We normally check the aircraft CG along the longitudinal axis and the lateral axis (sometimes referred to as the transverse axis) to ensure it is within limits. Until recently I was unaware of any aircraft that required a check and control of the CG along the vertical axis. None of the aircraft (B727, B747, DC-8, DC-9, L1011) that I have been involved in weight & balance detail for have required a vertical CG check. Recently, however, I have found that some B767 freighters do.
My question is: Are there aircraft other than some 767s that require a vertical CG check?
Edit in response to a comment: My purpose in asking the question was to learn how others might have handled a vertical CG check. You can see the method I used by going to http://terryliittschwager.com/WB/B767/load.html and searching the page for 'vertical'.
Additional edit in response to additional comments: Some comments have expressed the opinion that there is little or nothing that can be done about the vertical CG. In practice, the vertical CG of cargo (and thus the airplane) is easily affected by specifying which ULDs (unit load devices—the so-called "igloos") will be used for loading. ULDs come in various standard heights. 96", 64", and 45" are oft used heights but there are others, and an array of custom heights. A usually safe assumption is that the mean vertical CG across ULDs is no higher than half their height. In the case of the 767, the published weight & balance documentation gives tables for average CG heights of 42" and 36".