![](media/image1.wmf){width="3.33125in" height="0.7291666666666666in"}

February 29, 2008

Docket Management Facility

DOCKET FAA-2007-29305

U.S. Department of Transportation

1200 New Jersey Avenue, SE.

West Building, Ground Floor, Room W12-140

Washington, DC 20590-0001

Subject: Comments to Docket No. FAA-2007-29305, Notice 07-15, "Automatic
Dependent Surveillance\--Broadcast (ADS-B) Out Performance Requirements
to Support Air Traffic Control (ATC) Service"

Reference: Notice of Proposed Rulemaking (NPRM) published in the Federal
Register on October 5, 2007 (72 FR 56947)

Dear Sir or Madam:

Enclosed are comments from Boeing Commercial Airplanes concerning the
subject proposed rule. While we recognize the value and merit of ADS-B
as one of the central elements of the NextGen Air Transportation System,
we find that certain requirements of the NPRM should be substantially
amended to meet this goal. The attached comments detail our following
overall concerns, which are:

-   ADS-B needs to be integrated with the overall Communication,
    Navigation, and Surveillance solution for increased capacity, cost
    reductions, and enhanced safety.

-   The NPRM should allow use of existing ADS-B equipage for early
    applications, as is being done in Europe, Australia, and Canada.

-   Additional equipage to support an ADS-B mandate should be based on
    an agreed CNS-ATM plan and concept of operations which is globally
    accepted by ANSPs.

-   Financial and/or procedural incentives which ensure positive
    cost/benefits and early equipage should be considered.

-   The reported position accuracy, integrity, and availability
    requirements should not be based on WAAS (or SBAS), as long as
    transmitted positions meet the quality requirements for the intended
    applications.

-   The plan to continue radar separation concepts using ADS-B as a
    radar replacement does not appear to be appropriate.

-   All users generating ADS-B Out signals should use 1090MHz.

We urge the FAA to consider harmonizing the proposed requirements with
the other current international standards. Harmonization of regulations
and standards results in lower costs, fewer inefficiencies, and less
confusion for operators, manufacturers, and suppliers, as well as
national authorities.

We appreciate the opportunity to review this proposal and trust that you
will consider our comments prior to finalizing the document.

Please direct any comments or questions to Ms. Jill DeMarco of this
office at\
(425) 965-3005.

Sincerely,

/original signed by/

Daniel P. Mooney

Enclosure

**Boeing Commercial Airplanes**

**Comments to Docket FAA-2007-29305**

**FAA Notice of Proposed Rulemaking,**

**"Automatic Dependent Surveillance -- Broadcast (ADS-B) Out Performance
Requirements to Support\
Air Traffic Control (ATC) Service"**

