INSTRUMENT FLIGHT RULES WORKBOOK
9. Speeds are stated in separate digits followed by the word "knots." (The controller may
omit the word "knots" when using speed adjustment procedures, "Reduce/increase speed to ONE
FIVE ZERO.") Example:
250 --- TWO FIVE ZERO KNOTS
10. The phonetic alphabet (listed in section A of the IFR Supplement) should be used by pilots
when identifying their aircraft during initial contact with air traffic control facilities.
Additionally, use the phonetic equivalents for single letters and to spell out groups of letters or
difficult words during adverse communications conditions. Example:
FIVE --- FOXTROT INDIA VICTOR ECHO
11. The following are ground station voice calls used during most IFR flights:
-Airport Ground Control
"(NAME) CLEARANCE DELIVERY" -Airport Clearance Delivery
-Airport Control Tower
-Flight Service Station
-Military Weather Service (PMSV)
-ATC Departure Control
-Air Route Traffic Control Center
-ATC Approach Control
-Radar Ground Controlled Approach Facility at
named airport (for PAR or ASR approaches)
12. Common words and phrases which are used to terminate transmissions are:
ACKNOWLEDGE - Let me know that you have received and understand this
Words to acknowledge a message:
AFFIRMATIVE - Yes
I have received all of your last transmission (acknowledgment of
I have received your message, understand it and will comply.
Request confirmation of information; e.g., "Verify assigned
heading of 150."
READ BACK - Read all of this message back to me (verbatim).
GO AHEAD -
Proceed with your message.
SAY AGAIN - Request a repeat of the last transmission (the term "Repeat" is
gunfire control talk for send another salvo and therefore not used).
8-6 INTRODUCTION TO GROUND, AIRBORNE, LOST COMMUNICATION, AND
EMERGENCY VOICE PROCEDURES