8/15/19 AIM  or route different from that requested by the pilot. In addition, flow patterns have been established in certain congested areas or between congested areas whereby traffic capacity is increased by routing all traffic on preferred routes. Information on these flow patterns is available in offices where preflight briefing is furnished or where flight plans are accepted. 2. When required, air traffic clearances include data to assist pilots in identifying radio reporting points. It is the responsibility of pilots to notify ATC immediately if their radio equipment cannot receive the type of signals they must utilize to comply with their clearance. 1. The altitude or flight level instructions in an ATC clearance normally require that a pilot “MAINTAIN” the altitude or flight level at which the flight will operate when in controlled airspace. Altitude or flight level changes while en route should be requested prior to the time the change is desired. pattern is charted), an EFC time, and a best estimate of any additional en route/terminal delay. 2. If the holding pattern is charted and the controller doesn’t issue complete holding instruc- tions, the pilot is expected to hold as depicted on the appropriate chart. When the pattern is charted, the controller may omit all holding instructions except the charted holding direction and the statement AS PUBLISHED , e.g., “HOLD EAST AS PUBLISHED.”  Controllers must always issue complete holding instructions when pilots request them. 3. If no holding pattern is charted and holding instructions have not been issued, the pilot should ask ATC for holding instructions prior to reaching the fix. This procedure will eliminate the possibility of an aircraft entering a holding pattern other than that desired by ATC. If unable to obtain holding instructions prior to reaching the fix (due to frequency congestion, stuck microphone, etc.), hold in a standard pattern on the course on which you approached the fix and request further clearance as soon as possible. In this event, the altitude/flight level of the aircraft at the clearance limit will be protected so that separation will be provided as required. 4. When an aircraft is 3 minutes or less from a clearance limit and a clearance beyond the fix has not been received, the pilot is expected to start a speed reduction so that the aircraft will cross the fix, initially, at or below the maximum holding airspeed. 2. When possible, if the altitude assigned is different from the altitude requested by the pilot, ATC will inform the pilot when to expect climb or descent clearance or to request altitude change from another facility. If this has not been received prior to crossing the boundary of the ATC facility’s area and assignment at a different altitude is still desired, the pilot should reinitiate the request with the next facility. 3. The term “cruise” may be used instead of “MAINTAIN” to assign a block of airspace to a pilot from the minimum IFR altitude up to and including the altitude specified in the cruise clearance. The pilot may level off at any intermediate altitude within this block of airspace. Climb/descent within the block is to be made at the discretion of the pilot. However, once the pilot starts descent and verbally reports leaving an altitude in the block, the pilot may not return to that altitude without additional ATC clearance. 5. When no delay is expected, the controller should issue a clearance beyond the fix as soon as possible and, whenever possible, at least 5 minutes before the aircraft reaches the clearance limit. 6. Pilots should report to ATC the time and altitude/flight level at which the aircraft reaches the clearance limit and report leaving the clearance limit. In the event of two − way communications failure, pilots are required to comply with 14 CFR Section 91.185. a. Amendments to the initial clearance will be issued at any time an air traffic controller deems such 1. Whenever an aircraft has been cleared to a fix other than the destination airport and delay is expected, it is the responsibility of the ATC controller to issue complete holding instructions (unless the Pilot/Controller Glossary Term −  Cruise. REFERENCE − e. Holding Instructions. NOTE − 4 − 4 − 4. Amended Clearances d. Altitude Data. NOTE − Only those holding patterns depicted on U.S. government or commercially produced charts which meet FAA requirements should be used. ATC Clearances and Aircraft Separation 4 − 4 − 2