Title: AIDC/CPDLC - VHF Frequency/Frequencyvhfchannel

PDR Reference:				97100016
Originator Reference: 			VHF Frequency
SARPs Document Reference: 		CPDLC SARPs, Section 2.3.4.2
					AIDC SARPs, Section 3.2.7.1.1
Status: 					ADOPTED
PDR Revision Date: 			20/10/97 (SUBMITTED -> ACCEPTED -> PROPOSED)
					29/10/97 (RESOLVED)
					06/02/98 (alignment to ICAO 2.2 SARPs - see PDR 98050019)
PDR Submission Date: 			06/10/97
Submitting State/Organization: 		ATNP / WG3 / SG1
					ATNP / WG3 / SG2
Submitting Author Name:			Hamelink,J
					Leclerc, C
Submitting Author E-mail Address:	jhamelin@adsystech.com
					leclerc.claude@eurocontrol.be 
Submitting Author Supplemental 
Contact Information:				
					Tel: 1 301 589 3434 x114
					Fax: 1 301 589 9254
SARPs Date: 				CPDLC and AIDC IV1.1, March 97
SARPs Language: 			English

Summary of Defect:

There does not need to be two separate choices for "Frequencyvhf" and "Frequencyvhfchannel".  The "Frequencyvhfchannel" covers all frequencies in "Frequencyvhf".  Thus "Frequencyvhf" is redundant. 

If not changed the aircraft is required to handle an additional frequency choice that is not needed, and this is considered very inefficient.

In addition the frequency range listed is not quite correct.  

(Remark for CPDLC: this PDR supersedes PDR 97060012 (Range is wrong for VHF Frequency Variable) since it is proposed here to delete the current definition of the VHF Frequency variable).
 
Assigned SME:				Sub-Volume II and III SMEs

Proposed SARPs amendment:

CPDLC SARPs :
---------------------
Change 2.3.4.2 from:

Frequency ::=  CHOICE
	{
	frequencyhf		[0]	Frequencyhf,
	frequencyvhf		[1]	Frequencyvhf,
	frequencyuhf		[2]	Frequencyuhf,
	frequencysatchannel	[3]	Frequencysatchannel,
	frequencyvhfchannel	[4]	Frequencyvhfchannel
	} 

Frequencyvhf ::= INTEGER (14000..17000) 
--unit = Megahertz, Range (117.00000..138.00000), resolution = 0.025

Frequencyvhfchannel ::= INTEGER (23600..27600) 
--Range (118.000..138.000), resolution = 0.005

to:

Frequency ::=  CHOICE
	{
	frequencyhf		[0]	Frequencyhf,
	frequencyvhfchannel	[1]	Frequencyvhfchannel,
	frequencyuhf		[2]	Frequencyuhf,
	frequencysatchannel	[3]	Frequencysatchannel
	} 

Frequencyvhfchannel ::= INTEGER (23600..27398) 
-- Unit= VHF Channel, Range (118.000..136.990), resolution = 0.005

(Delete definition of frequencyvhf) 

Note (02/06/98): The name "frequencyvhfchannel" was not considered as suitable by ADSP which requested the CPDLC editor to rename the field "Frequencyvhf". The IV2.0 SARPs have therefore been updated as follows:

Frequency ::=  CHOICE
	{
	frequencyhf		[0]	Frequencyhf,
	frequencyvhf		[1]	Frequencyvhf,
	frequencyuhf		[2]	Frequencyuhf,
	frequencysatchannel	[3]	Frequencysatchannel
	} 

Frequencyvhf ::= INTEGER (23600..27398) 
-- Unit= Megahertz, Range (118.000..136.990), resolution = 0.005


AIDC SARPs:
------------------
Change 3.2.7.1.1 from:

Frequency ::= CHOICE
	{
	 frequencyHF		[0]	FrequencyHF,
	 frequencyVHF		[1]	FrequencyVHF,
	 frequencyUHF		[2]	FrequencyUHF,
	 frequencySatChannel	[3]	FrequencySatChannel
	}

FrequencyVHF ::= INTEGER (14000..17000) 
--unit = Megahertz, Range (117.000..138.000), resolution = 0.025

to:
 
Frequency ::= CHOICE
	{
	 frequencyHF		[0]	FrequencyHF,
	 frequencyVHFChannel	[1]	FrequencyVHFChannel,
	 frequencyUHF		[2]	FrequencyUHF,
	 frequencySatChannel	[3]	FrequencySatChannel
	}

FrequencyVHFChannel ::= INTEGER (23600..27398) 
-- Unit = VHF Channel, Range (118.000..136.990), resolution = 0.005

(Delete definition of frequencyVHF) 

SME Recommendation to CCB: 		-

CCB Decision:				atnp_ccb_chair: ACCEPTED (20/10/97)
						CCB-3: RESOLVED