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #1 of 52*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **GENERAL COMMENT ON THE PROPOSED RULE:**              |
| section of  |                                                        |
| the         | **The Proposed Amendment to Chapter I of title 14 CFR  |
| proposed    | 91 -- General Operating and Flight Rules**             |
| document    |                                                        |
| that is of  | **Proposed §91.225, Automatic Dependent                |
| concern.*** | Surveillance-Broadcast (ADS--B) Out equipment and      |
|             | use**                                                  |
|             |                                                        |
|             | **Page 96571, Column 1**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *(a) After January 1, 2020, and unless otherwise       |
| the FAA's   | authorized by ATC, no person may operate an aircraft   |
| proposed    | below Flight Level 240 (FL240) and in airspace         |
| requirement | described in paragraph (b) of this section unless the  |
| or text?*** | aircraft is equipped with ADS--B Out equipment that:   |
|             | (1) Meets the performance requirements in TSO--C166a   |
|             | (1090ES), or later version; or (2) Meets TSO--C154b    |
|             | (UAT), or later version; and ....*                     |
+-------------+--------------------------------------------------------+
| ***What     | Boeing recognizes the merit of ADS-B as one of the     |
| about this  | central elements of the NextGen air transportation     |
| proposed    | management system. However, the draft NPRM needs to be |
| requirement | substantially amended to meet this goal.               |
| do we want  |                                                        |
| changed?*** | We suggest the NPRM should include near-term, low cost |
|             | implementations that accelerate earlier benefits for   |
|             | operators. The NPRM should allow use of existing ADS-B |
|             | equipage for early applications as is being done in    |
|             | other international ADS-B implementations. ADS-B also  |
|             | needs to be considered in the context of a balanced    |
|             | NextGen C-N-S solution that will facilitate necessary  |
|             | capacity increases and cost reductions, with current   |
|             | or better safety.                                      |
|             |                                                        |
|             | We do not believe that the FAA\'s ADS-B plan outlined  |
|             | in the NPRM meets either of these necessary            |
|             | requirements, particularly with the NPRM's emphasis on |
|             | carrying existing \"radar separation concepts\"        |
|             | forward using ADS-B as a substitute for existing       |
|             | radar. This is not the appropriate foundation for      |
|             | NextGen.                                               |
|             |                                                        |
|             | We believe that the appropriate equipage mandate for   |
|             | ADS-B should be based on a NextGen CNS ATM plan and    |
|             | concept for the US which is harmonized globally. This  |
|             | plan is not in place, with NextGen concepts generally  |
|             | immature at this point. This plan should be a          |
|             | prerequisite for defining pertinent requirements for   |
|             | ADS-B, both ADS-B Out and ADS-B In and related Cockpit |
|             | Display of Traffic Information (CDTI). The concepts of |
|             | operations for NextGen should drive out required       |
|             | capability, based on proven applications and a         |
|             | verified cost-benefit analysis.                        |
|             |                                                        |
|             | Without this work having been done, there is no basis  |
|             | for the proposed position accuracy, integrity, and     |
|             | availability requirements specified for ADS-B in the   |
|             | draft NPRM. The requirements include elements that are |
|             | overly prescriptive in an attempt to anticipate        |
|             | advanced capability for applications and requirements  |
|             | that have not been defined, specified or that lack     |
|             | cost/benefit analysis based on a defined concept of    |
|             | operations. We are particularly troubled by the        |
|             | requirement for WAAS to meet the specified position    |
|             | accuracy and integrity performance requirements. This  |
|             | stipulation has been made without recognizing the      |
|             | upcoming future enhancements to GPS by the DOD and the |
|             | planned international GPS systems. These upcoming      |
|             | changes will offer attractive options to meet these    |
|             | requirements should the applications demand the        |
|             | proposed levels of performance.                        |
|             |                                                        |
|             | We also believe that ADS-B should be globally based on |
|             | the Mode-S 1090 MHz frequency. For this reason we      |
|             | disagree with the FAA proposal to introduce UAT for    |
|             | general aviation for the purposed of combined ADS-B    |
|             | services and other potential applications such as      |
|             | weather information. These applications should be      |
|             | separated from the ADS-B capability which is           |
|             | fundamentally intended to provide a traffic            |
|             | surveillance function.                                 |
|             |                                                        |
|             | To move ADS-B forward, Boeing suggests a two-phased    |
|             | ADS-B approach to ADS-B deployment in the NAS.         |
|             |                                                        |
|             | The current NPRM attempts to (1) establish a mandate   |
|             | for ADS-B Out and (2) include high performance ADS-B   |
|             | Out requirements that anticipate future ADS-B In       |
|             | capabilities currently not defined, all within one     |
|             | phase of deployment mandated on 1 Jan 2020. In a       |
|             | phased approach, the FAA could start with              |
|             | establishment of an earlier mandate for ADS-B Out      |
|             | operations (Phase I) with equipage performance         |
|             | requirements commensurate with the capabilities of     |
|             | current Version 0 1090ES equipage and known and        |
|             | published ADS-B Out requirements which support the     |
|             | ground surveillance mission. These requirements could  |
|             | be harmonized with other ANSPs around the world who    |
|             | also intend to utilize the Version 0 equipage for      |
|             | ADS-B Out operations. In addition, the Phase I mandate |
|             | should be tied to the successful deployment of the     |
|             | ADS-B ground infrastructure which will give the user   |
|             | community confidence that equipment expenditures will  |
|             | be utilized by the updated ground surveillance         |
|             | infrastructure.                                        |
|             |                                                        |
|             | We further recommend the FAA to consider financial     |
|             | and/or procedural incentives that encourage Version 1  |
|             | (DO-260A) equipage during Phase I to ensure a positive |
|             | cost/benefit ratio for airspace users choosing to      |
|             | equip early although development of a stable DO-260A   |
|             | standard, which will not require upgrade in the        |
|             | near-term, is still in work. With a phased approach,   |
|             | airspace users would not be forced to implement costly |
|             | ADS-B Out equipage upgrades with a high risk of        |
|             | further expenditures once ADS-B In standards become    |
|             | published and stable. Phase I would also allow the FAA |
|             | to gain valuable real-world experience with ADS-B Out  |
|             | operations before publishing the updated requirements  |
|             | for the second phase.                                  |
|             |                                                        |
|             | The second phase would support ADS-B In operations     |
|             | (Phase II), allow accelerated industry standards       |
|             | development for ADS-B In applications, and ensure      |
|             | harmonized ADS-B standardization world-wide. Boeing    |
|             | intends to support diligent development of ADS-B In    |
|             | standards within both the RTCA and RFG forums. The     |
|             | definition and deployment of ADS-B In airborne         |
|             | surveillance applications and deployment of DO-260A    |
|             | ADS-B transponders compatible with ADS-B In /CDTI      |
|             | operations could potentially be supported before the   |
|             | current January 1, 2020, mandate.                      |
|             |                                                        |
|             | There is a safety runway incursion problem today and   |
|             | ADS-B is foundational to future runway incursion risk  |
|             | reduction. Short-term mitigations exist, but industry  |
|             | needs an accelerated path to advanced ADS-B-In/CDTI    |
|             | applications which provides cockpit knowledge of       |
|             | traffic and other situational awareness such as runway |
|             | occupancy and alerting.                                |
|             |                                                        |
|             | The FAA could consider a mandate for the Phase II      |
|             | ADS-B In performance requirements after the standards  |
|             | and the impact to airplane and ground infrastructure   |
|             | are clearly understood. If benefits exist and the FAA  |
|             | commits to airspace and procedural upgrades, a mandate |
|             | should not be required. Phase II operations should be  |
|             | tied to the successful deployment of the ADS-B ground  |
|             | infrastructure and procedural approvals which will     |
|             | give the user community confidence that equipment      |
|             | expenditures will be utilized by the updated ground    |
|             | surveillance infrastructure. The additional time to    |
|             | define and complete ADS-B In standards would also      |
|             | provide the opportunity to perform alternatives        |
|             | analyses supporting selection of the most              |
|             | cost-effective CNS ATM enhancements (e.g. RNP) to      |
|             | solve specific operational constraints.                |
+-------------+--------------------------------------------------------+
| ***Why is   | The current NPRM does not take advantage of existing   |
| the change  | Version 0 1090ES (DO-260-like) equipage already        |
| ju          | deployed on a substantial number of the air transport  |
| stified?*** | category aircraft flying throughout the NAS. The FAA   |
|             | could gain considerable knowledge of ADS-B operations  |
|             | by utilizing Version 0 transponders in Non-radar       |
|             | Airspace (NRA) and en-route radar airspace (RAD). The  |
|             | current NPRM also attempts to anticipate ADS-B Out     |
|             | requirements introduced by ADS-B In operations and     |
|             | capabilities which are currently not defined. Since    |
|             | the ADS-B In standards will inevitably introduce new   |
|             | and different requirements for ADS-B Out performance,  |
|             | early installation of ADS-B Out equipage compatible    |
|             | with the requirements currently contained within the   |
|             | draft NPRM would have to be modified at a later date.  |
|             | The user community would prefer to make one change to  |
|             | surveillance equipage to avoid costly modification     |
|             | within a few years.                                    |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #2 of 52*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **I. Background -**                                    |
| section of  |                                                        |
| the         | **A. Vision of the Future**                            |
| proposed    |                                                        |
| document    | **(4^th^ and 5^th^ paragraphs under Section A.)**      |
| that is of  |                                                        |
| concern.*** | **Page 56949, Columns 1 and 2**                        |
+-------------+--------------------------------------------------------+
| ***What is  | *The solution to managing the anticipated growth in    |
| the FAA's   | the use of the NAS is the Next Generation Air          |
| proposed    | Transportation System, or NextGen, which will assure   |
| requirement | the safe and efficient movement of people and goods as |
| or text?*** | demand increases. ... NextGen will be an               |
|             | aircraft-centric system with performance-based         |
|             | requirements.*                                         |
+-------------+--------------------------------------------------------+
| ***What     | Text to be changed:                                    |
| about this  |                                                        |
| proposed    | > *NextGen will be an aircraft-centric system with     |
| requirement | > performance-based requirements.*                     |
| do we want  |                                                        |
| changed?*** | Suggested new text:                                    |
|             |                                                        |
|             | > *NextGen will be enabled by aircraft which provide   |
|             | > performance-based capabilities that are              |
|             | > operationally integrated with the ATM automation     |
|             | > system. These capabilities will enable new           |
|             | > operational concepts to expand traffic capacity and  |
|             | > to provide greater efficiency in managing expanded   |
|             | > air traffic.*                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | We recommend that the statement be expanded to include |
| the change  | new ground automation functionality such as            |
| ju          | multi-sensor data fusion that will integrate the new   |
| stified?*** | airplane capabilities into the ATM system and provide  |
|             | a basis for needed future traffic growth.              |
|             |                                                        |
|             | The emphasis of the NPRM and also the NextGen future   |
|             | concept seems to be on specifying enhanced technology  |
|             | and performance capabilities for the future aircraft   |
|             | fleet. It is doubtful that simply replacing Comm/ Nav/ |
|             | Surveillance capabilities aboard aircraft and in       |
|             | corresponding ATC systems with enhanced performance    |
|             | will accomplish the ambitious goals for increased      |
|             | traffic capacity, efficiency, and system growth        |
|             | without substantial improvements in ground system      |
|             | automation.                                            |
|             |                                                        |
|             | The NPRM only addresses traditional surveillance       |
|             | applications for ADS-B Out and associated performance  |
|             | requirements. Expanding NAS system capacity is likely  |
|             | to require major changes in ATM system automation      |
|             | functionality and to requirements for air-ground data  |
|             | communication which are scarcely addressed in this     |
|             | NPRM.                                                  |
|             |                                                        |
|             | "Aircraft-centric" is a buzz word that is really       |
|             | intended to convey that the aircraft is now an         |
|             | integral part of the airspace, air traffic, and        |
|             | operations solution set.                               |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #3 of 52*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **I. Background**                                      |
| section of  |                                                        |
| the         | **A. Vision of the Future**                            |
| proposed    |                                                        |
| document    | **(9^th^ paragraph under Section A.)**                 |
| that is of  |                                                        |
| concern.*** | **Page 56949, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *Most, if not all, of the surveillance capability as   |
| the FAA's   | well as the navigation and communications capabilities |
| proposed    | should be onboard the aircraft so the required         |
| requirement | capabilities will go wherever the aircraft goes.*      |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *While some of the surveillance capability as well   |
| requirement | > as the navigation and communications capabilities    |
| do we want  | > should be onboard the aircraft so the required       |
| changed?*** | > capabilities will go wherever the aircraft goes,     |
|             | > allocation of surveillance as well as navigation and |
|             | > communications capabilities and requirements will be |
|             | > made between the aircraft and the ground as a result |
|             | > of a reasoned system engineering process including   |
|             | > trade studies to determine the best functional       |
|             | > distribution with reasonable user cost.*             |
+-------------+--------------------------------------------------------+
| ***Why is   | Some functions could be much more economically         |
| the change  | implemented in several hundred ground systems rather   |
| ju          | than in tens of thousands of aircraft. See other       |
| stified?*** | comments for specific examples.                        |
|             |                                                        |
|             | In addition, the position performance requirements for |
|             | ADS-B surveillance specified in this NPRM are          |
|             | different from the performance requirements for        |
|             | navigation within the NAS. Position performance        |
|             | requirements for ADS-B are being developed without     |
|             | recognition of existing navigation capabilities.       |
|             | Requirements for navigation and surveillance need to   |
|             | be derived in a coordinated, not isolated, process     |
|             | that will not unnecessarily drive up cost.             |
|             |                                                        |
|             | The final solutions and allocations will also be       |
|             | dictated by aircraft safety requirements since, in     |
|             | this case, on-board surveillance and navigation have a |
|             | common source and common failures that must be         |
|             | considered.                                            |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| \# 4 of     |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **II. The ADS-B System**                               |
| section of  |                                                        |
| the         | **A. General**                                         |
| proposed    |                                                        |
| document    | **(2^nd^ paragraph under Section A.)**                 |
| that is of  |                                                        |
| concern.*** | **Page 56951, Column 1**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *In addition, ADS-B does not replace the requirement   |
| the FAA's   | for transponders. Transponders are still necessary for |
| proposed    | SSR, which is FAA's strategy in case of ADS-B          |
| requirement | failure.*                                              |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *In the near-term, ADS-B does not replace the        |
| requirement | > requirement for transponders. Transponders are still |
| do we want  | > necessary for SSR, which is FAA's strategy in case   |
| changed?*** | > of ADS-B failure. In the long-term, the FAA will     |
|             | > explore surveillance architectures which eliminate   |
|             | > the need for both SSR transponders and additional    |
|             | > ADS-B functionality.*                                |
+-------------+--------------------------------------------------------+
| ***Why is   | The FAA architecture requiring continued investment in |
| the change  | transponders in addition to new ADS-B equipage places  |
| ju          | an unnecessary investment burden on the entire         |
| stified?*** | industry. We recommend that the FAA reevaluate its     |
|             | strategy and architecture to eliminate this net        |
|             | addition of equipage required to facilitate ground     |
|             | surveillance functionality. We maintain that ADS-B     |
|             | should lead to reductions in airborne equipage, not    |
|             | require additional equipage, especially when there is  |
|             | no clear benefit over radar.                           |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #5 of 52*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **II. The ADS-B System**                               |
| section of  |                                                        |
| the         | **A. General**                                         |
| proposed    |                                                        |
| document    | **(3^rd^ paragraph under Section A.)**                 |
| that is of  |                                                        |
| concern.*** | **Page 56951, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *...Without ADS-B, the increase in demand could result |
| the FAA's   | in increased congestion and the denial of ATC service  |
| proposed    | to some users of the NAS.*                             |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *Without ADS-B **[and integration of new ATM         |
| requirement | > functionality such as multi-sensor data              |
| do we want  | > fusion]{.underline}**, the increase in demand could  |
| changed?*** | > result in increased congestion and the denial of ATC |
|             | > service to some users of the NAS.*                   |
+-------------+--------------------------------------------------------+
| ***Why is   | This section should note that, in the event of a GPS   |
| the change  | outage or interference event, or reduction in GNSS     |
| ju          | satellite capability, simply reverting to the backup   |
| stified?*** | radar infrastructure is likely to result in increased  |
|             | traffic congestion and reduced ATC service. Continuity |
|             | of en-route 5nm separation services could require      |
|             | additional backup capability, such as use of           |
|             | multi-sensor tracking and fusion, and/or use of ADS-B  |
|             | broadcast of available information such as FMS backup  |
|             | position and aircraft ground vector based on INS data. |
|             | Simply switching to the backup radar system is likely  |
|             | to be problematic for short outage periods, such as    |
|             | RAIM holes that transit through an airspace sector     |
|             | with average durations on the order of a few minutes,  |
