04-9104. Airworthiness Directives; NARCO Avionics Inc. AT150 Transponders

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain serial numbers (SNs) of NARCO Avionics Inc. AT150 transponders. This AD requires modification to the transponder by adding a resistor and transistor to the circuit board. This AD results from reports of AT150 transponders not recognizing and responding properly to Mode S interrogations from Mode S ground stations and Traffic Alert and Collision Avoidance System (TCAS-II) airborne equipment. We are issuing this AD to prevent loss of aircraft airspace separation and the possibility of mid-air collision.

DATES:

This AD becomes effective June 1, 2004. The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of June 1, 2004.

ADDRESSES:

You can get the service information identified in this AD from NARCO Avionics Inc., 270 Commerce Drive, Fort Washington, PA 19034; telephone [phone]; fax [phone].

You may examine the AD docket, by appointment, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA. You may examine the service information, by appointment, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Balram Rambrich, Aerospace Engineer, New York Aircraft Certification Office, FAA, Engine and Propeller Directorate, 10 Fifth Street, 3rd floor, Valley Stream, NY 11581-1200; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

The FAA proposed to amend 14 CFR Part 39 with a proposed airworthiness directive (AD). The proposed AD applies to certain SNs of NARCO Avionics Inc. AT150 transponders. We published the proposed AD in the Federal Register on February 20, 2003 (68 FR 816). That action proposed to require:

• For transponders not modified in accordance with NARCO Avionics Inc. Service Bulletin (SB) AT150 No. 1, dated July 29, 1977, modification of “Chassis Level A” transponders, serial numbers 10000 through 12598 inclusive, by adding a resistor and transistor to the circuit board, changing transponder to “Chassis Level B”, and transponder testing after the modification; and
• For transponders modified in accordance with NARCO Avionics Inc. SB No. AT150 No. 1, dated July 29, 1977, changing transponder to “Chassis Level B”, and transponder testing.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.

Request To Correct the Discussion Wording

One commenter, the manufacturer, requests that we correct the discussion section in the proposal. As written, the discussion states that the manufacturer determined that “Chassis Level A” AT150 transponders have a design error, which causes the P4 pulse not to be presented, causing the transponders to shut down. The commenter states that the AT150 transponder met all the requirements of technical standard order (TSO)-C-74C at the time of design. The commenter also states that NARCO Avionics Inc. SB AT150 No. 1, dated July 29, 1977, was issued because original design AT150 transponders did not work properly with particular Tele Instruments Corporation (TIC) and bench test equipment. Also, the commenter states that the incorporation of NARCO Avionics Inc. SB No. AT150 No. 1, dated July 29, 1977, resolves the P4 problem, which came about years after the original design. The implementation of the P4 pulse was an FAA requirement.

We partially agree. We agree that this problem in its entirety is not a design error because we implemented the P4 pulse requirement after approval of TSO-C-74C and because the problem with NARCO AT150 transponders was discovered during the P4 pulse testing. However, the AT150 transponder did not work properly with the TIC ramp and bench test equipment. The final rule does not repeat the discussion information found in the proposal. No changes to the final rule are made based on this comment.

Request To Correct Service Information Fax Number

One commenter, the manufacturer, requests that we correct the service information fax number to read [phone].

We agree. We corrected the fax number in the final rule.

Request To Correct Part Numbers

Two commenters request that we correct the part numbers for the transistor and resistor, which are transposed in the proposal.

We agree. We corrected the part numbers in the final rule.

Aircraft Models List

Three commenters state that the applicability section should not include a list of any particular aircraft models because the unsafe condition identified in the proposal involves the design of the transponder, not the aircraft. The commenters suggest using a generic statement, such as “all general aviation aircraft” rather than listing any specific aircraft models.

We do not agree. The commenters all start from the incorrect premise that the listing of aircraft in the proposed AD affects the applicability of the AD. The listing is provided only as a guide to operators as to some of the types of aircraft on which these transponders may be found. The AD applies to the transponder regardless of the installation, even if installed in an aircraft not found in the list. The list is provided for informational purposes only. However, because the presence of the list is causing more confusion than benefits we deleted the list from the applicability paragraph.

AD Should Not Be Issued Through Engine & Propeller Directorate

One commenter states that the FAA should not issue this AD through the Engine & Propeller Directorate.

We do not agree. While each engineering Directorate within the Aircraft Certification Service has an area of concentration, all of the Directorates have the expertise to deal with avionics issues, such as transponders. For example, the Rotorcraft Directorate issued an AD against Terra Corporation transponders in 1994, and recently the Small Aircraft Directorate issued an AD in December 2003 against Garmin transponders. Because we handle unsafe conditions that result from appliances, such as transponders, geographic basis, the Engine & Propeller Directorate appropriately issued the proposal and the AD in this case.

Conclusion

We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on 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.

For the reasons discussed above, I certify that this AD:

(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.

We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 2002-NE-32-AD” in your request.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

2004-08-16 NARCO Avionics Inc. AT150 Transponders: Amendment 39-13586. Docket No. 2002-NE-32-AD.

Effective Date

(a) This AD becomes effective June 1, 2004.

Affected ADs

(b) None.

Applicability

(c) This AD applies to NARCO Avionics Inc. AT150 transponders with “Chassis Level A”, serial numbers (SNs) 10000 through 12598 inclusive.

Unsafe Condition

(d) This AD results from reports of AT150 transponders not recognizing and responding properly to Mode S interrogations from Mode S ground stations and Traffic Alert and Collision Avoidance System (TCAS-II) airborne equipment. The actions specified in this AD are intended to prevent loss of aircraft airspace separation and the possibility of mid-air collision.

Compliance

(e) Compliance with this AD is required as indicated, unless already done.

Transponders Not Modified in Accordance With Service Bulletin AT150 No. 1

(f) For AT150 transponders with a SN listed in this AD that are not modified in accordance with NARCO service bulletin (SB) No. AT150 No. 1, dated July 29, 1977, within six months after the effective date of this AD, do the following:

(1) Install resistor part number (P/N) 312180102 and transistor P/N 755610028; and

(2) Change transponder to “Chassis Level B”; and

(3) Test transponders in accordance with the Corrective Action, Testing the Modification, and Return to Service paragraphs of NARCO SB No. AT150 No. 6, dated January 31, 2003.

Transponders Modified in Accordance With Service Bulletin AT150 No. 1

(g) For AT150 transponders with a SN listed in this AD, that are modified in accordance with NARCO SB No. AT150 No. 1, dated July 29, 1977, do the following:

(1) Within six months after the effective date of this AD, change transponder to “Chassis Level B”; and

(2) Test transponders in accordance with the Testing the Modification paragraph of NARCO SB No. AT150 No. 6, dated January 31, 2003; and

(3) Perform a bench test to the transponder before returning it to service. Information on bench testing can be found in AT150 Manual P/N 03606-0600.

Alternative Methods of Compliance

(h) The Manager, New York Aircraft Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.

Material Incorporated by Reference

(i) You must use NARCO SB No. AT150 No. 6, dated January 31, 2003, to perform the testing required by this AD. The Director of the Federal Register approved the incorporation by reference of this service bulletin in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You can get a copy from NARCO Avionics Inc., 270 Commerce Drive, Fort Washington, PA 19034; telephone [phone]; fax [phone]. You can review copies at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Related Information

(j) None.

Issued in Burlington, Massachusetts, on April 16, 2004.

Robert Guyotte,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.