Federal AviationAdministration
Data Communications Program
Data Comm Trials and Production Requirements: High Level Impact
Presented To: DCIT #23 Plenary
Prepared By: Data Comm Production Sub WG
Date: 9 May 2013
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DCIT #22 Action Item• Carry over from last DCIT meeting to show impact of
Trials on the Production system as risk mitigation. – Provide insight into the numbers and types of requirement
changes from DCIT and Trials that have impacted Production system.
• Include pre-DTAP PTR changes, e.g., drop UM73 and add UM79 and UM83
• Categorize the changes, e.g., break the system vs. nice-to-have vs. new requirements
– Provide high level assessment of impact to Production system• Risk reduction – show how these would have otherwise created
problems with Production system. • Qualitative assessment - ROM would be desirable but at least provide
High, Med, Low qualitative.
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
Requirement Changes: Life Cycle Impact• Pre-March 2012
– Major requirements changes prior to initial Production baseline in March 2012 (ERAM CDR Baseline, TDLS Initial Baseline WSSD 2.0)
– Requirements• Drop UM73 • Cleared as Filed• UM79, UM83 for revisions rather than UM80• Modifications for FMS auto loading, especially concerning transition fixes
– Benefits• Most required for operational acceptability• Allow auto-loading across various types of equipage• Identified variations/anomalies with FANS standards
– Impact• ~30 changes in March 2012 WSSD• Majority are high impact, e.g., operationally required and resulted in new
messages, new CHI
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
Requirement Changes Life Cycle Impact – cont’d• Post-March 2012 Changes
– Requirements • Delayed Session Termination • Dispatch Copy Format and Timing/Gate Request Message• Initial UM79• Second Frequency/Contact• Various PTRs (see next slides)
– Benefits• Additional modifications for operational acceptability • Additional sites/operational scenarios
– Impact• ~10 changes in Sept 2012, some to revise previous requirements• ~41 total WSSD changes• ~4 IRD changes across 3 IRDs• = ~45 total• DCL changes are generally high impact, e.g., operationally required and resulted
in new messages, new CHI• AOC changes are medium to low impact
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DTAP PTRs impact on S1P1 Summary• PTRs from DTAP
– Production SE tower sub-team scrubbed #1-110 with DTAP Test Team at Tech Ctr in Feb 2013; approx. 25 marked as potential impact to S1P1
– Current PTR file (April 23) has 155; MITRE has scrubbed 111-155 but these have not yet been reviewed by full Production sub-team team
– Most PTRs assumed to affect TDLS, but some could also impact ERAM, e.g., logon, or interfaces
– Rapid turnover during Trials testing (MEM and now EWR) is a challenge
• Categories– Avionics, including CHI– Ground System, including CHI– AOC Interface– Test Cases
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DTAP PTRs impact on S1P1 Summary- cont’d
• Impact– Many PTRs not applicable due to differences in architecture
and software systems – Most valuable in identifying avionics issues, which will be
applicable to Production as well– Some scenarios represent good test cases even if no
requirement or design change; mitigates risk of not finding lower level problems by providing complex scenarios
– May have resulted in design changes even if no specific requirement changes, e.g., FEC and CAF changes impact on CSCI allocations and CHI
– Quick Look – high level summary only• ~26 PTRs with requirement impact• ~25 PTRs with analysis, design or test impact
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DTAP PTRs Impact on Production: Quick Look
PTR Reqs17%
PTR Other Impact16%
N/A67%
PTR ReqsPTR Other ImpactN/A
Total DTAP PTRs = 155
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DCIT/DTAP-based High Level Requirements to Prod
# FunctionDescription/Purpose Status Resolution Comments Priority
Impact (H, M,
L)
1
Auto Loading for Complex Clearances Open
TBD if will be added to DCP requirement specifications.
No current differentiation about clearance types H H
2
Auto Loading Requirement on ATS Ground System
Provide clearances that are auto-loadable in the majority of avionics Open
TBD if will be added to DCP requirement specifications.
De facto operational requirement but not a program level requirement. Has been the source of multiple added system level requirements for messaging. H H
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Revised DCL using UM79, UM83 and UM169 in place of UM80 (full route clearance)
Need for partial routes to avoid FMS reloading issues with UM80 on revised DCL. Closed Added to WSSD 2.0
ATC Automation Rules for DTAP and TDLS to develop Revised DCLs using UM79, UM83, UM169 and where necessary us UM80. H H
4
Reject DM25 if free text concatenated
Standards allow but program does not. Nothing except DM25 will be accepted. Resolved
To be added to WSSD 3.0 in Jun 2013 M M
5Cleared as Filed (CAF)
Address FMS loading issues by sending CAF instead of UM80 for initial DCL Closed
To be added to WSSD 3.0 in Jun 2013 H H
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DCIT/DTAP-based Requirement Changes – cont’d
# FunctionDescription/Purpose Status Resolution Comments Priority
Impact (H, M,
L)
6Transition Fix in route clearance
Repetition and cross-checking, esp. for arrival procedures to allow FMS loading Resolved
To be added to WSSD 3.0 in Jun 2013
Some in earlier WSSD, but modifications still being added H H
7
Delayed Session Termination on Dept.
