03-17312. Airworthiness Directives; Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model CL-600-2B19 (Regional Jet series 100 & 400) airplanes, that requires a one-time inspection of the aft edge of the left and right main windshields to determine whether a certain placard is installed, and corrective actions if necessary. This action is necessary to prevent stress-related cracking of the windshields, and subsequent excessive frequency of abnormal procedures specified in the airplane flight manual and/or an emergency descent be accomplished, which poses an increased risk to passengers and crew members. This action is intended to address the identified unsafe condition.

DATES:

Effective August 14, 2003.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of August 14, 2003.

ADDRESSES:

The service information referenced in this AD may be obtained from Bombardier, Inc., Canadiar, Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, Canada. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Serge Napoleon, Aerospace Engineer, Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York 11581; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

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 certain Bombardier Model CL-600-2B19 series airplanes was published in the Federal Register on May 20, 2002 (67 FR 35461). That action proposed to require a one-time inspection of the aft edge of the left and right main windshields to determine whether a certain placard is installed, and corrective actions if necessary.

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.

Support for Notice of Proposed Rulemaking (NPRM)

One commenter supports the NPRM.

Request To Withdraw NPRM

One commenter, the windshield manufacturer, requests that the NPRM be withdrawn. The commenter states that it has invested a significant amount of time and resources to resolve the root cause of cracking of the windshields in service. The commenter also states that it has worked closely with the airplane manufacturer, operators, and regulatory agencies worldwide to resolve the cracking of the windshields in an expeditious manner. The commenter strongly believes that the issuance of an NPRM is unwarranted in light of its efforts, and the fact that the NPRM only affects, at most, 18 windshields. The commenter believes that these 18 windshields will be modified or replaced no later than December 31, 2002.

The FAA, while applauding the windshield manufacturer's efforts to resolve the cracking of the ply of the windshields, does not agree that the NPRM should be withdrawn. In issuing an AD, our intent is not to penalize the original equipment manufacturer, but to act in the interest of safety, and to ensure that all applicable airplanes conform to the corrective actions. While it is understandable that a manufacturer would like to minimize any adverse implications regarding the safety of its products, we reiterate that the purpose of an AD is to correct an identified unsafe condition in an airplane, regardless of where it is or what it is caused by. In essence, the AD serves to protect the flying public from the consequences of the unsafe condition. The AD also serves to protect the manufacturer from the liability that would be faced should the unsafe condition not be corrected. Until an AD is issued, there is no legal basis for requiring U.S. operators to comply with those actions. The AD is the vehicle for ensuring, by law, that all affected operators perform the necessary actions that will address the identified unsafe condition. In light of this, we have determined that this AD is appropriate and warranted.

Two commenters note that the “Background Information” section in the preamble of the NPRM states, “Until a new design for the main windshield can be developed by the manufacturer and approved by the FAA, operators have requested procedures for modifying the existing windshields to address the identified unsafe condition and to improve service performance.” The commenters state that such wording implies that a new design for the windshield does not exist.

The commenters point out that redesigned windshields, Bombardier part numbers (P/N) 601R33033-13 and -14 (PPG P/N NP139321-9 and -10 for spares), are already available and have been in service for some time on recently manufactured airplanes. According to one of the commenters, those windshields incorporated certain changes that would minimize the potential for structural ply fracture, and that, since their introduction, over 525 have been installed on in-service airplanes. One of the commenters believes that the identified unsafe condition has been successfully addressed by the current production configuration (i.e., main windshield units having Bombardier P/N 601R33033-13 or -14) and with windows currently in service on which Bombardier Service Bulletin 601R-56-004, dated August 16, 2001 (which is referenced in the NPRM as the appropriate source of service information for the proposed actions), has been done.

From these comments, we infer that the commenters are requesting that the NPRM be withdrawn. We do not agree. As discussed previously, this AD is the vehicle for ensuring, by law, that all affected operators perform the necessary actions that will address the identified unsafe condition.

The commenters are correct that main windshield units having Bombardier P/N 601R33033-13 or -14 have been in service for some time. Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, has approved Bombardier Service Bulletin 601R-56-003, Revision B, dated July 20, 2001, which describes procedures for replacing the main windshield units having P/N 601R33033-9 and -10 with units having Bombardier P/N 601R33033-13 or -14. However, the service bulletin does not specify Bombardier P/N 601R33033-13 or -14 as replacement parts for windshields having P/Ns 601R33033-1, -2, -5, and -6. In addition, Canadian airworthiness directive CF-2001-35R1, dated September 27, 2001, which this AD parallels, does not mandate Service Bulletin 601R-56-003. We also find that it will be less costly for operators to do the actions required by this AD than the replacement specified in Service Bulletin 601R-56-003.

