Title: FIS - Maximum Size of an ATIS Report

PDR Reference:	                 	97100022
Originator Reference:              	ATISREPSIZE
SARPs Document Reference:          FIS SARPs, Section 2.4.4.2.1
Status:                            		ADOPTED
PDR Revision Date:       		20/10/97 (SUBMITTED -> ACCEPTED -> PROPOSED)
				28/10/97 (RESOLVED)
PDR Submission Date:               	06/10/97
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 current ASN.1 for the ATIS report is overspecified. This results in the possible composition of an ATIS Report of 620 Kbytes.
The main factor is the maximum size of the free text fields (2047 characters).

The structure of most of the free text fields was not known when the ASN.1 description was issued. The knowledge of the exact contents of these fields allows now for a refinement of the ASN.1 which would result in a drastic reduction of the maximum size of the ATIS reports.

Assigned SME:                           Sub-Volume II SME

Proposed SARPs amendment:

1/ Change the following ASN.1 definitions from:

approachTypeOther			[1] FreeText
brakingActionQualityOther		[1] FreeText
presentWeather				[6] FreeText OPTIONAL,
specificATISInstructs			[9] FreeText OPTIONAL,
otherOperationInfo			[10] FreeText OPTIONAL,
runwaySurfaceConditions			[1] FreeText OPTIONAL,
runwayArrestingSystem			[3] FreeText OPTIONAL
trendTypeLandingForecast		[1] FreeText OPTIONAL
approachAreaMet			[0] FreeText OPTIONAL,
takeoffAreaMet				[1] FreeText OPTIONAL,
climboutAreaMet			[2] FreeText OPTIONAL,

to:

approachTypeOther			[1] IA5String (SIZE (1..30))
brakingActionQualityOther		[1] IA5String (SIZE (1..20))
presentWeather				[6] PresentWeather OPTIONAL,
specificATISInstructs			[9] IA5String (SIZE (1..64)) OPTIONAL,
otherOperationInfo			[10] IA5String (SIZE (1..512)) OPTIONAL,
runwaySurfaceConditions			[1] IA5String (SIZE (1..256) OPTIONAL,
runwayArrestingSystem			[3] SEQUENCE (SIZE(1..2)) OF RunwayArrestingSystem 						OPTIONAL
trendTypeLandingForecast		[1] IA5String (SIZE (1..256)) OPTIONAL
approachAreaMet			[0] IA5String (SIZE (1..128)) OPTIONAL,
takeoffAreaMet				[1] IA5String (SIZE (1..128)) OPTIONAL,
climboutAreaMet			[2] IA5String (SIZE (1..128)) OPTIONAL,

3/ Add the following ASN.1 definitions (following the alphabetic order):

PresentWeather ::= SEQUENCE 
	{
	 intensityOrProximity	[0] IntensityOrProximity OPTIONAL,
	 descriptor		[1] Descriptor OPTIONAL,
	 precipitation		[2] Precipitation OPTIONAL,
	 obscuration		[3] Obscuration OPTIONAL,
	 other			[4] Other OPTIONAL
	}

IntensityOrProximity ::= ENUMERATED 
	{
	 light 			(0),
	 moderate 		(1),
	 heavy 			(2),
	 inTheVicinity 		(3)
	}

Descriptor ::= ENUMERATED 
	{
	 shallow 		(0),
	 partial			(1),
	 patches			(2),
	 lowDrifting		(3),
	 blowing			(4),
	 shower			(5),
	 thunderstorm		(6),
	 freezing			(7)
	}

Precipitation ::= ENUMERATED 
	{
	 drizzle				(0),
	 rain				(1),
	 snow				(2),
	 snowGrains			(3),
	 iceCrystals			(4),
	 icePellets			(5),
	 hail				(6),
	 smallHailAndOrSnowPellets	(7),
	 unknownPrecipitation		(8)
	}

Obscuration ::= ENUMERATED 
	{
	 mist			(0),
	 fog			(1),
	 smoke			(2),
	 valcanicAsh		(3),
	 widespreadDust		(4),
	 sand			(5),
	 haze			(6),
	 spray			(7)
	}

Other ::= ENUMERATED 
	{
	 wellDevelopedDustSandWhirls		(0),
	 squalls					(1),
	 funnelCloudTornadoWaterspout		(2),
 	 sandstorm				(3),
	 duststorm				(4)
	}

RunwayArrestingSystem ::= SEQUENCE 
	{
	 location			RASLocation,
	 condition		RASCondition
	}

RASLocation ::= ENUMERATED
	{
	 arrivalEnd		(0),
	 departureEnd		(1)
	}

RASCondition ::= ENUMERATED
	{
	 up			(0),
	 down			(1),
	 unavailable 		(2)
	}

2/ Delete the FreeText ASN.1 definition.

SME Recommendation to CCB:              -

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