Landing gear (13)
I believe the answer is:
undercarriage
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">landing gear</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for undercarriage that I've seen before include "Aircraft's landing gear" , "Aircraft support" , "part of plane" , "(Aircraft) landing gear" , "part of the aircraft" .)