ATC: ROGER [NO DELAY EXPECTED or EXPECT (delay information)].
Degradation of Aircraft
Pilot Should Advise ATC of Aircraft Degradation When Performing Procedures or Maneuvers:
NAVIGATION PERFORMANCE UNABLE RNP (specify type) (or RNAV) [DUE TO (reason, e.g., LOSS OF RAIM or RAIM ALERT)]
BASIC GNSS (or SBAS, or GBAS) UNAVAILABLE FOR (specify operation) [FROM (time) TO (time) (or UNTIL FURTHER NOTICE)]
BASIC GNSS UNAVAILABLE [DUE TO (reason, e.g., LOSS OF RAIM or RAIM ALERT)]
NAVIGATION PERFORMANCE UNABLE (navigation aid type)
Emergency Descent
Pilot Shall Warn ATC When Performing an Emergency Descent (Mandatory):
EMERGENCY DESCENT (intentions)
ATC Shall Broadcast Information on Air When One or Several Aircraft Are Involved in an Emergency Descent:
ATTENTION ALL AIRCRAFT IN THE VICINITY OF [or AT] (significant point or location) EMERGENCY DESCENT IN PROGRESS FROM (level) (followed as necessary by specific instructions, clearances, traffic information, etc.)
Loss of Communication
ATC Instruction to an Aircraft Before Losing Communication:
[IF] RADIO CONTACT LOST (instructions)
IF NO TRANSMISSIONS RECEIVED FOR (number) MINUTES (or SECONDS) (instructions)
REPLY NOT RECEIVED (instructions)
ATC Instruction When Suspecting a Loss of Communication From an Aircraft:
IF YOU READ [manoeuvre instructions or SQUAWK (code or IDENT)]
(manoeuvre, SQUAWK or IDENT) OBSERVED. POSITION (position of aircraft). [(instructions)]
