Keel Beam 737
 

Can anybody explain me in simple words, what a keel beam is? How does it look like, what is it exactly?

For example there is a overheat sensor in the keel beam of a 737 to give a warning for a body wing overheat, but I can´t figure out what a keel beam is.

Thanks

Hello.

Keel beam reinforces the structure in the longitudinal direction, very roughly said.

Also, it has a role in increasing the crashworthiness of the structure for the crash loads by reducing the impact forces transmitted from the sub-floor area to the payload.


This is, IMHO, the simplest explanation I can give you.

Cheers

Boeing use lots of terms from boats. The Keel beam is at the bottom of the fuselage bridgeing the gap in the airframe where the wing structure passes thru a cut out of the cabin tube. At the forward end it attaches to a baulkhead frame casting, goes under the wing centre section fuel tank, thru the main gear bays, and attaches to another frame casting baulkend at the rear of wheel wells. Best places to view keel beam is in the wheel well, as the air condition packs bay doors are harder to open.
The keel beam ties the fuselage together, is about 24 inches by 12 inches cross section.
Over heat sensor to detect leaks from bleed ducts and air conditioning pack.

thanks a lot, that really helped me out.