|             | followed by restoration of GPS-based ADS-B             |
|             | surveillance.                                          |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #6 of 52*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **II. The ADS-B System**                               |
| section of  |                                                        |
| the         | **A. General**                                         |
| proposed    |                                                        |
| document    | **(5th paragraph under Section A.)**                   |
| that is of  |                                                        |
| concern.*** | **Page 56951, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *... This proposal only seeks to require ADS--B Out;   |
| the FAA's   | the FAA is not proposing to require ADS--B In at this  |
| proposed    | time.*                                                 |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *This proposal seeks a two phase approach which      |
| requirement | > first requires ADS-B Out and then, as a next step,   |
| do we want  | > requires and/or supports enhanced ADS-B Out          |
| changed?*** | > performance in support of cost beneficial ADS-B In   |
|             | > operations as a part of a focused second phase of    |
|             | > deployment.*                                         |
+-------------+--------------------------------------------------------+
| ***Why is   | To motivate operators to equip with ADS-B-In/CDTI and  |
| the change  | applications that provide significant return on their  |
| ju          | investments, we recommend that the proposal provide    |
| stified?*** | some assurances that airborne surveillance             |
|             | applications will be accommodated throughout the NAS.  |
|             | The ADS-B In airborne surveillance applications        |
|             | currently proposed by the FAA in the NPRM are very     |
|             | limited and there is skepticism within the industry as |
|             | to the ability to expand the proposed beneficial       |
|             | applications to airports other than Louisville in a    |
|             | reasonable timeframe.                                  |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #7 of 52*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **II. The ADS-B System**                               |
| section of  |                                                        |
| the         | **B. Ground Infrastructure**                           |
| proposed    |                                                        |
| document    | **Footnote 10**                                        |
| that is of  |                                                        |
| concern.*** | **Page 56951, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *Aircraft that are equipped with ADS-B can be          |
| the FAA's   | monitored through a direct reception of their ADS- B   |
| proposed    | signals in an air-to-air environment.*                 |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We request this text be clarified.                     |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | This statement is inconsistent with the remainder of   |
| the change  | the NPRM, which defines and highlights the FAA's dual  |
| ju          | frequency approach using both 1090 MHz and UAT. The    |
| stified?*** | 1090 MHz aircraft will not be able to view ADS-B       |
|             | signals emanating from UAT aircraft in an air-to-air   |
|             | environment. The FAA architecture includes a           |
|             | rebroadcast element, as described in section VA. ADS-B |
|             | In -- Avionics -- Paragraph 3. The dual frequency      |
|             | approach should be replaced with one frequency for the |
|             | reasons cited by the FAA in Section IV, paragraph B.2. |
|             | ,"The Proposal for ADS-B Out -- Avionics -- Broadcast  |
|             | Link Requirements for Different Flight Levels" (first  |
|             | paragraph): *"Having a single broadcast link at higher |
|             | altitudes would enable aircraft equipped for ADS-B In  |
|             | to benefit from potential future applications such as  |
|             | aircraft merging and spacing, and self-separation."*   |
|             |                                                        |
|             | This comment applies to all altitudes and, most        |
|             | importantly, to the terminal area environment.         |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #8 of 52*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **III. Summary of the Proposal**                       |
| section of  |                                                        |
| the         | **(2^nd^ paragraph under Section III.)**               |
| proposed    |                                                        |
| document    | **Page 56952, Column 1**                               |
| that is of  |                                                        |
| concern.*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What is  | *The FAA proposes to require aircraft flying at or     |
| the FAA's   | above Flight Level 240 (FL240) to have ADS-B Out       |
| proposed    | performance capabilities using the 1090 Extended       |
| requirement | Squitter (1090ES) broadcast link. Aircraft flying in   |
| or text?*** | the designated airspace below FL 240 would have to use |
|             | either the 1090ES or Universal Access Transceiver      |
|             | (UAT) broadcast link.*                                 |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *The FAA proposes that aircraft flying throughout    |
| requirement | > the NAS have ADS-B Out performance capabilities      |
| do we want  | > using the 1090 Extended Squitter (1090ES) broadcast  |
| changed?*** | > link.*                                               |
+-------------+--------------------------------------------------------+
| ***Why is   | Permitting use of two ADS-B link media that are not    |
| the change  | interoperable, other than through provision of ground  |
| ju          | services, seriously limits the utility of ADS-B for    |
| stified?*** | airborne surveillance applications, further            |
|             | discouraging operators from equipping for the more     |
|             | beneficial applications. While air transport aircraft  |
|             | may not encounter lower-performance, general aviation  |
|             | aircraft in the majority of their operations (on a     |
|             | time basis), designating a flight level below which an |
|             | alternate broadcast link may be utilized, leaves the   |
|             | door open for operators of many turboprop models that  |
|             | do utilize air transport airports to equip with        |
|             | UAT-based ADS-B.                                       |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #9 of 52*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **III. Summary of the Proposal**                       |
| section of  |                                                        |
| the         | **(3rd paragraph under Section III.)**                 |
| proposed    |                                                        |
| document    | **Page 56952, Column 1**                               |
| that is of  |                                                        |
| concern.*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What is  | *The implementation of ADS--B requires two data links  |
| the FAA's   | to support the full set of applications. UAT is        |
| proposed    | intended to support applications for the general       |
| requirement | aviation user community that are not needed by air     |
| or text?*** | carriers because air carriers have weather radar, fly  |
|             | at high altitudes, and have other aeronautical links.  |
|             | UAT-equipped general aviation aircraft are not         |
|             | generally equipped with weather radar and would be     |
|             | flying at low altitudes. The 1090ES link is the        |
|             | internationally agreed upon link for ADS--B, and is    |
|             | intended to support applications for air carriers and  |
|             | other high-performance aircraft. The 1090ES broadcast  |
|             | link does not support applications available from      |
|             | FIS--B, like weather and related flight information.   |
|             | This is because of the bandwidth limitations of the    |
|             | 1090ES link for transmitting the large message         |
|             | structures required by FIS--B. Weather and flight      |
|             | information for 1090ES equipped aircraft is generally  |
|             | provided by commercial products.*                      |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *The FAA proposes that aircraft flying throughout    |
| requirement | > the NAS have ADS-B Out performance capabilities      |
| do we want  | > using the 1090 Extended Squitter (1090ES) broadcast  |
| changed?*** | > link.*                                               |
+-------------+--------------------------------------------------------+
| ***Why is   | Making UAT an ADS-B link because GA aircraft will      |
| the change  | benefit from an unrelated function using the same link |
| ju          | does not appear to be a good reason for marginalizing  |
| stified?*** | the operational utility of both GA and Air Transport   |
|             | ADS-B link media at a common frequency. Other          |
|             | commercial sources of weather and other aeronautical   |
|             | data are currently available and growing and might be  |
|             | implemented at much lower cost than by using a UAT     |
|             | system that must also satisfy the performance          |
|             | requirements of a separation system. The fundamental   |
|             | air-to-air surveillance element of ADS-B In cannot be  |
|             | assured to operate with sufficient latency as cited by |
|             | the FAA in Section IV, paragraph B.2., 1st paragraph,  |
|             | in the preamble to the NPRM. *"Having a single         |
|             | broadcast link at higher altitudes would enable        |
|             | aircraft equipped for ADS-B In to benefit from         |
|             | potential future applications such as aircraft merging |
|             | and spacing, and self-separation. These applications   |
|             | are enabled by having aircraft identify each other on  |
|             | the same data link without the need to employ ADS--R,  |
|             | which would increase the latency of the                |
|             | transmission."*                                        |
|             |                                                        |
|             | This comment applies to all altitudes and, most        |
|             | importantly, to the terminal area environment.         |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #10 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **A. Advantages of ADS-B Out**                         |
| proposed    |                                                        |
| document    | **(1^st^ paragraph under Section A.)**                 |
| that is of  |                                                        |
| concern.*** | **Page 56952, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *ADS--B Out, as proposed in this notice, would enhance |
| the FAA's   | surveillance and broadcast services in both the        |
| proposed    | en-route and terminal environments and provide ATC     |
| requirement | with more accurate information to safely separate      |
| or text?*** | aircraft in the air.*                                  |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *Upgrades in airborne equipage, along with           |
| requirement | > improvements in ground system automation which       |
| do we want  | > support future FAA approved operational procedures   |
| changed?*** | > would enhance surveillance and broadcast services in |
|             | > both the en-route and terminal environments and      |
|             | > provide ATC with more accurate information to safely |
|             | > separate aircraft in the air.*                       |
+-------------+--------------------------------------------------------+
| ***Why is   | We maintain that there must be associated assurances   |
| the change  | of improvements in ground system automation consistent |
| ju          | with the operational environment that will exist at    |
| stified?*** | the point when a significant number of aircraft are    |
|             | suitably equipped to provide benefit from ADS-B out    |
|             | equipage. It will take more than "more accurate        |
|             | information" to provide the level of benefit that the  |
|             | cost of ADS-B Out must justify.                        |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #11 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **A. Advantages of ADS-B Out**                         |
| proposed    |                                                        |
| document    | **(3rd paragraph under Section A.)**                   |
| that is of  |                                                        |
| concern.*** | **Page 56952, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *If ATC had more precise aircraft position information |
| the FAA's   | it could position, separate and provide speed and      |
| proposed    | direction instructions to aircraft with improved       |
| requirement | precision and timing. ...*                             |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *If ATC had more precise aircraft position           |
| requirement | > information **[along with new NextGen operating      |
| do we want  | > concepts]{.underline}**, it could position,          |
| changed?*** | > separate, and provide speed and direction            |
|             | > instructions to aircraft with improved precision and |
|             | > timing.*                                             |
+-------------+--------------------------------------------------------+
| ***Why is   | ADS-B operations alone will not lead to advances       |
| the change  | required by NextGen. The proposed new rule must have   |
| ju          | as its foundation a thorough, vetted NextGen operating |
| stified?*** | concept to then build a supporting architecture that   |
|             | meets the FAA's requirement for a positive business    |
|             | case and enable the NAS to achieve 3x capacity.        |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #12 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **A. Advantages of ADS-B Out**                         |
| proposed    |                                                        |
| document    | **(3rd paragraph under Section A.)**                   |
| that is of  |                                                        |
| concern.*** | **Page 56952, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *... Additionally, with ADS-B Out, ATC would receive   |
| the FAA's   | updated information broadcast by aircraft more         |
| proposed    | frequently than with radar, and would be able to track |
| requirement | a more closely monitored flight path. This would       |
| or text?*** | result in ATC providing fewer instructions to pilots,  |
|             | thus having more time to accommodate additional        |
|             | aircraft within the allotted airspace. ...*            |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *Additionally, with ADS-B Out **[and other NextGen   |
| requirement | > system capabilities such as RNAV (RNP) path          |
| do we want  | > clearances]{.underline}**, ATC would receive updated |
| changed?*** | > information broadcast by aircraft more frequently    |
|             | > than with radar, and would be able to track a more   |
|             | > closely monitored flight path. ~~This would result   |
|             | > in ATC providing fewer~~ **[With the expected        |
|             | > reduction in ATC instructions based upon RNAV (RNP)  |
|             | > clearances, ADS-B Out would offer the potential for  |
|             | > further reduction in ATC]{.underline}** instructions |
|             | > to pilots, thus having more time to accommodate      |
|             | > additional aircraft within the allotted airspace.*   |
+-------------+--------------------------------------------------------+
| ***Why is   | It is unlikely that ADS-B Out alone would result in    |
| the change  | ATC providing fewer instructions to pilots in sectors  |
| ju          | that are R/T limited (i.e., in sectors where voice     |
| stified?*** | communication of clearances limits the number of       |
|             | aircraft that can be serviced). However, recent        |
|             | studies have shown that use of more strategic RNAV or  |
|             | RNAV (RNP) clearances can significantly reduce use of  |
|             | voice communications, thereby resulting in fewer       |
|             | instructions to pilots. ADS-B Out can support such     |
|             | concepts of operation, particularly for low-RNP        |
|             | procedures with very tight lateral tolerances in       |
|             | terminal airspace, by providing suitable conformance   |
|             | monitoring for such operations where radar conformance |
|             | monitoring may not be adequate. The NPRM seems to be   |
|             | saying in this section that ADS-B Out is adequate by   |
|             | itself to reduce controller workload and to increase   |
|             | sector capacity. This example shows that the use of    |
|             | hybrid operational concepts using other system         |
|             | enablers in addition to ADS-B may be required to       |
|             | achieve the stated growth in traffic capacity in       |
|             | already congested airspace sectors.                    |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| 13 of 52*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **A. Advantages of ADS-B Out**                         |
| proposed    |                                                        |
| document    | **(5th paragraph under Section A.)**                   |
| that is of  |                                                        |
| concern.*** | **Page 56952, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *... Therefore, this rulemaking is expected to help    |
| the FAA's   | achieve a level of surveillance accuracy that would    |
| proposed    | support reducing aircraft separation standards. ...*   |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *Therefore, this rulemaking is expected to help      |
| requirement | > achieve a level of surveillance accuracy that would  |
| do we want  | > support ~~reducing~~ **[current]{.underline}**       |
| changed?*** | > aircraft separation standards.*                      |
+-------------+--------------------------------------------------------+
| ***Why is   | We do not find the justification for assuming that     |
| the change  | increased ADS-B performance will enable future reduced |
| ju          | separation standards to be appropriate. When increased |
| stified?*** | performance levels have been achieved in the past,     |
|             | such as increased accuracy with newer monopulse SSR    |
|             | radars, the bar is simply raised for future systems to |
|             | at least equal the performance of the existing         |
|             | systems, as a basis for [current]{.underline}          |
|             | separation minima.                                     |
|             |                                                        |
|             | We do not consider that accuracy and integrity of      |
|             | ADS-B Out position reports necessarily implies         |
|             | capability for reduced separation standards. In        |
|             | particular, the update rate at the controller's        |
|             | display needs to be compatible with the reduced        |
|             | separation as well. For example, a display update rate |
|             | no greater than 5 seconds is probably required for     |
|             | reduced 3 nm separations in en-route airspace, similar |
|             | to terminal airspace today. Even with a 0.1 nm         |
|             | accuracy (NACp=7), today's 12-second display update    |
|             | rate will not support reduced separations in en-route  |
|             | airspace, since display accuracy in en-route           |
|             | automation systems is dominated by display latency,    |
|             | which can result in errors as large as 1.7 nm prior to |
|             | display refresh.                                       |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #14 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **1. 1090ES and UAT Broadcast Links -**                |
| that is of  |                                                        |
| concern.*** | **(2^nd^ paragraph under Section 1.)**                 |
|             |                                                        |
|             | **Page 56953, Column 1**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *... These modified parameters (NIC, NAC, and SIL)     |
| the FAA's   | provide a level of accuracy and integrity with respect |
| proposed    | to the information transmitted in the ADS-B Out        |
| requirement | message that would enable ATC to provide improved      |
| or text?*** | surveillance and separation services based on the      |
|             | information it receives from the aircraft.*            |
+-------------+--------------------------------------------------------+
| ***What     | We recommend that this paragraph either be deleted or  |
| about this  | modified to highlight anticipated changes in the data  |
| proposed    | sources that will provide improved accuracy and        |
| requirement | integrity, which support improved surveillance and     |
| do we want  | separation services.                                   |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | We do not consider that the paragraph should suggest   |
| the change  | that the transition from 'NUC' to 'NIC', 'NAC' and     |
| ju          | 'SIL' increases the accuracy and integrity of received |
| stified?*** | data. There is no change in the data sources           |
|             | associated with this transition; the change is simply  |
|             | in the receiving entity's knowledge about the accuracy |
|             | and/or the integrity concerning transmitted data.      |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #15 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **1. 1090ES and UAT Broadcast Links -**                |
| that is of  |                                                        |
| concern.*** | **(3^rd^ paragraph under Section 1.)**                 |
|             |                                                        |
|             | **Page 56953, Column 1**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *... There are some aircraft equipped today with       |
| the FAA's   | legacy 1090ES ADS-B systems. Operators of these        |
| proposed    | aircraft would need to modify their broadcast link     |
| requirement | equipment to meet the proposed requirements defined in |
| or text?*** | TSO-C166a.*                                            |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *There are some aircraft equipped today with legacy  |
| requirement | > 1090ES ADS-B systems. In a phased implementation     |
| do we want  | > approach these legacy systems would be utilized for  |
| changed?*** | > specific airspace (i.e. NRA and en-route RAD) to     |
|             | > gain useful practical experience with the ADS-B      |
|             | > system. The requirements for legacy Version 0 1090ES |
|             | > equipage could be harmonized with other ANSPs around |
|             | > the world which also intend to utilize the Version 0 |
|             | > equipage for ADS-B Out operations.*                  |
+-------------+--------------------------------------------------------+
| ***Why is   | There is no performance-based or CONOPS-based          |
| the change  | requirement for re-equipping legacy ADS-B aircraft.    |
| ju          | Service should be provided at a level commensurate     |
| stified?*** | with the performance of existing systems and           |
