October 31, 2007 Mr. Jim Ryan, AFS-220 Orville Wright Building (FOB10A) FAA National Headquarters 800 Independence Ave. SW Washington, DC 20591 RE: Proposed Advisory Circular 120-42B, Extended Operations (ETOPS) and Polar Operations Dear Mr. Ryan: The Extended Operations (ETOPS) final rule was published in the Federal Register on January 16, 2007 1. Two subsequent changes dated February 15, 2007 2 and May 10, 2007 3 have also been published. This final rule applies to air carrier (part 121), commuter, and on-demand (part 135) turbine powered multiengine airplanes used in extended-range operations. All cargo operations in airplanes with more than two engines were exempted from most of the rule. It established regulations governing the design, operation and maintenance of certain airplanes operated on flights that fly long distances from an adequate airport. The proposed Advisory Circular (AC) provides further guidance for these extended operations to those conducting operations under 14 CFR part 121. It also further clarifies the rule s requirements for Polar operations. On behalf of our members, the Air Transport Association (ATA) appreciates the opportunity to comment on the draft AC, which addresses an important aspect of aviation safety and security. ATA is the principal trade organization of the U.S. scheduled airline industry. Its member airlines 4 account for ninety-three percent of the passenger and cargo traffic carried annually by U.S. scheduled airlines. ATA members currently operate 4,339 large transport airplanes under the operating rules of 14 CFR part 121. The ATA and its member airlines have a vested interest in the safety and security of commercial aviation. With the support of manufacturers, suppliers, and the FAA, our members have achieved a truly remarkable record of safety, gaining the confidence of the traveling public and ensuring the safety of commercial aviation. Member airlines have operated their fleets in the ETOPS environment since 1985 under the guidance of the de-facto rule which this AC proposes to supersede (120-42A). The proposed AC would apply in various degrees to all of our members existing operations and future ETOPS programs. For these reasons, ATA has a unique interest in the product of this comment process. 1 See http://a257.g.akamaitech.net/7/257/2422/01jan20071800/edocket.access.gpo.gov/2007/pdf/07-39.pdf 2 See http://a257.g.akamaitech.net/7/257/2422/01jan20071800/edocket.access.gpo.gov/2007/pdf/07-704.pdf 3 See http://a257.g.akamaitech.net/7/257/2422/01jan20071800/edocket.access.gpo.gov/2007/pdf/e7-8810.pdf 4 ATA is the principal trade and service organization of the U.S. scheduled airline industry. ATA airline members are: ABX Air, Inc.; Alaska Airlines, Inc.; Aloha Airlines; American Airlines, Inc.; ASTAR Air Cargo, Inc.; Atlas Air, Inc.; Continental Airlines, Inc.; Delta Air Lines, Inc.; Evergreen International Airlines, Inc.; Federal Express Corporation; Hawaiian Airlines; JetBlue Airways Corp.; Midwest Airlines, Inc.; Northwest Airlines, Inc.; Southwest Airlines Co.; United Airlines, Inc.; UPS Airlines; and US Airways, Inc. ATA Airline Associate Members are: Air Canada, Air Jamaica Ltd. and Mexicana.
