It’s been a decade and a half since our own Dean Benedict wrote an excellent “Windshields 101” column on King Air windshields. With the current inability to obtain a replacement in anything near a timely fashion, I think it’s time to revisit what we know and what we don’t.
Since the waiting list for replacement is measured in months, if not years, then protecting what you have now is critical. Some great tips were discussed at the 2026 King Air Gathering, so I’ll share some of that wisdom here and add additional information.
Getting a replacement
It is worth understanding that your order for a replacement windshield may drop quite low on the fulfillment list as the windows arrive at Textron Aviation. AOG situations receive preferential placement and you’ll need to substantiate that AOG through photographs and communicating with your customer service representatives. Precautionary orders, or just for delamination, will fall to the bottom of the list.
Getting in line for “repaired/overhauled” is even farther down the list, since the reality is that the manufacturing process is the same. Only the terminal blocks and serial number are retained. The backstory is that this “repaired” category provided the manufacturer with a way to sell windshields around the agreement they originally struck with Textron Aviation for new windshields. Current fulfillment for repaired windshields is still years away, even for parts suppliers who have been waiting for years already.
Photo credit: Joe Casey
Many operators are shopping the used windshield market. Most used ones will have signs of delamination, but they still offer a viable solution for operators who are grounded. Ask the seller for photos; the level of detail in any photography and the information supplied can help a buyer judge the confidence of the seller in the condition of that window they are selling.
Be sure to request documentation. Your installer will require a signed “As Removed From” tag from your seller as a minimum, even if they are unwilling to provide an FAA Form 8130 with the windshield. Someone declaring serviceability in the form of a tag or 8130 would be nice, but the installer can make that determination before installing the windshield. The “As Removed From” tag establishes traceability back to a certificated aircraft and that closes the loop to identify the windshield as an FAA-approved part.
In addition, ask for the specific ohmmeter readings of the heating elements and the thermistor, then have your installer check again on part arrival. Putting a windshield in only to find out it doesn’t heat properly is a sure path to a bad day.
Avoiding the need for a replacement
First, consider whether you need a replacement at all. Delamination is a common condition that evolves over time and often resembles a bubble between the windowpanes. There are no structural limitations to delamination, and unless the condition has progressed to the point of serious obstruction to the pilot’s view, the aircraft remains airworthy. There are aftermarket companies that advertise repairs for delamination, but unless the windshield is unusable due to extensive delamination, I wouldn’t take the risk on a windshield you can continue to use.
Fog or haze is something I hear about quite regularly, particularly during winter months, although it seems that the right combination of temperatures at altitude can also bring it to life. Communiqué ME-TP-004 speaks to the condition, and often the cure is to operate the windshield heat for several hours while on a power cart. A better method is to use a heat blanket designed for the windshield for several hours. The blankets are a bit scarce since they’re quite expensive. Shops that do the reapplication of PPG’s Surface Seal will have them. Some northern shops have made a blanket investment just for this haze symptom.
Windshield heat is a different matter. If your windshield heat is completely inoperative, that prohibits flight into known or forecast icing conditions. If there are partially inoperative segments, the maintenance limits allow for the loss of up to one-third of the heated area for continued airworthiness. I was unable to find any such references in the flight manuals, but published data is useful, nonetheless.
Preventative measures
Regarding prevention, there’s likely nothing more critical to examine than the windshield hump seals. These are the rubber hump found all the way around the perimeter of the glass. They provide the seal between the glass and the window frame. If there’s a way in, then water will find it at 250+ knots. You likely won’t have any sign of water inside the cabin, but bypassing the hump seal allows it along the edge of the glass/vinyl/glass sandwich. At a minimum, that can contribute to delamination, but I’m sure many instances of glass fracture are a result of that trapped water freezing.
Close inspection is easy, but a bit time-consuming. Request that your shop (and you should be willing to pay for the time) push gently at the seal every inch or so with a tongue depressor, looking for any point of separation. Feel free to do this as a pilot. Don’t expect the shop to provide this level of scrutiny during standard phase/detail inspections.
Hump seal repair isn’t particularly hard. It’s a bit messy and uses typical two-part polysulfide aircraft sealants. The repair area is sculpted to shape using a scraper cut to fit the hump. The chemicals can be separately obtained and the shaping tool fashioned from dimensions found in the PPG Repair Procedures document SIL-Beech-12-08. There is also a complete kit, part number HSKKINGAIR, that is available directly from PPG (cheapest), Textron Aviation or other parts suppliers. There is an Approved 1998 Raytheon Field Repair allowing for the use of aluminum speed tape for a maximum of seven days if you can’t make an immediate repair.
Another preventative measure that may seem obvious, but I regularly see ignored is any foreign “stuff” put up on the glareshield. Any scratches to the glass are grounding items unless you enjoy flying your King Air around unpressurized. Small scratches can be the start of the big bang failure of the glass cracking. Unless you’ve experienced a windshield failure in flight, you may not appreciate the shock of the noise, and with an interior pane failure you’ll have the rain of glass fragments falling into your lap.
If you fly King Airs enough, it’s not a question of if you’ll experience a windshield failure, but more a question of when. If it’s your first time, don’t panic. The window hasn’t gone anywhere (they don’t), but your flight manual will have you dial down the pressurization a bit for the rest of the flight. I’d be very hesitant to put a reflective shade on the inside. The possible heat generation isn’t worth the risk either. PPG and Textron Aviation have never made any recommendation except for outside shades.
Cleaning – news straight from PPG
Just plain old cleaning has been a point of contention for years now. There is a coating on the windshield that is both hydrophobic and provides static dissipation. Doing anything to compromise the coating (PPG Surface Seal) is a bad idea and expensive to have repaired. Communiqués on this date back to 1995, and that old one from 1995 has a list of acceptable cleaners and things that could come in contact with the coatings. However, in 2020 PPG changed the formulation to Gen III. It remains to be seen if the new formulation is as robust as the old one to various chemicals that people use.
I submitted a request for an update on cleaning information to Textron Team Turboprop, which they promptly forwarded to PPG. Fortunately, just before our publishing deadline, PPG came through with guidance that Team Turboprop will soon submit as a Publications Change Request (PCR). I’m sharing the verbatim email contents from PPG’s Product Support Engineering team here:
The procedure for cleaning Surface Seal-coated glass did not change with the introduction of Gen III. The current recommended cleaning procedure is as follows:
Cleaning
A. Cleaning Materials/Agents
(1) Equivalent substitutes may be used for listed items.
(a) 50% water and 50% isopropyl alcohol solution
(b) Mild liquid soap (detergents formulated for washing dishes by hand such as Dawn, Joy, Palmolive or Ivory are recommended)
(c) Rymplecloth, chamois, sponge or equivalent soft cloth
(d) Water
(2) Do not use powdered detergents, abrasive cleaners, any strong acids or any strong bases.
(3) Use only clean, soft cloths. Using scrapers, Scotch-Brite, as well as rough or soiled cloths can damage the coating surface.
B. Cleaning Procedures
(1) Remove watches and rings which may cause scratches before any windshield maintenance.
(2) Remove all excess amounts of dirt and other foreign matter from the glass surface with clean water. Preferred initial application is by spraying or flooding the surface to wash away any abrasive materials. If spraying or flooding is impractical, a clean sponge or soft cloth should be used.
(3) Wash gently with a clean, soft cloth using a 50% water and 50% isopropyl alcohol solution containing a mild liquid soap in a 2% to 5% concentration.
(4) Rinse thoroughly with clean water and dry with a damp chamois, sponge or cloth.
If isopropyl alcohol is not available, a mild liquid soap solution will suffice. PPG does not recommend the use of any type of Windex or industrial cleaners on windows coated with Surface Seal.
PPG is unable to validate the list of “materials that do not affect Surface Seal” in Model Communiqué 99-005. However, we can state that this was never a list of recommended cleaning materials; these are materials that passed chemical resistance testing.
Final thoughts
There’s no way to predict if PPG will ever increase its production to pre-pandemic levels and catch up with the massive backlog of windshields. However, I believe it’s highly unlikely. This is not just about King Airs. Many general aviation aircraft are experiencing the same supply issues. We’re unfortunately small fish in a big pond of commercial airliners. There are always rumors of an aftermarket supplier coming to the rescue. I certainly hope the rumors are true, but until then, prevention is your best bet.
As always, if you have any questions or requests, you can reach out through the email below.