AD 2000-11-13

This amendment adopts a new airworthiness directive (AD), applicable to certain Fokker Model F.28 Mark 1000, 2000, 3000, and 4000 series airplanes, that requires a one-time review of the maintenance records to determine if tripping of the fuel boost pump circuit breakers has been recorded, repetitive inspections to detect fuel leakage from the fuel boost pump wiring conduits, and corrective actions, if necessary. This amendment also requires replacement of the three single wires inside the metal conduit of the fuel boost pumps with new wires protected by a polyamide sleeve, which terminates the repetitive inspections. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent the fuel boost pump wiring from chafing, which could result in electrical arcing and a possible fuel tank ignition source.

Final rule.

2000-11-13 FOKKER SERVICES B.V.: Amendment 39-11761. Docket 99-NM-358-AD.

Applicability: Model F.28 Mark 1000, 2000, 3000, and 4000 series airplanes having serial numbers 11003 through 11241 inclusive and 11991 through 11994 inclusive, certificated in any category.

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 (f) 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 actionsto address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent the fuel boost pump wiring from chafing, which could result in electrical arcing and a possible fuel tank ignition source, accomplish the following:

Inspections and Corrective Actions

(a) Within 30 days after the effective date of this AD, perform a one-time inspection of the maintenance records of the airplane to determine if tripping of the fuel boost pump circuit breakers has been reported within the last 30 days, in accordance with Part 1 of the Accomplishment Instructions of Fokker Service Bulletin SBF28/28-046, dated September 1, 1999.

(b) If resettable or unresettable tripping of the circuit breaker of the fuel boost pump is reported during the inspection required by paragraph (a) of this AD, or if such tripping is reported at any time subsequent to that inspection: Within 10 days after the date of the inspection or any occurrence, accomplish the applicable repair (including a resistance check and inspections of the wire and conduit for discrepancies), in accordance with Part 2 of the Accomplishment Instructions of Fokker Service Bulletin SBF28/28-046, dated September 1, 1999. If any discrepancy is detected during any inspection performed during the repair, prior to further flight, repair in accordance with the service bulletin.

(c) In the event of any resettable or unresettable tripping of the circuit breakers of the fuel boost pump as indicated in paragraph (b) of this AD, the airplane may be operated for a period not to exceed 10 days after the occurrence, provided the circuit breaker of the fuel boost pump and fuel boost pump switch have been properly deactivated and placarded for flightcrew awareness, in accordance with the FAA-approved Master Minimum Equipment List (MMEL).

(d) Within 30 days after the effective date of this AD, perform a general visual inspection to detect signs of fuel leakage from the wiring conduits of thefuel boost pumps, in accordance with Part 1 of the Accomplishment Instructions of Fokker Service Bulletin F28/28-046, dated September 1, 1999. If any fuel leakage is detected during the inspection, prior to further flight, isolate the fuel leak, and repair in accordance with Part 2 of the Accomplishment Instructions of the service bulletin. Thereafter, repeat the inspection at intervals not to exceed 90 days.

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 under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, 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."

Replacement of Wires

(e) Replace the existing three single wires (including inspections) inside the metal conduits of the fuel boost pumps with three twisted wires protected by a polyamide braided wire sleeve, in accordance with Part 3 of the Accomplishment Instructions of Fokker Service Bulletin F28/28-046, dated September 1, 1999, at the time specified in paragraph (e)(1) or (e)(2) of this AD, as applicable. If any discrepancy is detected during any inspection required by this paragraph, prior to further flight, repair in accordance with the service bulletin. Accomplishment of the actions required by this paragraph constitutes terminating action for the actions required by this AD.

(1) For airplanes that have accumulated less than 40,000 total flight hours as of the effective date of this AD: Within 2 years after the effective date of this AD.

(2) For airplanes that have accumulated 40,000 or more total flight hours as of the effective date of this AD: Within 1 year after the effective date of this AD.

Alternative Methods ofCompliance

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

NOTE 3: 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

(g) 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

(h) The actions shall be done in accordance with Fokker Service Bulletin SBF28/28-046,dated September 1, 1999. 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 Fokker Services B.V., P.O. Box 231, 2150 AE Nieuw-Vennep, the Netherlands. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 4: The subject of this AD is addressed in Dutch airworthiness directive BLA 1999-114, dated September 13, 1999.

