03-18082. Airworthiness Directives; Boeing Model 747-400, 747-400D, 747-400F, 757-200, 757-200PF, 757-200CB, 767-200, 767-300, and 767-300F Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing transport category airplane models, as listed above. This proposal would require a modification of the air data computer (ADC) system, which involves installing certain new circuit breakers, relays, and related components, and making various wiring changes in and between the flight deck and main equipment center. For certain airplanes, this proposal also would require accomplishment of various other actions prior to or concurrently with the modification of the ADC system. This action is necessary to ensure that the flightcrew is able to silence an erroneous overspeed or stall aural warning. A persistent erroneous warning could confuse and distract the flightcrew and lead to an increase in the flightcrew's workload. Such a situation could lead the flightcrew to act on hazardously misleading information, which could result in loss of control of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by September 2, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-40-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-40-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Elizabeth Zurcher, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2003-NM-40-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-40-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports indicating that an erroneous overspeed aural warning that cannot be silenced may occur on certain Boeing Model 747-400, 747-400D, 747-400F, 757-200, 757-200PF, 757-200CB, 767-200, 767-300, and 767-300F series airplanes. When the air data computer (ADC) detects an overspeed condition, the ADC sends a warning through the Engine Indicating and Crew Alerting System (EICAS) and aural warning systems. If the flightcrew finds that this warning is erroneous, following flightcrew procedures to eliminate the erroneous ADC source will remove the erroneous air data source from the flightcrew display and from use in computation of navigation and flight control solutions, but the erroneous aural warning will not be silenced. Inability to silence an erroneous warning could confuse and distract the flightcrew, and lead to an increase in the flightcrew's workload. An erroneous aural warning that cannot be silenced may also cause the flightcrew to act based on misleading information. This may have been a factor in previous airplane incidents in which flightcrew actions based on hazardously misleading information have resulted in loss of control of the airplane.

Explanation of Relevant Service Information

We have reviewed and approved the following Boeing Alert Service Bulletins:

• 747-34A2460, Revision 2, dated June 14, 2001 (for Model 747-400, -400D, and -400F series airplanes), which describes procedures for re-routing wires associated with ADC overspeed warnings to eliminate erroneous overspeed warnings. The procedures involve replacing the P1-1 and P3-1 module assemblies in the flight deck with improved assemblies, installing various wires in and between the flight deck and main equipment center of the airplane, and performing a test of the source select module and a system functional test. This service bulletin specifies that Boeing Service Bulletin 747-31-2179, 747-31-2180, or 747-31-2217 must be accomplished either previously or concurrently. Boeing Alert Service Bulletin 747-34A2460, Revision 2, refers to Boeing Component Service Bulletins 233U2200-31-01 and 233U2205-31-01, both dated April 20, 1995, as additional sources for instructions to change the ADC computer source select switch on the P1-1 and P3-1 panels, respectively.
• 757-34A0222, dated March 28, 2002 (for Model 757-200,-200PF, and -200CB series airplanes), which describes procedures for installing a circuit breaker and replacing an existing lightplate assembly with a new, improved lightplate assembly in the flight compartment; installing two relays and removing a certain relay in the main equipment center; making various wiring changes in the flight compartment and main equipment center; and performing tests of the flight data acquisition unit, flight data recorder system, and stall and overspeed warnings. These changes are intended to allow the flightcrew to silence an erroneous aural overspeed or stall warning by switching away from a failed ADC that is generating the warning. This service bulletin specifies that Boeing Service Bulletin 757-31-0059 must be accomplished either previously or concurrently.
• 767-34A0332, dated January 10, 2002 (for Model 767-200, -300, and -300F series airplanes), which describes procedures for installing two circuit breakers in the flight deck, installing two relays in the main equipment center, making various wiring changes in the flight deck and main equipment center, and doing a system functional test. These changes are intended to allow the flightcrew to silence an erroneous aural overspeed or stall warning by switching away from a failed ADC that is generating the warning. This service bulletin specifies that Boeing Service Bulletins 767-31-0091, 767-31-0098, 767-31-0099, 767-31-0100, or 767-31-0101, as applicable, must be accomplished either previously or concurrently.