|             | experience gained in use of ADS-B before final         |
|             | requirements are set (see European and Australian      |
|             | usage models). The European mandate for elementary and |
|             | enhanced surveillance is already in place. This NPRM   |
|             | should allow continued use of the legacy Version 0     |
|             | 1090ES ADS-B equipment to gain a critical mass of      |
|             | users and early system benefits.                       |
|             |                                                        |
|             | The upgrade to DO-260A-based equipment will be costly  |
|             | and, at the point where this upgrade will become       |
|             | available (when equipment is available), there will    |
|             | still be no guarantee that the equipment will support  |
|             | the more beneficial (airborne surveillance)            |
|             | applications that are likely to follow. Such           |
|             | uncertainty will delay operator decisions to upgrade   |
|             | or equip, delaying return on investment. Operators     |
|             | have already invested in Version 0 1090ES and there is |
|             | an opportunity to gain early benefits of NAS ADS-B     |
|             | deployment by using this equipment in a transition     |
|             | step, at minimum until 2020.                           |
|             |                                                        |
|             | In addition, the FAA has not defined any specific      |
|             | benefits or new procedures in the NPRM for             |
|             | ADS-B-equipped and compliant airborne users that will  |
|             | be available by a specific date; either before or      |
|             | after the 2020 deadline. The cost-to-benefit ratio is  |
|             | undefined. The benefits for early adopters are not     |
|             | evident. We recommend that the FAA define when new     |
|             | procedures for ADS-B in non-radar airspace and radar   |
|             | airspace will be available by a specific date to users |
|             | that are equipped per the requirements of this NPRM.   |
|             | In the absence of any clear benefits to the users,     |
|             | existing Version 0 equipment should be allowed to be   |
|             | operated in the NAS until the FAA defines a program    |
|             | that contains both costs and benefits and establishes  |
|             | a reasonable ratio between them.                       |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #16 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **1. 1090ES and UAT Broadcast Links -**                |
| that is of  |                                                        |
| concern.*** | **(4^th^ paragraph under Section 1.)**                 |
|             |                                                        |
|             | **Page 56953, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *... The United States faces unique challenges in air  |
| the FAA's   | traffic control due to its high density airspace and   |
| proposed    | stringent safety requirements. In order to maintain    |
| requirement | safety and capacity, given a state of increased air    |
| or text?*** | traffic, advanced surveillance technologies will be    |
|             | necessary. The earlier standards in RTCA/DO-260 do not |
|             | provide the performance standards necessary to meet    |
|             | the requirements of the NAS.*                          |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *The United States faces unique challenges in air    |
| requirement | > traffic control due to its high density airspace and |
| do we want  | > stringent safety requirements. In order to maintain  |
| changed?*** | > safety and capacity, given a state of increased air  |
|             | > traffic, advanced surveillance technologies will be  |
|             | > necessary **[for high density                        |
|             | > airspace.]{.underline}** The earlier standards in    |
|             | > RTCA/DO-260 ~~do not provide the performance         |
|             | > standards necessary to meet the requirements of the  |
|             | > NAS~~ **[are adequate to provide the performance     |
|             | > standards necessary to meet the requirements of the  |
|             | > non-high density airspace of the                     |
|             | > NAS.]{.underline}***                                 |
+-------------+--------------------------------------------------------+
| ***Why is   | We maintain that equipment compatible with the earlier |
| the change  | standards in RTCA/DO-260 meet the requirements of most |
| ju          | of the NAS and do not meet the performance standards   |
| stified?*** | requirements of only high density airspace. It would   |
|             | be preferable to allow those aircraft with existing    |
|             | equipage to be provided with a level of service        |
|             | consistent with the performance of the equipment and   |
|             | introduce more stringent requirements specifically in  |
|             | high density airspace. We recommend that the proposal  |
|             | recognize the difference between requirements in       |
|             | low-to-medium density airspace and the requirements    |
|             | that are needed for high density airspace.             |
|             |                                                        |
|             | We request that the FAA not apply the most stringent   |
|             | performance requirements to the [entire]{.underline}   |
|             | National Airspace System or to the entire set of       |
|             | applications. Instead, the performance requirements    |
|             | should be tailored to the application or separation    |
|             | standard for that region. It is possible, that many    |
|             | aircraft with legacy avionics will never venture into  |
|             | the areas in which the increased requirements are      |
|             | necessary or justified. Further, many will never find  |
|             | a business case for the equipment supporting airborne  |
|             | surveillance applications; however, this proposed rule |
|             | would require that they support a mandate for high     |
|             | performance and resulting high cost equipment.         |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #17 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **1. 1090ES and UAT Broadcast Links -**                |
| that is of  |                                                        |
| concern.*** | **(4^th^ paragraph under Section 1.)**                 |
|             |                                                        |
|             | **Page 56953, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *... RTCA/DO-260A provides a means to transmit the     |
| the FAA's   | Secondary Surveillance Radar beacon codes that         |
| proposed    | currently service the NAS and will continue to be      |
| requirement | required as a backup to ADS-B. ...*                    |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We recommend that FAA delete this requirement.         |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | The need to include SSR beacon codes in DO-260A        |
| the change  | equipage when all aircraft have working systems        |
| ju          | already installed supporting the requirement results   |
| stified?*** | in significant additional cost to the user community.  |
|             | The transponder will continue to provide beacon codes  |
|             | in the ground system's radar backup mode.              |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #18 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **2. Broadcast Link Requirements for Different Flight  |
| that is of  | Levels**                                               |
| concern.*** |                                                        |
|             | **(1^st^ paragraph under Section 2.)**                 |
|             |                                                        |
|             | **Page 56953, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *"... Some general aviation aircraft are already       |
| the FAA's   | equipped with UAT broadcast link. ..."*                |
| proposed    |                                                        |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We recommend that this statement be reconsidered or    |
| about this  | clarified.                                             |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | The statement implies that the equipped aircraft can   |
| the change  | participate in the NAS ADS-B network. However, in      |
| ju          | other areas of the NPRM, the FAA states these UAT      |
| stified?*** | units will have to be upgraded. We note that there are |
|             | very few GA installations of UAT transponders, and all |
|             | would have to be upgraded to be compatible with the    |
|             | proposed requirements of this NPRM.                    |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #19 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **2. Broadcast Link Requirements for Different Flight  |
| that is of  | Levels**                                               |
| concern.*** |                                                        |
|             | **(1^st^ paragraph under Section 2.)**                 |
|             |                                                        |
|             | **Page 56953, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *"... Having a single broadcast link at higher         |
| the FAA's   | altitudes would enable aircraft equipped with ADS-B In |
| proposed    | to benefit from potential future applications such as  |
| requirement | aircraft merging and spacing and self separation.      |
| or text?*** | These applications are.... Aircraft identify each      |
|             | other on the same datalink without the need to employ  |
|             | ADS-R which could increase the latency of the          |
|             | transmission. ...*                                     |
+-------------+--------------------------------------------------------+
| ***What     | We recommend that this text be reconsidered or         |
| about this  | clarified.                                             |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | The FAA acknowledges that a single datalink will       |
| the change  | enable advanced ADS-B In applications at high altitude |
| ju          | that may be limited by ADS-R in cases of two links.    |
| stified?*** | This limitation will also limit use of these same      |
|             | applications at the low altitudes (below FL240). To    |
|             | facilitate advanced ADS-B In applications below FL240  |
|             | in future years, we recommend that the FAA utilize a   |
|             | single datalink for all the NAS.                       |
|             |                                                        |
|             | This justification for dissimilar ADS-B links          |
|             | presupposes that the airborne surveillance             |
|             | applications mentioned will be used only at high       |
|             | altitude. Since much of the ATM system delay is        |
|             | associated with arrivals at and departures from        |
|             | airports, airborne surveillance functions must be able |
|             | to provide benefit at all altitudes and on the ground  |
|             | if a satisfactory return on investment and the full    |
|             | range of operational enhancement is to be achieved.    |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #20 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **2. Broadcast Link Requirements for Different Flight  |
| that is of  | Levels**                                               |
| concern.*** |                                                        |
|             | **(1^st^ paragraph under Section 2.)**                 |
|             |                                                        |
|             | **Page 56953, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *... The FAA proposes to require that aircraft flying  |
| the FAA's   | at or above FL240 have ADS-B Out performance           |
| proposed    | capability using the 1090ES broadcast link. ...*       |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We request that this text be reconsidered.             |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | It is not apparent that the interference effects and   |
| the change  | performance impacts of the new additional ADS-B Out    |
| ju          | traffic in the1090 MHz frequency band on the existing  |
| stified?*** | users of the band \[such as ground Secondary           |
|             | Surveillance Radars (SSR's), airborne Mode S           |
|             | transponders, and TCAS\] has been adequately assessed. |
|             | The FAA has identified interference in the 1090 MHz    |
|             | band as a major program risk. We recommend that, prior |
|             | to the implementation of the ADS-B final rule, the FAA |
|             | should commission a comprehensive study on the         |
|             | interference effects and performance impacts of        |
|             | additional ADS-B Out traffic in the1090 MHz frequency  |
|             | band on the existing user receivers:                   |
|             |                                                        |
|             | -   ground Secondary Surveillance Radars,              |
|             |                                                        |
|             | -   airborne Mode S transponders, and                  |
|             |                                                        |
|             | -   TCAS.                                              |
|             |                                                        |
|             | Existing RF studies commissioned by the FAA, such as   |
|             | the Technical Link Assessment Team (TLAT) in 2001,     |
|             | have only assessed the impacts of the existing 1090    |
|             | user transmit traffic on ADS-B In receiver             |
|             | performance. In order to evaluate whether the 1090 MHz |
|             | band can provide adequate capacity for long term       |
|             | (2020) use, both interference scenarios should be      |
|             | evaluated.                                             |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #21 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **3. Part 91 Appendix H \-- Broadcast Message          |
| that is of  | Elements**                                             |
| concern.*** |                                                        |
|             | **(1^st^ paragraph under Section 3)**                  |
|             |                                                        |
|             | **Page 56954, Column 1**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *The message elements required support future NextGen  |
| the FAA's   | air-to-air applications such as reduced horizontal     |
| proposed    | separation and self separation.*                       |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We recommend deletion of this statement.               |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | ADS-B-out functionality and performance requirements   |
| the change  | in the resulting rule should only be based on          |
| ju          | established safety, performance, and interoperability  |
| stified?*** | requirements. A practical approach would be to define  |
|             | requirements that will meet known standards for the    |
|             | limited applications in the FAA's ADS-B plan, and      |
|             | implement use of the applications in the field.        |
|             | Downstream requirements would then be recognized and   |
|             | developed as a result of in-service experience.        |
|             |                                                        |
|             | No data currently exist to confirm the statement that  |
|             | defined standards will support separation reductions   |
|             | or self-separation in airborne surveillance            |
|             | operations. Insufficient study has been performed to   |
|             | establish if the message elements and the performance  |
|             | of the associated data will be adequate to support     |
|             | some of the applications that are proposed in the      |
|             | Surveillance and Broadcast Services (SBS) Program      |
|             | Office plans, much less the separation and             |
|             | self-separation applications mentioned here. (This     |
|             | fact is acknowledged at the end of the same paragraph  |
|             | in the NPRM.)                                          |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #22 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **3. Part 91 Appendix H \-- Broadcast Message          |
| that is of  | Elements**                                             |
| concern.*** |                                                        |
|             | **Paragraph (g)**                                      |
|             |                                                        |
|             | **Page 56954, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *"(g) An indication if ATC services are requested.     |
| the FAA's   | (Requires flight crew entry.) This message element     |
| proposed    | would identify to air traffic controllers if services  |
| requirement | are requested and whether the aircraft is in fact      |
| or text?*** | receiving ATC services. "*                             |
+-------------+--------------------------------------------------------+
| ***What     | We recommend deleting this requirement.                |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | We suggest that it is not adequate to rely on pilot    |
| the change  | entry to provide such a service to the air traffic     |
| ju          | service provider. Reliability of such a function must  |
| stified?*** | be highly suspect, given the need for crew entry,      |
|             | especially in high stress circumstances in which the   |
|             | function might prove to be most useful. In addition,   |
|             | to provide such a function would require additional    |
|             | controls or complex logic.                             |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #23 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **3. Part 91 Appendix H \-- Broadcast Message Elements |
| that is of  | Paragraph (h)**                                        |
| concern.*** |                                                        |
|             | **Page 56954, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *"(h) An indication of the Mode 3/A transponder code   |
| the FAA's   | specified by ATC. (Requires flight crew entry.) ..."*  |
| proposed    |                                                        |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We recommend deleting this requirement.                |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | We do not consider that the requirement associated     |
| the change  | with this text (see Section IV. Paragraph B.1., 4^th^  |
| ju          | paragraph, in the preamble of the NPRM) is necessary   |
| stified?*** | and it should be deleted. This requirement represents  |
|             | additional cost to the operator of currently equipped  |
|             | aircraft. Sufficient data are available in the ADS-B   |
|             | report to provide at least as reliable a function.     |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #24 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **3. Part 91 Appendix H \-- Broadcast Message          |
| that is of  | Elements**                                             |
| concern.*** |                                                        |
|             | **Paragraph (n)**                                      |
|             |                                                        |
|             | **Page 56955, Column 1**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *(n) An indication whether a cockpit display of        |
| the FAA's   | traffic information (CDTI) is installed and operable.  |
| proposed    | ...*                                                   |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We recommend deleting this requirement.                |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | It is unlikely that a single bit will provide enough   |
| the change  | information to be useful to either air traffic         |
| ju          | services or to other aircraft crews in airborne        |
| stified?*** | surveillance applications. Airborne systems are likely |
|             | to have differing capabilities depending on the        |
|             | business models of the aircraft operators and on the   |
|             | number of applications accommodated by the air traffic |
|             | management environment. Initial implementation without |
|             | this message element (which is not required for the    |
|             | ground surveillance applications addressed by the      |
|             | NPRM) would allow in-service assessment of the         |
|             | operational need for the information and required      |
|             | content. The FAA has stated in the NPRM that they are  |
|             | not mandating ADS-B In. Mandating this indicator in    |
|             | the message set would require airframe and equipment   |
|             | manufacturers to implement a small fraction of the     |
|             | ADS-B In system in advance of the final requirements,  |
|             | without any obvious benefit to either the users or the |
|             | airspace.                                              |
|             |                                                        |
|             | We recommend deleting this message as a mandatory      |
|             | element until the utility of the message element or    |
|             | some higher-resolution alternative is understood.      |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #25 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **3. Part 91 Appendix H \-- Broadcast Message          |
| that is of  | Elements**                                             |
| concern.*** |                                                        |
|             | **Paragraph (n)**                                      |
|             |                                                        |
|             | **Page 56955, Column 1**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *" ... A CDTI is necessary for aircraft to have ADS-B  |
| the FAA's   | In capability. ..."*                                   |
| proposed    |                                                        |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We recommend either deleting or clarifying this        |
| about this  | requirement.                                           |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | The statement does not justify the requirement and is  |
| the change  | inconsistent with the definition of ADS-B-In in        |
| ju          | Section II (The ADS-B System), paragraph A. (General), |
| stified?*** | 5^th^ paragraph, in the rule preamble. .               |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #26 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **3. Part 91 Appendix H \-- Broadcast Message          |
| that is of  | Elements**                                             |
| concern.*** |                                                        |
|             | **Paragraph (o)**                                      |
|             |                                                        |
|             | **Page 56955, Column 1**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *"(o) An indication of the aircraft's geometric        |
| the FAA's   | altitude..."*                                          |
| proposed    |                                                        |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We suggest deleting this requirement.                  |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | The requirement to broadcast this element is           |
