A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to various transport category airplanes equipped with certain Mode C air traffic control (ATC) transponders manufactured by Rockwell Collins, Inc., was published in the Federal Register on January 5, 2001 (66 FR 1054). That action proposed to require testing each transponder; replacing certain parts in any transponder that fails the initial test and performing additional test(s); and making repairs, as necessary, so that the transponder passes the test.
Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. Two commenters state that the airplanes they operate are not affected by the proposed rule.
Change Paragraphs (a) and (b)
One commenter states that Rockwell Collins Service InformationLetter (SIL) 00-1, dated May 25, 2000, as specified in the preamble of the proposed rule, implies that the only approved "ramp-tester" to test their 621A-3 transponder is the ATC-601. However, the commenter indicates that all "approved" transponder ramp-testers must meet the criteria set forth in Federal Aviation Regulation 91.413, Part 43, Appendix F. The commenter asks if this proposed AD will change those criteria, and states that, if not, operators should be able to use any transponder ramp-tester that meets those requirements. The commenter adds that verification that a ramp-tester meets the FAR requirements can be confirmed by the manufacturer's technical data sheets and current calibration certificates.
The FAA does not agree that "any" transponder ramp-tester meets the requirements in paragraphs (a) and (b) of the final rule. As specified in the preamble of the proposed rule, "The document (SIL 00- 1), subtitled '621A-3 Transponder Overhaul Manual Test Equipment Modification Recommendation,' indicates that some operators using ATC ramp tester model number 601 (ATC-601) to verify performance of Mode C transponders with single Gillham encoded altitude input were experiencing a high reject rate of the 621A-3 transponders manufactured by Rockwell Collins, Inc. The service letter states that the ATC-601 ramp tester is capable of detecting out-of-tolerance errors in the framing pulse width, whereas the ATC-600 ramp tester previously used to test the transponders did not detect these pulse width errors." We concur that certain other ramp-testers may be used, and we have added a new Note 2 (and renumbered subsequent notes) to this final rule that specifies "approved" transponder ramp-testers.
Another commenter states that, to perform the pulse width test specified in paragraph (a) of the proposed rule, a bench check of the transponder is required, and adds that operators may be removing properly operating transponders to comply with the proposed rule. Thecommenter asks that an option be given to allow operators to perform a functional test with a Mode S ATC test set per the applicable airplane maintenance manual. The commenter adds that, if the transponder passes the functional test, it would not be necessary to remove the transponder from the airplane for a bench check.
We partially agree with the commenter. We do not agree that a bench check of the transponder is required to perform the pulse width test; the pulse width test can be done either with the transponder on the airplane or by removing the transponder and doing a bench check, depending on the capabilities of the test equipment used. We agree that the Mode S ATC is an approved test set, and that test set is specified in Note 2 of this final rule.
The same commenter asks that the final rule specify that any bench check done on a transponder before the effective date of the final rule, in accordance with the service information specified in the proposed rule, is acceptable for compliance with the pulse width tests specified in paragraphs (a) and (b) of the proposed rule. The commenter adds that if the FAA agrees to include the bench check, submission of the reporting requirements specified in paragraph (d) of the proposed rule should be amended to allow for a compliance time of more than 60 days after completion of the bench check. The commenter recommends a 30-day grace period after the effective date of the final rule for the reporting requirement.
We agree and have added a new Note 3 to this final rule to specify that bench checks used to perform the tests per Rockwell Collins Air Transport Systems Overhaul Manual with Illustrated Parts List, Temporary Revision No. 34-44-00-38, dated April 20, 2000, are acceptable for compliance with paragraph (a) of this final rule. Additionally, we have changed the reporting requirement specified in paragraph (d) of this final rule to specify that the report may be submitted within 60 days AFTER the effective date of the AD.
