Federal Aviation Administration (FAA), Department of Transportation (DOT).
Notice of proposed rulemaking (NPRM).
The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 727 airplanes. This proposed AD would require determining whether any float switches are installed in the fuel tanks, and corrective actions if necessary. This proposed AD is prompted by reports of contamination of the fueling float switch by moisture or fuel, and chafing of the float switch wiring against the fuel tank conduit. We are proposing this AD to prevent such contamination and chafing, which could present an ignition source inside the fuel tank that could cause a fire or explosion.
We must receive comments on this proposed AD by May 19, 2005.
Use one of the following addresses to submit comments on this proposed AD.
- DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
- Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
- Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, Washington, DC 20590.
- By fax: (202) 493-2251.
- Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
For service information identified in this proposed AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.
You can examine the contents of this AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2005-20799; the directorate identifier for this docket is 2004-NM-264-AD.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Sulmo Mariano, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6501; fax (425) 917-6590.End Further Info End Preamble Start Supplemental Information
We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2005-20799; Directorate Identifier 2004-NM-264-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments submitted by the closing date and may amend the proposed AD in light of those comments.
We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You can review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.
Examining the Docket
You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.
Boeing has performed a quality analysis on float switches removed from Model 737-200 series airplanes. Investigation revealed cracked potting material, which permitted moisture and fuel to enter the switch cavity. Fuel and moisture contamination inside the float switch reed cavity could provide an electrical path between the switch and the airplane structure that could result in electrical arcing that could lead to a fuel tank explosion. Also, Boeing reported worn float switch wiring insulation in the center fuel tank due to chafing of the wires against the walls of the conduit housing the wires. Wire chafing against the conduit could present an ignition source inside the fuel tank that could cause a fire or explosion.
The float switch wiring installation is similar on Model 727 and 737-200 series airplanes. Therefore, the unsafe condition could exist on Model 727 airplanes equipped with the same float switch model found on the 737-200 series airplanes.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 727-28A0127, dated August 26, 2004. The service bulletin describes procedures for replacing Ametek Model F8300-146 float switches with new switches and installing a liner system inside the electrical cable conduit in the main and auxiliary fuel tanks.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or Start Printed Page 16980develop on other airplanes of this same type design. Therefore, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and the Service Bulletin.”
Differences Between the Proposed AD and the Service Bulletin
The service bulletin affects Model 727 airplanes “with active Boeing fueling float switch shutoff systems installed” and requires replacing the float switches and installing a liner system. However, this proposed AD would apply to all Model 727 airplanes and would require first determining whether any fuel float switches are installed in the fuel tanks. For those airplanes with float switches, this proposed AD would then require identifying the float switches, replacing Ametek Model F8300-146 float switches with new switches, and installing the liner system. We have determined that the effectivity in the service bulletin may not encompass all possible scenarios involving the subject float switches. Because the auxiliary fuel tanks have been moved from airplane to airplane—via field approval or supplemental type certificate, the proposed applicability and requirements would ensure that all subject float switch designs are replaced.
These differences have been coordinated with Boeing and are intended to adequately address the unsafe condition.
Costs of Compliance
There are about 1,300 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 800 airplanes of U.S. registry.
The proposed inspections (for presence and model of float switch) would take about 1 work hour, at an average labor rate of $65 per hour. Based on these figures, the estimated cost of the proposed inspections for U.S. operators is $52,000, or $65 per airplane.
The following table provides the estimated costs for U.S. operators to replace the float switches, if necessary. We estimate that about 162 airplanes may require parts replacement.
|Airplane||Airplane model||Number of auxiliary fuel tanks||Work hours||Average hourly labor rate||Parts||Cost per airplane|
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.
We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.
For the reasons discussed above, I certify that the 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. 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.
We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD. See the ADDRESSES section for a location to examine the regulatory evaluation.Start List of Subjects
List of Subjects in 14 CFR Part 39End List of Subjects
The Proposed Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:Start Part
PART 39—AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):
Boeing: Docket No. FAA-2005-20799; Directorate Identifier 2004-NM-264-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by May 19, 2005.
(c) This AD applies to all Boeing Model 727 airplanes, certificated in any category.
(d) This AD was prompted by reports of contamination of the fueling float switch by moisture or fuel, and chafing of the float switch wiring against the fuel tank conduit. We are issuing this AD to prevent such contamination and chafing, which could present an ignition source inside the fuel tank that could cause a fire or explosion. Start Printed Page 16981
(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Inspection for Float Switches
(f) Within 48 months after the effective date of this AD, inspect the wing and auxiliary fuel tanks to determine if any float switches are present. Instead of an inspection of the fuel tanks, a review of airplane maintenance records is acceptable if the presence of any float switch can be conclusively determined from that review.
(1) If no float switches are present: No further work is required by this paragraph.
(2) If any float switch is present: Before further flight, inspect to identify the float switch models. Instead of an inspection of the fuel tanks, a review of airplane maintenance records is acceptable if the identity of the float switch can be conclusively determined from that review.
(i) If a float switch other than an Ametek Model F8300-146 float switch is installed: Before further flight, install a liner system inside the float switch electrical cable conduit in the fuel tanks by doing all applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 727-28A0127, dated August 26, 2004.
(ii) If any Ametek Model F8300-146 float switch is installed: Before further flight, replace it with a new switch and install a liner system inside the float switch electrical cable conduit in the fuel tanks, by doing all applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 727-28A0127, dated August 26, 2004.
Boeing Alert Service Bulletin 727-28A0127 segregates the work into nine work packages for the six fuel tank configurations identified in the service bulletin. The work packages do not have to be completed sequentially. Each work package can be done independently or simultaneously. However, all work packages, as applicable for each fuel tank configuration, must be done to complete the requirements of this AD.
(g) As of the effective date of this AD, no person may install an Ametek Model F8300-146 float switch in a fuel tank on any airplane.
Alternative Methods of Compliance (AMOCs)
(h) The Manager, Seattle Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.
Issued in Renton, Washington, on March 28, 2005.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 05-6577 Filed 4-1-05; 8:45 am]
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