03-4236. Airworthiness Directives; Boeing Model 737-600, 737-700, 737-700C, 737-800, 737-900, 757, and 767 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 Boeing Model 737-600, 737-700, 737-700C, 737-800, 737-900, 757, and 767 series airplanes. This proposal would require revising the Airplane Flight Manual (AFM) to advise the flightcrew to don oxygen masks as a first and immediate step when a cabin altitude warning occurs. This action is necessary to prevent incapacitation of the flightcrew due to lack of oxygen, 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 April 10, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-282-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. 2002-NM-282-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 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:

Donald Eiford, 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 2002-NM-282-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. 2002-NM-282-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On October 25, 1999, a Learjet Model 35 airplane operating under part 135 of the Federal Aviation Regulations (14 CFR part 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 indicated that the windows of the Model 35 airplane were apparently frosted over, which prevented the flightcrews of the chase airplanes from observing the interior of the Model 35 airplane. The flightcrews of the chase airplanes reported that they did not observe any damage to the airplane. Subsequently, the Model 35 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 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 and 36 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 Learjet Model 35A and 36A 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 aural 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 could lead to incapacitation of the flightcrew and loss of control of the airplane.

Explanation of Applicability of Proposed AD

We have previously issued AD 2003-03-15, amendment 13039 (68 FR 4892, January 31, 2003). That AD revises the AFM for various Boeing and McDonnell Douglas transport category airplanes to advise the flightcrew to don oxygen masks as a first and immediate step when the cabin altitude aural warning sounds. Boeing Model 737-600, 737-700, 737-700C, 737-800, 737-900, 757, and 767 series airplanes were not included in the applicability of that AD because we determined that appropriate instructions for donning oxygen masks were included in the Airplane Operations Manual for those airplanes.

After the issuance of the NPRM for AD 2003-03-15, we repeated the review of the AFMs for Boeing Model 737-600, 737-700, 737-700C, 737-800, 737-900, 757, and 767 series airplanes. Based on the results of this second review, we have determined that further rulemaking is necessary to ensure that the AFMs for those airplanes contain appropriate instructions for the flightcrew to immediately don emergency oxygen masks when a cabin altitude aural warning occurs. This proposed AD follows from that determination.

Other Related Rulemaking

We have previously issued AD 2000-23-10, amendment 39-11980 (65 FR 70294, November 22, 2000), which applies to all Lockheed Model 188A and 188C series airplanes. That AD requires a revision of the AFM to add procedures for donning the flightcrew oxygen masks when the cabin altitude aural warning sounds. The requirements of that AD are intended to prevent incapacitation of the flightcrew as a result of lack of oxygen and consequent loss of control of the airplane.

We have also previously issued AD 2001-22-10, amendment 39-12489 (66 FR 54425, October 29, 2001), which applies to all Dassault Model Mystere-Falcon 50, Mystere-Falcon 900, and Falcon 900EX series airplanes. That AD requires revising the Emergency Procedures and Abnormal Procedures sections of the AFM to advise the flightcrew to immediately don oxygen masks in the event of significant pressurization or oxygen level changes. The requirements of that AD are intended to prevent incapacitation of the flightcrew due to lack of oxygen, which could result in their inability to continue to control the airplane.

We are continuing to review emergency procedures in the AFMs for other airplane models to ensure that the AFMs contain appropriate instructions for donning the flightcrew oxygen masks. We may consider further rulemaking based on the results of these reviews.

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 revising the Emergency Procedures or Non-Normal Procedures section of the AFM, as applicable, to advise the flightcrew to don oxygen masks as a first and immediate step when the cabin altitude aural warning sounds.

Cost Impact

There are approximately 3,107 airplanes of the affected design in the worldwide fleet. The FAA estimates that 1,599 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 AFM revision, 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 $95,940, 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:

-

Boeing: Docket 2002-NM-282-AD.

Applicability: All Model 737-600, 737-700, 737-700C, 737-800, 737-900, 757, and 767 series airplanes; certificated in any category.

Note 1:

The requirements of this AD are similar to those in AD 2003-03-15, amendment 39-13039, which applies to various Boeing and McDonnell Douglas transport category airplanes.

Compliance: Required as indicated, unless accomplished previously.

To prevent incapacitation of the flightcrew due to lack of oxygen, which could result in loss of control of the airplane, accomplish the following:

Revision to the Airplane Flight Manual

(a) Within 90 days after the effective date of this AD: For the applicable airplane models listed in the “For—” column of Table 1 of this AD, revise the procedures regarding donning oxygen masks in the event of rapid depressurization, as contained in the Emergency Procedures or Non-Normal Procedures section of the Airplane Flight Manual (AFM), as applicable, by replacing the text in the “Replace—” column of Table 1 of this AD with the information in the applicable figure referenced in the “With the Information In—” column of Table 1 of this AD. This may be accomplished by recording the AD number of this AD on the applicable figure and inserting it into the AFM. Table 1 and Figures 1 through 3 follow:

Table 1.—AFM Revisions

For—	Replace—	With the information in—
Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes	“Rapid Depressurization (With airplane altitude above 14,000 feet M.S.L.) Oxygen Masks & Regulators—ON, 100%”.	Figure 1 of this AD.
Boeing Model 757-200, -200PF, -200CB; and Boeing Model 767-200, -300, and -300F series airplanes	“Rapid Depressurization Recall Oxygen Masks and Regulators—ON”.	Figure 2 of this AD.
Boeing Model 757-300 series airplanes	“Rapid Depressurization Put on oxygen masks, and establish crew communications.”	Figure 3 of this AD.
Boeing Model 767-400ER series airplanes	“Rapid Depressurization Turn on oxygen masks, and establish crew communications.”	Figure 3 of this AD.

Figure 1

For Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes:

Insert the information in this figure into the “Non-Normal Procedures” section of the FAA-approved Airplane Flight Manual.

Cabin Altitude Warning or Rapid Depressurization

Condition: The CABIN ALT or CABIN ALTITUDE light illuminated indicates cabin altitude is excessive:

Oxygen Masks & Regulators ON, 100%

The rest of the steps under this heading in the AFM are unchanged.

Figure 2

For Boeing Model 757-200, -200PF, and -200CB; and Model 767-200, -300, and -300F Series Airplanes:

Insert the information in this figure into the “Emergency Procedures” section of the FAA-approved Airplane Flight Manual.

Cabin Altitude Warning or Rapid Depressurization

Condition: The CABIN ALT or CABIN ALTITUDE light illuminated indicates cabin altitude is excessive:

RECALL

Oxygen Masks & Regulators ON, 100%

The rest of the steps under this heading in the AFM are unchanged.

Figure 3

For Boeing Model 757-300 and 767-400ER Series Airplanes:

Insert the information in this figure into the “Non-Normal Procedures” section of the FAA-approved Airplane Flight Manual.

Cabin Altitude Warning or Rapid Depressurization

Condition: The CABIN ALT or CABIN ALTITUDE light illuminated indicates cabin altitude is excessive:

Put on oxygen masks and establish crew communications.”

The rest of the steps under this heading in the AFM are unchanged.

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, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Operations Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 2:

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

Special Flight Permits

(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.

Issued in Renton, Washington, on February 13, 2003.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.