CAP 413 - Descent to Low Level; Jamming Phraseology; Speechless Procedures

CAP 413 Radiotelephony Manual
Chapter 10 Page 14
3.14 Descent to Low Level
When a pilot requires descent below a controller's terrain safe level, the controller
should remind him of terrain responsibility as part of the approval for further descent.
Controllers should also consider informing the pilot of reduced traffic information if
the additional descent has surveillance coverage implications.
3.15 Jamming Phraseology
When an ATS unit is suffering from the effects of jamming or interference on a
frequency or a radar, the phrases below may be used to request the jamming or
interference to be stopped. If the callsign causing the jamming is not known then the
phrase "All Stations" can be used or the phrase 'Hooter' can be used on the
emergency frequency 243.0 MHz.
3.16 Speechless Procedures
If an aircraft loses the ability to transmit speech, pilots should adopt the speechless
procedure and all controllers should be familiar with this phraseology.
Before a recovery is effected, certain information common to all types of speechless
emergencies is to be ascertained using the speechless code. The
 symbol denotes
short carrier-wave only transmissions and a long-dash indicates a long transmission.
The code uses these transmissions as follows:
 = Yes
  = No
 = Say Again
    = Homing/Request Assistance
—
  — = Further Emergency
In addition pilots will use one long transmission to indicate the requested manouevre
or action has been completed. Controllers should be aware that giving more than one
instruction at once may require subsequent yes/no type questioning to ascertain
which instruction has been completed.
If the aircraft answers no (
 ) then the controller should try to ascertain the pilot's
intentions using a questioning technique that allows yes/no answers and render what
assistance he can.
Tiger 2, request descent to low-level Tiger 2, taking your own terrain
clearance, descent approved.
Tiger 2, my own terrain clearance,
descent approved.
Rider 21, cease jamming Rider 21, jamming ceased [at time
(number)]
   
Speechless aircraft, Markston
Approach, do you require recovery
to Markston?
17 November 2011