Executive Summary The FAA developed advisory circulars (AC 120-42, June 6, 1985; AC 120-42A, December 30, 1988) that provided guidance for the operation of part 121 two-engine airplanes beyond the regulatory limits 5. These Advisory Circulars introduced the term ETOPS for these extended operations and addressed airplane and engine design aspects, maintenance programs, and operations. Under this guidance, ETOPS operations for part 121 two-engine airplanes are permitted to fly up to 180 minutes from an airport sufficient to accommodate a landing, provided certain criteria are met. 6 We appreciate the FAA s effort to improve guidance applicable to operators and applicants of ETOPS operations. The regulations are complex, technical, and specific, and the scope of their applicability poses management challenges. We appreciate the FAA s extension of the comment period for the draft AC, and appreciated the allowance of the FAA to engage ATA members earlier this year in the formation of the initial draft which was submitted to the FAA by the industry in March of this year. After taking these comments into consideration the FAA should publish a revised proposal of the AC for a second iteration of public review and comment. Issue With The Tone Of The Draft Advisory Circular The draft Advisory Circular (AC) has a tone that appears to contradict the essence of an AC. AC s are used for guidance and should not be written with a commanding tone. As previously stated, AC 120-42 and -42A were the only material available on ETOPS operations, and for this reasoning, these guidance Advisory Circulars became de-facto rule and were accepted as more directive in nature. The directive nature of the AC is not the case now that the ETOPS rule has been published. Our members believe the proposed AC, while providing guidance to the rule, is too commanding. For instance, the word must is used numerous times throughout the AC and being recommended guidance they feel many of these musts can and should be changed to a more guidance type word such as should. As noted in five of the below comments and an additional 12 other areas at the end of this letter, the ATA recommends these sentences with the word must be changed to should. The FAA Should Not Publish New Guidance In The Proposed AC That Is Not In The Current Rule ATA members commented on two areas where the guidance material in the proposed AC is not published in the current rule. The first area is in Chapter 3, Section 301, paragraph d. sub-paragraph 7. While describing guidance for dual maintenance, the proposed AC states The certificate holder s program should include detailed servicing instructions, or make readily available servicing instructions, and provide related OJT, regardless of whether one individual or multiple individuals perform the tasks. Our members propose to remove the latter part of this statement and propose the sentence read The certificate holder s program should include detailed servicing instructions, or make readily available servicing instructions. The second such area is in Chapter 3, Section 302, paragraph c. The proposed guidance states In the line maintenance environment, ETOPS-qualified maintenance personnel are those who have successfully completed the certificate holder s ETOPS training program, and who have satisfactorily performed extended range tasks under the direct supervision of an FAA certificated maintenance person. The person giving the direct supervision must have had previous experience with maintaining the particular make and model airplane used by the certificate holder. Therefore, ATA members propose to revise this sentence 5 Section 121.161 allows an operator to fly farther from an airport in a two-engine airplane if authorized by the FAA. The FAA granted such authorizations for Caribbean operations in the 1970 s. Since the mid-1980 s, the FAA has provided formal ETOPS guidance for part 121 operators on how to receive two-engine ETOPS authorization. 6 72 Fed. Reg. at 1809
and delete the latter part of the sentence and propose it to read In the line maintenance environment, ETOPS-qualified maintenance personnel are those who have successfully completed the certificate holder s ETOPS qualification program. Additional Specific Comments 1. Chapter 2 Background on ETOPS a. Section 205 sub paragraph b. Existing: Limiting expanded ETOPS authority beyond 180 minutes (for two engine airplanes) has been extended and serves several purposes. Proposed: Limited expanded ETOPS authority beyond 180 minutes (for two engine airplanes) has been extended and serves several purposes. Justification: Grammatical clarity. 2. Chapter 3 Requirements for ETOPS Operations a. Section 301 sub paragraph c. (3) Existing: However, the certificate holder clearly must identify the ETOPS related tasks on their PDSC because non-etops qualified maintenance personnel may accomplish the non- ETOPS tasks. Proposed: However, the certificate holder must clearly identify the ETOPS related tasks on their PDSC if non-etops qualified maintenance personnel are to accomplish the non- ETOPS tasks. Justification: Some airlines may choose to have ER trained technicians accomplish all tasks on the PDSC regardless of whether the tasks are ETOPS related. b. Section 301 sub paragraph c. (3) Existing: An ETOPS-qualified maintenance individual must complete all ETOPS-related tasks and an ETOPS-qualified maintenance individual, with an airframe and powerplant rating; must certify the entire check. Proposed: An ETOPS-qualified maintenance individual must complete all ETOPS-related tasks and an ETOPS-qualified maintenance individual, with an airframe and powerplant rating, or equivalent NAA rating, must certify the entire check. Justification: There is prior FAA guidance in CFR Part 43 that certifies other qualified individuals to perform maintenance and repair with proper training and certification. 7 Additionally, the emphasis for ETOPS related tasks should require proper training and 7 14 CFR 43.17 states A person holding a valid Transport Canada Civil Aviation Maintenance Engineer license and appropriate ratings may, with respect to a U.S.-registered aircraft located in Canada, perform maintenance, preventive maintenance, and alterations in accordance with the requirements of paragraph (d) of this section and approve that affective aircraft for return to service in accordance with the requirements of paragraph (e) of this section ETOPS Qualified Person means a person, performing maintenance for the certificate holder, who has satisfactorily completed the certificate holder's ETOPS training program.