In light of these findings, we have determined that this AD is appropriate and warranted. However, under the provisions of paragraph (b) of the final rule, we may consider requests for approval of an alternative method of compliance if sufficient data are submitted to substantiate that such a design change would provide an acceptable level of safety.

Request To Delete Reference to Unsafe Condition

One commenter requests that all references to “unsafe condition” in the NPRM be deleted. The commenter states that the main windshield, pre-mod configuration, on Model CL-600-2B19 (Regional Jet series 100 & 400) airplanes does not exhibit an unsafe condition. The commenter also states that any unsafe condition would result from the flight deck crew being required to operate the airplane in a non-standard manner, not from the windshield itself. The commenter is concerned that the reference to an “unsafe condition” will create a negative impression about the Bombardier regional jets.

We do not agree. The individual ply of the windshields on the affected Model CL-600-2B19 (Regional Jet series 100 & 400) airplanes has cracked at an unacceptable rate. When such cracking has occurred, abnormal procedures specified in the airplane flight manual and/or an emergency descent of the airplane have been accomplished at an excessive frequency, which exposed the airplane and its occupants to unacceptable risks. Furthermore, of the significant number of single-ply fractures that have occurred, there was one reported case of the First Officer's windshield cracking (inner ply) during cruise flight and pieces of glass falling on the flightcrew. In addition, TCCA issued Canadian airworthiness directive CF-2001-35R1, dated September 27, 2001, in order to reduce the risk exposure that resulted from airplane emergency descent performed as a result of the cracking of the windshield ply. TCCA issued that airworthiness directive in order to ensure the continued airworthiness of these airplanes in Canada. As such, we have determined that, while cracking of the windshield may not result in loss of pressurization of the airplane, if the flightcrew follows necessary procedures, the need to predictably and routinely rely on those procedures, together with the risk of injury to the flightcrew, presents an unsafe condition.

Two commenters do not agree with the statement of unsafe condition specified in the NPRM (i.e., to prevent failure of the main windshields due to stress-related cracking, which could cause cabin depressurization and emergency descent, and adversely affect continued safe flight of the airplane). The commenters state that the results of fail-safe testing demonstrate the structural integrity of the windshield with all three plies fractured. The commenters conclude that, while a ply fracture may interrupt the normal flight scenario, this stress-cracking issue would not result in loss of cabin pressurization.

Based on the reasons described previously, one of the commenters also requests that the word “failure” in the statement of unsafe condition be replaced with either “ply fracture” or “cracking issue.” The commenter has “strong concerns” with the use of the word “failure” to describe the events that occurred. The commenter states that the events can more accurately be described as single-ply fractures, and that the use of the word failure implies that the windshield can result in an unsafe condition.

From these comments, we infer that the commenter is requesting that the unsafe condition specified in the NPRM be revised. We agree. As of January 1, 2001, there have been approximately 292 windshield units returned to the windshield manufacturer due to structural ply failures. None of these windshield breakage incidents resulted in loss of pressurization of the airplane. Therefore, we agree with the commenters that stress-related cracking of the windshields would not result in loss of pressurization. We have revised the final rule to specify the unsafe condition as “to prevent stress-related cracking of the windshields, and subsequent excessive frequency of abnormal procedures specified in the airplane flight manual and/or an emergency descent be accomplished, which poses an increased risk to passengers and crew members.”

Request To Revise Applicability

One commenter requests that PPG P/Ns NP139321-1 through -6 inclusive be included in the applicability of the NPRM. The commenter states such a change will ensure that all parts are covered.

We do not agree. This AD parallels the applicability of Canadian airworthiness directive CF-2001-35R1, dated September 27, 2001, and the effectivity of Bombardier Service Bulletin 601R-56-004, dated August 16, 2001 (which is referenced in this AD as the appropriate source of service information for accomplishing the required actions). Paragraph 1.M, “Relationship Chart,” of Bombardier Service Bulletin 601R-56-004 lists the corresponding PPG P/Ns for the affected Bombardier windshields. So, the relationship between the PPG and Bombardier P/Ns is well established. Therefore, no change to the final rule is necessary in this regard.

