AD 96-13-13

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Fokker Model F28 Mark 0100 series airplanes, that currently requires certain maximum brake wear limits to be incorporated into the FAA-approved maintenance inspection program. That AD also currently requires that the Airplane Flight Manual (AFM) be revised to include certain procedures concerning operations in the event of a rejected takeoff (RTO). This amendment requires the incorporation of new maximum brake wear limits for additional brake units into the FAA-approved maintenance program. This action also deletes the previous requirement for the AFM revision. This amendment is prompted by the determination of the maximum allowable brake wear limits for additional brake unit part numbers. The actions specified by the AD are intended to prevent the loss of brake effectiveness during a high energy RTO.

Final rule

96-13-13 FOKKER: Amendment 39-9682. Docket 95-NM-224-AD. Supersedes AD 94-06-06, Amendment 39-8854.
Applicability: Model F28 Mark 0100 and F28 Mark 0070 series airplanes, equipped with Aircraft Braking Systems Corp. brakes having part number (P/N) 5008132-2, -3, -4, -5, -6, -7, -8, or 5011809; 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 (c) 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 loss of brake effectiveness during a high energy rejected take off (RTO), accomplish the following:

NOTE 2: An alternate wear measurement (AWM) is a measurement of the brake stack that determines stack wear. This measurement is used for any brake assembly without a wear indicator pin, or any brake assembly having a damaged wear indicator pin. The brake wear can be determined by measuring the distance from the back of the pressure plate subassembly to the inboard face of the brake housing at the wear indicator location.

(a) For Model F28 Mark 0100 series airplanes: Within 180 days after April 13, 1994 (the effective date of AD 94-06-06, amendment 39-8854), accomplish the requirements of paragraphs (a)(1) and (a)(2) of this AD:

(1) Incorporate the maximum brake wear limits specified in the following tables into the FAA-approved maintenance inspection program and comply with these measurements thereafter.

Brake Manufacturer:
Aircraft Braking Systems Corporation (ABS)

Table 1
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Maximum Settings - Non Refurbished Brakes

Brake P/N
Maximum Wear
Pin Measurement
(inch/mm)
Alternate
Wear Measurement
(inch/mm)
5008132-2
1.85" (47 mm)
4.00" (101.6 mm)
5008132-3
1.85" (47 mm)
4.00" (101.6 mm)
5008132-4
2.10" (53.3 mm)
4.25" (107.9 mm)
5008132-5
2.10" (53.3 mm)
4.25" (107.9 mm)
5008132-6
2.10" (53.3 mm)
4.25" (107.9 mm)
5008132-7
2.10" (53.3 mm)
4.25" (107.9 mm)

NOTE 3: Measuring instructions for non refurbished brakes can be found in the ABS Component Maintenance Manual with Illustrated Parts List AP-652 (Fokker Manual No. 32-43-77) or in ABS Service Bulletin Fo100-32-35. ABS Service Bulletin Fo100-32-35 does not contain measurement information relative to brake P/N's 5008132-2 and -3.

Table 2
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Maximum Settings - Refurbished Brakes

Brake P/N
Maximum Wear
Pin Measurement
(inch/mm)
Alternate
Wear Measurement
(inch/mm)
5008132-2
1.85" (47 mm)
4.00" (101.6 mm)
5008132-3
1.85" (47 mm)
4.00" (101.6 mm)
5008132-4
2.20" (55.9 mm)
4.35" (110.5 mm)
5008132-5
2.20" (55.9 mm)
4.35" (110.5 mm)
5008132-6
2.20" (55.9 mm)
4.35" (110.5 mm)
5008132-7
2.20" (55.9 mm)
4.35" (110.5 mm)

NOTE 4: Refurbished brakes will have "R11-3" etched on the brake housing adjacent to the shuttle valve.

NOTE 5: Measuring instructions for refurbished brakes can be found in the ABS Component Maintenance Manual with Illustrated Parts List AP-652 (Fokker Manual No. 32-43-77) or in ABS Service Bulletin Fo100-32-38.

(2) For brakes on which a heat stack kit having an "R" after the part number (i.e., 5010322-2R; also called "short stacks") have been installed: Operators must use the maximum wear pin length which is based on the measured wear of the thinnest disk in the stack and is specified on the Airworthiness Tag that accompanies each heat stack kit (i.e., for airplanes equipped with brakes having short stacks installed, do not use either the standard maximum wear pin measurements or the alternate brake wear measurements specified in either Table 1 or Table 2 of this AD to determine brake wear.)

(b) Within 180 days after the effective date of this AD, incorporate the maximum brake wear pin limits specified in paragraphs (b)(1) and (b)(2) of this AD, as applicable, into the FAA-approved maintenance program and comply with these measurements thereafter. If any brake has measured wear beyond the maximum wear limits specified in those paragraphs, prior to further flight, replace it with a brake that is within the wear limits specified in the applicable paragraph.