qualifications, not the license requirement as 121.378 already stipulates the certificate requirements. c. Section 301 sub paragraph c. (3) Existing: The term immediately has historically meant to mean no more than 2 to 4 hours before flight. Proposed: The term immediately has historically meant to mean no more than 2 to 4 hours before the scheduled departure time. Justification: This is justified due to the fact that after a PDSC has been performed, other factors, such as weather or ATC delays can interrupt the scheduled departure time however, the check need not performed again in such cases. d. Section 301 sub paragraph c. (3) Existing: For example, when an overweight landing inspection reveals a mechanical discrepancy that requires maintenance intervention, another PDSC is required. Proposed: For example, when an overweight landing inspection reveals an ETOPS Significant System discrepancy that requires maintenance intervention, another PDSC is required. Justification: To synchronize and make note of the importance of the ETOPS Significant System definition, number 9, from Appendix 1, Definitions. e. Section 301 sub paragraph d (5) Existing: The FAA recognizes that sometimes ETOPS dual maintenance actions cannot be avoided or precluded because of unforeseen circumstances that occur during ETOPS operations. In the line maintenance arena, one example would be when an ETOPS airplane has inbound discrepancies on both engines oil systems, or there is a generator replacement on one engine, and an oil system discrepancy on the other engine. Another example is if both of the SATCOM systems require maintenance at the same time during a turnaround flight. Additionally, staggering maintenance on ETOPS Significant Systems in the heavy maintenance arena is not always possible or feasible. However, to minimize human factor common cause risk, the certificate holder should attempt to minimize dual maintenance on ETOPS Significant Systems wherever/whenever possible. (6) In any event, when dual maintenance is performed on an ETOPS Significant System, the certificate holder must have written procedures in its ETOPS maintenance document that addresses this situation. At a minimum, the certificate holder must ensure: (a) Separate ETOPS-qualified maintenance persons perform the tasks, or (b) The maintenance action on each of the elements in the ETOPS Significant System is performed by the same technician under the direct supervision of a second ETOPS qualified individual, and (c) It verifies the effectiveness of the corrective actions to those ETOPS Significant Systems before the airplane enters the ETOPS area of operation. This verification action must be performed using ground verification methods, and in some instances, in-flight verification methods described in the next section of this AC. On an exception basis, the same ETOPS-
qualified technician, under the supervision of an ETOPS-qualified Centralized Maintenance Control person, may perform the dual maintenance and the ground verification methods only if in-flight verification action is performed. Proposed: The FAA recognizes that sometimes ETOPS dual maintenance actions cannot be avoided or precluded because of unforeseen circumstances that occur during ETOPS operations. In the line maintenance arena, one example would be when an ETOPS airplane has inbound discrepancies on both engines oil systems, or there is a generator replacement on one engine, and an oil system discrepancy on the other engine. Another example is if both of the SATCOM systems require maintenance at the same time during a turnaround flight. However, to minimize human factor common cause risk, the certificate holder should attempt to minimize dual maintenance on ETOPS Significant Systems wherever/whenever possible in the Line Maintenance arena. (6) In any event, when dual maintenance is performed on an ETOPS Significant System, the certificate holder must have written procedures in its ETOPS maintenance document that addresses this situation. At a minimum, the certificate holder must ensure: (a) Separate ETOPS-qualified maintenance persons perform the tasks, or (b) The maintenance action on each of the elements in the ETOPS Significant System is performed by the same technician under the direct supervision of a second ETOPS qualified individual, and (c) It verifies the effectiveness of the corrective actions to those ETOPS Significant Systems before the airplane enters the ETOPS area of operation. This verification action must be performed using ground verification methods, and in some instances, in-flight verification methods described in the next section of this AC. On an exception basis, the same ETOPS-qualified technician, under the supervision of an ETOPS-qualified Centralized Maintenance Control person, may perform the dual maintenance and the ground verification methods only if in-flight verification action is performed. NEW sub paragraph 301 d (7): Additionally, staggering maintenance on ETOPS Significant Systems in the heavy maintenance arena is not always possible or feasible. To minimize the risks that may occur as a result of dual maintenance actions in the heavy maintenance arena, unless the operator also complies with the requirements above in paragraph 6 in the heavy maintenance arena, the following requirements should be followed: (a) Mechanics working on ETOPS Significant Systems during heavy maintenance visits should receive ETOPS awareness training. The training should include a basic understanding of ETOPS principles, including dual maintenance and the need to minimize human factor common cause risks associated with dual maintenance. (b) Persons that release aircraft undergoing heavy maintenance on ETOPS aircraft should be ETOPS qualified. (c) Following maintenance, the aircraft must be operated on a test flight or verification flight. This flight would be used to verify there are no ETOPS Significant System discrepancies. Justification: Based on the scheduling and overall complexity of maintenance performed during a heavy maintenance visit, it is difficult to either stagger dual maintenance tasks or to be certain they were never accomplished by the same mechanic. It is far better to admit that
