 When the men refused to withdraw the letters or elaborate on the reason for their actions, Cobby contacted his immediate superior, Air Vice Marshal Bill Bostock, head of RAAF Command, the Air Force's main operational command.Bostock arrived on Morotai the next day and interviewed the pilots, asking them to tear up the letters, without success.His methods were later construed as an attempt to "make the situation go away or to at least cover it up".