com
Selkirk Aviation, 208-664-9589, www.selkirk-aviation.com
Plane Parts Company, 310-318-1902, www.planeparts.com