dual maintenance will be done in a heavy maintenance visit and therefore require a test flight or verification flight to verify that all ETOPS Significant Systems operate normally. f. Section 301 sub paragraph d. (6) (a) Existing: Separate ETOPS qualified maintenance persons perform the tasks. Proposed: Separate ETOPS trained maintenance persons perform the tasks. Justification: The proposal pertains to the use of ETOPS qualified personnel in the heavy or line maintenance arena where mechanics are not performing a PDSC. The change should be made to be consistent with other references throughout the AC that require ETOPS training but not necessarily an ETOPS qualification. g. Section 301 sub paragraph d. (6) (b) Existing: The maintenance action on each of the elements in the ETOPS significant system is performed by the same technician under the direct supervision of a second ETOPS qualified individual. Proposed: The maintenance action on each of the elements in the ETOPS Significant System is performed by the same technician under the direct supervision of a second ETOPS trained individual. Justification: The proposal pertains to the use of ETOPS qualified personnel in the heavy or line maintenance arena where mechanics are not performing a PDSC. The change should be made to be consistent with other references throughout the AC that require ETOPS training but not necessarily an ETOPS qualification. h. Section 301 sub paragraph f. (1) Existing: The certificate holder must identify all tasks that must be accomplished or certified as complete by ETOPS qualified personnel. Proposed: The certificate holder must identify all tasks that must be accomplished or certified as complete by ETOPS trained personnel. Justification: The proposal pertains to the use of ETOPS qualified personnel in the heavy or line maintenance arena where mechanics are not performing a PDSC. The change should be made to be consistent with other references throughout the AC that require ETOPS training but not necessarily an ETOPS qualification. i. Section 301 sub paragraph f. (2) Existing: In the event that maintenance is performed on an ETOPS airplane by personnel who are not ETOPS trained, then actions must be verified per the certificate holder s ETOPS verification program. Proposed: In the event that ETOPS Significant System maintenance is performed on an ETOPS airplane by personnel who are not ETOPS trained, then actions must be verified per the certificate holder s ETOPS verification program. Justification: To synchronize and make note of the importance of the ETOPS Significant System definition, number 9, from Appendix 1, Definitions.
j. Section 301 sub paragraph i. (1) Existing: The certificate holder should submit a monthly ETOPS reliability report to its CHDO. Proposed: The certificate holder should submit regular ETOPS reliability reports to its CHDO. Justification: The current language is overly prescriptive of what an operator may report. Some operators report bi-weekly while others may report quarterly. The Certificate Holder and CHDO should have the flexibility to determine the appropriate ETOPS reliability reporting intervals. k. Section 301 sub paragraph i. (4) Existing: The certificate holder must conduct an investigation into the cause of the occurrence of any event listed in 121.703 and 121.374 (h)(1) in conjunction with manufacturers and submit its findings to its CHDO. Proposed: The certificate holder must conduct an investigation into the cause of the occurrence of any event listed in 121.703 and 121.374 (h)(1) and submit its findings and any necessary corrective action taken to its CHDO. Justification: To match the requirement in 121.374 Continuous airworthiness maintenance program (CAMP) for two engine ETOPS. l. Section 301 sub paragraph n. (4) Existing: The certificate holder should provide its CHDO a matrix detailing the CMP standard for its proposed ETOPS fleet. The matrix should specifically include each CMP item number, revision level, item description, and reference documentation describing the incorporation method, date, and place. Proposed: The certificate holder should provide its CHDO a matrix detailing the CMP standard for its proposed ETOPS fleet. The matrix should specifically include each CMP item number, revision level, item description, and reference documentation describing the incorporation method and date. Justification: Place of compliance would be very difficult to identify if not new from factory Also, the benefit of having that information would be unrelated to accomplishing the goal of verifying aircraft conformity. m. Section 302 sub paragraph b. Existing: For example, a mechanic who is performing pre-departure service checks may be required to have a higher level of ETOPS training and certification than a mechanic performing routine tasks on non ETOPS significant systems during a heavy maintenance check. Proposed: For example, a mechanic who is performing pre-departure service checks may be required to have a higher level of ETOPS training and qualification than a mechanic performing routine tasks on non ETOPS significant systems during a heavy maintenance check.