(1) For Model F28 Mark 0100 and 0070 series airplanes:Table 3.
__________________________________________________________________________

Maximum Settings- Non-Refurbished Brakes
(Original Equipment Manufacturer)

Brake Unit
Part Number

Maximum Wear
Pin Measurement

Alternate Brake
Wear Measurement
Measure in Accordance with
Aircraft Braking Systems (ABS)
Component Maintenance Manual
with Illustrated Parts List
(CMM w/IPL) Number
5008132-2
1.85"(47 mm)
4.00" (101.6 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-3
1.85"(47 mm)
4.00" (101.6 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-4
2.10"(53.3 mm)
4.25" (107.9 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-5
2.10"(53.3 mm)
4.25" (107.9 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-6
2.10"(53.3 mm)
4.25" (107.9 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-7
2.10"(53.3 mm)
4.25" (107.9 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-8
2.20"(55.9 mm)
4.35"(110.5 mm)
CMM w/IPL AP-652 (32-43-77)

Table 4.
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Maximum Settings - Refurbished Brakes
(R11-3 on Brake Housing)

Brake Unit
Part Number

Maximum Wear
Pin Measurement

Alternate Brake
Wear Measurement
Measure In Accordance With
Aircraft Braking Systems (ABS)
Component Maintenance Manual
with Illustrated Parts List
(CMM w/IPL) Number
5008132-2
1.85" (47 mm)
4.00" (101.6 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-3
1.85" (47 mm)
4.00" (101.6 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-4
2.20" (55.9 mm)
4.35" (110.5 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-5
2.20" (55.9 mm)
4.35" (110.5 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-6
2.20" (55.9 mm)
4.35" (110.5 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-7
2.20" (55.9 mm)
4.35" (110.5 mm)
CMM w/IPL AP-652 (32-43-77)
5008132-8
2.20" (55.9 mm)
4.35" (110.5 mm)
CMM w/IPL AP-652 (32-43-77)

(2) For Model F28 Mark 0100 and 0070 series airplanes equipped a brake unit having P/N 5011809, A5011809, or B5011809: The maximum wear pin measurement is 2.50" (63.5 mm), with an alternate brake wear measurement of 4.35" (110.5 mm). The measurement shall be done in accordance with Aircraft Braking Systems (ABS) Component Maintenance Manual (CMM) with Illustrated Parts List (IPL) AP-747 (32-43-65).

(c) 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, Standardization Branch, ANM-113, 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, Standardization Branch, ANM-113.

NOTE 6: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(d) 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.

(e) This amendment becomes effective on August 1, 1996.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 94-06-06, amendment 39-8854 (59 FR 11713, March 14, 1994), which is applicable to certain Fokker Model F28 Mark 0100 series airplanes, was published in the Federal Register on February 12, 1996 (61 FR 5331). The action proposed to require the incorporation of new maximum brake wear limits for additional brake units into the FAA-approved maintenance program. The action also proposed to delete a previous requirement for a revision to the Airplane Flight Manual (AFM) that pertained to reporting certain rejected takeoff conditions to maintenance.

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

Request to Extend Compliance Time
One commenter requests that the proposed compliance time of 180 days for incorporating the maximum brake wear pin limits into the maintenance program be extended to 360 days. This commenter, a U.S. operator, requests this extension in order to ensure that the new information provided in the AD can be inserted in its fleet s required manuals during a normal revision cycle. This would avoid the costs and time associated with having to issue a temporary partial revision and/or supplement.

The FAA does not concur. 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 practical aspect of incorporating and implementing the required maintenance program change within a reasonable period of time for the majority of affected operators. Additionally, the FAA has issued numerous other AD s, applicable to transport category airplanes, with requirements and compliance times similar to this one [for example, reference AD 94-09-03, amendment 39-8891 (59 FR 18713, April 20, 1994), pertaining to British Aerospace Model BAe 146 series airplanes; AD 94-11-07, amendment 39-8923 (59 FR 28475, June 2, 1994), pertaining to British Aerospace Model BAC 1-11 series airplanes; and AD 94-26-05, amendment 39-9101, (60 FR 3, January 3, 1995), pertaining to Airbus Model A300, A310, and A320 series airplanes]. The 180-day compliance time specified in each of the previously issued AD s apparently has posed no problem in implementation for operators that are subject to those AD s. The FAA considers that the brake wear limits should be followed as soon as this information can reasonably be incorporated into an affected operator s maintenance program. Since the issuance of temporary manual revisions is a common practice among operators, the FAA cannot find that the incorporation of information required by this AD within the 180-day time period would be an undue burden on any operator.

Request to Clarify Service Information
This same commenter requests clarification as to the appropriate manual that should be used to determine the limits for refurbished brakes. The commenter points out an apparent discrepancy in the proposed AD between Note 5 in proposed paragraph (a)(1) and Table 4: Both reference the Aircraft Braking Systems (ABS) Component Maintenance Manual with Illustrated Parts List, but one specifies the document number as "AP-652," while the other specifies "AP-625."

The FAA notes this typographical error. The correct document number is AP-652, which was shown correctly in Note 5 of the proposal. The FAA has revised Table 4 of the final rule to indicate this correct document number.

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 changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
There are approximately 124 Model F28 Mark 0100 and 0070 series airplanes of U.S. registry and 5 U.S. operators that will be affected by this AD.

The actions that are currently required by AD 94-06-06 take approximately 20 work hours per operator to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact on U.S. operators of the actions currently required is estimated to be $6,000, or $1,200 per operator.

The new actions that are required by this AD action will take approximately 20 work hours per operator to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact on U.S. operators of the new requirements of this AD is estimated to be $6,000, or $1,200 per operator.

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 ifthis 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, 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 removing amendment 39-8854 (59 FR 11713, March 14, 1994), and by adding a new airworthiness directive (AD), amendment 39-9682, to read as follows: