[Federal Register Volume 59, Number 49 (Monday, March 14, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-5700]


[[Page Unknown]]

[Federal Register: March 14, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-NM-132-AD; Amendment 39-8854; AD 94-06-06]

 

Airworthiness Directives; Fokker Model F28 Mark 0100 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Fokker Model F28 Mark 0100 series airplanes, that 
requires certain maximum brake wear limits to be incorporated into the 
FAA-approved maintenance inspection program. This amendment also 
requires that the Airplane Flight Manual be revised to include certain 
procedures concerning operations in the event of a rejected takeoff 
(RTO). This amendment is prompted by an accident in which a transport 
category airplane executed an RTO and was unable to stop on the runway 
due to worn brakes; and the subsequent review of allowable brake wear 
limits for all transport category airplanes. The actions specified by 
this AD are intended to prevent the loss of brake effectiveness during 
a high energy RTO.

EFFECTIVE DATE: April 13, 1994.

ADDRESSES: Information concerning this amendment may be obtained from 
or examined at the Federal Aviation Administration (FAA), Transport 
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056.

FOR FURTHER INFORMATION CONTACT: Mark Quam, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2145; fax (206) 227-1320.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations to include an airworthiness directive (AD) that is 
applicable to certain Fokker Model F28 Mark 0100 series airplanes was 
published in the Federal Register on November 1, 1993 (58 FR 58307). 
That action proposed to require that certain maximum brake wear limits 
be incorporated into the FAA-approved maintenance inspection program; 
and that the Airplane Flight Manual (AFM) be revised to include certain 
procedures concerning operations in the event of a rejected takeoff 
(RTO).
    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 proposal.
    Another commenter, the Air Transport Association (ATA) of America, 
questions the need for the proposed AD. This commenter is aware of the 
FAA's efforts to review and determine allowable aircraft brake wear 
limits, since those efforts prompted the issuance of a series of AD's, 
applicable to U.S.-manufactured airplanes, to mandate maximum brake 
wear limits. While those U.S.-manufactured airplanes were certified to 
new brake criteria, the commenter points out that airplanes such as the 
Fokker Model F28 Mark 0100, which were certified under the Joint 
Airworthiness Regulations (JAR) criteria, are certified to worn brake 
standards. In light of this, the commenter questions why the FAA 
indicated that the proposed AD was prompted by the 1988 accident 
involving worn brakes on a McDonnell Douglas Model DC-10 airplane. This 
commenter states that U.S. operators of Fokker Model F28 Mark 0100 
series airplanes, at the time of airplane delivery, implemented within 
their maintenance programs the same worn brake criteria as proposed in 
the notice; additionally, these operators' FAA-approved AFM's already 
reflect this criteria. Therefore, this commenter argues that there is 
no basis for adopting the proposed rule unless it can be shown that 
U.S. operators cannot safely administer to certified brake wear 
criteria within their approved maintenance programs.
    The FAA does not concur with this commenter's suggestion that this 
AD action is not appropriate. The accident involving the Model DC-10 
was the primary reason prompting this AD and the previously-issued AD's 
to mandate specific maximum brake wear limits on transport category 
airplane. During the process of promulgating those AD's, the FAA became 
aware that not all operators were following the manufacturer's 
recommended brake wear limits. For example, in one case, three 
different operators of the same model of airplane were found to be 
