Figure 2-71. ATC holding instructions.  Aircraft Speed and Altitude  CHERRELYN  D  ( H ) 117.2 CHL  331°  269°  221° 126° V214  Figure 2-72. Clearance limit holding.  2-50  Speed and altitude restrictions in clearances are subject  to misinterpretation, as evidenced in this case where a  corporate flight crew treated instructions in a published  procedure as a clearance. The aircraft was at FL 310 and  had already programmed the ‘expect-crossing altitude’ of  ATC issues speed adjustments if the flight is being radar  controlled to achieve or maintain required or desired  spacing. They express speed adjustments in terms of knots  based on indicated airspeed in 10 knot increments except  that at or above FL 240 speeds may be expressed in terms  of Mach numbers in 0.01 increments. The use of Mach  numbers by ATC is restricted to turbojets. If complying  with speed adjustments, pilots are expected to maintain  that speed within plus or minus 10 knots or 0.02 Mach.  the pilot may level off at 10,000 feet MSL on descent to  comply with the 14 CFR Part 91 indicated airspeed limit of  250 knots. Leveling off at any other time on descent may  seriously affect air traffic handling by ATC. It is imperative  that pilots make every effort to fulfill ATC expected actions  on descent to aid in safely handling and expediting air  traffic.  During the en route descent phase of flight, an additional  benefit a FMS is that it provides fuel saving idle thrust  descent to your destination airport. This allows an  uninterrupted profile descent from level cruising altitude  to an appropriate MIA, except where level flight is required  for speed adjustment. Controllers anticipate and plan that  NOT FOR NAVIGATION "...Hold southeast  of PINNE Intersection as published.  Expect further clearance at 1645."  There are at least three items in a clearance for a charted holding pattern:  •  Direction to hold from the holding fix   Holding fix  •  Expect further clearance time  A clearance for an uncharted holding pattern contains additional information:  • Direction to hold from holding fix  Holding fix  • The holding course (a specified radial,  magnetic bearing, airway or route number)  • The outbound leg length in minutes or  nautical miles when DME is used  • Nonstandard pattern, if used  Expect further clearance time  "...Hold west  of Horst Intersection  on Victor 8  5 mile legs  left turns  expect further clearance at 1430." 