Avoid cockpit alert during critical takeoff phase when flight departs Resolved
To be added to WSSD 3.0 in Jun 2013 H H
8
AOC Courtesy Copy/Dispatch Copy Format
Change to format and content of AOC message. Resolved
To be added to TIMS-CSP IRD in July 2013
Some in earlier IRD, but modifications still being added M M
9
Gate Request(surface location) Message
Change in timing of Dispatch/Courtesy Copy resulted in new message for gate ID at earlier time. Resolved
Modification to surface location message be added to WSSD 3.0 in Jun 2013
Some in earlier WSSD, but modifications still being added M M
10 NAT Tracks
Handle NAT Tracks, which are defined dynamically (daily) Resolved
To be added to WSSD 3.0 in Jun 2013
Same short-term fix using Initial UM79 as for International Flights H H
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Initial UM79 for International Flights
Handle NAT Tracks and unknown route elements in international flight plans Resolved
To be added to WSSD 3.0 in Jun 2013 H H
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DCIT/DTAP-based Requirement Changes – cont’d
# FunctionDescription/Purpose Status Resolution Comments Priority
Impact (H, M,
L)
12
Ignore optional 24-bit address in Logon Info
Ground systems to ignore for FANS since some are not set correctly. Closed
Lower level CMAP and TDLS derivations checked to ensure not being used L L
13
AOC Courtesy Copy/Dispatch Copy Content
Provide full route string on any DCC that does not have it, for both initial and revisions. Resolved
To be added to WSSD 3.0 in Jun 2013 and IRD in July 2013
Some in earlier documents, but modifications still being added M M
14
UM169 content and format for clearance data items
Route elements not included in the route clearance UM xx but required in the DCL clearance; inserted as free text in UM169. Multiple instances, e.g., SIDs and climbout procedures. Resolved
To be added to WSSD 3.0 in Jun 2013 H H
15Controller override of CAF
Provide CHI and override functionality to allow controller to force a full route clearance ( or as much of the route as possible.) Resolved
To be added to WSSD 3.0 in Jun 2013
Initial override (no CAF) modified to address international flights. H H
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DCIT/DTAP-based Requirement Changes – cont’d
# FunctionDescription/Purpose Status Resolution Comments Priority
Impact (H, M,
L)
16 UM83 switch
Allow UM83 functionality to be built in but disabled on initial release Rejected
Production will build UM83 H H
17Multiple DM25 requests
Provide manual uplink of full route clearance on subsequent clearance requests Resolved
To be added to WSSD 3.0 in Jun 2013
Controller to manually send a UM80, or UM79 if a UM80 cannot be sent H H
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Arrival/Departure procedure inclusion in DCL
Arrival and Departure procedures are optional. If included and revised, send even if no change. Resolved
To be added to WSSD 3.0 in Jun 2013
Clarified during earlier tower reviews also that DP is optional. Added requirements to include SID, transition, and Climb-out whenever one of three is modified
H H
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Notify controller of outstanding UNABLEs
If flight departs with unprocessed UNABLE, notify controller Resolved
To be added to WSSD 3.0 in Jun 2013 M M
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
Observations/Lessons Learned: Maturity
• Ideal = Serial – Trials “try out” and
validate operational requirements
– If valid, then transferred to Production for system implementation
• Reality = Parallel– Trials still changing
requirements • Production baselined in March
2012 for Logon and flight data (En Route)
• Tower held open to 4/15/13
– Trials mitigate operational acceptability risk but may add schedule risk to Production
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
Observations/Lessons Learned – cont’d• Handoff/Tech Transfer from DCIT/DTAP to
Production– New Requirements
• Need tech transfer documentation vehicle to clearly capture the problem, disposition across multiple spec docs, and track
• Formal DCIT Plenary agreement on Req->DTAP specs->Trials ->Refine Req ->Handoff to Production->Production specs->SW Development
• PTRs are bugs against Reqs; should not be used for new requirements, although some are listed as out of scope on PTR list
– Forum• DCIT WG reps, DTAP and S1P1 SE need to all be involved in
“handoff” to ensure operational and system requirements are well understood
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
Observations/Lessons Learned – cont’d• Implementation in Production
– Impacted by differences in system architectures• May require different requirements for Production system• May result in different potential impact than when proposed for
Trials
– Considerable SE LOE to understand, analyze and evaluate the DTAP PTRs for applicability to Production system• Understand requirement discrepancy, especially at lower levels• Evaluate maturity and consistency with other system requirements• Assess impact
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
Observations/Lessons Learned – cont’d• En Route Trials
– Start DCIT En Route Trials as soon as possible to gain the most benefit
– Need Serial, not Parallel– En Route use cases and specs will
soon be leaving the station...
