驾驶舱3号风挡的划痕和掉块放行标准

ryn_82 · 发表于 2021-10-4 23:16:38

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公司737NG机队驾驶舱3号风挡没有选装加温构型的，都是非加温构型的，所以3号风挡常见的损伤就是划痕和掉块。

不加温3号风挡件号：

65-16323-XX

65-38210-XX

加温3号风挡件号：05-71763-33和-34

掉块 chip

关于掉块（chip），手册的标准是深度不大于0.05英寸（1.27mm），并且不影响视线:

驾驶舱3号风挡的划痕和掉块放行标准-2.jpg

Replace or repair the stretched acrylic window panes if limits are larger than the following：

1)A chip, or group of chips, on the surface of a structural pane that are more than 0.05 in. (1.27 mm) in depth are a cause for the removal of the window.

2)A chip, or group of chips, that decreases the visual quality on a pane of the window is a cause for the removal of the window.

参考SDS，机队737NG的风挡都是丙烯酸树脂（Acrylic）风挡：

驾驶舱3号风挡的划痕和掉块放行标准-3.jpg

Acrylic 3号风挡由内外两层透明塑料板组成。两层透明塑料板均为承重结构件，中间是空气夹层用来保温。

所以3号风挡的内层和外层都是结构层（structural pane)，而不像1号和2号风挡，外层是非结构层。

● 典型案例

右三号风挡内侧表面上有四处缺损，尺寸分别:

2*9mm，最深0.07mm
23*7mm，最深0.36mm
4*3mm，最深0.11mm
3*3mm最深0.22mm

深度均小于1.27mm，在手册标准范围内，开NRC后续更换风挡

划痕 scratch

划痕的标准在表601：

驾驶舱3号风挡的划痕和掉块放行标准-9.jpg

这里一定要注意旗标[1]的信息：

Footnote Information:

*[1] If the scratch depth is between the table values, use the data for the next larger scratch depth.

如果划痕深度在表格的值之间，则使用下一个较大划痕深度对应的标准。

● 典型案例

维修人员报告左3号窗内表面有3处划痕，尺寸分别为：

0.8*70*0.01mm
0.8*73*0.01mm
0.7*80*0.01mm

划痕深度均为0.01mm，长度均小于101.6mm，总长度223mm也小于254mm，在手册标准范围内；

1处凿痕尺寸1*7*0.02mm，在手册标准范围内。

开NRC后续更换风挡。

维护提示

再报告缺陷和确定标准时，一定要分清chip与scratch，它们的定义在风挡检查程序里有：

驾驶舱3号风挡的划痕和掉块放行标准-13.jpg

Scratch: The linear removal or displacement of material from the surface of a pane.

Chips: The removal of material from the surface of a glass or acrylic pane, usually from the impact with a hard object. The descriptions that follow are a list of different types of chips.

(a) External chips:

1) Shell type chips are in the surface or edge of the pane. These chips have a circular or curved shape with many fine lines or ridges that follow the outline of the edge of the chip that give it almost the same shape of a shell. The width of the chip is more than its depth.

2) “V” shaped chips have the shape of a sharp narrow "V". Depth of the chip is equal to or larger than the width.

(b) Internal chips:

1) Peel Chips - Chips that occur on the internal surface of glass panes. Chipped areas have a curved, rough grained shape, and are easily seen in reflected light. The chipped area can have small glass flakes, usually white. The view through the window will distort through the rough surface of the chip. Usually the chips start very small but can continue to grow with the continued use of the airplane.