E8-26373. Airworthiness Directives; Boeing Model 737 Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

We are adopting a new airworthiness directive (AD) for all Boeing Model 737 airplanes. This AD requires revising the airplane flight manual to include a new flightcrew briefing that must be done before the first flight of the day and following any change in flightcrew members, and to advise the flightcrew of this additional briefing. This AD results from continuing reports that flightcrews have failed to recognize and react properly to the cabin altitude warning horn. We are issuing this AD to prevent failure of the flightcrew to recognize and react properly to a valid cabin altitude warning horn, which could result in incapacitation of the flightcrew due to hypoxia (lack of oxygen in body) and consequent loss of airplane control.

DATES:

This AD is effective November 25, 2008.

We must receive comments on this AD by January 9, 2009.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Gregg Nesemeier, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Discussion

On June 15, 2006, we issued related AD 2006-13-13, amendment 39-14666 (71 FR 35781, June 22, 2006). (A correction of that AD was published in the Federal Register on July 3, 2006 (71 FR 37980).) That AD applies to all Boeing Model 737 airplanes. That AD requires revising the airplane flight manual (AFM) to advise the flightcrew of improved procedures for pre-flight setup of the cabin pressurization system, as well as improved procedures for interpreting and responding to the cabin altitude/configuration warning horn. That AD resulted from reports that airplanes had failed to pressurize, and that the flightcrews failed to react properly to the cabin altitude warning horn. The actions specified in that AD are intended to prevent failure of the airplane to pressurize and subsequent failure of the flightcrew to recognize and react to a valid cabin altitude warning horn, which could result in incapacitation of the flightcrew due to hypoxia (lack of oxygen in body) and consequent loss of airplane control.

Actions Since Related AD Was Issued

Since we issued AD 2006-13-13, we have received continuing reports of in-service events involving failure of the flightcrew to recognize and react properly to valid cabin altitude warning horns. Therefore, we have determined that a new flightcrew briefing before the first flight of the day and following any change in flight crewmembers, in addition to the existing AFM procedures, is necessary to mitigate the risk of additional events.

FAA's Determination and Requirements of This AD

We are issuing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the(se) same type design(s). This AD requires revising the AFM to include a new flightcrew briefing that must be done before the first flight of the day and following any change in flightcrew members, and to advise the flightcrew of this additional briefing.

Interim Action

We consider this AD interim action. The manufacturer has advised that it currently is developing a design change in the cabin altitude warning system that will address the unsafe condition identified by this AD. Once this design change is developed, approved, and available, we might consider additional rulemaking.

FAA's Justification and Determination of the Effective Date and Compliance Time

We are issuing this AD to prevent failure of the flightcrew to recognize and react to a valid cabin altitude warning horn, which could result in incapacitation of the flightcrew due to hypoxia (lack of oxygen in body) and consequent loss of airplane control. This action follows related rulemaking action we took in response to a report resulting from the investigation by the Air Accident Investigation and Aviation Safety Board of Greece into the August 14, 2005, Helios Airways accident near Athens, Greece. This action affects the entire fleet of Boeing Model 737 airplanes (nearly 5,000 airplanes worldwide); these airplanes have a very high utilization rate. Because of our requirement to promote safe flight of civil aircraft and thus the critical need to assure that the flightcrew recognizes and reacts properly to a valid cabin altitude warning horn and the compliance time involved with this action, this AD must be issued immediately.

We acknowledge that a compliance time of 120 days is unusually long for an AFM-change/immediately adopted rule. However, in this case, we have determined that it is necessary to provide sufficient time for operators to adequately prepare to meet the requirements of the AD. This preparation includes obtaining regulatory acceptance (from principal operations inspectors) of the required flightcrew preflight briefing aids, publication of flightcrew briefing aids in sufficient quantities, and familiarization of flightcrews with the AD briefing requirements. The time required to prepare to implement the AD requirements is increased by the size of the affected fleet. We have further determined that a 120-day compliance time will provide an adequate level of safety. Therefore, a compliance time of 120 days has been specified in order to provide operators with sufficient time to accomplish the requirements of this AD.