| the change  | surprising as we are aware of no commitment by any ATS |
| ju          | service provider, or capability in current NAS ATS     |
| stified?*** | automation systems, to perform the geometric           |
|             | validation processing implied by this requirement. In  |
|             | fact, there is no requirement or recommendation        |
|             | regarding use of this data element in either the       |
|             | Non-Radar Airspace (NRA) standards document, or the    |
|             | current draft RAD airspace standards document. This    |
|             | requirement seems to be a "nice to have" message       |
|             | element, rather than something functionally required   |
|             | for ADS-B separation services.                         |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #27 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **4. Navigation Position Sensor and the Accuracy and   |
| that is of  | Integrity of the ADS-B Message**                       |
| concern.*** |                                                        |
|             | **(5^th^ paragraph under Section 4.)**                 |
|             |                                                        |
|             | **Page 56955, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *ADS-B performance is intended to go beyond today's    |
| the FAA's   | standards for accuracy and provide a platform for      |
| proposed    | NextGen. In order to accomplish that goal, we propose  |
| requirement | a minimum accuracy value of NACp 9 (30 m 95%           |
| or text?*** | horizontal position accuracy) in all airspace areas    |
|             | that ADS-B would be required.*                         |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *ADS-B performance is intended to go beyond today's  |
| requirement | > standards for accuracy and provide a platform for    |
| do we want  | > NextGen. In order to accomplish that goal, we        |
| changed?*** | > propose a minimum accuracy value of NACp ~~9 (30~~   |
|             | > **[8 (92.6 m]{.underline}** 95% horizontal position  |
|             | > accuracy) in ~~all~~ **[specific]{.underline}**      |
|             | > airspace areas that ADS-B would be required.*        |
+-------------+--------------------------------------------------------+
| ***Why is   | The proposed NACp 9 requirement is unnecessary, and    |
| the change  | needs to be reduced to no more than NACp 8, on the     |
| ju          | basis that there are existing terminal area procedures |
| stified?*** | which may require this accuracy level. In addition,    |
|             | there is similarly little value in requiring NACp\>7   |
|             | in en-route airspace.                                  |
|             |                                                        |
|             | This requirement is neither necessary nor practical to |
|             | implement in any airspace other than for airport       |
|             | surface operations. Recent work of the RAD standards   |
|             | committee has shown a possible requirement for ADS-B   |
|             | NACp 8 levels for certain parallel approach operations |
|             | currently feasible with standard SSR airport radars.   |
|             | There is no requirement for any of the ADS-B Out       |
|             | operations in terminal or final approach airspace      |
|             | being developed by the RAD committee that require a    |
|             | NACp 9 or better. In view of transmit latency          |
|             | limitations and other end-to-end system limitations,   |
|             | the broadcast of NACp 9 is simply impractical in       |
|             | en-route and terminal airspace, and is unlikely to     |
|             | provide any practical value to justify the extra cost  |
|             | for avionics upgrades to achieve this level of         |
|             | performance.                                           |
|             |                                                        |
|             | In addition to the arguments above, it is              |
|             | inconceivable that separation standards will be        |
|             | reduced below that of the flight technical error in    |
|             | aircraft path following, no matter what instantaneous  |
|             | position accuracy can be achieved by ADS-B systems.    |
|             | Current RNAV and RNAV (RNP) systems can only maintain  |
|             | intended lateral flight path accuracy on the order of  |
|             | several tenths of one nm in terminal airspace, for     |
|             | example, and can be substantially larger in en-route   |
|             | airspace. It is not clear how an accuracy greater than |
|             | NACp 8 can be of any value when the predicted aircraft |
|             | path cannot be estimated better than several tenths of |
|             | one nm.                                                |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #28 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **4. Navigation Position Sensor and the Accuracy and   |
| that is of  | Integrity of the ADS-B Message**                       |
| concern.*** |                                                        |
|             | **(5^th^ paragraph under Section 4.)**                 |
|             |                                                        |
|             | **Page 56955, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *In today's radar surveillance environment, aircraft   |
| the FAA's   | position accuracy is required to be within 0.3 nm      |
| proposed    | enroute and 0.1 nm within terminal airspace.....*      |
| requirement |                                                        |
| or text?*** | *ADS--B performance is intended to go beyond today's   |
|             | standards for accuracy and provide a platform for      |
|             | NextGen. In order to accomplish that goal, we propose  |
|             | a minimum accuracy value of NACp 9 in all airspace     |
|             | areas that ADS--B would be required. This proposed     |
|             | accuracy requirement would provide horizontal position |
|             | information for ADS--B Out equipped aircraft to within |
|             | 30 meters (0.016NM) horizontally and vertical          |
|             | (geometric) position accuracy to within 45 meters.     |
|             | This proposed accuracy requirement could make it       |
|             | possible for future airspace separation to be reduced  |
|             | from today's current separation minima.*               |
+-------------+--------------------------------------------------------+
| ***What     | We request clarification of this text.                 |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | This discussion is not based on any defined concept of |
| the change  | operations or commitment to achieve reduced            |
| ju          | separation. Justification for the stated requirements  |
| stified?*** | is unclear. We recommend that the FAA provide a        |
|             | documented concept of operations that supports NextGen |
|             | with stated separation based on technical analysis.    |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #29 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **4. Navigation Position Sensor and the Accuracy and   |
| that is of  | Integrity of the ADS-B Message**                       |
| concern.*** |                                                        |
|             | **(5^th^ paragraph under Section 4.)**                 |
|             |                                                        |
|             | **Page 56956, Column 1**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *This proposed accuracy requirement would provide      |
| the FAA's   | horizontal position information for ADS--B Out         |
| proposed    | equipped aircraft to within 30 meters (0.016NM)        |
| requirement | horizontally and vertical (geometric) position         |
| or text?*** | accuracy to within 45 meters.*                         |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *The proposed accuracy requirement would provide     |
| requirement | > horizontal position information for ADS-B Out        |
| do we want  | > equipped aircraft to within* ~~*30 meters (0.016NM)  |
| changed?*** | > horizontally and vertical (geometric) position       |
|             | > accuracy to within 45 meters*~~ ***[92.6 meters      |
|             | > (0.05 nm) horizontally (NACp 8).]{.underline}***     |
+-------------+--------------------------------------------------------+
| ***Why is   | We recommend that the vertical (geometric) position    |
| the change  | accuracy requirement be deleted from the NPRM. The     |
| ju          | vertical (geometric) position accuracy requirement     |
| stified?*** | should also be deleted from the NACp requirements for  |
|             | the values of NACp = 9, 10, and 11.                    |
|             |                                                        |
|             | The NACp 9 accuracy requirement also needs to be       |
|             | changed to a NACp 8 requirement, consistent with our   |
|             | Comment #27, above.                                    |
|             |                                                        |
|             | The ADS-B applications (both ADS-B Out and ADS-B In)   |
|             | listed in this NPRM do not require vertical position   |
|             | data accuracy. The vertical data accuracy requirement  |
|             | does not appear to be justified by any operational     |
|             | requirement. The current combined NACp encoding        |
|             | penalizes the availability of precise horizontal       |
|             | positioning accuracy. If VEPU is required by future    |
|             | applications, it should be encoded in a separate field |
|             | so as not to penalize the availability of precise      |
|             | horizontal positioning accuracy for NACp values        |
|             | greater than 8. This precise horizontal-only           |
|             | capability could support near-term surface             |
|             | applications that would not require vertical data      |
|             | accuracy.                                              |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #30 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **4. Navigation Position Sensor and the Accuracy and   |
| that is of  | Integrity of the ADS-B Message**                       |
| concern.*** |                                                        |
|             | **(7^th^ paragraph under Section 4.)**                 |
|             |                                                        |
|             | **Page 56956, Column 1**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *This proposed NACp of 9 would also provide the        |
| the FAA's   | necessary accuracy to enable certain applications on   |
| proposed    | the surface at the nation's busiest airports. ...*     |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *For those aircraft capable of broadcasting NACp 8,  |
| requirement | > this accuracy level is sufficient to enable initial  |
| do we want  | > ADS-B In applications on the surface at the nation's |
| changed?*** | > busiest airports. For lesser equipped aircraft at    |
|             | > airports with ASDE or ASDE-X surface surveillance    |
|             | > systems, TIS-B would provide a transitional means of |
|             | > surveillance for ADS-B In surface applications.*     |
+-------------+--------------------------------------------------------+
| ***Why is   | It is not clear why [all]{.underline} ADS-B Out        |
| the change  | aircraft are required to support a low percentage of   |
| ju          | ADS-B In aircraft that are performing airport surface  |
| stified?*** | surveillance (ASSA) and final approach awareness       |
|             | (FAROA) operations at the nation's busiest airports.   |
|             | We can assume that ASDE or ASDE-X surveillance sensors |
|             | are available to support tower and airport surface     |
|             | operations at these airports, since multilateration    |
|             | and primary radar are the primary means of surface     |
|             | surveillance in the 2010 to 2025 time frame. We        |
|             | suggest developing and using TIS-B based on the        |
|             | existing ASDE or ASDE-X systems to support users       |
|             | desiring comprehensive surface surveillance for ADS-B  |
|             | In surface applications. The use of TIS-B would enable |
|             | ADS-B In aircraft to see all nearby aircraft, not just |
|             | a small subset of aircraft that meets all the avionics |
|             | requirements to be useful for surveillance on the      |
|             | airport surface. We suggest that the FAA not put a     |
|             | general requirement for NACp 9 on all ADS-B Out        |
|             | systems intended for NAS use when the vast majority of |
|             | airplane users will receive no benefits from this      |
|             | requirement. Tower controllers at busy airports will   |
|             | be using other surveillance means, and the requirement |
|             | to support ADS-B In surface surveillance at busy       |
|             | airports can be met with TIS-B systems at a fraction   |
|             | of the cost of equipping all aircraft for NACp 9       |
|             | operations.                                            |
|             |                                                        |
|             | Moreover, why not accept aircraft with a NACp 8        |
|             | broadcast on the airport surface to support such       |
|             | operations, as specified in the ASA MASPS (DO-289)?    |
|             | From an economic standpoint, it makes more sense to    |
|             | accept GPS-based positions with a NACp 8 rather than   |
|             | suppressing such broadcasts, since the actual accuracy |
|             | of such systems is about 20 m (95%) when SA is off,    |
|             | which is adequate for surface situation awareness      |
|             | applications. Again, the requirement should be reduced |
|             | to NACp 8, at least when the satellite constellation   |
|             | is adequate and no faulted satellites are detected.    |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #31 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **4. Navigation Position Sensor and the Accuracy and   |
| that is of  | Integrity of the ADS-B Message**                       |
| concern.*** |                                                        |
|             | **(9^th^ paragraph under Section 4.)**                 |
|             |                                                        |
|             | **Page 56956, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *" ... For ADS-B Out, the FAA proposes a NIC value of  |
| the FAA's   | 7. This would bound the error to within 0.2 nm. ..."*  |
| proposed    |                                                        |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *For ADS-B Out, the FAA proposes a NIC value of      |
| requirement | > ~~7~~ **[6]{.underline}**. This would bound the      |
| do we want  | > error to within ~~0.2 nm~~ **[0.6                    |
| changed?*** | > nm]{.underline}**.*                                  |
+-------------+--------------------------------------------------------+
| ***Why is   | We recommend that the minimum NIC requirement be       |
| the change  | reduced from NIC 7 to NIC 6, since this performance    |
| ju          | level is adequate for all RAD en-route and terminal    |
| stified?*** | area separation standards.                             |
|             |                                                        |
|             | Recent studies performed for the RAD standards group   |
|             | have shown that the tightest requirements for ADS-B    |
|             | Out in terminal area airspace associated with closely  |
|             | spaced parallel runways such as independent parallel   |
|             | approaches with runway spacings \>= 4300 ft., can be   |
|             | met with NIC =6, NACp=8 requirements, provided radar   |
|             | monitoring and alerting of excessive ADS-B position    |
|             | errors are implemented during final approach. All      |
|             | other RAD standards in en-route and terminal airspace  |
|             | require lesser performance levels or, at most, NIC 6,  |
|             | NACp 8 requirements. The NIC 7 requirement is thus     |
|             | unnecessary to meet existing en-route and terminal     |
|             | area separation requirements. The argument that NIC 7  |
|             | could be needed for future operations in the 2020 time |
|             | frame does not seem sufficient basis for requiring     |
|             | expensive avionics upgrades that would likely require  |
|             | augmented GPS system upgrades on virtually every       |
|             | airplane in the existing fleet. This requirement needs |
|             | to be reduced to NIC 6, consistent with known ADS-B    |
|             | Out requirements for radar based separation standards. |
|             | Users that intend to provision for ADS-B In            |
|             | applications (or to support RNP=0.1 Navigation         |
|             | operations) may want to implement ADS-B with NIC=7     |
|             | performance capability. However, users that have no    |
|             | intention of upgrading to ADS-B In should not be       |
|             | required to meet performance levels that are in excess |
|             | of proposed NAS ADS-B Out separation applications.     |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #32 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **4. Navigation Position Sensor and the Accuracy and   |
| that is of  | Integrity of the ADS-B Message**                       |
| concern.*** |                                                        |
|             | **(10^th^ paragraph under Section 4.)**                |
|             |                                                        |
|             | **Page 56956, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *The SIL specifies the ADS-B Out avionics integrity    |
| the FAA's   | level [and]{.underline} the probability that the       |
| proposed    | position error may be larger than the reported NIC.    |
| requirement | ...*                                                   |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *The SIL specifies ~~the ADS-B Out avionics          |
| requirement | > integrity level [and]{.underline} the~~              |
| do we want  | > **[probability per flight hour]{.underline}** that   |
| changed?*** | > the position error may be larger than the reported   |
|             | > NIC.*                                                |
+-------------+--------------------------------------------------------+
| ***Why is   | The NPRM is in conflict with the text of Change 2 of   |
| the change  | DO-260A, Section 2.2.3.2.7.2.9, which defines the      |
| ju          | encoding for SIL only in terms of the probability of   |
| stified?*** | the integrity containment region described by the NIC  |
|             | parameter being exceeded for the selected geometric    |
|             | position source, including any external signals used   |
|             | by the source."                                        |
|             |                                                        |
|             | The NPRM also does not state how the probability of a  |
|             | containment violation is calculated. Is the            |
|             | probability averaged over a one year period? Is a      |
|             | one-second RAIM outage considered a containment        |
|             | violation? The NPRM needs to delete any reference to   |
|             | avionics integrity level in the definition of SIL.     |
|             |                                                        |
|             | Given the current state of confusion on the definition |
|             | of SIL in DO-260A (there are three distinct choices in |
|             | the Note that accompanies the encoding table), there   |
|             | will likely be inconsistent encoding of SIL in the NAS |
|             | based on interpretation of the NPRM requirements.      |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #33 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **4. Navigation Position Sensor and the Accuracy and   |
| that is of  | Integrity of the ADS-B Message**                       |
| concern.*** |                                                        |
|             | **(11^th^ paragraph under Section 4.)**                |
|             |                                                        |
|             | **Page 56956, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *" ... Universal compliance with accuracy [and         |
| the FAA's   | integrity]{.underline} requirements would ensure that  |
| proposed    | ADS-B In applications could provide accurate data even |
| requirement | in a closely spaced environment such as an airport     |
| or text?*** | surface. ..."*                                         |
+-------------+--------------------------------------------------------+
| ***What     | We recommend deleting this statement.                  |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | The current industry requirements in the Airborne      |
| the change  | Surveillance and Separation Assurance Processing       |
| ju          | (ASSAP) / Cockpit Display of Traffic Information       |
| stified?*** | (CDTI) minimum operating performance standards for     |
|             | Airport Surface Situation Awareness (ASSA) / Final     |
|             | Approach Runway Occupancy Awareness (FAROA ) do not    |
|             | require a NIC or SIL value for target traffic when on  |
|             | the surface. In light of this, it would be appropriate |
|             | to delete any requirement for NIC or SIL to be         |
|             | transmitted by surface traffic or vehicles.            |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #34 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **4. Navigation Position Sensor and the Accuracy and   |
| that is of  | Integrity of the ADS-B Message**                       |
| concern.*** |                                                        |
|             | **(12^th^ paragraph under Section 4.)**                |
|             |                                                        |
|             | **Page 56956, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *Presently, GPS augmented by the Wide Area             |
| the FAA's   | Augmentation System (WAAS) is the only navigation      |
| proposed    | position service that provides the level of accuracy   |
| requirement | and integrity to enable ADS-B Out to be used for       |
| or text?*** | NAS-based surveillance operations with sufficient      |
|             | availability.*                                         |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *GPS augmented by the Wide Area Augmentation System  |
| requirement | > (WAAS) is one means to provide a navigation          |
| do we want  | > positioning service with the level of accuracy and   |
| changed?*** | > integrity to enable ADS-B Out performance sufficient |
|             | > for current and near-term future NAS-based           |
|             | > surveillance operations with adequate availability.  |
|             | > Other systems such as SA-off or SA aware GPS         |
|             | > receivers as specified in DO-229C may also be able   |
|             | > to achieve an equivalent level of performance for    |
|             | > normal GPS satellite constellations.*                |
+-------------+--------------------------------------------------------+
| ***Why is   | The arguments above cite reasons that the containment  |
| the change  | integrity and accuracy performance standards should be |
| ju          | reduced to NIC=6, NACp=8 levels to support current     |
| stified?*** | en-route and terminal area separation standards.       |
|             | Current legacy GPS receivers certified to TSO-C129A    |
|             | standards are expected to meet NIC 6, NACp 8           |
