From Longman Dictionary of Contemporary Englishundercarriageun‧der‧car‧riage /ˈʌndəˌkærɪdʒ $ -ər-/ noun [countable] TTAthe wheels of an aircraft, train etc and the structure that holds them
Examples from the Corpus
undercarriage• The critical stage would be when he lowered his undercarriage.• The control tower confirmed that the pilot was going to attempt to land and that the aircraft's undercarriage was indeed jammed.• Others were already wriggling around in the Alice's undercarriage, zeroing in on the inlets.• The dark red Seneca changed profile as the undercarriage cycled down.• As he pushed the nose down for the final approach, he extended down the undercarriage.• He came in too fast and had to swing to avoid something at the end of his run - the undercarriage collapsed.• I would not relish a low-level left-engine-out go-around since the undercarriage can not be raised and single-engine gear-down climb would be earth-tangential. 