Constraints from Hinode/EIS on the Expansion of Active Region Loops Along the Line of Sight

We explore the constraints that can be placed on the dimensions of coronal loops out of the plane of the sky by utilizing spectroscopic observations from the Hinode/EUV Imaging Spectrometer (EIS). The usual assumption is that loop cross sections are circular. Changes in intensity not constant with the measured width are assumed to be the result of changing density and/or filling factor. Here we instead focus on the possibility that the loop dimensions may be changing along the line of sight while the filling factor remains constant. We apply these ideas to two cool (5.5<logT<6.2) loops observed by EIS with supporting observations from Solar Dynamics Observatory's Atmospheric Imaging Assembly (SDO/AIA) and the Solar TErrestrial RElations Observatory-A's Extreme Ultraviolet Imager (STEREO-A/EUVI). Our results are generally consistent with non-expanding loops, but allow for line-of-sight expansion factors up to 3-4. The uncertainties are sizable and are driven by count rate statistics, radiometric calibration of EIS, and the selection of the loop backgrounds.