44 Deportation of foreign nationals by air Extract from the 13th General Report [CPT/Inf (2003) 35] 27. As from the beginning of its activities, the CPT has examined the conditions of detention of persons deprived of their liberty under aliens legislation, and this issue was dealt with in a section of the CPT’s 7th General Report (CPT/Inf (97) 10, paragraphs 24 to 36). The CPT set out in that report some basic rules concerning the use of force and means of restraint in the context of procedures for the deportation of immigration detainees. 28. The CPT’s visits since that report have enabled it to flesh out its knowledge of practices concerning the deportation of foreign nationals by air. During its visits, the CPT has concentrated on procedures involving forcible departure with an escort1, and on a number of cases brought to its attention, in particular because of the death of the deported person, the extent of the means of restraint used and/or allegations of ill-treatment. The CPT did not confine its examination to the procedure followed when the person concerned boarded the plane and during the flight; it also monitored many other aspects, such as detention prior to deportation, steps taken to prepare for the immigration detainee’s return to the country of destination, measures to ensure suitable selection and training of escort staff, internal and external systems for monitoring the conduct of staff responsible for deportation escorts, measures taken following an abortive deportation attempt, etc. 29. In order to be able to make a detailed study of the procedures and means used during deportation operations, the CPT obtained copies of the relevant instructions and directives. It also obtained copies of many other documents (statistics on deportation operations, escort assignment orders, escort assignment reports, incident reports, reports in the context of legal proceedings, medical certificates, etc.) and examined the restraint equipment used during deportation operations. It also had detailed interviews in various countries with those in charge of units responsible for deportation operations and with prospective deportees met on the spot, some of whom had been brought back to holding facilities after an abortive deportation attempt. 1 Deportation procedures tend to be classified according to a number of factors, such as the extent to which force is used, the type of means of restraint employed, and the number of persons escorting the deportee. For example, one of the countries visited recently distinguished between departures in which no resistance was offered, forcible departures without an escort and forcible departures with an escort. In general, the most problematic procedures were those involving the combined use of force, several means of restraint and a large number of escort staff until the deportee's arrival in the country of final destination.