jergar999

Ha. I diverted this week due to this:

It must be an epidemic.

The cracks are through both panes and the airplane depressurized slowly. This was my 4th windshield failure, my second in the King Airs.

1av8trix

I have had two windshield failures in King Airs. I have gotten ferry permits for both. Both times, the FAA stipulated that a mechanic had to look at the windshield before it was ferried to determine if it was safe.

Both my windshield failures were also the outer ply of the windshield only.

floydbird

Did you stipulate that the mechanic that made the determination as to the safety of the windshield sit in the seat directly behind the windshield during the ferry flight?

MTCowboy

I've ALWAYS turned on the windshield heat (both) to 'NORM' taking the active and turned them off clearing the RWY and (knocking on wood) never had one fail or denominate. Been doing that for 10 years in all a/c and 4 years in the KA.

nocnik

I am just curious can some one explain to me the purpose of normal and high setting on the king air windshield heating system. When would high be used?

Thanks

Ewfflyer

Just guessing, but this is what I do in the Meridian's, the low is called "De-Fog" in these planes, but it has a high setting also. I would use that whenever you are getting accumulation greater than the low/normal mode can handle. Or say you just descended into icing, and need to get the window cleared ASAP for the approach. Otherwise I leave it off, or on the defog conditions permitting. I would never leave it in high unless it's just that damn cold and nasty out. Don't want it to get too hot and then cause more problems than you had

fixedwing

Normal is used in most icing conditions. The high setting would be used if you encountered icing severe enough to build on the windshield with the normal heat on.

The high setting heats a smaller portion of the glass with greater intensity.

BANYO4

I am a pilot and also the DOM for some King Air’s. The main problem with the windshields on the King Air’s is with the outer ply cracking. This is usually caused by water getting between the ply’s freezing causing the ply’s to de-laminate and crack. I have seen this happen on one of our King Air’s it is about a 19K bad day. After this happened the first time I implemented a 50 hour inspection of the sealant on the external edges and a mandatory removal and reseal of the PRC around the windows each phase inspection. It usually runs about $600.00 with Labor and the PRC but prevents us having to replace a 15K plus windshield, the labor, down time and if you have pax on board an unscheduled stop for them.

Just my 2 cents

Ska350

Quote:
Originally Posted by nocnik
I am just curious can some one explain to me the purpose of normal and high setting on the king air windshield heating system. When would high be used?

Thanks

Like they said, if ice begins to build on the windshield faster than the NORM setting will clear, go to HI. That's the only time you have to pull that Lever-Lock out is to get it into HI. It applies the same amount of heat (amps) as NORM but to a smaller area. Get up close to the windshield and look at the difference in the heater wire sizes. The smaller wires are what you use in HI. Same amperage, smaller wires = more heat. The 226 kts shouldn't be a problem.
FYI, we have no company policy on when to turn it on and all our pilots have different ideas about the "when". We fly air-ambulance out of ground temperatures that most folks don't even find at altitude and we've had only 2 or 3 crack in the last 8 years (out of 6 200s). Last night it was -43 for a low (PAFA) and -52 up the "road" a ways (PFYU). If that's not enough to frost your mittens, Ft. MacPherson clocked in last night at -74! Now I'm sorry but that's just TOO COLD. I'm so glad we live over here where it's a site warmer.
PPG builds a good windshield. Section 2 in the POH has guidelines for cracked windshields but there's no provision in the Master MEL "King Air 200/F90" to MEL. Ya gotta have a Ferry Permit.

Ska350

Jergar999
A King Air windshield is basically a King Air windshield but I'm wondering if the cracked WS in your posted picture is a 90 or a 100?
Thanks. Just curious.