Theundercarriage of an aeroplane is the part, including the wheels, which supports the aeroplane when it is on theground and when it is landing or taking off.
[mainly British]regional note: in AM, use landing gear
undercarriage in British English
(ˈʌndəˌkærɪdʒ)
noun
1. Also called: landing gear
the assembly of wheels, shock absorbers, struts, etc, that supports an aircraft on the ground and enables it to take off and land
2.
the framework that supports the body of a vehicle, carriage, etc
undercarriage in American English
(ˈʌndərˌkærɪdʒ)
noun
1.
a supporting frame or structure, as of an automobile