Explanation of Other Related Service Information (747-400, -400D and “400F)

We have reviewed and approved Boeing Service Bulletins 747-31-2179, dated May 26, 1994 (for Boeing Model 747-400 and -400F series airplanes equipped with Pratt & Whitney PW4000 series engines), and 747-31-2180, dated March 17, 1994 (for Boeing Model 747-400 and -400F series airplanes equipped with Rolls-Royce engines). These service bulletins described procedures for replacing the three Electronic Flight Information System (EFIS)/EICAS interface units (EIU) with improved EIUs and installing new software in six integrated display units (IDU) and three EIUs.

We have also reviewed and approved Boeing Service Bulletin 747-31-2217, dated May 19, 1994 (for Boeing Model 747-400, -400D, and -400F series airplanes equipped with General Electric (GE) engines). That service bulletin describes procedures for installing new software in six IDUs and three EIUs.

Boeing Service Bulletin 747-31-2217 specifies that the changes in Boeing Service Bulletins 747-31-2178, dated July 1, 1993, and 747-45-2010, dated December 17, 1992, must be accomplished prior to the actions in Boeing Service Bulletin 747-31-2217. We have reviewed and approved those service bulletins. Boeing Service Bulletin 747-31-2178 describes procedures for replacing three EIUs with improved EIUs and installing new software in six IDUs and three EIUs. Boeing Service Bulletin 747-45-2010 describes procedures for installing new software in the central maintenance computer (CMC).

Boeing Service Bulletin 747-45-2010 specifies that, for airplanes equipped with GE engines, the actions in Boeing Service Bulletins 747-45-2005 and 747-31-2163 must be accomplished prior to or concurrently with those specified in Boeing Service Bulletin 747-45-2010. We have reviewed and approved those service bulletins. Boeing Service Bulletin 747-45-2005, dated February 8, 1990, describes procedures for a modification that involves replacing certain CMCs with improved CMCs, modifying related wiring, and modifying the data loader control panel. Boeing Service Bulletin 747-31-2163, dated February 14, 1991, describes procedures for installing new software in six IDUs and three EIUs.

Explanation of Other Related Service Information (757-200, -200CB, -200PF; 767)

We also have reviewed and approved the following Boeing service bulletins, which all describe procedures for performing an EICAS readout comparison to ensure that the applicable software is used, replacing the existing EICAS computers with new EICAS computers that can be upgraded with certain software, and making related wiring changes:

Boeing service bulletin (all including Appendices A, B, and C)-	Service bulletin revision level-	Service bulletin date-	Effectivity-
757-31-0059	Revision 3	March 29, 2001	Boeing Model 757-200, -200CB, and -200PF series airplanes.
767-31-0091	Revision 3	April 27, 2000	Model 767 series airplanes with certain GE CF6-80C2 Full Authority Digital Electronic Engine Control (FADEC) series engines.
767-31-0098	Revision 2	October 21, 1999	Model 767-200 and -300 series airplanes with certain GE Power Management Computer (PMC) engines.
767-31-0099	Revision 3	February 8, 2001	Model 767-300 series airplanes with certain Rolls Royce engines.
767-31-0100	Revision 2	July 29, 1999	Model 767 series airplanes with certain Pratt & Whitney PW4000 series engines.
767-31-0101	Original	July 6, 2000	Model 767-200 and -300 series airplanes with Pratt & Whitney JT9D series engines.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the applicable service bulletins described previously, except as discussed below.

Differences Between Service Bulletins and Proposed AD

Operators should note that Boeing Alert Service Bulletins 747-34A2460, Revision 2, 757-34A0222, and 767-34A0332 recommend accomplishing the modification as soon as manpower, materials, and facilities are available. We have determined that such a non-specific compliance time would not address the identified unsafe condition in a timely manner. In developing an appropriate compliance time for this AD, we considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, and the time necessary to perform the proposed actions. In light of these factors, we find a 24-month compliance time for completing the proposed actions to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Also, Boeing Service Bulletins 747-34A2460, Revision 2, and 757-34A0222 specify that operators may accomplish certain actions per a specific chapter of the Airplane Maintenance Manual (AMM) or an “operator's equivalent procedure.” However, this proposed AD would require operators to accomplish the actions per the chapter of the AMM specified in the service bulletin. An “operator's equivalent procedure” may be used only if approved as an alternative method of compliance per paragraph (e) of this AD.

Changes to 14 CFR Part 39/Effect on the Proposed AD

On July 10, 2002, we issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs our airworthiness directives system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance (AMOCs). Because we have now included this material in part 39, only the office authorized to approve AMOCs is identified in each individual AD.