|             | performance levels with sufficient availability for    |
|             | NAS ADS-B surveillance use, assuming normal GPS        |
|             | satellite constellation operations. Consequently, the  |
|             | requirements need to be reduced to minimum levels to   |
|             | support such operations, relieving users of the        |
|             | financial burden to replace existing GPS receivers     |
|             | when implementing ADS-B avionics for future NAS ADS-B  |
|             | surveillance operations. It is unlikely that ADS-B In  |
|             | will be economically feasible for older existing       |
|             | aircraft, or that users will upgrade beyond mandated   |
|             | performance limits for such aircraft. For such users,  |
|             | the performance levels should be true minimums, not    |
|             | requiring unnecessary avionics upgrades such as        |
|             | WAAS-capable GPS receivers.                            |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #35 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **4. Navigation Position Sensor and the Accuracy and   |
| that is of  | Integrity of the ADS-B Message**                       |
| concern.*** |                                                        |
|             | **(13^th^ paragraph under Section 4.)**                |
|             |                                                        |
|             | **Page 56956, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *In order to meet the proposed performance             |
| the FAA's   | requirements using the GPS/WAAS system, aircraft would |
| proposed    | be required to have equipment installed onboard the    |
| requirement | aircraft that meets one of the following: (1)          |
| or text?*** | TSO--C145b, Airborne Navigation Sensors using the GPS  |
|             | augmented by WAAS; or (2) TSO--C146b Stand-Alone       |
|             | Airborne Navigation Equipment using the GPS augmented  |
|             | by WAAS.*                                              |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *In order to meet the proposed performance           |
| requirement | > requirements using the GPS/WAAS system, aircraft     |
| do we want  | > would be required to have equipment installed        |
| changed?*** | > onboard the aircraft that meets one of the           |
|             | > following: (1) TSO--C145b, Airborne Navigation       |
|             | > Sensors using the GPS augmented by WAAS; or (2)      |
|             | > TSO--C146b, Stand-Alone Airborne Navigation          |
|             | > Equipment using the GPS augmented by WAAS*; ***[or   |
|             | > (3) TSO-C129A, Airborne Navigation Sensors using     |
|             | > GPS.]{.underline}***                                 |
+-------------+--------------------------------------------------------+
| ***Why is   | Assuming that the minimum performance levels are       |
| the change  | changed to NIC 6 and NACp 8, as recommended in our     |
| ju          | comments above, the proposed text should be changed to |
| stified?*** | add a third category, i.e., "(3) TSO-C129A Airborne    |
|             | Navigation Sensors using GPS."                         |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #36 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **6. Latency of the ADS-B Out Broadcast Message        |
| that is of  | Elements**                                             |
| concern.*** |                                                        |
|             | **2^nd^ Paragraph under Section 6.**                   |
|             |                                                        |
|             | **Page 56957, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *Under this proposal, the navigation sensor would      |
| the FAA's   | process information received by the aircraft's         |
| proposed    | antenna(s) and forward this information to the ADS-B   |
| requirement | broadcast link avionics in less than 0.5 seconds. That |
| or text?*** | processed information would then be transmitted in the |
|             | ADS-B message from the ADS-B Out broadcast link        |
|             | avionics in less than 1.0 second from the time it was  |
|             | received from the navigation sensor.*                  |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *Under this proposal, the total airplane system      |
| requirement | > would process GNSS information received by the       |
| do we want  | > aircraft's antenna(s) and transmit the ADS-B message |
| changed?*** | > from the ADS-B Out broadcast link avionics in less   |
|             | > than 1.5 seconds with 95% probability and less than  |
|             | > 3.0 seconds with 99.9 percent probability.*          |
+-------------+--------------------------------------------------------+
| ***Why is   | In an effort to make the NPRM consistent with          |
| the change  | international standards and specifications, we         |
| ju          | recommend that the FAA change the required latency     |
| stified?*** | value to allow for a distribution of latency times,    |
|             | rather than a single maximum value.                    |
|             |                                                        |
|             | The 1.5 second latency specification (A1 -\> D) is not |
|             | consistent with current RTCA Airborne Surveillance     |
|             | Applications (ASA) Minimum Aviation System Performance |
|             | Standards (MASPS), which specify a maximum 1.0 second  |
|             | latency for NAV source processing and reporting, and a |
|             | maximum of 1.1 second latency from the time of         |
|             | position measurement to the time of applicability of   |
|             | the broadcast position report, i.e., a total of 2.1    |
|             | seconds transmit latency (A1 -\> D). Other standards,  |
|             | such as the EUROCAE ADS-B-NRA (Non-Radar Area) Safety, |
|             | Performance, and Interoperability Requirements (SPR)   |
|             | document imply a latency of 1.5 seconds on the         |
|             | position message with 95% probability but do not       |
|             | specify a limiting value from input antenna to         |
|             | downlink broadcast, nor allow time for separate        |
|             | broadcast of position messages and position quality    |
|             | messages to the receive side for integration into a    |
|             | single position update report.                         |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #37 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **B. Avionics**                                        |
| proposed    |                                                        |
| document    | **6. Latency of the ADS-B Out Broadcast Message        |
| that is of  | Elements**                                             |
| concern.*** |                                                        |
|             | **2^nd^ Paragraph under Section 6.**                   |
|             |                                                        |
|             | **Page 56957, Column 2**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *Under this proposal, the navigation sensor would      |
| the FAA's   | process information received by the aircraft's         |
| proposed    | antenna(s) and forward this information to the ADS-B   |
| requirement | broadcast link avionics in less than 0.5 seconds. That |
| or text?*** | processed information would then be transmitted in the |
|             | ADS-B message from the ADS-B Out broadcast link        |
|             | avionics in less than 1.0 second from the time it was  |
|             | received from the navigation sensor.*                  |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *Under this proposal, the total latency from the     |
| requirement | > time of applicability of the reported position       |
| do we want  | > output to the transmission of the ADS-B state vector |
| changed?*** | > message must be less than 1.5 seconds with 95%       |
|             | > probability.*                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | The notion of information received at the GPS antenna  |
| the change  | is ambiguous in the sense that the elements of the     |
| ju          | navigation message come in over a relatively large     |
| stified?*** | span of time. Even pseudo-range measurements are       |
|             | accomplished by integrating over a period of time. The |
|             | time that information is received at the antenna is    |
|             | not an appropriate point of reference. A GPS receiver  |
|             | outputs a position message at a specified measurement  |
|             | time of applicability. An ADS-B system may further     |
|             | extrapolate the position to a different time of        |
|             | applicability (in order to compensate for the effects  |
|             | of latency). To the extent that latency values need to |
|             | be specified at all, they should be specified relative |
|             | to the time of applicability for the reported data. In |
|             | addition, as stated in our previous Comment #36, the   |
|             | stated latency is not consistent with either the RTCA  |
|             | or EUROCAE standards that specify such latency at a    |
|             | probability level, not as a maximum limiting value.    |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #38 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **C. Operational Procedures**                          |
| proposed    |                                                        |
| document    | **3. Pilot Procedures**                                |
| that is of  |                                                        |
| concern.*** | **1^st^ paragraph under Section 3**                    |
|             |                                                        |
|             | **Page 56959, Column1**                                |
+-------------+--------------------------------------------------------+
| ***What is  | *In accordance with proper preflight actions, each     |
| the FAA's   | operator would have to verify ADS-B Out availability   |
| proposed    | for the flight planned route through the appropriate   |
| requirement | flight planning information sources. ...*              |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We recommend deleting this requirement.                |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | The NPRM does not contain an availability requirement  |
| the change  | for ADS-B Out functions, so the value of this activity |
| ju          | is not clear. It is also not clear what contribution   |
| stified?*** | or data the "flight planning information sources"      |
|             | would provide for this activity. We therefore          |
|             | recommend that this verification requirement be        |
|             | deleted. Without a specific requirement and process,   |
|             | the answer for ADS-B availability would not have a     |
|             | consistent definition and value for air traffic        |
|             | service providers.                                     |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #39 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **C. Operational Procedures**                          |
| proposed    |                                                        |
| document    | **3. Pilot Procedures**                                |
| that is of  |                                                        |
| concern.*** | **1^st^ paragraph under Section 3**                    |
|             |                                                        |
|             | **Page 56959, Column2**                                |
+-------------+--------------------------------------------------------+
| ***What is  | *... (3) turn off the ADS-B equipment if directed by   |
| the FAA's   | ATC; ...*                                              |
| proposed    |                                                        |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | We recommend deleting this requirement.                |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | For ground surveillance use, it would be far more      |
| the change  | cost-effective for the ground system to be able to     |
| ju          | selectively filter out erroneous or otherwise unwanted |
| stified?*** | surveillance data than to add additional functionality |
|             | to the flight deck (e.g., additional switch if TCAS    |
|             | and ATC SSR services are not to be simultaneously      |
|             | disabled). In addition, while ATC may not be able to   |
|             | use degraded data, those data may be suitable for      |
|             | situational awareness on the flight deck of other      |
|             | aircraft (i.e. on a CDTI).                             |
|             |                                                        |
|             | For security reasons, it is essential that the pilot   |
|             | be capable of controlling emissions from the airplane  |
|             | (for example, external terrorist tracking of aircraft  |
|             | movement through ADS-B monitoring). For the near-term, |
|             | the transponder on/off switch will suffice in          |
|             | providing the pilot the ability to control the ADS-B   |
|             | emissions, although this action should rarely be taken |
|             | since TCAS and ATC SSR interactions will also be       |
|             | terminated. In the long-term, it may become beneficial |
|             | to enable the pilot to control independent functions   |
|             | of the transponder and disable the ADS-B function      |
|             | alone.                                                 |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #40 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IV. The Proposal for ADS-B Out**                     |
| section of  |                                                        |
| the         | **C. Operational Procedures**                          |
| proposed    |                                                        |
| document    | **4. Backup Surveillance Strategy -**                  |
| that is of  |                                                        |
| concern.*** | **(5^th^ paragraph under Section 4.)**                 |
|             |                                                        |
|             | **Page 56959, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *During interference outages of GNSS (scheduled or     |
| the FAA's   | unscheduled), the FAA expects to revert to the         |
| proposed    | ground-based surveillance system and temporarily allow |
| requirement | operations without ADS-B Out in required airspace.     |
| or text?*** | Pilots would be notified of such action via the Notice |
|             | to Airmen (NOTAM) system. The FAA also expects to      |
|             | revert to the backup surveillance system during        |
|             | significant degradation in the GPS constellation. ...* |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *During interference outages of GNSS (scheduled or   |
| requirement | > unscheduled), the FAA expects to revert to the       |
| do we want  | > ground-based surveillance system and temporarily     |
| changed?*** | > allow operations without ADS-B Out in required       |
|             | > airspace. Pilots would be notified of such action    |
|             | > via the Notice to Airmen (NOTAM) system. The FAA     |
|             | > also expects to revert to the backup surveillance    |
|             | > system during significant degradation in the GPS     |
|             | > constellation. **[The effect of reversion to radar   |
|             | > based operations can be mitigated during short       |
|             | > duration GPS outages by use of multi-sensor data     |
|             | > fusion and by use of non-GPS ADS-B Out surveillance, |
|             | > i.e. FMS or INS based state vector data broadcasts.  |
|             | > These mitigation strategies may provide surveillance |
|             | > quality sufficient for continuity of operations for  |
|             | > equipped aircraft during short duration events such  |
|             | > as local RAIM degradations that typically last on    |
|             | > the order of a few minutes.]{.underline}***          |
+-------------+--------------------------------------------------------+
| ***Why is   | This section, as written in the NPRM, fails to note    |
| the change  | that, in the event of a GPS outage or interference     |
| ju          | event or reduction in satellite capability, the use of |
| stified?*** | surveillance integration technology such as            |
|             | multi-sensor tracking and fusion and use of non-GPS    |
|             | backup ADS-B services could mitigate such events. For  |
|             | example, ADS-B broadcast of available information      |
|             | (such as track ID, baro-altitude, FMS backup           |
|             | positioning, and aircraft ground vector based on INS   |
|             | or FMS data) could be used together with the backup    |
|             | radar systems to maintain track quality and continuity |
|             | of surveillance services in the event of local         |
|             | disruptions and outages of GPS positioning. Simply     |
|             | switching to the backup radar system is likely to be   |
|             | problematic for short outage periods, such as RAIM     |
|             | holes that transit through an airspace sector with     |
|             | average durations on the order of a few minutes,       |
|             | followed by restoration of GPS-based ADS-B             |
|             | surveillance.                                          |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #41 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **V. ADS-B In**                                        |
| section of  |                                                        |
| the         | **B. Applications and Services**                       |
| proposed    |                                                        |
| document    | **(3^rd^ paragraph under Section B.)**                 |
| that is of  |                                                        |
| concern.*** | **Page 56960, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *" ... This comprehensive air traffic situational      |
| the FAA's   | awareness would be provided by Traffic Information     |
| proposed    | Service -- Broadcast (TIS-B) until all aircraft are    |
| requirement | equipped with ADS-B Out... "*                          |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | > *This ~~comprehensive~~ air traffic situational      |
| requirement | > awareness would be provided by Traffic Information   |
| do we want  | > Service -- Broadcast (TIS-B) until all aircraft are  |
| changed?*** | > equipped with ADS-B Out...*                          |
+-------------+--------------------------------------------------------+
| ***Why is   | The FAA has defined a minimum level of service         |
| the change  | coverage for TIS-B in upper airspace only up to FL     |
| ju          | 240, as discussed in the Surveillance and Broadcast    |
| stified?*** | Services (SBS) Final Program Requirements (FPR)        |
|             | Specification, Version 2.0, dated Feb. 1, 2007,        |
|             | Section 3.2.3.3.8.                                     |
|             |                                                        |
|             | The FAA has not defined a specific minimum level of    |
|             | service coverage for TIS-B on the airport surface;     |
|             | there is only a note in FPR Section 3.2.3.3.5 that     |
|             | states *"The TIS-B service volume is a region of       |
|             | coincident coverage from ground based surveillance     |
|             | sensors."* Since many radars suppress ground clutter,  |
|             | this language will not ensure all surface targets are  |
|             | sensed at an airport. The FAA TIS-B / FIS-B Essential  |
|             | Services Specification, Version 1.1, dated April 4,    |
|             | 2007, does not modify either of these requirements. A  |
|             | minimum service coverage for TIS-B on the airport      |
|             | surface and at all enroute flight levels should be     |
|             | defined.                                               |
|             |                                                        |
|             | The FAA has identified Airport Surface Situational     |
|             | Awareness (ASSA) / Final Approach Runway Awareness     |
|             | (FAROA) as one of the initial ADS-B In applications    |
|             | that would be supported by the Segment 1 thru 4        |
|             | design. If a guaranteed level of coverage for TIS-B on |
|             | the airport surface is not assured, the ability of     |
|             | TIS-B to support ASSA / FAROA during the transition    |
|             | period and provide the expected benefits will be       |
|             | severely compromised.                                  |
|             |                                                        |
|             | Similarly, if a guaranteed level of coverage for TIS-B |
|             | at all enroute flight levels is not assured, the       |
|             | ability of TIS-B to support the transition             |
|             | applications and provide the expected benefits will be |
|             | severely compromised. Many ADS-B application           |
|             | operational scenarios are active above FL240.          |
|             |                                                        |
|             | In light of this, the current level of service         |
|             | coverage for TIS-B is not "comprehensive" and we       |
|             | suggest that this word be removed from the TIS-B       |
|             | Section.                                               |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #42 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **V. ADS-B In**                                        |
| section of  |                                                        |
| the         | **B. Applications and Services**                       |
| proposed    |                                                        |
| document    | **(4^th^ paragraph under Section B.)**                 |
| that is of  |                                                        |
| concern.*** | **Page 56960, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | Description of Traffic Information Service --          |
| the FAA's   | Broadcast (TIS-B). The FAA indicates that TIS-B will   |
| proposed    | support a SIL level of 2 and a non-zero NIC level in   |
| requirement | order to provide quantifiable benefits during the      |
| or text?*** | ADS-B transition period.                               |
+-------------+--------------------------------------------------------+
| ***What     | We recommend a target SIL of greater than or equal to  |
| about this  | 2, which is consistent with the ADS-B SIL.             |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | Currently the FAA plans to implement TIS-B for         |
| the change  | Segments 1 thru 4 with a Surveillance Integrity Level  |
| ju          | (SIL) = 0 and a Navigation Integrity Category (NIC) =  |
| stified?*** | 0 in accordance with the FAA TIS-B / FIS-B Essential   |
|             | Services Specification, Version 1.1, dated April 4,    |
|             | 2007, Section 3.2.2.1.3.3.                             |
|             |                                                        |
|             | This level of service from SIL would severely limit    |
|             | its usefulness for both ADS-B Out ground applications  |
|             | and ADS-B In airborne applications. As TIS-B will      |
|             | provide ADS-B format reports for all unequipped        |
|             | aircraft, both General Aviation and Air Transport      |
|             | classes, it will support a significant number of       |
|             | airplanes (perhaps a majority) throughout the          |
|             | transition period prior to the 2020 deadline per the   |
