King Air Windshield Heat

[compressor stall]

Reading the Report into the Norwegian B200 in which the crew mistook the smell of the windhield heat burning for a farting patient, the following caught my eye.

Det er standard prosedyre at ”Windshield Anti-Ice” skal tilkobles på ”Before Taxi Checklist” og være på under hele flyturen, fordi frontrutene blir mer motstandsdyktige mot belastninger som f. eks. treff av fugl).


(My translation)

"It is standard procedure that Windshield Anti-Ice shall be enabled on the Before Taxi Checklist and remain on for the whole flight because the windows are more likely to withstand against impact e.g. birdstrike."



Where is this in the Flight Manual? Mine states that they are to be turned on before take off checklist.

Is this an operators procedure or a Raytheon one that I am not aware of? I ask because birdstrike is a reasonably high probability in some areas out here.

Thanks

CS

[ferrydude]

use of the heat prior to taxi can severely limit the life of the heating element. Manual calls for it prior to takeoff so as to have some cooling air flow

[OzExpat]

Without knowing the context of this incident stallie, I'd have to suggest that it could be SOP in Norway, due to the extremely low temperatures that they get. They probably don't need any extra cooling airflow while taxying.

[wetcoast]

I have always believed the heat to be used for windshield life. At a higher temperature it is more malleable. Thefore, when the heat is on the windshield can deal with both temperature and pressurization changes easier. I have never had a windshield blow out unless at full pressurization. I also believe that the shield heats should not be on until after takeoff simply because of the distortion of view.

[Sheep Guts]

Correct Oz. It all depends in conditions. On hot humid mornings in Mexico we turned it on after start up. Gets rid of a foggy windshield quickly. Our SOP says we should turn it on through 10,000 feet. Different from Beech but they are bloody expensive to replace and you want them to work when you need them. And thats in Icing Conditions above 10,000 what ever comes first.

Had them on the Twotter Ive been flying aswell. Bloody waste, but hey they are Canadian Machines.

[KingAir]

I fly in Northern Canada and our SOPs are to turn the windshield heat during our lineup checks. However, due to the weird visuals you get through the heated windshield, most of our pilots, including myself, prefer to leave them off until the after takeoff checks. We also turn them off for landing. In the summer, if we are in VFR conditions, we leave the windshield off for the entire flight...depending on the temperatures up at altitude of course.

[Crossunder]

Don't know which Company this was, but Lufttransport's "Before taxi Checklist", item #8-a states that the windshield heat be Checked - not turned on...
The "Before take-off" check states:
ICE PROTECTION - SET
It does not mention anything about the W/S heat.
The "Climb checklist", on the other hand, requires that you check the windshield heat to be "Normal" or "High".

[BoeingMEL]

Mmmmm all good points BUT.... one good reason for switching windshield heating on as part of after-start checks concerns the standby compass.... the B200s I've flown all showed a 20-35 degree difference with heating on. Presumably compass swing is carried out with de-ice, navaids and normal elecs selected on? BM

[Master Warning!]

I've also heard that thing about birdstrikes before.
My Ops Manual says to put it on during line-up. Beechcraft says that the heat can be used at any time. But sooner or later the heat will cause the windshield to crack, we have 3 cracked ones lying around to prove it. When the last one went I was sitting behind it at FL 270:ooh: :oh: :uhoh: , it's not a pleasant experience. Remember the old car windscreens, that's how mine looked.

@ sheep guts, I personally think it's better to use it as a anti-ice system than as a de-ice system. My experience is that when you put it on when you are in icing conditions in stead of before ,you run the risk of having to land with an iced up windshield. A lot of times I found the windshield heat not sufficient to get rid of the ice, only when we passed the freezing level the ice broke off, so in winter you might have a problem.

About the distortion, I dont't find it a big problem. You should try the Beechjet 400A where you have to land with the heat on, THAT'S distortion;)