Because an unsafe condition exists that requires the immediate adoption of this AD, we find that notice and opportunity for prior public comment hereon are impracticable and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety, and we did not provide you with notice and an opportunity to provide your comments before it becomes effective. However, we invite you to send any written data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2008-1166; Directorate Identifier 2008-NM-179-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this AD.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. “Subtitle VII: Aviation Programs,” describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in “Subtitle VII, Part A, Subpart III, Section 44701: General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA 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 AD:

2008-23-07 Boeing: Amendment 39-15728. Docket No. FAA-2008-1166; Directorate Identifier 2008-NM-179-AD.

Effective Date

(a) This airworthiness directive (AD) is effective November 25, 2008.

Affected ADs

(b) This AD is related to AD 2006-13-13, amendment 39-14666; paragraph (a) of AD 2003-03-15 R1, amendment 39-13366; and paragraph (a) of AD 2003-14-08, amendment 39-13227. This AD does not supersede the requirements of AD 2006-13-13, AD 2003-03-15 R1, or AD 2003-14-08.

Applicability

(c) This AD applies to all Boeing Model 737-100, -200, -200C, -300, -400, -500, -600, -700, -700C, -800, -900, and -900ER series airplanes, certificated in any category.

Unsafe Condition

(d) This AD results from continuing reports that flightcrews have failed to recognize and react properly to the cabin altitude warning horn. We are issuing this AD to prevent failure of the flightcrew to recognize and react to a valid cabin altitude warning horn, which could result in incapacitation of the flightcrew due to hypoxia (lack of oxygen in body) and consequent loss of airplane control.

Compliance

(e) Comply with this AD within the compliance times specified, unless already done.

Revising the Airplane Flight Manual (AFM)

(f) Within 120 days after the effective date of this AD, revise the Limitations Section of the applicable Boeing 737 AFM to include the following statement. This may be done by inserting a copy of this AD into the applicable AFM.

“CABIN ALTITUDE WARNING TAKEOFF BRIEFING (required by AD 2008-23-07)

With the CABIN ALTITUDE and TAKEOFF CONFIG lights not installed, or installed but not activated:

As part of the Takeoff Briefing before engine start for the first flight of the day or following any change of either flightcrew member, the pilot-in-command will ensure the Cabin Altitude Warning indications and procedures are briefed in accordance with the procedures contained in the Normal Procedures section of this manual.”

(g) Within 120 days after the effective date of this AD, revise the Normal Procedures Section of the applicable Boeing 737 AFM to include the following statement. This may be done by inserting a copy of this AD into the applicable AFM.

“CABIN ALTITUDE WARNING TAKEOFF BRIEFING (required by AD 2008-23-07)

The following briefing is important to further reduce the risk of flightcrew incapacitation due to hypoxia. Because of the dual purpose of the intermittent cabin altitude/takeoff configuration warning horn, this briefing serves to remind flightcrews that the sounding of the cabin altitude warning horn in flight requires immediate action, beginning with the immediate donning of oxygen masks. Upon completion of the applicable WARNING HORN—CABIN ALTITUDE OR CONFIGURATION non-normal checklist memory items, other alerts and indications on the flight deck (e.g., air/ground sensing system failures, equipment cooling OFF, etc.) may then be addressed.

Memory item cabin altitude warning indications and procedures must be briefed on airplanes in which the CABIN ALTITUDE and TAKEOFF CONFIG lights are not installed, or are installed but not activated. This will be included as an additional item on the Takeoff briefing before engine start for the first flight of the day, or following any change of either flightcrew member.

The briefing must include the following items.

—Whenever the intermittent warning horn sounds in flight:

1. Immediately, don oxygen masks and set regulators to 100%.

2. Establish crew communications.

3. Do the CABIN ALTITUDE WARNING OR RAPID DEPRESSURIZATION checklist.

—Both pilots must verify on the overhead Cabin Altitude Panel that the cabin altitude is stabilized at or below 10,000 feet before removing oxygen masks.”

Special Flight Permit

(h) Special flight permits are prohibited.

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, ATTN: Gregg Nesemeier, 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]; has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

Material Incorporated by Reference

(j) None.

Issued in Renton, Washington, on October 24, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.