Explanation of Cost Impact

We have reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate.

Cost Impact

There are approximately 1,872 airplanes of the affected designs in the worldwide fleet. The FAA estimates that 36 Model 747-400, -400D, and -400F series airplanes; 639 Model 757-200, -200CB, and -200PF series airplanes; and 244 Model 767-200, -300, and -300F series airplanes; of U.S. registry would be affected by this proposed AD. Estimates of the costs to accomplish the proposed actions are provided in the following table:

Service bulletin	Work hours per airplane	Hourly labor rate	Parts cost per airplane	Cost per airplane
747-34A2460	158	$65	$1,448-$1,735	$11,718-$12,005
747-31-2179	2	65	None	130
747-31-2180	2	65	None	130
747-31-2217	2	65	None	130
747-31-2178	5	65	None	325
747-45-2010	2	65	None	130
747-45-2005	2	65	None	130
747-31-2163	2	65	None	130
757-34A0222	107	65	12,571-12,953	19,526-19,908
757-31-0059	5	65	None	325
767-34A0332	55	65	9,988-11,167	13,563-14,742
767-31-0091	7	65	None	455
767-31-0098	5	65	None	325
767-31-0099	24	65	None	1,560
767-31-0100	8	65	None	520
767-31-0101	6	65	None	390

We estimate that the total cost to accomplish all actions that may be required for all airplanes that would be affected by this AD may be as much as $17,783,875.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed 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 proposed herein would 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

Boeing: Docket 2003-NM-40-AD.

Applicability: Airplanes as listed in Table 1 of this AD, certificated in any category. Table 1 of this AD follows:

Table 1.—Applicability

Airplane Model—	As Listed in Boeing Alert Service Bulletin—
747-400, 747-400D, 747-400F series airplanes	747-34A2460, Revision 2, dated June 14, 2001.
757-200, 757-200PF, 757-200CB series airplanes	757-34A0222, dated March 28, 2002.
767-200, 767-300, and 767-300F series airplanes	767-34A0332, dated January 10, 2002.

Compliance: Required as indicated, unless accomplished previously.

To ensure that the flightcrew is able to silence an erroneous overspeed or stall aural warning, accomplish the following:

Modification of Air Data Computer System

(a) Within 24 months after the effective date of this AD, modify the air data computer system, as specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD, as applicable.

(1) For Model 747-400, -400D, and -400F series airplanes: Re-route wires associated with air data computer (ADC) overspeed warnings, replace the P1-1 and P3-1 module assemblies in the flight deck with improved module assemblies, install various wires in and between the flight deck and main equipment center of the airplane, and perform a test of the source select module and a system functional test, according to Boeing Alert Service Bulletin 747-34A2460, Revision 2, dated June 14, 2001.

Note 1:

Boeing Service Bulletin 747-34A2460, Revision 2, refers to Boeing Component Service Bulletins 233U2200-31-01 and 233U2205-31-01, both dated April 20, 1995, as additional sources for instructions to change the ADC computer source select switch on the P1-1 and P3-1 panels, respectively.

(2) For Model 757-200, -200PF, and -200CB series airplanes: Install a circuit breaker and replace an existing lightplate assembly with a new, improved lightplate assembly in the flight compartment; install two relays and remove a certain relay in the main equipment center; make various wiring changes in the flight compartment and main equipment center; and perform tests of the flight data acquisition unit, flight data recorder system, and stall and overspeed warnings. Do these actions according to Boeing Alert Service Bulletin 757-34A0222, dated March 28, 2002.

(3) For Model 767-200, -300, and -300F series airplanes: Install two circuit breakers in the flight deck, install two relays in the main equipment center, make various wiring changes in the flight deck and main equipment center, and do a system functional test, according to Boeing Alert Service Bulletin 767-34A0332, dated January 10, 2002.

Actions Required To Be Accomplished Prior to or Concurrently With Paragraph (a)

(b) Prior to or concurrently with accomplishment of paragraph (a) of this AD, accomplish paragraph (b)(1) or (b)(2) of this AD, as applicable.

