980 Questions

[donv]

Descend, reduce the pressure differential, and carry on is what the checklist says. You can fly one additional leg to a repair station after you land, respecting the reduced pressure differential, according to the AFM.

Wow!
just wondering your take on this of the cause?  Cold temp?
Did you decent to lower altitudes when this happened?  Did (does) one slow the machine up a bit to baby it back to airport?  Just wondering the correct response to an issue like this?   And i hope you get it fix quickly!

[JimC]

That's what scares me about that particular flight - Bermuda.

Let's say you have enough fuel to fly to Bermuda, go missed, and go to your alternate (back to the US.)

Now let's say you have to make the return leg at lower altitude and higher fuel burn due to a broken windshield (or  an FCU failure, or...)

Will you make it?

Bermuda is so beautiful, and leaves you with soooooo few options when things go pear-shaped.

[JMA]

So as it was told to me-  the internal glass is 'the strong pane' and the outside glass that was cracked mostly holds the wiring for the heated windshield in place.
Please let me know if I understand this correctly.  We have been waiting over 4 months for a new windshield, and flown multiple legs with it cracked.
Since 1980 I think we are at double digit replacements at this point.

Bermuda you better get right, we were dodging storms most of the way there.  Then on the return flight were rerouted multiple times to find an open customs agent as PHL said they were 'busy'.

https://flightaware.com/live/flight/N515AM/history/20220818/1500Z/TXKF/KBWI

[donv]

Unfortunately, I am pretty sure that both windshield panes are the same. I know that on some airplanes, the Westwind/Jet Commander in particular, you are right that the inner one is structural and the outer one is heat. However, on the Commander both panes are the same, and either one can crack. In my case, it was the internal pane.

[JimC]

Since 1980 I think we are at double digit replacements at this point.

Was it the same side each time?

If it was each side evenly, then that means you get about 8 years out of a windshield, or $6500/year for the windshield budget.

If it was one side only then something's weird.

[donv]

That does seem like a lot. My airplane has had one replacement on the left, and I think one replacement on the right, since 1980.

[Adam Frisch]

Let me ask you this - would you give up the heated window, if it meant a Lexan or plastic window could be a replacement part that never broke?

[Bruce Byerly]

Let me ask you this - would you give up the heated window, if it meant a Lexan or plastic window could be a replacement part that never broke?

Q: Does it defrost?

if the answer is “no,” then, sadly, it won’t work without some significant reeingineering.  Unless it’s a  at low altitude flight, most flights with pax onboard and/or at altitude, the windows are frosted over.  Even plastic Citation windows are cost a major portion of that of a Commamder and they usually don’t last as long and are kind of terrible to fly with.

[donv]

Absolutely not. In addition to what Bruce said, the reality is that those windshields last a long time. In fact, I remember hearing complaints about how short the life of the plastic Shrike windshields were.

As I mentioned, one of my windshields lasted almost 40 years, and the other one went 24. They have a five year warranty!

Let me ask you this - would you give up the heated window, if it meant a Lexan or plastic window could be a replacement part that never broke?

[JMA]

I may be high on double digits, but we have had both sides including both internal and external panes break.  Some was just bad luck (landscaper at FBO kicked up a rock and hit windshield one time), some happened mid-air.

Thanks Don, so would it be considered dangerous to fly?  Again, its not that we don't want it fixed, we just can't get one.

[donv]

I wouldn't fly it again. Yes, one pane is supposed to be structurally enough, but the first pane broke and they are the same age, so eventually the other one will break too. And if the second one goes, that would be bad news.

[JMA]

Not related to 980, but thats a long ferry flight

https://www.msn.com/en-us/travel/news/the-story-behind-the-cessna-172-that-flew-from-california-to-hawaii/ar-AA11htBS?cvid=2944c94961f94f79b30be6dc7448ecf0#image=1

[donv]

I'm a bit surprised that you can't get one. I realize it's the old supply chain thing again, but Twin Commander (and some of the service centers) used to keep these in stock-- in fact Twin Commander was running a special deal on windshields not long ago! I guess they depleted their inventory.

[JMA]

If you know of any please let me know.

[JMA]

Sorry, I just tend to post in the same thread, even if topic may not be related.
Anyway, trying to do a bit of sleuthing, and although many many decades ago, perhaps Bruce may be able to help.
My father prior to owning the 980 had a 690.  He bought it from Byerly (I believe your uncle sold him that and the 980 Bruce).   He recently told me it had come from South Africa and the back passenger bench had a large gas tank under the seat as it was used by a local missionary to reach far out destinations.  Byerly re-registered to something NXXXCF, but my father cannot remember the tail number.  Anything in the books possibly Bruce?