Another commenter notes that paragraph (b) of the proposed rule specifies that the transmitter tube and resistor be replaced (if any malfunction is detected), per Rockwell Collins Service Bulletin 621A-3- 34-21, Revision 1, dated November 14, 1975. The commenter states that the referenced service bulletin specifies removal of the resistor (only) on units having serial numbers 7192 and below. The commenter interprets paragraph (b) of the proposed rule as requiring replacement of the transmitter tube and resistor regardless of the unit serial number. The commenter recommends paragraph (b) of the proposed rule be changed to specify that resistor removal is only required on units with serial numbers 7192 and below.
We concur with the commenter and have changed paragraph (b) of the final rule to add paragraphs (b)(1) and (b)(2) to require replacement of the transmitter tube and resistor for transponders having serial numbers up to and including 7192; and replacement of the transmitter tube (only) for transponders having serial numbers 7193 and subsequent.
Credit for Transponders Previously Modified
One commenter asks if the proposed rule will apply to transponders that have already been modified using the procedures specified in Rockwell Collins, Inc. SIL 00-1, which references Rockwell Collins Service Bulletin 621A-3-34-21, Revision 1, dated November 14, 1975, cited in the proposed rule as the appropriate source of service information doing the replacement.
We agree that if the replacement required by paragraph (b) of this final rule was done prior to the effective date of the AD using the service information cited in the final rule, it is acceptable for compliance. Therefore, we have added a new Note 4 to this final rule (and renumbered subsequent notes) that specifies previous modification of the transponder is acceptable for compliance with this AD.
Change Paragraph (c)
One commenter states that paragraph (c) of the proposed rule cites the air data computer or interconnect wiring as possibly being defective. The commenter notes that this is in error because the pulse width cannot be affected by the air data computer or its wiring. The commenter adds that the pulse width can be affected by antenna/wiring faults.
We agree with the commenter and have changed paragraph (c) of this final rule to remove the references to repair of the air data computer or wiring connections.
The same commenter notes that paragraph (c) of the proposed rule specifies that, if malfunction of the transponder is detected, the transponder must be repaired prior to further flight. The commenter asks that the final rule allow for continued operation of the airplane in accordance with the Minimum Equipment List (MEL), provided the defective transponder is not operated.
Note 5 of this final rule (which was Note 2 of the proposed rule) addresses the commenter's concern. That note specifies that the airplane may be operated in accordance with the provisions and limitations specified in the FAA-approved Master Minimum Equipment List (MMEL), provided that only one Mode C transponder on the airplane is inoperative.
Delete Paragraph (c)
One commenter states that paragraphs (a) and (b) of the proposed rule discuss actions for off-wing shop tests per the transponder overhaul manual (OM), but paragraph (c) implies that an on-wing test must be accomplished. The commenter asks that paragraph (c) of the proposed rule be deleted. The commenter notes that any transponder tested in accordance with the OM will not be returned to service unless it can pass the pulse width test. The commenter adds that both the aircraft wiring and interfacing equipment were previously tested per AD 99-23-22 R1, amendment 39-11473 (64 FR 70181, December 16, 1999), which addressed concerns specific to the Rockwell Collins 621A-3 transponders. The commenter states that no additional testing should be required.
We donot agree with the commenter. Paragraph (c) of this final rule requires repair of the transponder if a malfunction is detected; no on-wing test is required by that paragraph. No change to the final rule is necessary in this regard.
Change to Final Rule
We have changed the point of contact for information concerning this final rule to Elizabeth Zurcher, Aerospace Engineer, FAA, Seattle Aircraft Certification Office, Systems and Equipment Branch, ANM-130S.
Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
Cost Impact
There are approximately 800 airplanes with transponders with the affected part in the worldwide fleet. The FAA estimates that approximately 400 airplanes of U.S. registry will be affected by this AD, that it will take approximately 4 work hours per airplane to accomplish the required test, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $96,000, or $240 per airplane.
The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.
Regulatory Impact
The regulations adopted herein will not have a substantial direct effecton the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.
For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: