receiver, including the navigation receivers. It is possible ATC  may try to make contact with pilots over a VOR, VORTAC,  NDB, or localizer frequency. In addition to monitoring  NAVAID receivers, attempt to reestablish communications  by contacting ATC on a previously assigned frequency or  calling an FSS.  The primary objective of the regulations governing  communication failures is to preclude extended IFR  no-radio operations within the ATC system since these  operations may adversely affect other users of the airspace.  If the radio fails while operating on an IFR clearance, but  in VFR conditions, or if encountering VFR conditions at  any time after the failure, continue the flight under VFR  conditions, if possible, and land as soon as practicable. The  requirement to land as soon as practicable should not be  construed to mean as soon as possible. Pilots retain the  prerogative of exercising their best judgment and are not  required to land at an unauthorized airport, at an airport  unsuitable for the type of aircraft flown, or to land only  Other equipment installed in an aircraft may impair your  ability to safely operate under IFR. If a malfunction of  such equipment (e.g., weather radar) affects any safety or  IFR capability, reports should be made as stated above.  When reporting GPS anomalies, be very specific and  include the location, altitude, and duration of the anomaly.  Deliberate GPS interference or outage areas resulting from  pre-approved government tests will be disseminated in  NOTAMs. These outages should not be reported to ATC,  as this condition is known and not an anomaly. See also  AIM 1-1-13.  minutes short of their intended destination. However, if  IFR conditions prevail, pilots must comply with procedures  designated in the CFRs to ensure aircraft separation.  If pilots must continue their flight under IFR after  experiencing two-way radio communication failure, they  should fly one of the following routes:  Two-way radio communication failure procedures for IFR  operations are outlined in 14 CFR Part 91, § 91.185. Unless  otherwise authorized by ATC, pilots operating under IFR  are expected to comply with this regulation. Expanded  procedures for communication failures are found in the  Aeronautical Information Manual (AIM). Pilots can use the  transponder to alert ATC to a radio communication failure by  squawking code 7600. [Figure 2-69] If only the transmitter  is inoperative, listen for ATC instructions on any operational  2-47  • In the absence of an assigned or expected route, the  route filed in the flight plan.  • In the absence of an assigned route, the route ATC  has advised to expect in a further clearance.  • If being radar vectored, the direct route from the  point of radio failure to the fix, route, or airway  specified in the radar vector clearance.  • The route assigned by ATC in the last clearance  received.  9. Any information relating to the safety of flight.  8. Any loss, in controlled airspace, of VOR, TACAN,  ADF, low frequency navigation receiver capability,  GPS anomalies while using installed IFR-certified  GPS/GNSS receivers, complete or partial loss of ILS  receiver capability or impairment of air/ground  communications capability. Reports should include  aircraft identification, equipment affected, degree  to which the capability to operate under IFR in the  ATC system is impaired, and the nature and extent  of assistance desired from ATC.  7. When leaving any assigned holding fix or point.  Note: The reports stated in subparagraphs 6 and  7 may be omitted by pilots of aircraft involved in  instrument training at military terminal area facilities  when radar service is being provided.  6. The time and altitude or flight level upon reaching  a holding fix or point to which cleared.  5. Change in the average true airspeed (at cruising  altitude) when it varies by 5 percent or 10 knots  (whichever is greater) from that filed in the flight  plan.  4. When approach has been missed. (Request clearance  for specific action (i.e., to alternative airport, another  approach).  3. When unable to climb/descend at a rate of a least  500 feet per minute (fpm).  Communication Failure  Figure 2-69. Two-way radio communications failure transponder code.  When an aircraft squawks code 7600 during a two-way radio  communication failure, the information block on the radar  screen flashes RDOF (radio failure) to alert the controller. 