Justification: Appendix 1 definitions ETOPS-Qualified Personnel A person performing maintenance for the certificate holder, who has satisfactorily completed the certificate holder s ETOPS training program. n. Section 302 sub paragraph b. Existing: A technician working ETOPS significant systems in an HMV (Heavy Maintenance Visit) environment must be appropriately trained for ETOPS but need not be ETOPS certificated. Proposed: A technician working ETOPS Significant Systems in an HMV (Heavy Maintenance Visit) environment should be appropriately trained for ETOPS but need not be ETOPS qualified. Justification: A subsequent revision to the final ETOPS rule 8 which specifically states In the NPRM, the wording was for a qualified mechanic to perform this task. In reviewing the section, the FAA has determined that the appropriate term is trained mechanic. There is no specific ETOPS certification that a person could present to prove certification or qualification, but a properly trained mechanic who is ETOPS qualified is a term understood by the ETOPS community. o. Section 302 sub paragraph c. Existing: In the line maintenance environment, ETOPS-qualified maintenance personnel are those who have successfully completed the certificate holders ETOPS training program, and who have satisfactorily performed extended range tasks under the direct supervision of an FAA-certificated maintenance person. Proposed: In the line maintenance environment, ETOPS-qualified maintenance personnel are those who have successfully completed the certificate holders ETOPS qualification program. Justification: Reference Appendix 1. Definition 10 - ETOPS Qualified personnel - A person performing maintenance for the certificate holder, who has satisfactorily completed the certificate holders ETOPS training program. The different levels of ETOPS training are acknowledged in section 302 b. The term ETOPS qualified identifies a specific level of training that is not consistent amongst operators. Using a more generic term such as ETOPS trained allows individual operators to identify their unique levels of ETOPS training requirements and limitations. For second half of sentence removal, see page 2 in the paragraph titled The FAA Should Not Publish New Guidance In The Proposed AC That Is Not In The Current Rule p. Section 304 sub paragraph b. Existing: The certificate holder must designate check airmen specifically for ETOPS. Proposed: The certificate holder should designate check airmen specifically for ETOPS. Justification: Certificate holder pilots flying ETOPS are qualified to fly ETOPS and would not be giving a check ride or line audit without being ETOPS qualified whether they are designated or not is inconsequential. 8 Fed Register, Vol 72, No. 90 page 26541
3. Appendix 1. Definitions 10. Existing: ETOPS-Qualified Personnel. A person performing maintenance for the certificate holder, who has satisfactorily completed the certificate holder s ETOPS training program. Proposed: ETOPS-Qualified Personnel. A person performing maintenance for the certificate holder, who has satisfactorily completed the certificate holder s ETOPS qualification program Justification: The different levels of ETOPS training are acknowledged in section 302 b. The term ETOPS qualified identifies a specific level of training that is not consistent amongst operators. Identifying a qualifier such as completed the highest level of the certificate holder s ETOPS training program should bring some consistency in allowing individual operators to identify their unique levels of ETOPS training requirements and limitations. 4. In reference to Appendix 2, 207 minute ETOPS Area of Applicability the FAA should consider an expansion to 207 minute ETOPS operations in the Central Pacific area to include operations between Hawaii and Asia. This issue has been discussed on several occasions in the past with the FAA and it has been the FAA s opinion that 240 minute ETOPS would satisfy the need for additional flexibility in the Central Pacific between Hawaii and Asia. The Boeing company has not set a date for certification of the 777-200ER to 240 minutes, or beyond. Latest opinion estimates mid to late 2008 before 240 minute certification occurs. Operators are threatened by the significant risk of losing one of two essential mid-pacific alternate airports, Wake Island. The closing of Wake Island is under consideration by the Department of Defense and coupled with any non-availability of Midway Island airport could result in severe operational problems for flights between Hawaii and Japan. Operators feel there is no solid FAA justification in limiting the area of operation for 207 minute ETOPS, and that on a flight by flight basis, approval for 207 minute ETOPS should be granted in the Central Pacific region. a. Appendix 2. ETOPS Approvals - Airplanes with Two Engines - 207 Min - Requirement 4. Existing: The certificate holder must make every effort to plan ETOPS within 180 minutes or less, if possible. Proposed: The certificate holder should make every effort to plan ETOPS within 180 minutes, if possible. Justification: There is no requirement at the 180 minute approval level to make every effort to operate less than 180 minutes. b. Appendix 2. ETOPS Approvals - Airplanes with Two Engines - 207 Min - Requirement 12. Existing: The certificate holder must track how many times 207-minute authority is used. Proposed: The certificate holder should track and notify the CHDO how many times 207- minute authority is used. Justification: Previous guidance exists on the requirement to submit to the CHDO all 207- minute ETOPS operations.
