King Air 200 windshield question

[BushwickBill]

Our windshield failed today. No one was hurt and overall it was uneventful yet highly unnerving.

The windshield is cracked so badly you can't see through it and there is at least one spot where the cracks are on the inside. Small flakes of plexi glass are on the glare shield.

Apparently the maintenance shop says it is cool to ferry the aircraft unpressurized to a different airport.

I think this seems like an unnecessary risk. Also I can't imagine that the aircraft would be legal to fly even if it is safe.

What do you guys think? Does anyone have any particulars on if the aircraft is still airworthy?


Thanks

 

[kingairyahoo]

...according to the POH, its legal

 

[avbug]

Airworthy means in conformity with the aircraft certification data, and that it's in a safe condition for flight. Unpressurized shouldn't present an issue, but that's up to the PIC to determine, and the Mechanic who authorizes your special flight authorization ("ferry permit") to make the flight.

With the cracked windscreen, it's not in conformity with the certified condition of the aircraft, so the next standard to which you should look is "a properly altered condition, acceptable to the administrator." This may be a Form 337 as a major repair or alteration, an STC, or in this case, the issuance of a "ferry permit."

Without pressurization you can ferry it anyway, but you really ought not without maintenance approval, and when getting this, make it official in the form of a special flight authorization, or "ferry permit."

 

[saab fixr]

no way i would sign a permit if its failed to the point where pieces are coming in the cockpit whos to say it wont fail completely when you pick up airspeed Play it safe and get another one and change it Besides that are your pilots willing to fly it in that condition most i know wont do it if there is a chance of total failure your call be careful

 

[BushwickBill]

Well after looking through the POH it looks like the aircraft is good to go. Thanks for the info on the ferry permit.

Unfortunitly for aviation and mankind in general, saab fixer seems to be in the minority of mechanics.

I must say that even after I had the mask and fog goggles on and was back down through 250, I was pretty scared. Cracks were still forming until the speed was down to 140-120. I was happy to get out of the airplane. I didn't think it could possibly be legal to fly. I wasn't that keen on looking at my training material either. After that experience I wanted to look for waves, trails, beers or shaved poon. So thanks for pointing me in the right direction.

Ferry flight manana. I'll keep you guys posted.

 

[avbug]

no way i would sign a permit if its failed to the point where pieces are coming in the cockpit whos to say it wont fail completely when you pick up airspeed Play it safe and get another one and change it Besides that are your pilots willing to fly it in that condition most i know wont do it if there is a chance of total failure your call be careful

You might be surprised.

The heated windscreen in the King Air 200 has several options, but is layered glass. Failures in layers aren't unheard of; it happens. Delaminations, cracking or failures in various layers aren't that unusual. Beech authorizes certain operations without the necessity of a special flight permit, though one ought to obtain one and use the aircraft flight manual as contributing approved data in gettin gthe signature from a reluctant mechanic.

Unpressurized, the aircraft really offers very little hazard.

You might even be surprised at the dynamic pressure present at the windscreen itself. Many would tend to assume that significant dynamic pressure exists over the face of the windscreen during forward flight. A tuft test may yield unexpected results.

Earlier this year I had an explosive depressurization in a Cessna 421 when the windscreen blew out. It failed, blew out, and took some of the interior with it, as well as the glareshield, part of the top of the windscreen, a checklist, and other things in the cockpit. The glareshield over the instrument panel, as well as the top of the panel, was outside the aircraft in front of the cockpit. No airflow entered the cockpit at all; in fact, I was able to put my hand outside the cockpit without any sense of airflow over it at all.

Point is, while this wasn't a King Air, while you may think a fracture in a windscreen is going to cause an implosion into the cockpit with attendant shattering of glass and other dangers, your fears are misplaced. The pressure on that windscreen pushing inward isn't what you think it is. The pressures on the King Air windscreen are those pushing outward during pressurization.

I must say that even after I had the mask and fog goggles on and was back down through 250, I was pretty scared. Cracks were still forming until the speed was down to 140-120. I was happy to get out of the airplane.

Quite natural, but not really warranted. Doubtless you did a find job addressing the problem, running a checklist, and getting back on the ground. Once the airframe was unpressurized (and hopefully windshield heat off), the risk to you was largely no longer an issue. Never the less, one should never assume, and clearly you didn't. Look at it as a good learning experience.

 

[BushwickBill]

Quite natural, but not really warranted. Doubtless you did a find job addressing the problem, running a checklist, and getting back on the ground. Once the airframe was unpressurized (and hopefully windshield heat off), the risk to you was largely no longer an issue. Never the less, one should never assume, and clearly you didn't. Look at it as a good learning experience.

Sorry but why does the windshield heat matter? It's not on the cracked or shattered windshield checklist from flight safety.

That's also very interesting what you said about the airflow and pressure on the window. I was afraid the windshield was going to cave in and rip my face off... I was really freaking out about it for a little bit.

 

[erj-145mech]

With one windshield damaged, turning on the w/s heat could damage the other windshield or the temp control box.

Do not let Flight Safety tell you how to operate the airplane, the manufacturer specifies how the airplane is configured for a maintenance flight for a particular inop system. FSI didn't design or provide sustaining engineering for any airplane. They're the best for training, and teaching systems, and thats the limit of their expertise.

 

[avbug]

I was afraid the windshield was going to cave in and rip my face off...

If you get a chance, spend some time observing the replacement of the windscreen, and you'll understand why the windscreen is a lot more robust, than you thought, and that you needn't fear.

So far as windscreen heat, you have a distinct possibility that the heat is part of the reason for the failure. That aside, with an electrically heated windscreen, do you think applying electricity to a broken component is a good idea?

 

[wooferdog]

Here. Read this.

http://www.pirep.org/forum/viewtopic.php?t=4095&sid=d1eaca96c5d3300958b919aabac3cf8e