Section 41 is the portion of a Boeing aircraft, extending from the nose to just aft of the cockpit windows. Along with the wings, it is one of the most complex parts of an aircraft, and includes the largest share (around 40%) of an aircraft's avionics and control systems.

Other portions of the aircraft are numbered as well, but those numbers often vary, and Section 41 plays a particularly important role.

Being a very complex item, several Boeing aircraft share their Section 41.

• The 707/720, 727, and 737 have a common Section 41. Newer versions of the 737 have a different avionics package.
• The 767 and 777 also share the frontal portion. These aircraft have vastly different avionics, however.

The identity of this portion of Boeing aircraft came to higher prominence during the investigation of the Pan Am Flight 103 incident in 1988.