c. Appendix 2. ETOPS Approvals - Airplanes with Two Engines - 240 Min - Requirement 4. Existing: The certificate holder must make every effort to plan ETOPS within 180 minutes or less, if possible. Proposed: The certificate holder should make every effort to plan ETOPS within 180 minutes, if possible. Justification: There is no requirement at the 180 minute approval level to make every effort to operate less than 180 minutes. Finally, as mentioned above, ATA operators recommend the FAA consider the below sentences in the proposed AC where the word must is used in a command type tone. Our operators used a professional writing tool to scan the proposed AC while searching for indications of the word must in a subjective nature. During the search, the tool made the following 12 suggestions, in addition to those noted above, for changing the word must to should. 1. Page 53047 existing Fuel Planning must account for the possibility of decompression or failure of an engine with considerations for in-flight icing conditions. Propose changing the must to should. 2. Page 53047 existing - Because it is accepted that increased diversion times potentially increase the risk of the operation a certificate holder must make every effort to plan ETOPS with a maximum diversion distance of 180 minutes or less, if possible. Propose changing the must to should. 3. Page 53047 existing However, like twin-engine operators, the three- and four-engine operator is required to designate the nearest available ETOPS alternate along the planned route of flight and must remain within a 240 minute diversion time if possible. Propose changing the must to should. 4. Page 53049 existing All certificate holders must design the flight operations and, if applicable, the maintenance programs for ETOPS with an objective to preclude diversions and, if a diversion does occur, to protect that diversion. Propose changing the must to should. 5. Page 53049 existing Although the demands on the flight crewmember may increase, a manufacturer applying for ETOPS type design approval must consider crew workload, operational implications and the crew s and passengers physiological needs during continued operation failure effects for the longest diversion time for which it seeks approval. Propose changing the must to should. 6. Page 53051 existing Ground maintenance personnel must coordinate with flight operations personnel whenever an in-flight verification is required. Propose changing the must to should. 7. Page 53052 existing The certificate holder also must investigate any indication of a high IFSD rate; however, it must consider that in the case of the smaller fleet, the high IFSD rate may be because of the limited number of engine operating hours used as the denominator for the rate calculation. Propose changing the must to should. 8. Page 53053 existing These altitudes must be representative of the ETOPS routes flown. Propose changing the must to should. 9. Page 53057 existing (b) The pilot in command (PIC) must have access to the weather and status of services and facilities at all adequate airports with weather greater than approach minimums other than the designated ETOPS alternates along the planned route that could be used for diversion before accepting the flight release. Propose changing the must to should.
10. Page 53058 (last sentence) to page 53059 existing When an airplane with more than two engines bypasses a suitable alternate, the PIC must carefully weigh the risk associated with the next possible failure which could complicate or compound the current engine inoperative condition. Propose changing the must to should. 11. Page 53061 existing Due to the nature of these operations and the climatic issues involved during the majority of the year, certificate holders undertaking these operations must ascertain that facilities at an airport, or in the immediate area, are sufficiently robust to protect the passengers and crew from the elements, and to see to their welfare during the time required to transport them towards their destination under the passenger recovery plan discussed in paragraph (5) below. Propose changing the must to should. 12. Page 53062 existing Certificate holders operating ETOPS routes must use the most reliable voicebased communications technology available for communications between the flight crew and air traffic services, and the flight crew and the certificate holder per 121.99. Propose changing the must to should. The ATA appreciates the FAA s cooperation in extending the comment period to accommodate our operators input. The ATA urges a review of our operators input and consideration to revise the proposed AC in light of the above comments. Thank you for consideration of these comments. Sincerely, Director Engineering and Maintenance cc: Jim Ballough AFS 1 Bob Reich AFS-220 Mario Giordano AFS-303