|             | FAA's own equipage predictions.                        |
|             |                                                        |
|             | The FAA's decision to not improve the TIS-B            |
|             | integration with existing surveillance assets (SSR's)  |
|             | in order to develop a non-zero SIL and NIC for this    |
|             | service will reduce the surveillance value of TIS-B    |
|             | and could limit the overall ability of ADS-B to be     |
|             | integrated into the NAS during the transition period.  |
|             | It is unclear whether the TIS-B service will support   |
|             | the initial ADS-B In applications and provide the      |
|             | expected benefit values given these limitations.       |
|             |                                                        |
|             | A target SIL of greater than or equal to 2 is          |
|             | therefore suggested, which is consistent with the      |
|             | ADS-B SIL.                                             |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #43 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IX. Rulemaking Notices and Analyses**                |
| section of  |                                                        |
| the         | **"Total Benefits and Costs of this Rule "**           |
| proposed    |                                                        |
| document    | **Page 56964, Column 3**                               |
| that is of  |                                                        |
| concern.*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What is  | *The proposed rule requires aircraft to equip only     |
| the FAA's   | with ADS-B Out when flying in certain airspace.        |
| proposed    | Operators may choose to equip more fully with ADS-B In |
| requirement | and Out, and so we also address these costs and        |
| or text?*** | benefits... The additional cost of the ADS-B In ground |
|             | equipment is estimated at \$533 million (\$283 million |
|             | at 7% present value). We did not estimate the cost for |
|             | aircraft operators to equip with ADS-B In because we   |
|             | concluded the requirements for ADS-B In are            |
|             | insufficient in detail and do not yet support the      |
|             | development of a cost estimate.*                       |
+-------------+--------------------------------------------------------+
| ***What     | We request a more comprehensive cost vs benefits       |
| about this  | analysis for this important rule.                      |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | In order to carry out a thorough costs vs. benefits    |
| the change  | analysis of this proposed rule, the full costs and     |
| ju          | benefits of ADS-B Out [and]{.underline} In need to be  |
| stified?*** | determined. The FAA needs to determine the ADS-B In    |
|             | applications and requirements so that the avionics     |
|             | costs for ADS-B In can be determined. If a cost        |
|             | estimate for ADS-B In avionics cannot be determined at |
|             | this time, then both the benefits and the costs of     |
|             | ADS-B In should not be used in this NPRM's economic    |
|             | analysis.                                              |
|             |                                                        |
|             | We recommend a phased approach for the requirements,   |
|             | such that only the costs and the benefits of ADS-B Out |
|             | are considered for this Phase I of the deployment,     |
|             | since requirements for ADS-B In are insufficient in    |
|             | detail and do not yet support the development of a     |
|             | costs vs. benefits estimation. The benefits and costs  |
|             | of ADS-B In should be considered for a "Phase 2," to   |
|             | be accomplished after an accelerated industry effort   |
|             | is conducted to develop the standards and performance  |
|             | requirements for ADS-B In applications.                |
|             |                                                        |
|             | Additionally, the FAA should include user costs for    |
|             | both ADS-B Out and In when evaluating full costs and   |
|             | benefits for ADS-B.                                    |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #44 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IX. Rulemaking Notices and Analyses**                |
| section of  |                                                        |
| the         | **"Total Benefits and Costs of this Rule "**           |
| proposed    |                                                        |
| document    | **Page 56964, Column 3**                               |
| that is of  |                                                        |
| concern.*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What is  | *The estimated cost of this proposed rule ranges from  |
| the FAA's   | a low of \$2.3 billion to a high of \$8.5 billion.     |
| proposed    | These costs include costs to the government and the    |
| requirement | aviation industry. ... The aviation industry would     |
| or text?*** | begin incurring costs for avionics equipage in 2012    |
|             | and would incur total costs ranging from \$1.27        |
|             | billion (\$670 million at 7% present value) 32 to      |
|             | \$7.46 billion (\$3.6 billion at 7% present value) 33  |
|             | with an estimated midpoint of \$4.32 billion (\$2.12   |
|             | billion at 7% present value) 34 from 2012 to 2035.*    |
+-------------+--------------------------------------------------------+
| ***What     | The economics of the proposed rule should be such that |
| about this  | users are motivated to equip based on the benefits     |
| proposed    | that would entail.                                     |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | If the cost to government and users is low (\$2.3      |
| the change  | billion) and if user costs are \$1.27 billion, then    |
| ju          | users would incur 55% of the costs. However, if the    |
| stified?*** | costs to government and users is high (\$8.5 billion)  |
|             | and if user costs are \$7.46 billion, then users are   |
|             | incurring 88% of the costs. In either case, users will |
|             | incur more than 50% of the costs.                      |
|             |                                                        |
|             | While this cost allocation appears to be unbalanced    |
|             | toward the user, we recommend that the FAA develop and |
|             | promote a system that motivates the users to equip,    |
|             | based on clearly understood and published benefits     |
|             | analyses. If the benefits outweigh the costs for       |
|             | users, they will be motivated to pay these costs       |
|             | regardless of the percentage of the total cost for     |
|             | government and industry. The key is for the FAA to     |
|             | promote a system and applications that motivate users  |
|             | to equip.                                              |
|             |                                                        |
|             | It appears there should be a more balanced allocation  |
|             | of expenditures between government and users.          |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #45 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IX. Rulemaking Notices and Analyses**                |
| section of  |                                                        |
| the         | **"Total Benefits and Costs of this Rule "**           |
| proposed    |                                                        |
| document    | **Page 56964, Column 3**                               |
| that is of  |                                                        |
| concern.*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What is  | *The estimated cost of this proposed rule ranges from  |
| the FAA's   | a low of \$2.3 billion (\$1.6 billion at 7% present    |
| proposed    | value) to a high of \$8.5 billion dollars (\$4.5       |
| requirement | billion at 7% present value). These costs include      |
| or text?*** | costs to the government, as well as to the aviation    |
|             | industry and other users of the airspace, to deploy    |
|             | ADS--B and are incremental to maintaining surveillance |
|             | via current technology (radar). ......... The          |
|             | estimated quantified potential benefits of the         |
|             | proposed rule are about \$10 billion (\$2.7 billion at |
|             | 7% present value) 35 and primarily result from fuel,   |
|             | operating cost and time savings from more efficient    |
|             | flights.*                                              |
+-------------+--------------------------------------------------------+
| ***What     | The costs of avionics used in the FAA's analyses are   |
| about this  | too low.                                               |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | Based on Boeing estimates, the cost of avionics for    |
| the change  | ADS-B Out for transport category aircraft are          |
| ju          | realistically 3 to 4 times the values estimated by the |
| stified?*** | FAA. If the costs for ADS-B Out are found to be higher |
|             | than the high projection of \$8.5 billion, and if the  |
|             | benefits of ADS-B Out \[according to Table 4.2 in the  |
|             | FAA/Air Traffic Organization report "Surveillance and  |
|             | Broadcast Services Benefits Basis of Estimate" (SBS    |
|             | Benefits BOE), dated August 2007\] are indeed \$9.2    |
|             | billion (or even \$10 billion as stated in the NPRM),  |
|             | then the benefits will not outweigh the costs of ADS-B |
|             | Out.                                                   |
|             |                                                        |
|             | Users will not equip if the costs outweigh the         |
|             | benefits by 3 or 4 times.                              |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #46 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IX. Rulemaking Notices and Analyses**                |
| section of  |                                                        |
| the         | **"Total Benefits and Costs of this Rule "**           |
| proposed    |                                                        |
| document    | **Page 56965, Column 1**                               |
| that is of  |                                                        |
| concern.*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What is  | *The estimated quantified potential benefits of the    |
| the FAA's   | proposed rule are about **\$10 billion** (\$2.7        |
| proposed    | billion at 7% present value) and primarily result from |
| requirement | fuel, operating cost and time savings from more        |
| or text?*** | efficient flights. The proposed rule would make it     |
|             | more likely that aircraft operators would equip with   |
|             | ADS-B In equipment, which could result in estimated    |
|             | additional benefits of **\$3.9 billion** (\$1.0        |
|             | billion at 7% present value).*                         |
+-------------+--------------------------------------------------------+
| ***What     | We request that the FAA re-review the benefit data     |
| about this  | provided in the NPRM and reconcile the figures with    |
| proposed    | other estimates that have been provided to the public  |
| requirement | on this same subject.                                  |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | The FAA's economic analysis in the NPRM lists total    |
| the change  | potential benefits of ADS-B Out and In at \$13.9       |
| ju          | billion; however, the FAA's SBS Benefits BOE report,   |
| stified?*** | dated August 2007, presents the potential benefits of  |
|             | the proposed rule at \$18.5 billion (\$5 billion at 7% |
|             | present value) (see Tables 4.1 and 4.2, and in         |
|             | Executive Summary table in the report). The cost       |
|             | numbers should be consistent. From the SBS Benefits    |
|             | BOE report, one cannot determine the numbers used to   |
|             | derive the estimates in the SBS program table.         |
|             |                                                        |
|             | It is essential that those affected by the             |
|             | requirements of the rule be provided with an accurate  |
|             | benefit evaluation and the detailed analysis used to   |
|             | quantify each of the benefits.                         |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #47 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IX. Rulemaking Notices and Analyses**                |
| section of  |                                                        |
| the         | **"Total Benefits and Costs of this Rule "**           |
| proposed    |                                                        |
| document    | **Page 56965, Column 1**                               |
| that is of  |                                                        |
| concern.*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What is  | *"The estimated quantified potential benefits of the   |
| the FAA's   | proposed rule are about **\$10 billion** (\$2.7        |
| proposed    | billion at 7% present value) and primarily result from |
| requirement | fuel, operating cost and time savings from more        |
| or text?*** | efficient flights. The proposed rule would make it     |
|             | more likely that aircraft operators would equip with   |
|             | ADS-B In equipment, which could result in estimated    |
|             | additional benefits of **\$3.9 billion** (\$1.0        |
|             | billion at 7% present value)."*                        |
+-------------+--------------------------------------------------------+
| ***What     | We request that the FAA provide additional information |
| about this  | concerning the benefits of the rule requirements for   |
| proposed    | various stakeholders.                                  |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | The FAA's SBS Benefits BOE report (Table 4.2) lists    |
| the change  | the benefits of ADS-B Out and In by location (CONUS,   |
| ju          | Alaska, and Gulf of Mexico) and application. In order  |
| stified?*** | for stakeholders to make sound business decisions,     |
|             | each should understand which stakeholder gets which    |
|             | benefit. The NPRM combines all benefits together. We   |
|             | request that the FAA present the information in Table  |
|             | 4.2, such that applications are divided into ADS-B Out |
|             | and In, by region, and stakeholder (FAA or user)       |
|             | benefit. This would provide a better picture for each  |
|             | user of the benefits.                                  |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #48 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IX. Rulemaking Notices and Analyses**                |
| section of  |                                                        |
| the         | **"Total Benefits and Costs of this Rule "**           |
| proposed    |                                                        |
| document    | **Page 56965, Column 1**                               |
| that is of  |                                                        |
| concern.*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What is  | *We concluded that ADS-B In and Out would be cost      |
| the FAA's   | beneficial at a present value of 7% if the costs for   |
| proposed    | the ADS-B Out avionics are low (\$670 million at 7%    |
| requirement | present value) and the avionics costs for ADS-B In do  |
| or text?*** | not exceed \$1.85 billion at 7% present value.*        |
|             |                                                        |
|             | *We also concluded that ADS-B In and Out would be cost |
|             | beneficial at a 3% present value if the costs for the  |
|             | ADS-B Out avionics are low (\$950 million at 3%        |
|             | present value) and the ADS-B In avionics do not exceed |
|             | \$5.3 billion at 3% present value or if the costs for  |
|             | the ADS-B Out avionics are high (\$5.35 billion at 3%  |
|             | present value) and the ADS-B In avionics costs do not  |
|             | exceed \$870 million."*                                |
+-------------+--------------------------------------------------------+
| ***What     | We request clarification of this text.                 |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | Specifically, we request that FAA evaluate the 2^nd^   |
| the change  | half of the first paragraph of the text -- what are    |
| ju          | the cost beneficial values of ADS-B Out and In         |
| stified?*** | avionics at a present value of 7% if the costs for the |
|             | ADS-B Out avionics are high?                           |
|             |                                                        |
|             | We suggest that FAA estimate the range of costs for    |
|             | ADS-B Out and In to determine total costs and          |
|             | benefits.                                              |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #49 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IX. Rulemaking Notices and Analyses**                |
| section of  |                                                        |
| the         | **"Total Benefits and Costs of this Rule "**           |
| proposed    |                                                        |
| document    | **Page 56965, Column 1**                               |
| that is of  |                                                        |
| concern.*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What is  | *"We also concluded that ADS-B In and Out would be     |
| the FAA's   | cost beneficial at a 3% present value if the costs for |
| proposed    | the ADS-B Out avionics are low (\$950 million at 3%    |
| requirement | present value) and the ADS-B In avionics do not exceed |
| or text?*** | \$5.3 billion at 3% present value or if the costs for  |
|             | the ADS-B Out avionics are high (\$5.35 billion at 3%  |
|             | present value) and the ADS-B In avionics costs do not  |
|             | exceed \$870 million."*                                |
+-------------+--------------------------------------------------------+
| ***What     | We request that the FAA reconsider or clarify this     |
| about this  | text.                                                  |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | Based on our avionics experience and the cost of CDTI  |
| the change  | that is required for ADS-B In, we cannot consider that |
| ju          | the cost of avionics for ADS-B In would be less than   |
| stified?*** | the cost of avionics for ADS-B Out, even with a more   |
|             | rapid equipage rate for ADS-B Out over ADS-B In. We    |
|             | recommend that the FAA provide clarification of its    |
|             | conclusions in this respect.                           |
|             |                                                        |
|             | Users will benefit from a valid estimate of the costs  |
|             | of avionics in order to evaluate the NPRM costs and    |
|             | benefits.                                              |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #50 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IX -- Rulemaking Notices and Analyses**              |
| section of  |                                                        |
| the         | **"Reduced Carbon Dioxide Emissions"**                 |
| proposed    |                                                        |
| document    | **Page 56965, Column 2**                               |
| that is of  |                                                        |
| concern.*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What is  | The FAA notes that the report titled, "ADS-B Benefits  |
| the FAA's   | Enabled from Improved En-route Conflict Probe          |
| proposed    | Performance," is included in the docket established    |
| requirement | for this rulemaking.                                   |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | No suggested new text.                                 |
| about this  |                                                        |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | General comment: The FAA includes the emissions        |
| the change  | reduction benefits from en-route conflict probe and    |
| ju          | ADS-B as detailed in the referenced report. The report |
| stified?*** | overall provides detailed analyses, with clear         |
|             | indications of costs and benefits. We suggest that the |
|             | FAA's presentation of benefits in the NPRM would be    |
|             | enhanced if the same level of detailed analysis were   |
|             | applied.                                               |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #51 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IX -- Rulemaking Notices and Analyses --**           |
| section of  |                                                        |
| the         | **Annual Burden Estimate --**                          |
| proposed    |                                                        |
| document    | **Table titled: "ADS--B EQUIPMENT AND INSTALLATION     |
| that is of  | HOURS & COST & RESPONDENTS"**                          |
| concern.*** |                                                        |
|             | **Page 5693, Column 3**                                |
+-------------+--------------------------------------------------------+
| ***What is  | *The FAA estimates that the cost of compliance to the  |
| the FAA's   | NPRM for turbojets is from a low value of \$3,862 up   |
| proposed    | to a maximum value of \$135,736.*                      |
| requirement |                                                        |
| or text?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***What     | Suggested new text:                                    |
| about this  |                                                        |
| proposed    | *The FAA estimates that the cost of compliance with    |
| requirement | the NPRM for turbojets is from a low value of          |
| do we want  | ~~\$3,862~~ **[\$16,000]{.underline}** up to a maximum |
| changed?*** | value of* *~~\$135,736~~ **[\$510,000]{.underline}**.* |
+-------------+--------------------------------------------------------+
| ***Why is   | The values in the NPRM text present an unrealistically |
| the change  | low assessment of the cost of compliance with the      |
| ju          | NPRM's requirements and need to be updated.            |
| stified?*** |                                                        |
|             | The Boeing Company submitted preliminary cost data to  |
|             | the FAA in early 2007 in response to their requests    |
|             | received in the fourth quarter of 2006. The data was   |
|             | generated based on our understanding of the ADS-B Out  |
|             | requirements at that time. That cost data that we      |
|             | provided to the FAA ranged from \$16K to \$510K, which |
|             | were several times higher than the values that the FAA |
|             | actually published in the NPRM. It is not clear why    |
|             | the FAA's cost estimates in the NPRM are so            |
|             | inconsistent with the data that we provided. In        |
|             | addition, the NPRM requirements are much more          |
|             | stringent than the groundrules that the preliminary    |
|             | Boeing data were based on, and the cost of compliance  |
|             | will now be significantly increased over our previous  |
|             | estimate.                                              |
+-------------+--------------------------------------------------------+

