The Ground Level Event of April 29, l973, was recorded by Pioneer 11 at 1.07 AU and 6¿ west of the earth-sun line. The anisotropy and the omnidirectional intensity of protons between 1 MeV and a few GeV, and of relativistic electrons, were consistent with (1) and impulsive-like injection of electrons and 20- to 56-MeV protons, (2) a long-lived injection of 1-MeV protons lasting ?13 hours, (3) mean free paths near 1 AU of 0.35 AU at a few GeV and 1-MeV protons energies, but only 0.1 AU at 10- to 50-MeV proton energies, and 0.03 AU for 1-MeV electrons. The rigidity dependence of &lgr;11 is anomalous in the 1- to 50-MeV proton region, according to current scattering theory. By invoking a radial dependence in K(r) that is radically different for 1-MeV and 10- to 50-MeV protons, the anomaly can be reduced but not removed. Although an azimuthal dependence may be inherent in the results, observations of B, V, and &sgr;2y do not discount the anomalous &lgr;11(R) dependence. A possible interpretation, at least for protons, is that as rigidity is decreased, propagation changes from diffusive to a 'supercohernet' mode where focusing by the diverging field is dominant. However, the small 0.5-MeV electron mean free path does not fit the extension of such a scheme to lower rigidities. Finally, later in the event a rapid intensity decreases in 1-MeV protons reflects a strong spatial gradient across the solar surface, which is due to poor access of particles across magnetic field lines of an 'open' region and also possibly across the leading edge of a magnetic cell of opposite polarity.