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The B777 lightweight assembly consists of an aluminium, CNC machined window plug, and an optional spacer ring. All parts have Parts Manufacturer Approval (PMA) and are approved and certified via a Supplemental Type Certificate (STC) with worldwide validation. The assembly uses the same seal and retaining clips as the acrylic window assembly already on the airplane for ease and economy of installation. The spacer ring is used in lieu of the acrylic middle pane for additional weight savings and to reduce maintenance by eliminating all acrylic elements. The assembly has also been certified by FAA test to negate the requirement for a bonding strap to simplify installation still further. Detailed installation and maintenance instructions are provided for in service inspection and repair.
The part numbers used at each location are shown below.
Part Number & Location
- LAP4012-1 Window Plug - All window locations
- LAP5006-1 Spacer Ring - All window locations
Benefits of using lightweight window plugs:
Saves weight: The window plug weighs 1.2 pounds and spacer ring weighs 0.3 pounds. The weight of the acrylic windows being replaced is 4.2 pounds which results in a 2.7 pounds weight savings per window and 324 pounds per airplane (120 windows) for a typical passenger-to-freighter (P2F) conversion, however there isn’t an available P2F program at this time.
Saves fuel: At today’s fuel prices the window plug installation can pay for itself in less than three years.
Saves money: Lower component cost.
Easy to use: Simple as replacing a window.
Less installation time: The assembly has been certified by FAA test to negate the requirement for a bonding strap which considerably reduces installation time.
Lower maintenance: All acrylic elements require frequent inspection. The use of the spacer ring eliminates all acrylic elements therefore significantly reducing maintenance.
Proven reliability: All parts are PMA approved and certified via FAA STC and worldwide validation. To date there are more than 80,000 parts in service with a perfect history.