Title: FIS - ASN.1 definition of VerticalVisibility

PDR Reference:	                      	97080013
Originator Reference:                   	VertVis
SARPs Document Reference:          FIS SARPs, Section 2.4.4.2.1
Status:                                 	ADOPTED
PDR Revision Date:                      	22/09/97 (SUBMITTED -> ACCEPTED)
				06/10/97 (ACCEPTED -> PROPOSED)
				29/10/97 (RESOLVED)
PDR Submission Date:                    29/08/97
Submitting State/Organization:        ATNP / WG3 / SG2
Submitting Author Name:                Picard, F
Submitting Author E-mail Address: picard_frederic@stna.dgac.fr
Submitting Author Supplemental 
Contact Information:                    	ph 33 5 62 14 55 33
                                        		fx 33 5 62 14 54 01
SARPs Date:                             	IV1.1, March 97
SARPs Language:	              English

Summary of Defect:

The following ASN.1 definition of VerticalVisibility
VerticalVisibility::= CHOICE
	{
 	 visibilityDistance	[0] Visibility,
	 noValueAvailable       	[1] NULL
	}

is useless. There is no other ASN.1 field referring to VerticalVisibility.
The vertical visibility should be expressed in an ATIS report through the CloudSkyCoverGroup field. Two operational values have not been included in this field: "sky obscured" and "indefinite".

Assigned SME:                           Sub-Volume II SME

Proposed SARPs amendment:

1/ Remove the VerticalVisibility type from the ASN.1 definition.
2/ Change the CloudAmount ASN.1 definition from:
CloudAmount ::= ENUMERATED
	{
	 skyclear	(0),
	 scattered	(1),
	 broken		(2),
	 overcast	(3)
	}
to:
CloudAmount ::= ENUMERATED
	{
	 skyclear		(0),
	 scattered		(1),
	 broken			(2),
	 overcast	 	(3),
	 skyobscured		(4),
	 indefinite		(5)
	}

SME Recommendation to CCB: 
CCB Decision:                           			atnp_ccb_chair: SUBMITTED (29/08/97)
						atnp_ccb_chair: ACCEPTED (22/09/97)
						CCB-3: RESOLVED