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The B747-8 lightweight assembly consists of an aluminium, CNC machined window plug, and an optional spacer ring. All parts have Parts Manufacture Approval (PMA) 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 STA 2090.45 thru 2211.13
- LAP4012‑3 STA 309.42 thru 410.25; STA 509.70 thru 770.45; STA 870.45 thru 1210.45; STA 1361.45 thru 1630.45; STA 1730.45 thru 2070.45
- LAP4012‑5 STA 269.25 thru 289.34
- LAP4012‑7 STA 229.30 thru 249.17
- LAP4012‑9 STA 188.79 thru 208.93
- LAP4012‑11 STA 148.5 thru 168.57
- LAP4012‑13 STA 470.45 thru 650.45; STA 730.45 thru 910.45
- LAP4012‑15 STA 930.45; (LHS ONLY)
- LAP4003‑1 DOOR STA 472.84; STA 839.55; STA 1304.2; STA 1703.55
- LAP4003‑3 DOOR STA 2270.45
- LAP5003‑1 Spacer Ring Only door locations (for photo, see B747 page)
- LAP5006‑1 Spacer Ring All window locations except doors
Benefits of using lightweight window plugs:
Saves weight: The window plug weighs 1.2 pounds the 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 621 pounds per airplane (230 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 just over two 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 40,000 parts in service with a perfect history.