Page 14 - April 2015 Volume 9, Number 4

A close-up look at a delaminated area of the windshield. The cracks running through and around the delaminated area were what caused the windshield to be replaced.
So, check out your POH under “Limitations” and you will find instructions to adjust the cabin pressurization differential to between 2.0 and 4.5 PSID, and to descend to FL 250 or below. You will also learn how long you may continue flying in non-icing conditions before replacing the windshield – you may be surprised at what you learn.
Windshield Heat and Longevity
Use your windshield heat properly to ensure long-lived windshields. Pilots who run “strictly by the book,” use windshield heat all the time. But many King Air pilots dispense with windshield heat in hot weather because they don’t like the distortion created by the heating grid.
As you well know, it’s quite possible to start a trip in hot weather and encounter icing conditions at
altitude. If you embark on a trip with the windshield heat in the “off” position (either by choice or by mistake) and you decide to turn it on later to combat the threat of icing, you run the risk of thermal shock to the windshield.
Thermal shock can cause delamination, it can exacerbate existing delamination, and it can cause full-on windshield failure. Of course, safety is always your priority, but should you find yourself in this predicament, consider whether or not it would be safe to continue flying without windshield heat. Again, safety is uppermost at all times. I cannot stress that emphatically enough. But thermal shock is a good thing to avoid where possible.
Delamination
Delamination does not necessarily condemn a windshield. It is noted at inspections and monitored to see if it
12 • KING AIR MAGAZINE
APRIL 2015