Variation of the onset delay time of SEP events from flare onset with respect to the longitudinal separation ΔΦ of the observer’s field line footpoint from the flare location for 1 MeV electrons (top panel), ∼100 keV electrons (central panel), and ≥25 MeV protons (bottom panel). All symbols are the same as in Fig. 2. Green, orange, and pink arrows represent the sectors of well-connected and poorly connected western and eastern events, respectively.