ICAO DOC 8168 Section 3
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1.10.5 The ranges of speeds (IAS) in Tables III-1-1 and III-1-2 take account of the handling speeds when aircraft perform the manoeuvres specified and are to beused in calculating procedures. For conversion of these speeds to TAS, see Attachment F to Part III.
1.10.6 Permanent change of category (maximum
landing mass).
An operator may impose a permanent, lower, landing mass, and use this mass for determining Vat if approved by the State of the Operator. The category defined for a given aeroplane shall be a permanent value and thus independent of changing day-to-day operations.
1.10.7 Where airspace requirements are critical for a specific category of aircraft, procedures may be based on lower speed category aircraft, provided use of the procedure is restricted to those categories. Alternatively the procedure may be specified as limited to a specific maximum IAS for a particular segment without reference to category.
Also from 8168
Note.- The Vat speeds given in Column 2 of Table 111-1 -1 are converted exactly from those in Table ill-I -2, since they determine the category of aircraft. The speeds given in the remaining columns are converted and rounded to the nearest multiple of five for operational reasons and from the standpoint of operational safety are considered to be equivalent.
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Last edited by FlapsOne; 27th February 2007 at 15:12.