observing three different maximum brake wear limits. Further, the FAA 
is aware that, until recently, not all manufacturers had provided brake 
wear limits that met the FAA criteria, e.g., landing distance 
predicated upon single engine-out, maximum takeoff weight, and fully 
worn brakes. The purpose of this AD is in no way an attempt to question 
the ability of U.S. operators to safely administer to brake wear limits 
criteria; its purpose is to establish what those brake wear limits are.
    Several commenters request that the proposed rule be revised to 
eliminate the requirement to replace the landing gear sliding member 
after an RTO event. One of these commenters suggests that, instead of 
requiring replacement, the proposed rule could require inspections of 
the sliding member, using procedures that are currently included in the 
Fokker F28 Mark 0100 Aircraft Maintenance Manual (AMM) 05-51-01. This 
commenter states that similar inspection procedures exist for most 
other commercial aircraft, and those procedures have proven to be a 
safe and effective method of evaluating landing gears for the effects 
of high brake heat. This commenter also suggests that additional 
procedures could include inspection of the axles for evidence of 
discolored or peeling paint with cadmium plating that is blistered, 
wrinkled, or mottled (signs of cadmium melting and resolidifying). 
Cadmium melts at 610  deg.F, which is very close to the tempering 
temperature of ultra-high strength steels; therefore, if the cadmium is 
not melted, it is unlikely that any heat damage has been done to the 
steel sliding member axle. This commenter notes that this criteria has 
been used for other aircraft, and this commenter plans to contact 
Fokker to request that this type of inspection criteria be added to the 
Fokker F28 Mark 0100 AMM. Further, another commenter states that, on 
other aircraft models in its fleet, it regularly performs a visual 
inspection of the pistons following an RTO to determine the amount of 
heat that the piston has been subjected to; the degree of discoloration 
of the paint on the axle and the amount of damage to the hydraulic 
hoses are evidence of the amount of heat. This commenter also plans to 
contact Fokker to request the inclusion of this inspection in the AMM.
    The FAA does not concur with the suggestion to revise the proposed 
rule, at least at this time. The FAA has queried Fokker directly about 
the inspection procedures suggested by these commenters; however, 
Fokker was not aware of any effective nondestructive inspection 
technique that can be used to establish whether cadmium embrittlement 
has taken place on the axle after an RTO. Fokker did indicate that it 
is currently working with the manufacturer of the brakes to devise a 
way to limit the exposure of the sliding member to heat from the 
brakes, which in turn would limit the need to replace the sliding 
member. Once an inspection or other procedure is developed that would 
preclude the necessity of replacing the sliding member, the FAA would 
consider further rulemaking on this issue. In the meantime, under the 
provisions of paragraph (d) of the final rule, the FAA would consider 
requests for the use of alternative methods of complying with this 
rule, provided sufficient data are presented to justify such requests.
    One commenter requests that the proposed entry in the maintenance 
program [as specified in paragraph (b) of the proposal] and the 
proposed entry in the AFM [as specified in paragraph (c) of the 
proposal] be revised. This commenter states that calculations have 
shown that only when ``flap 0'' is selected, there is a possibility to 
reach an energy level that can cause the axle to overheat. Therefore, 
those entries should include a statement that, during the RTO scenario, 
the flaps would have to be at 0 degrees. The commenter suggests that 
the wording of both entries be changed to read as follows:

    ``If flap 0 is selected, and if a takeoff is rejected at a speed 
greater than 90 percent of * * *''

The FAA concurs and has revised paragraphs (b) and (c) of the final 
rule accordingly.
    This same commenter suggests that the AFM entry proposed in 
paragraph (c) be reworded to include language that is more familiar to 
pilots, who will be the primary users of this information in the 
Limitations Section. Specifically, the commenter suggests that pilots 
would be more familiar with the term ``V1'' (takeoff decision 
speed) than with ``VMBE'' (maximum brake energy limit speed). The 
commenter states that use of V1 as a reference is more appropriate 
than VMBE in this context, as well, since it is more conservative 
with respect to the axle overheat problem. Along this same line, the 
commenter suggests that the AFM wording be revised to indicate that 
``the rejected takeoff conditions should be reported to maintenance 
personnel prior to the next takeoff'' and that ``further dispatch may 
be affected.'' The FAA concurs with all of these suggestions and has 
revised paragraph (c) of the final rule accordingly.

    Note: If a pilot were to report a rejected takeoff event to 
maintenance personnel and refer the V1 speed involved, 
maintenance personnel can recalculate the V1 figure to a 
VMBE figure by means of a graph incorporated into the AMM.

    This commenter also suggests that proposed paragraph (b) be revised 
to specify the part numbers of the main landing gears (MLG) equipped 
with the sliding members that need to be replaced. Adding a reference 
to the MLG part numbers would avoid any relationship between the 
currently-installed Dowty MLG's and other brands of MLG's that are 
expected to be certified and installed in the near future. The FAA 
concurs with this suggestion and has revised paragraph (b) of the final 
rule accordingly.
    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.
    The FAA estimates that 83 airplanes of U.S. registry and 2 U.S. 
operators will be affected by this AD.
    Although the rule requires the incorporation of maximum brake wear 
limits into the FAA-approved maintenance inspection program, no other 
specific additional action, inspection, or part replacement costs 
relative to that requirement are involved; such actions are currently a 
part of the normal maintenance program. However, it is estimated that 
it will require 20 work hours, at an average labor rate of $55 per work 
hour, for each operator to incorporate the brake wear limitations into 
its FAA-approved maintenance inspection program. Based on these 
figures, the total cost impact of that requirement on U.S. operators is 
estimated to be $2,200, or $1,100 per operator.
    Additionally, the FAA estimates that it will take approximately 1 
work hour per airplane to accomplish the required AFM revision, and 
that the average labor rate is $55 per work hour. Based on these 
figures, the total cost impact of that requirement on U.S. operators is 
estimated to be $4,565, or $55 per airplane.
    The total 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.
    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 14 CFR part 
39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

94-06-06 Fokker: Amendment 39-8854. Docket 93-NM-132-AD.

    Applicability: Model F28 Mark 0100 series airplanes, equipped 
with brake part numbers (P/N) identified in paragraph (a) of this 
AD, certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent the loss of brake effectiveness during a rejected 
takeoff, accomplish the following:
    (a) Within 180 days after the effective date of this AD, 
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. 

   Table 1.--Brake Manufacturer: Aircraft Braking Systems Corp. (ABS)   
------------------------------------------------------------------------
                            Maximum settings--Non refurbished brakes    
                       -------------------------------------------------
       Brake P/N            Maximum wear pin          Alternate wear    
                         measurement (inch/mm)    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 1: 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/Ns 5008132-2 and -3.

                                Table 2                                 
------------------------------------------------------------------------
                              Maximum settings--Refurbished brakes      
                       -------------------------------------------------
       Brake P/N            Maximum wear-pin          Alternate wear    
                         measurement-(inch/mm)-   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 2: Refurbished brakes will have ``R11-3'' etched on the 
brake housing adjacent to the shuttle valve. -
    Note 3: 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) Any brake using a heat stack kit with an ``R'' after the P/N 
must use the wear pin length specified on the Airworthiness Tag that 
accompanies each heat stack kit, and must not use the ``Alternate 
Wear Measurement'' noted in Table 1 of this AD under ``Non-
Refurbished Brakes'' to determine the brake's maximum wear limit. 
Any of these brakes that are worn more than the maximum wear limit 
must be replaced, prior to further flight, with a brake that is 
within the limits specified in Table 2 of this AD.
    (b) Within 180 days after the effective date of this AD, 
incorporate the following information into the FAA-approved 
maintenance program:
    ``If flap 0 is selected; and if a takeoff is rejected at a speed 
greater than 90 percent of the scheduled Maximum Brake Energy limit 
speed (VMBE) for the applicable weight, altitude, temperature, 
wind conditions, runway slope and brake configuration (if 
applicable); and if any brake is worn to 90 percent or more of its 
brake wear limit: The main landing gear sliding member (identified 
with one of the following main landing gear part numbers: 201072011, 
201072012, 201072013, 201072014, 201072015, or 201072016) should be 
replaced with a serviceable sliding member in accordance with Fokker 
Aircraft Maintenance Manual, section 32-11-08.

    Note: Only the sliding member with a brake that is more than 90 
percent worn has to be replaced.''

    (c) Within 180 days after the effective date of this AD, revise 
the Limitations Section of the FAA-approved AFM, by adding the 
following information. This may be accomplished by inserting a copy 
of this AD in the AFM.
    ``If flap 0 is selected, and if a takeoff is rejected at a speed 
greater than 90 percent of the scheduled takeoff decision speed 
(V1) for the applicable weight, altitude, temperature, wind 
conditions, runway slope, and brake configuration (if applicable), 
as specified in the FAA-approved AFM, report the rejected takeoff 
conditions to maintenance prior to next takeoff. Dispatch may be 
affected.''
    (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, 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 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (e) Special flight permits may be issued in accordance with 
Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the 
airplane to a location where the requirements of this AD can be 
accomplished.
    (f) This amendment becomes effective on April 13, 1994.

    Issued in Renton, Washington, on March 7, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-5700 Filed 3-11-94; 8:45 am]
BILLING CODE 4910-13-U