Title: CPDLC - Y Response Required for MAYDAY and PAN PAN PAN Messages

PDR Reference:				97100038
Originator Reference:			Yresp
SARPs Document Reference:		CPDLC SARPs, Section 2.3.4.2.1 and 
						Table 2.3.7-5
Status:					ADOPTED
PDR Revision date:			29/10/97 (SUBMITTED -> RESOLVED)
PDR Submission Date:			24/10/97
Submitting State/Organization:	FAA
Submitting Author Name:			Hamelink,J
Submitting Author E-mail Address:	jhamelin@adsystech.com
Submitting Author Supplemental
Contact Information:	
						Tel: 1 301 589 3434 x114
						Fax: 1 301 589 9254
SARPs Date:					IV1.1, March 97
SARPs Language:				English

Summary of Defect:
The ADSP Manual is being aligned to existing ICAO annexes.  In this process is was found that the PAN PAN PAN and MAYDAY messages require a response.  This change is being made by the ICAO ADSP secretariat, and must be incorporated into the CPDLC SARPs for consistency.  This is only a message attribute change and does not affect "bits on the wire".

Assigned SME:				Sub-Volume II SME

Proposed SARPs amendment:

1. Change the response for downlink message elements DM55 and DM56
in section 2.3.4 from: 

--	PAN PAN PAN		Urg(U)/Alr(H)/Resp(N)
	dM55NULL 		[55] NULL,

--	MAYDAY MAYDAY MAYDAY	Urg(D)/Alr(H)/Resp(N)
	dM56NULL 		[56] NULL,

To:

--	PAN PAN PAN		Urg(U)/Alr(H)/Resp(Y)
	dM55NULL 		[55] NULL,

--	MAYDAY MAYDAY MAYDAY	Urg(D)/Alr(H)/Resp(Y)
	dM56NULL 		[56] NULL,

2. Change table 2.3.7-25 in section 2.3.7 from:

	Message Intent/Use	Message Element		URG ALRT RESP
55	Urgency prefix.		PAN PAN PAN			U    H	 N
56	Distress prefix.		MAYDAY MAYDAY MAYDAY	D    H	 N

to:

	Message Intent/Use	Message Element		URG ALRT RESP
55	Urgency prefix.		PAN PAN PAN			U    H	 Y
56	Distress prefix.		MAYDAY MAYDAY MAYDAY	D    H	 Y

Note. It is rumoured that this issue may occur to all of the messages in the emergency messages downlink table, except for "SQUAWING 7500". Confirmation could not be obtained prior to 10/27/97 of this happening for sure.

SME Recommendation to CCB:		-

CCB Decision:				CCB-3: RESOLVED