Factual Information 2015:Appendix 1.6E/1.6E.16
This page contains an extract from MH370/01/15 Factual Information which accompanied the (first) Interim Statement released by The Malaysian ICAO Annex 13 Safety Investigation Team for MH370 on 8th March 2015.
1.6E.16 Structures
The B777-200 is a transport category aircraft certified to Federal Aviation Regulations (FAR) Part 25. The structure construction is a conventional skin, frame, stringers and longeron to handle the flight load on the aircraft during its operation. The structure components are fuselage, wing and empennage which also consist of the horizontal and vertical stabilizers. Control surfaces to control the aircraft manoeuvrability are attached to the wing, and empennage. Engine assemblies are attached to the wings and the landing gear system to the part of the fuselage. The fuselage has numerous cut-outs for doors, windows and inspection doors.
1.6E.16.1 Fuselage
The fuselage is a semi-monocoque thin wall structure, which consists of skin panel, frames and stringers. The fuselage is designed with frames and stringers. Keel beam, located at the underside of the fuselage, provides structural reinforcement and provides protection to the underside of the centre fuel tank in the event of an emergency landing. Boeing has introduced modern materials on the B777-200 structure, which are improved Aluminum Alloy 7055 and carbon fiber with toughened resin (composite).
1.6E.16.2 Wings
The B777-200 wings comprise of two outer wings and a centre wing box. The wings are conventional design with front and rear spars together with the upper and lower wing skins reinforced with stringers. The two outer wings are attached to the wing box using wing joint fittings.
1.6E.16.3 Engine Nacelle Attachments
The B777-200 engine nacelle and pylon assemblies are attached to the wing by four fuse pins. The fuse pins are designed to fail in the event of abnormal loads being applied to the nacelle, such as during an emergency landing, in order to preserve the wing structure and allow the engine assembly to separate cleanly.
1.6E.16.4 Landing Gear System
The main landing gear drag brace is joined to the rear face of the rear spar web, the terminal fitting and the back-up fitting. Attached to the innermost rib is a further back-up fitting which again attaches through the rear spar web to the main landing gear drag brace fitting. The wing box also forms part of the centre fuel tank and the wing fuel tanks.
Source: Malaysian ICAO Annex 13 Safety Investigation Team for MH370, 8 March 2015, Factual Information MH370/01/15
The Factual Information was updated in 2018 by the Safety Investigation Report MH370/01/2018 which added new content but did not include all of the previous data.