AD 97-24-16

This amendment adopts a new airworthiness directive (AD), applicable to certain Fokker Model F28 Mark 0070 and 0100 series airplanes, that requires a one-time operational test of a certain pitot heating system, repair or replacement of failed elements, and repair or replacement of the pitot heating system with a new improved system. This amendment also requires installation of new power supply wiring with increased gauge thickness, and a circuit breaker with an increased amperage rating. This amendment is prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent icing of the No. 1 pitot tube, which could result in failure of the No. 1 Air Data Computer, or output of erroneous airspeed data to all on-side subsidiary systems, including the Automatic Flight Control and Augmentation System.

Final rule

97-24-16 FOKKER: Amendment 39-10223. Docket 95-NM-29-AD.
Applicability: Model F28 Mark 0070 and 0100 series airplanes, certificated in any category, and having the following serial numbers:

11244 through 11495, inclusive;
11497 through 11507, inclusive;
11509;
11511 through 11517, inclusive;
11519 through 11523, inclusive;
11527 through 11529, inclusive;
11532;
11536 through 11541, inclusive;
11543;
11545;
11547;
11549;
11551;
11553 through 11565, inclusive;
11567;
11570;
11573; and
11574.
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 (d) 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 icing of the No. 1 pitot tube, which could result in failure of the No. 1 Air Data Computer (ADC #1) or output of erroneous airspeed data to all on-side subsidiary systems, including the Automatic Flight Control and Augmentation System (AFCAS), accomplish the following:

(a) For airplanes that have type 853JB pitot tubes installed: Within 30 days after the effective date of this AD, perform an operational test of the No. 1 pitot heating system in accordance with Part 1 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-30-015, Revision 2, dated January 25, 1995.

(1) If the pitot heatingsystem passes the operational test, accomplish the requirements of either paragraph (b)(1) or (b)(2) of this AD, as applicable, at the time specified.

(2) If any pitot tube heating element is found to be inoperative, prior to further flight, repair or replace the failed element with a serviceable element, in accordance with the Fokker 100 Aircraft Maintenance Manual (AMM).

(b) For airplanes on which Fokker Service Bulletin SBF100-30-017, dated August 23, 1995, has not been accomplished: At the applicable time specified in either paragraph (b)(1) or (b)(2) of this AD, replace the type 853JB or type 853KK No. 1 pitot tube, with a type 853BR pitot tube; and install the inverter, current sensor, wiring, and circuit breaker; in accordance with Fokker Service Bulletin SBF100-30-019, dated June 20, 1996.

(1) For airplanes with the flight warning system (FWS) speed comparator not activated and with a type 853JB No. 1 pitot tube installed: Accomplish the replacement within 9months after the effective date of this AD.

(2) For airplanes with the FWS speed comparator activated or with a type 853KK No. 1 pitot tube installed: Accomplish the replacement within 18 months after the effective date of this AD.

(c) For airplanes on which Fokker Service Bulletin SBF100-30-017, dated August 23, 1995, has been accomplished, either in service or factory-incorporated: Within 18 months after the effective date of this AD, replace the No. 1 pitot heating circuit breaker and modify the power supply electrical wiring, in accordance with Fokker Service Bulletin SBF100-30-020, dated June 20, 1996.

(d) 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 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.

(e) 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.

(f) The actions shall be done in accordance with Fokker Service Bulletin SBF100-30-015, Revision 2, dated January 25, 1995; Fokker Service Bulletin SBF100-30-019, dated June 20, 1996; and Fokker Service Bulletin SBF100-30-020, dated June 20, 1996. Revision 2 of Fokker Service Bulletin SBF100-30-015 contains the following list of effective pages:

Page Number
Revision Level
Shown on Page
Date
Shown on Page
1, 3, 9, 15, 17, 18,
22, 35, 36, 38
2
January 25, 1995
2, 12, 14, 16, 25
26, 30-32, 37
1
September 14, 1994
4-8, 10, 11, 13, 19-21,
23, 24, 27-29, 33, 34,
39
Original
July 7, 1994

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., Technical Support Department, P.O. Box 75047, 1117 ZN Schiphol Airport, 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 3: The subject of this AD is addressed in Netherlands airworthiness directive BLA 94-114(A), dated August 5, 1994.

(g) This amendment becomes effective on January 2, 1998.

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 F28 Mark 0070 and 0100 series airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on February 3, 1997 (62 FR 4944). That action proposed to require a one-time operational test of the No. 1 pitot heating system, repair or replacement of failed elements, and repair or replacement of the pitot heating system with a new improved system. That action also proposed to require installation of new power supply wiring with increased gauge thickness, and a circuit breaker with an increased amperage rating.

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

One commenter supports the proposed rule.

Requests to Extend the Compliance Time for Replacement of Pitot Tube
Two commenters request that the compliance time, specified in paragraph (b)(2) of the proposed AD, for accomplishing the replacement of the pitot tube and associated electrical modifications be extended from the proposed 18 months to 24 months. The commenters state that such an extension will allow the replacement to be accomplished during a regularly scheduled heavy maintenance check for all but 7 of its affected airplanes, and thereby minimize any additional expenses that would be associated with special scheduling.

The FAA does not concur with the commenters request. In developing an appropriate compliance time for this action, the FAA considered not only the degree of urgency associated with addressing the subject unsafe condition, but the manufacturer's and foreign airworthiness authority s recommendations as to an appropriate compliance time, the availability of required parts, and the practical aspect of installing the required replacement within an interval of time that parallels the normal scheduled maintenance for the majority of affected operators. The FAA has determined that the compliance time, as proposed, represents the maximum interval of time allowable for the affected airplanes to continue to operate prior to accomplishing the required replacement without compromising safety. In addition, the commenters have not provided any data to substantiate why an extension of the compliance time would not compromise safety.

In consideration of all of these factors, and in consideration of the amount of time that has already elapsed since issuance of the original NPRM, the FAA has determined that further delay of this modification is not appropriate. However, under the provisions of paragraph (d) of the final rule, the FAA may approve requests for adjustments to the compliance time if data are submitted to substantiate that such an adjustment would provide an acceptable level of safety.

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 as proposed.

Cost Impact
The FAA estimates that 129 Fokker Model F28 Mark 0100 and 0070 series airplanes of U.S. registry will be affected by this AD.

The required operational check will take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact for the operational check required by this AD on U.S. operators is estimated to be $7,740, or $60 per airplane.

The required replacement of the pitot heating system will take approximately 36 work hours per airplane, at an average labor rate of $60 per work hour. Required parts will cost approximately $16,000 per airplane. Based on these figures, the cost impact of this replacement required by this AD on U.S. operators is estimated to be $18,160 per airplane.

For airplanes on which replacement of the pitot heating system has been accomplished previously, the required installation of the power supply electrical wiring and circuit breaker will take approximately 12 work hours per airplane, at an average labor rate of $60 per work hour. Required parts will cost approximately $350 per airplane. Based on these figures, the cost impact is estimated to be $1,070 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 substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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 Administrationamends 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: