The angular distribution of particles produced in relativistic heavy-ion collisions is commonly described in terms of their complex ow coecients Vn(; pT). This description implicitly assumes that two-particle distributions of a single collision can be described by the product of the complex ow coecients; a property commonly referred to as factorization. The amplitude and phase of the coecients uctuate event-by-event and thereby break the factorization assumption for distributions which are averaged over many events. Additionally, factorization may also be broken by non- ow processes such as di-jets. This analysis studies the factorization of sample-average two-particle distributions in the (a; b)-plane in Pb{Pb collisions at psNN = 5:02TeV. The analysis is performed over the large pseudorapidity range of &#x100000;3 < < 5 by combining the Forward Multiplicity Detector (FMD) and the Inner Tracking System (ITS) of the ALICE detector in a novel analysis method. The original factorization assumption is found to hold for particle pairs with a minimal longitudinal separation of min = 2:6 0:2. A modied factorization assumption which accounts for a jj-dependent attenuation of the two-particle Fourier coecients due to uctuations is also investigated. The attenuation eect is quantied by the empirical parameter F 2 which is found to be in agreement with previous CMS observation at psNN = 2:76TeV as well as with AMPT model calculations