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
Back Up
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
History - DCIT Requirement Changes• Primary Focus of DCIT is on the Trials
• Jan – June 2011, DCIT #1-6 – Focus on team organization (WGs, charter, agreements, Trials site selection,
processes)
• June 2011, DCIT 6– Flight Deck WG. Initial “requirements” discussions, e.g., complex clearances and
autoloading into FMS, Tailored Arrivals– Initial operational E2E description, e.g., ops requirements– Outbrief on AOC-Tower data exchange, e.g., flight plan, courtesy copies (aka dispatch
message), Subscriber DB
• July-Sep 2011, DCIT 7-9– Initial ops requirements for Revised DCLs using UM79, UM83 rather than UM80– Initial discussions about airways, intersections, other auto-loading problems.– Initial discussions about session termination changes
• Oct – Nov 2011, DCIT 10-11– Initial discussions about providing DCL 45 min prior to P-Time– Reject of DM25 with concatenated free text– Initial discussions about CAF
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
History-cont’d• Jan – Mar 2012, DCIT 12-13
– AOC Courtesy Copy initial format discussions– Initial delayed session termination requirements– CAF requirements
• Apr-June 2012, DCIT 14-16– Added route string to AOC Dispatch message for CAF
• July – Dec 2012, DCIT 17-20– Refinements based on additional avionics and DTAP testing
• Multiple AFN Log On’s• DM25, including multiple downlink requests• CAF• Lat/longs, NAT Tracks
• Jan – Mar 2013, DCIT 21-22– AOC Dispatch Message format changes, e.g., headers– UM83 switch (revert to UM80 when disabled)– Route string to AOC message on revisions
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DTAP-S1P1 Differences: CPDLC
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# Status Function/Topic
DTAP S1P1 Comments
1 Res Session Initiation/FP Correlation
DTAP starts on logon
S1P1 starts session on controller approval of DCL
Known Difference. TBD if requires procedure changes
2 Res STANDBY DTAP sends STANDBY
No STANDBY Known Difference. TBD if requires procedure changes
3 Open World-wide Fix processing
DTAP NAV database
ERAM NAV database
TBD if DTAP will change to use HCS/ERAM DB
4 Res Oceanic Tracks (North Atlantic)
Use Initial UM79 when not in DTAP NAV DB
Use Initial UM79 when not in ERAM NAV database
Fix for NAT is same as International; S1P1 implementation specs TBD
5 Res Arrival Autoroute inclusion in clearance
DTAP includes arrival auto-route (AAR)
S1P1 does not include auto-route (AAR)
Resolved. Changes to DTAP SSS to disqualify flights if include an AAR
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DTAP-S1P1 Differences: Controller Impacts
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# Status Function/Topic
DTAP S1P1 Comments
6 Res Controller CHI Differences
Modified COTS display
Modified current TDLS PDC display
Known Differences. Open issues.
7 Open What Route/How much of the route will be cleared
Uses HADDS routes and DTAP NAV DB
Uses ERAM-generated Data Comm route
Expect differences for Initial UM79 for international flights since NAV DBs are different.
8 Res Manual Closure of Transactions
Allows manual No manual closure
Known Difference. May require procedure changes
9 Open Automode capability
No automode; all DCLs need controller action
Automode; only revised DCLs need controller action
Plans to implement in future DTAP
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DCP Production-Trials ImpactDCIT #23, 9 May 2013
DTAP-S1P1 Differences: AOC Messages
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# Status Function/Topic
DTAP S1P1 Comments
10 Res DCL vs PDC Flight Identification
FRC DCL in REM field; prevents PDC and IDs DCL
ICAO 2012 codes in Fld 18, Subscriber DB default
Known Difference
11 Res FP Coding for NAT Tracks
Users file lat/lon in FP for NAT
Use Initial UM79 when not in ERAM NAV database
DTAP to use initial UM79. TBD if users will still file lat/lon for NAT, but assume no.
12 Res Fallback to PDC
N/A Hierarchy and fallback mechanism from DCL to PDC
Known Difference. Includes timing requirements for DCL/PDC changes; user preferences
13 Res AOC Interface for Dispatch Message
BATAP and MATIP COTS protocols
Same IFCET MHP protocol, same as current PDC
Known Difference. AOCs may need to change SW to use TDLS protocol
14 Open Gate ID response timing
Combined with Dispatch Message
New separate GREQ message due to timing requirements
DTAP to build Gate Request in later release?