+-------------+--------------------------------------------------------+
| ***COMMENT  |                                                        |
| #52 of      |                                                        |
| 52***       |                                                        |
+-------------+--------------------------------------------------------+
| ***Specific | **IX. Rulemaking Notices and Analyses**                |
| section of  |                                                        |
| the         | **Analysis of Alternatives**                           |
| proposed    |                                                        |
| document    | **Alternative Two**                                    |
| that is of  |                                                        |
| concern.*** | **Page 56969, Column 3**                               |
+-------------+--------------------------------------------------------+
| ***What is  | *Multilateration meets the need for accurate           |
| the FAA's   | surveillance and is less costly than ADS-B (but more   |
| proposed    | costly than radar) but cannot achieve the same level   |
| requirement | of benefits that ADS-B can. Multilateration would      |
| or text?*** | provide the same benefits as radar, but at a higher    |
|             | cost.*                                                 |
+-------------+--------------------------------------------------------+
| ***What     | We recommend that additional information be provided   |
| about this  | to explain how FAA reached this conclusion.            |
| proposed    |                                                        |
| requirement |                                                        |
| do we want  |                                                        |
| changed?*** |                                                        |
+-------------+--------------------------------------------------------+
| ***Why is   | In evaluating the statements in this section, it       |
| the change  | appears that the FAA chose the highest cost            |
| ju          | alternative that also provided the highest level of    |
| stified?*** | benefits. We request that FAA provide the user         |
|             | community with the complete background data analysis   |
|             | and process that was followed to reach the conclusion  |
|             | that multilateration cannot provide the same level of  |
|             | benefits as ADS-B.                                     |
|             |                                                        |
|             | We consider the one paragraph provided in the NPRM not |
|             | a sufficient or thorough evaluation of this system,    |
|             | which other air traffic providers in other regions of  |
|             | the world have adopted either as a standalone          |
|             | surveillance system or integrated with ADS-B.          |
+-------------+--------------------------------------------------------+

bcc (E-MAIL) for Letter to Docket FAA-2007-23905-

DeMarco, Jill

Richards, William R

O'Brien, Kathleen