03-6996. Airworthiness Directives; Israel Aircraft Industries, Ltd., Model 1124 and 1124A 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 all Israel Aircraft Industries, Ltd., Model 1124 and 1124A series airplanes. This proposal would require revising the airplane flight manual to advise the flightcrew to don oxygen masks as a first and immediate step following a cabin altitude alert. This action is necessary to prevent incapacitation of the flightcrew due to lack of oxygen. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by April 24, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-01-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-01-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 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Gulfstream Aerospace Corporation, P.O. Box 2206, Mail Station D25, Savannah, Georgia 31402. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Tim Dulin, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 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-01-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-01-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On October 25, 1999, a Learjet Model 35 series airplane operating under 14 CFR 135 departed Orlando International Airport en route to Dallas, Texas. Air traffic control lost communication with the airplane near Gainesville, Florida. Air Force and National Guard airplanes intercepted the airplane, but the flightcrews of the chase airplanes reported that the windows of the Model 35 series airplane were apparently frosted over, which prevented the flightcrews of the chase airplanes from observing the interior of the Model 35 series airplane. The flightcrews of the chase airplanes reported that they did not observe any damage to the airplane. Subsequently, the Model 35 series airplane ran out of fuel and crashed in South Dakota. To date, causal factors of the accident have not been determined. However, lack of the Learjet flightcrew's response to air traffic control poses the possibility of flightcrew incapacitation and raises concerns with the pressurization and oxygen systems.

Recognizing these concerns, the FAA initiated a special certification review (SCR) to determine if pressurization and oxygen systems on Model 35 series airplanes were certificated properly, and to determine if any unsafe design features exist in the pressurization and oxygen systems.

The SCR team found that there have been several accidents and incidents that may have involved incapacitation of the flightcrews during flight. In one case, the airplane flightcrew did not activate the pressurization system or don their oxygen masks and the airplane flew in excess of 35,000 feet altitude. In another case, the airplane flightcrews did not don their oxygen masks when the cabin altitude aural warning was activated. Further review by the SCR team indicates that the Airplane Flight Manual (AFM) of Learjet Model 35/36 series airplanes does not have an emergency procedure that requires donning the flightcrew oxygen masks when the cabin altitude aural warning is activated. Additional review has found that the AFMs of Model 35A and 36A series airplanes also do not contain appropriate flightcrew actions when the cabin altitude aural warning is activated. However, the AFMs do contain an abnormal procedure that allows the flightcrew to troubleshoot the pressurization system prior to donning the oxygen masks after the cabin altitude warning sounds. Troubleshooting may delay donning of the oxygen masks to the point that flightcrews may become incapable of donning their oxygen masks.

The SCR findings indicated that the most likely cause for incapacitation was hypoxia (lack of oxygen). The only other plausible cause of incapacitation is exposure to toxic substances. However, no evidence was found to support the existence of toxic substances.

Delayed response of the flightcrew in donning oxygen masks as a first and immediate action upon the activation of the cabin altitude warning horn could lead to incapacitation of the flightcrew.

A review of the emergency procedures in the AFM for Model 1124 and 1124A series airplanes revealed that the procedures for the flightcrew to don emergency oxygen masks is not the first and immediate step, but rather the second step when the warning horn sounds. Time spent troubleshooting the pressurization system following a cabin altitude alert may result in the flightcrew's incapacitation and consequent inability to continue to control the airplane before they are able to don oxygen masks. Therefore, these airplanes may be subject to the identified unsafe condition.

Explanation of Relevant Service Information

Israel Aircraft Industries has issued Temporary Revision (TR) No. 3 to the 1124 Westwind Airplane Flight Manual (AFM) and TR No. 5 to the 1124A Westwind AFM. Both TRs are dated January 16, 2001. The TRs advise the flightcrew to don oxygen masks as a first and immediate step following a cabin altitude alert to prevent incapacitation of the flightcrew due to lack of oxygen. (Previously the AFMs advised the flightcrew to check the cabin altitude and differential pressure gauge before donning oxygen masks.) Accomplishment of the AFM revision is intended to adequately address the identified unsafe condition. The Civil Aviation Administration of Israel (CAAI), which is the airworthiness authority for Israel, approved these TRs and issued Israeli airworthiness directive 21-02-07-01, dated July 22, 2002, which mandates compliance with the TRs to ensure the continued airworthiness of these airplanes in Israel.

FAA's Conclusions

These airplane models are manufactured in Israel and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAAI has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAAI, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require an AFM revision to advise the flightcrew to don oxygen masks as a first and immediate step following a cabin altitude alert.

Cost Impact

The FAA estimates that 198 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $11,880, or $60 per airplane.

The cost impact figure discussed above is 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:

-

Israel Aircraft Industries, LTD.: Docket 2003-NM-01-AD.

Applicability: All Model 1124 and 1124A series airplanes, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent incapacitation of the flightcrew due to lack of oxygen, accomplish the following:

Revision to Airplane Flight Manual (AFM)

(a) Within 1 month after the effective date of this AD, revise the Emergency Procedures section of the FAA-approved AFM, as specified in paragraph (a)(1) or (a)(2) of this AD, as applicable.

(1) For Model 1124 series airplanes: Insert TR 3, dated January 16, 2001, into the 1124 Westwind AFM.

(2) For Model 1124A series airplanes: Insert TR 5, dated January 16, 2001, into the 1124A Westwind AFM.

(b) When the information in the TRs identified in paragraph (a) of this AD has been incorporated into the general revisions of the respective AFM, the general revisions may be incorporated into the AFMs, and these TRs may be removed from the AFM.

Alternative Methods of Compliance

(c) 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, International Branch, ANM-116, Transport Airplane Directorate, FAA. Operators shall submit their requests through an appropriate FAA Principal Operations Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

Note 1:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

Special Flight Permits

(d) 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.

Note 2:

The subject of this AD is addressed in Israeli airworthiness directive 21-02-07-01, dated July 22, 2002.

Issued in Renton, Washington, on March 18, 2003.

Michael J. Kaszycki,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.