The effective electron loss coefficient of the D region is determined as a function of height for four daytime instances over 49-hour time span during the November 2-5, 1969, solar proton event (SPE). The four altitude profiles of this coefficient are seen to be in very good agreement with one another, suggesting that at least for this SPE the average profile is a characteristic function of the disturbed D region over a considerable ionization production rate range. Our results are compared with the determinations of several other groups. The behavior of the loss coefficient at twilight and night is briefly discussed.