Next on the list for overhaul is the windows. Big decision selecting a brand of windows and the method for replacement. The old windows were fairly crazed and definitely time for replacement.
The blog post should have been titled How to change your Cessna windscreen less than 10 hours. Most shops budget 30-40-50 hours to change a windscreen. Mine was completed in less than 10 hours by following the process listed below. I learned this technique from a local A&P and local paint shop that does dozens of Cessna windows a year.
Which brand and model?
Looking at all the options, It was decided to go with Great Lakes Aero windows all around with the Solar Control Grey option. This is the exact shade of grey Cessna uses on its new aircraft. The company is family owned and easy to work with through all phases of the process. They offer a special discount if all windows are replaced in one order.
Great Lakes makes a very high quality window that requires very little if any fitment. They are also OEM suppliers for Cirrus, Mooney, and Great Lakes. This provided a lot of confidence as to the level of quality. Paying the 30% uplift for solar control windows is a decision paying dividends. Glare and UV is greatly reduced without loss of visibility. UV is more intense with altitude, and really appreciate the extra protection for vision, skin, and preservation of the plane’s interior.
My A&P and I followed the Cessna maintenance manual procedure for replacing all windows.
After taking this approach, it’s difficult to understand why people take 30-40-50 hours to change a front windscreen by drilling out the lower valance, when the Cessna prescribed procedure takes about 8-10 hours? $100 hr shop rate computes about $3000 or more of unnecessary labor.
Following Cessna’s procedure is not only less expensive, but the log book can legally state “Installed according to Cessna Maintenance Manual”.
(Click on images to enlarge)
High level of the Cessna windscreen installation process followed:
1) Remove all trim and fairings touching wind screen (DO NOT remove lower front windscreen valance)
2) Cut a horizontal slot across the mid-point of the windscreen
3) Wiggle windscreen out, have 2 people pressing it out by sitting in the front seats with feet on the inside of windscreen. Later learned from a paint shop to cut the windscreen laterally across the midpoint for even simpler removal.
4) Clean the channels of old packing compound and grit.
5) Get a Great Lakes Aero windscreen, press it into the top clip and let the windscreen bottom rest over the lower valance
6) With a fine Sharpe, mark areas that need trimming to fit. (DO NOT use the old windscreen as a template, surprising how many are incorrect)
7) Follow directions to trim and trial fit. Top tip for the windscreen, snap it into the top track and lower it until the lip of the new windscreen is resting over the lower valance cowl strip. Or rest the windscreen along the top track and factor in the additional thickness of the windscreen when checking lower valance clearance. It will be obvious where the window needs to be trimmed if it extends beyond the side or bottom channels. DO NOT use the old windscreen as a template!
8) Remove the windscreen and trim where marked from step 7
9) Make sure the window to valance is properly packed with the special black caulk the factory uses, U554426. Some use the similar 3M Strip Calk window sealant, however this product softens in heat and oozes out the mounting channel. The factory also uses PRC/Proseal type product around all aft windows & non operable windows, except for the front windscreen.
10) Follow Great Lakes Aero’s install instructions placing the lower edge in to the lower valance tracks; then using thin sheetrock knives stuck between the top clip and the windscreen to allow the top windscreen lip to slip into the snap fit in the upper track. The thin aluminum of the knives provide a smooth surface for the window to slide into place.
The windscreen replacement process articulated in Cessna’s Maintenance Manual. The process is pretty simple, especially if the one extra steps is added; Cutting a horizontal slot across the mid-point of the windscreen to remove pressure on the old windscreens
Proof of Cessna Factory New Sealant Usage
Happy to report no more leaks, squeaks, or clouded vision. No regrets taking a no compromise approach to replacing the windows. BTW, Great Lakes does provide free samples of their material to help decide which direction to take.
One important item to note, all windows were replaced with factory original thicknesses, except for the operable side window. Increasing thickness adds lots of weight and complications with fitment and with adjacent interior components.
Perform some additional due diligence before upgrading thickness. The exception is the operable side windows. Cessna factory side window thickness requires a plastic edge bead spacer to fit the mounting channel, and coincidentally the thicker side window fits perfectly without the requirement for this edge spacer. In this particular case the thicker side window for operable types is actually a superior installation. The edge only needs a layer of vinyl tape and that’s it, fits easy and snug.
Where to go for help
Changing windscreens is a speciality job. I was fortunate to have an A&P who had installed windows previously accordingly to the Cessna maintenance manual, and also great advice from our local aircraft paint shop T&P. Many maintenance shops are not familiar with the factory prescribed process for removing windows. Take time to ask around and particularly inquire how many Cessna windscreen replacements they perform in a year. Consider shopping bids at local or regional aviation paint shops. They typically replace windows many times a year and many have the technique down pat.
The savings realized using the maintenance manual approach completely pays for premium solar control windows and labor to install.