Revise Cost Impact

One commenter states that the work hour estimate for accomplishing the modification service bulletin is grossly underestimated. The commenter expects to utilize two mechanics with an elapsed time of seven hours to accomplish the modification. The commenter also states that, contrary to the 339 airplanes listed as affected in the worldwide fleet in the Cost Impact section of the NPRM, there are 476 airplanes within the potential affected worldwide fleet of which 282 are currently under U.S. registry.

From this comment, we infer that the commenter is requesting that the Cost Impact section of the NPRM be revised. We agree partially. We do not agree with the commenter that the required inspection takes seven hours. As stated in the Cost Impact section of the NPRM, “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.” The specific action for this AD is the required inspection, which is also indicated in the Cost Impact section. In addition, Bombardier Service Bulletin 601R-56-004, dated August 16, 2001, which is referenced in this AD as the appropriate source of service information for accomplishing the required actions, specifies 1 work hour for accomplishing the inspection.

We agree with the commenter that the number of affected airplanes is higher than previously approximated; the cost impact information, below, has been revised accordingly.

Explanation of Change to Applicability

We have revised the applicability of the final rule to identify model designations as published in the most recent type certificate data sheet for the affected models.

Explanation of Change to Labor Rate

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, has been revised to reflect this increase in the specified hourly labor rate.

Conclusion

After careful review of the available data, including the comments noted above, we have determined that air safety and the public interest require the adoption of the rule 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.

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

On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. However, for clarity and consistency in this final rule, we have retained the language of the NPRM regarding that material.

Interim Action

This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Cost Impact

There are approximately 476 Model CL-600-2B19 (Regional Jet series 100 & 400) airplanes of the affected design in the worldwide fleet. We estimate that 282 airplanes of U.S. registry will be affected by this AD.

We estimate that it will take approximately 1 work hour per airplane to accomplish the inspection, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the required inspection is estimated to be $18,330, or $65 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.

Should an operator be required to accomplish the corrective actions, it will take approximately 1 work hour per airplane to accomplish at an average labor rate of $65 per work hour. Required parts will be provided by the manufacturer at no cost to the operator. Based on these figures, the cost impact of the corrective actions is estimated to be $65 per airplane.

Regulatory Impact

The regulations adopted herein 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. 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.

§ 39.13

[Amended]

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

AD 2003-14-02 Bombardier, Inc. (Formerly Canadair): Amendment 39-13221. Docket 2001-NM-322-AD.

Applicability: Model CL-600-2B19 (Regional Jet series 100 & 400) airplanes; certificated in any category; serial numbers 7003 and subsequent; equipped with main windshield units, part numbers 601R33033-1, -2, -5, -6, -9, or -10.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent stress-related cracking of the windshields, and subsequent excessive frequency of abnormal procedures specified in the airplane flight manual and/or an emergency descent be accomplished, which poses an increased risk to passengers and crew members; accomplish the following:

Inspection and Corrective Action

(a) For airplanes equipped with windshield units that have accumulated fewer than 2,500 total flight cycles as of the effective date of this AD: Within 6 months after the effective date of this AD, accomplish a one-time general visual inspection of the aft edges of the left and right main windshields to determine whether a placard having part number (P/N) CSB-NP-139321-002-1 is installed, per the Accomplishment Instructions of Bombardier Service Bulletin 601R-56-004, dated August 16, 2001.

(1) If a placard having P/N CSB-NP-139321-002-1 is installed, no further action is required by this AD.

(2) If a placard having a part number other than CSB-NP-139321-002-1 is installed, before further flight, accomplish the corrective actions (including modifying the main windshields by replacing nine of the hi-lok pins installed in the lower forward corner of the windshields with hi-lok pins having a reduced diameter shank, installing a placard having the correct part number on the inner retainer near the part identification placard located along the aft edge of the window, and replacing any torn or deformed gasket), per the Accomplishment Instructions of the service bulletin.

Note 2:

For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Note 3:

Bombardier Service Bulletin 601R-56-004, dated August 16, 2001, references PPG Industries, Inc., Service Bulletin CSB-NP-139321-002, Revision C, dated July 31, 2001, as an additional source of service information for accomplishment of the modification of the left and right main windshields.

Alternative Methods of Compliance

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, New York Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

Note 4:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

Special Flight Permit

(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Incorporation by Reference

(d) The actions shall be done in accordance with Bombardier Service Bulletin 601R-56-004, dated August 16, 2001. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, Canada. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Note 5:

The subject of this AD is addressed in Canadian airworthiness directive CF-2001-35R1, dated September 27, 2001.

Effective Date

(e) This amendment becomes effective on August 14, 2003.

Issued in Renton, Washington, on July 1, 2003.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.