01-27666. Airworthiness Directives; Fokker Model F.28 Mark 0070 and 0100 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) this is applicable to certain Fokker Model F.28 Mark 0070 and 0100 series airplanes. This proposal would require repetitive operational tests for discrepancies of the heating system of pitot tube #1, and replacement of the pilot tube, if necessary. This proposal also would require eventual modification of the alternating current sensing circuit for pitot tube #1, which would terminate the repetitive operational test requirement. This action is necessary to prevent failure of the heating system of pitot tube #1 due to a short circuit, which may go undetected and lead to the pilot receiving erroneous airspeed indications, resulting in reduced control of the airplane. The action is intended to address the identified unsafe condition.

DATES:

Comments must be received by December 5, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-128-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 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. 2001-NM-128-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 Fokker Services, V.V., P.O. Box 231, 2150 AE Nieuw-Vennep, the Netherlands. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Tom Rodriguez, 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 issues-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin specific 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 2001-NM-128-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. 2001-NM-128-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports that the captain's airspeed indicator failed during flight in icing conditions on certain Fokker Model F.28 Mark 0070 and 0100 series airplanes. Another report advises that an operator reported snow on the pitot tube while the pitot tube's heating element was switched on. Investigation has revealed that these conditions are caused by a short circuit in the pitot tube's heating element, which can remain undetected because of the placement of the alternating current (AC) sensing circuit for pitot tube #1. Undetected failure of the pitot tube heating system can lead to pitot tube #1 being blocked by ice. This condition, if not corrected, could lead to the pilot receiving erroneous airspeed indications, resulting in reduced control of the airplane.

Explanation of Relevant Service Information

Fokker Services B.V. has issued Fokker Service Bulletin SBF100-30-025, Revision 1, dated March 14, 2001, which describes procedures for repetitive operational tests for discrepancies of the heating system of pitot tube #1, and replacement of the pitot tube, if necessary. The operational tests are intended to ensure that the heaters of the pitot tube and mast are functioning. The service bulletin also describes procedures for modification of the AC sensing circuit for pitot tube #1. The modification involves removing the supply current wire from the AC current sensor for the pitot tube, removing the wire that grounds the heating system of pitot tube #1, installing the supply current wire to the inverter, installing the return current wire from from pitot tube #1 to the AC current sensor, and grounding the AC current sensor. Accomplishment of this modification will ensure that the flight crew will be able to detect a short circuit in the heating system of pitot tube #1, should such a short circuit occur. Therefore, such modification eliminates the need for the repetitive operational tests. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

U.S. Type Certification of the Airplane

This aiplane model is manufactured in the Netherlands and is 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.

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 accomplishment of the actions specified in the service bulletin described previously. The proposed AD also would require that operators report results of inspection findings to the airplane manufacturer.

Cost Impact

The FAA estimates that 129 airplanes of U.S registry would be affected by this proposed AD.

It would take approximately 1 work hour per airplane to accomplish the proposed operational test, at the average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $7,740, or $60 per airplane, per test cycle.

It would take approximately 34 work hours per airplane to accomplish the proposed modification, at the average labor rate of $60 per work hour. Required parts would cost approximately $350 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $308,310, or $2,390 per airplane.

The cost impact figures discussed above are 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); an (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.

Fokker Services B.V.: Docket 2001-NM-128-AD.

Applicability: Model F.28 Mark 0070 and 0100 series airplanes, serial numbers 11244 through 11585 inclusive, on which Fokker Service Bulletin SBF100-30-019 or SBF100-30-020 has been accomplished, certificated in any category.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (e) 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 actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the heating system of pitot tube #1 due to a short circuit, which may go undetected and lead to the pilot receiving erroneous airspeed indications, resulting in reduced control of the airplane, accomplish the following:

Operational Test

(a) Within 3 months after the effective date of this AD, do an operational test for discrepancies (i.e., correct functioning) of the heating system of pitot tube #1, according to Fokker Service Bulletin SFB100-30-025, Revision 1, dated March 14, 2001. Repeat the operational test every 12 months, until paragraph (d) of this AD has been done.

Replacement of Pitot Tube

(b) If any discrepancy is found during the operational test required by paragraph (a) of this AD: Before further flight, replace pitot tube #1 with a new pitot tube, according to Fokker Service Bulletin SBF100-30-025, Revision 1, dated March 14, 2001.

Reporting Requirement

(c) At the applicable time specified in paragraph (c)(1) or (c)(2) of this AD: Use page 38 of Fokker Service Bulletin SBF100-30-025, Revision 1, dated March 14, 2001, to submit a report of findings from each operational test (both positive and negative) to Fokker Services B.V., Attn: Manager Airline Support, P.O. Box 231, 2150 AE Nieuw-Vennep, the Netherlands. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

(1) For airplanes on which the operational test is accomplished after the effective date of this AD: Submit the report within 5 days after performing the test required by paragraph (a) of this AD.

(2) For airplanes on which the operational test is accomplished before the effective date of this AD: Submit the report within 5 days after the effective date of this AD.

Modification

(d) Within 36 months after the effective date of this AD, modify the alternating current (AC) sensing circuit for pitot tube #1 (including removing the supply current wire from the AC current sensor for the pitot tube, removing the wire that grounds the heating system of pitot tube #1, installing the supply current wire to the inverter, installing the return current wire from pitot tube #1 to the AC current sensor, and grounding the AC current sensor), according to Fokker Service Bulletin SBF100-30-025, Revision 1, dated March 14, 2001. Such modification terminates the repetitive operational tests required by paragraph (a) of this AD.

Alternative Methods of Compliance

(e) 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 Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

Note 2:

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

(f) 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.

Dated: Issued in Renton, Washington, on October 30, 2001.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.