(1) For Boeing Model 747-400, -400D, and -400F series airplanes: Do the actions specified in Table 2 of this AD, as applicable:

Table 2.—Boeing Model 747-400, -400D, and -400F Series Airplanes—Prior/Concurrent Actions

For airplanes listed in—	Accomplish all actions associated with—	According to the accomplishment instructions of—
Boeing Service Bulletin 747-31-2179, dated May 26, 1994	Replacing the three Electronic Flight Information System (EFIS)/Engine Indicating and Crew Alerting System (EICAS) interface units (EIU) in the main equipment center with improved EIUs and installing new software in six integrated display units (IDU) and three EIUs	Boeing Service Bulletin 747-31-2179.
Boeing Service Bulletin 747-31-2180, dated March 17, 1994	Replacing the three EIUs in the main equipment center with improved EIUs and installing new software in six IDUs and three EIUs	Boeing Service Bulletin 747-31-2180.
Boeing Service Bulletin 747-31-2217 dated May 19, 1994	Installing new software in six IDUs and three EIUs	Boeing Service Bulletin 747-31-2217.
Boeing Service Bulletins 747-31-2217 and 747-31-2178; and dated July 1, 1993	Replacing three EIUs with improved EIUs and installing new software in six IDUs and three EIUs	Boeing Service Bulletin 747-31-2178.
Boeing Service Bulletins 747-31-2217 and 747-45-2010, dated December 17, 1992	Installing new software in the central maintenance computer (CMC)	Boeing Service Bulletin 747-45-2010.
Boeing Service Bulletins 747-31-2217 and 747-45-2005, dated February 8, 1990	Replacing certain CMCs with improved CMCs, modifying related wiring, and modifying the data loader control panel	Boeing Service Bulletin 747-45-2005.
Boeing Service Bulletins 747-31-2217 and 747-31-2163, dated February 14, 1991	Installing new software in six IDUs and three EIUs	Boeing Service Bulletin 747-31-2163.

Replacement of EICAS Computers

(2) For airplanes identified in any of the service bulletins listed in Table 3 of this AD: Prior to or concurrently with accomplishment of the actions required by paragraph (a) of this AD, accomplish all actions associated with replacing the existing EICAS computers with improved EICAS computers, according to the applicable service bulletin specified in Table 3 of this AD. The actions include performing an EICAS readout comparison to ensure that the applicable software is used; replacing the existing EICAS computers with new, improved EICAS computers that can be upgraded with certain software; and making related wiring changes. Table 3 of this AD follows:

Table 3.—Service Bulletins for Replacement of EICAS Computers

Boeing Service Bulletin (all including Appendices A, B, and C)—	Service bulletin revision level—	Service bulletin date—
757-31-0059	Revision 3	March 29, 2001.
767-31-0091	Revision 3	April 27, 2000.
767-31-0098	Revision 2	October 21, ­1999.
767-31-0099	Revision 3	February 8, 2001.
767-31-0100	Revision 2	July 29, 1999.
767-31-0101	Original	July 6, 2000.

Parts Installation

(c) As of the effective date of this AD, no person may install, on any airplane, a part having a part number listed in the “Existing Part Number” column of the table under paragraph 2.E. of Boeing Alert Service Bulletin 747-34A2460, Revision 2, dated June 14, 2000; 757-31-0059, Revision 3, dated March 29, 2001; 767-31-0091, Revision 3, dated April 27, 2000; 767-31-0098, Revision 2, dated October 21, 1999; 767-31-0099, Revision 3, dated February 8, 2001; 767-31-0100, Revision 2, dated July 29, 1999; or 767-31-0101, dated July 6, 2000; or under paragraph II.D. of Boeing Service Bulletins 747-31-2179, dated May 26, 1994; 747-31-2180, dated March 17, 1994; 747-31-2178, dated July 1, 1993; 747-45-2010, dated December 17, 1992; 747-45-2005, dated February 8, 1990; or 747-31-2163, dated February 14, 1991.

Operator's “Equivalent Procedure'

(d) Where Boeing Service Bulletins 747-34A2460, Revision 2, dated June 14, 2000; and 757-34A0222, dated March 28, 2002; specify that certain actions may be accomplished per an operator's “equivalent procedure': These actions must be accomplished per the chapter of the applicable Boeing 747 or 757 Airplane Maintenance Manual specified in the applicable service bulletin. An operator's “equivalent procedure” cannot be used unless the operator receives FAA approval for that procedure according to paragraph (e) of this AD.

Alternative Methods of Compliance

(e) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance for this AD.

Issued in Renton, Washington, on July 11, 2003.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.