(i) This amendment becomes effective on July 11, 2000.

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 Fokker Model F.28 Mark 1000, 2000, 3000, and 4000 series airplanes was published in the Federal Register on February 8, 2000 (65 FR 6046). That action proposed to require a one-time review of the maintenance records to determine if tripping of the fuel boost pump circuit breakers has been recorded, repetitive inspections to detect fuel leakage from the fuel boost pump wiring conduits, and corrective actions, if necessary. That action also proposed to require replacement of the three single wires inside the metal conduit sleeve of the fuel boost pumps with new wires protected by a polyamide sleeve, which would terminate the repetitive inspections.

Comments Received
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given tothe comments received.

Type Certificate Holder
One commenter requests that the Discussion and Explanation of Relevant Service Information sections be revised to refer to Fokker Services B.V. as the current type certificate holder, rather than the now defunct airplane manufacturer. The commenter advises that Fokker Services B.V. is conducting the Fuel System Safety Program mentioned in the Discussion section, and is also the issuer of the relevant service information. The FAA acknowledges the accuracy of this information; however, since these sections are not repeated in the final rule, no change is made to the AD.

Statement of Unsafe Condition
The same commenter requests that the statement of unsafe condition be corrected in several areas of the proposed AD. The commenter notes that electrical arcing has only been observed between the metal conduit and the fuel boost pump wiring, and states that the description of the unsafe condition should be revised to remove the statement that such arcing "could result in a possible fuel tank ignition source." The commenter states that since no arc-through of the metal conduit has been observed, and the conduit is submerged in fuel during all phases of flight, it is very unlikely that the arcing could serve as an ignition source for the fuel vapors inside the fuel tank. The commenter requests that the Summary, Discussion, and Compliance sections of the AD be revised to eliminate such a statement, and suggests that the actions required by the proposed AD are instead intended to prevent repetitive electrical arcing between damaged fuel boost pump wiring and the metal conduit, ignition of fuel vapors within the metal conduit, and/or chafing of the fuel boost pump wiring.

The FAA does not concur. Although the commenter states that it is very unlikely that the arcing could lead to an ignition source for the fuel vapors inside the fuel tank, insufficient data were provided to the FAA to demonstrate that such arcing could not create an ignition source in the fuel tank. Additionally, although other conditions will be prevented by accomplishment of the actions required by this AD, the possible ignition of fuel vapors is the unsafe condition being addressed by this AD. No change is made to the final rule.

Reference to Metal Conduit
The same commenter requests that the phrase "replacement of the three single wires inside the metal conduit sleeve" in the Summary section of the proposed AD be revised to delete the word "sleeve" to describe the replacement more accurately. The FAA concurs. The use of the word "sleeve" in this context was an inadvertent error in terminology, although the replacement is described accurately in the text of the AD. The Summary section of the final rule has been revised accordingly.

Description of Service Information
The same commenter requests that the Explanation of Relevant Service Information section be revised in several areas pertaining to the description of the procedures contained in Part 2, Paragraph D., of the Accomplishment Instructions of Fokker Service Bulletin SBF28/28-046, dated September 1, 1999. The commenter's suggestions include expanding the description of the corrective actions to list all such actions, and clarifying that certain actions are to be accomplished subsequent to and depending on the results of the resistance check. The FAA acknowledges that more detailed descriptions of all corrective actions could have been included, but has determined that the description provided in the proposed AD was sufficient to give adequate notice to operators concerning required actions. Since this information is not retained in the final rule, no change is made to the AD in this regard.

Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the change described previously. The FAAhas determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.
Cost Impact
The FAA estimates that 22 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per airplane to accomplish the required review of the maintenance records, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the review on U.S. operators is estimated to be $1,320, or $60 per airplane.

It will take approximately 3 work hours per airplane to accomplish the required repetitive inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $3,960, or $180 per airplane, per inspection cycle.

It will take approximately 33 work hours per airplane to accomplish the required modification, at an average labor rate of $60 per work hour. Required parts will cost approximately $1,355 per airplane. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $73,370, or $3,335 per airplane.

The cost impact figures discussed above are 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.

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: