Airworthiness Directives; Fokker Model F28 Mark 0100 Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-193-AD]

Airworthiness Directives; Fokker Model F28 Mark 0100 Series

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness

directive (AD) that is applicable to certain Fokker Model F28 Mark 0100

series airplanes. This proposal would require inspections to detect

corrosion in the wheel axles of the main landing gear (MLG) sliding

members; and, if any corrosion is found, rework of corroded areas and

an inspection to detect cracks in the wheel axles; and, if any crack is

found, replacement of the cracked sliding member. This proposal is

prompted by a report that a MLG wheel axle failed during push back of

an in-service airplane from the terminal. The actions specified by the

proposed AD are intended to prevent failure of the MLG wheel axle due

to the problems associated with corrosion and cracking.

DATES: Comments must be received by March 29, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 93-NM-193-AD, 1601 Lind Avenue SW., Renton,

Washington 98055-4056. Comments may be inspected at this location

between 9 a.m. and 3 p.m., Monday through Friday, except Federal

holidays.

The service information referenced in the proposed rule may be

obtained from Fokker Aircraft USA, Inc., 1199 North Fairfax Street,

Alexandria, Virginia 22314. This information may be examined at the

FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton,

Washington.

FOR FURTHER INFORMATION CONTACT: Tim Dulin, Aerospace Engineer,

Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)

227-2141; fax (206) 227-1320.

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 notice may be changed in

light of the comments received.

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 notice must submit a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket Number 93-NM-193-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-103, Attention: Rules

Docket No. 93-NM-193-AD, 1601 Lind Avenue SW., Renton, Washington

98055-4056.

Discussion

The Rijksluchtvaartdienst (RLD), which is the airworthiness

authority for the Netherlands, recently notified the FAA that an unsafe

condition may exist on certain Fokker Model F28 Mark 0100 series

airplanes. The RLD advises that an operator of Model F28 Mark 0100

series airplanes reported the failure of a main landing gear (MLG)

wheel axle during push back of an in-service airplane from the

terminal. Subsequent non-destructive testing (NDT) inspection of the

operator's fleet of Model F28 Mark 0100 series airplanes revealed that

corrosion was present on most MLG wheel axles examined. Although no

cracks were found during this inspection, preliminary findings indicate

that the crack which led to the failed axle had initiated from a

corrosion pit located on the radius of the brake abutment flange on the

axle. Corrosion and cracking in a MLG wheel axle, if not detected and

corrected in a timely manner, could result in failure of the MLG wheel

axle.

Fokker has issued Service Bulletin SBF100-32-079, Revision 1, dated

October 4, 1993, that describes procedures for removal of the MLG

wheels and brakes, inspections of the wheel axles, and reinstallation

of MLG wheels and brakes. The Fokker service bulletin references Dowty

Aerospace Service Bulletin F100-32-63, Revision 2, dated September 23,

1993, as the appropriate source of service information for the wheel

axle inspection. The Dowty Aerospace service bulletin describes

procedures for a visual inspection to detect corrosion in the wheel

axles of the MLG sliding members; and, if any corrosion is found,

rework of corroded areas and an NDT inspection to detect cracks in the

wheel axles; and, if any crack is found, replacement of the cracked

sliding member.

Fokker Service Bulletin SBF100-32-080, dated October 4, 1993, and

Dowty Aerospace Service Bulletin F100-32-64, dated September 23, 1993,

describe procedures for accomplishing the corresponding repetitive

actions described in the service bulletins discussed previously. The

RLD classified these service bulletins as mandatory and issued

Netherlands Airworthiness Directive BLA 93-108/2 (A), dated November 1,

1993, in order to assure the continued airworthiness of these airplanes

in the Netherlands.

This airplane model is manufactured in the Netherlands and is type

certificated for operation in the United States under the provisions of

Sec. 21.29 of the Federal Aviation Regulations and the applicable

bilateral airworthiness agreement. Pursuant to this bilateral

airworthiness agreement, the RLD has kept the FAA informed of the

situation described above. The FAA has examined the findings of the

RLD, reviewed all available information, and determined that AD action

is necessary for products of this type design that are certificated for

operation in the United States.

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 repetitive visual

inspections to detect corrosion in the wheel axles of the MLG sliding

members; and, if any corrosion is found, rework of corroded areas and

an NDT inspection to detect cracks in the wheel axles; and, if any

crack is found, replacement of the cracked sliding member. The actions

would be required to be accomplished in accordance with the service

bulletins described previously.

The FAA estimates that 100 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 14 work

hours per airplane to accomplish the proposed actions, and that the

average labor rate is $55 per work hour. Based on these figures, the

recurring cost impact of the proposed AD on U.S. operators (for four

inspections per year) is estimated to be $308,000 per year, or $3,080

per airplane per year. This total cost figure assumes that no operator

has yet accomplished the proposed requirements of this AD action.

The regulations proposed herein would 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

proposal would not have sufficient federalism implications to warrant

the preparation of a Federalism Assessment.

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);

and (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 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:

FOKKER: Docket 93-NM-193-AD.

Applicability: Model F28 Mark 0100 series airplanes equipped

with Dowty Aerospace main landing gear (MLG) part number 201072011,

201072012, 201072013, 201072014, 201072015, or 201072016;

certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent failure of the MLG wheel axle, accomplish the

following:

(a) Within 30 days after the effective date of this AD, remove

the MLG wheels and brakes and perform a visual inspection to detect

corrosion in the wheel axles of the MLG sliding members in

accordance with Fokker Service Bulletin F100-32-079, Revision 1,

dated October 4, 1993, and paragraph 2.A. of the Accomplishment

Instructions of Dowty Aerospace Service Bulletin F100-32-63,

Revision 2, dated September 23, 1993.

(b) Repeat the inspection required by paragraph (a) of this AD

thereafter at intervals not to exceed 3 months in accordance with

Fokker Service Bulletin SBF100-32-080, dated October 4, 1993, and

Dowty Aerospace Service Bulletin F100-32-64, dated September 23,

1993.

(c) If any corrosion is found during any inspection required by

paragraph (a) or (b) of this AD, prior to further flight, rework the

affected area and perform a non-destructive testing (NDT) inspection

to detect cracks in the MLG wheel axles, in accordance with Appendix

A of Dowty Aerospace Service Bulletin F100-32-63, Revision 2, dated

September 23, 1993 (if corrosion is found during the initial

inspection required by this AD); or Dowty Aerospace Service Bulletin

F100-32-64, dated September 23, 1993 (if corrosion is found during a

repetitive inspection required by this AD); as applicable. After

rework, continue to perform repetitive inspections of the affected

area in accordance with paragraph (b) of this AD.

(d) If any crack is found during the inspections required by

paragraph (c) of this AD, prior to further flight, replace the

affected sliding member with a serviceable sliding member in

accordance with Dowty Aerospace Service Bulletin F100-32-63,

Revision 2, dated September 23, 1993 (if any crack is found during

the initial inspection required by this AD); or Dowty Aerospace

Service Bulletin F100-32-64, dated September 23, 1993 (if any crack

is found during a repetitive inspection required by this AD); as

applicable. After replacement of the affected sliding member,

continue to perform the repetitive inspections in accordance with

paragraph (b) of this AD.

(e) As of the effective date of this AD, no person shall install

a Dowty Aerospace MLG, part number 201072011, 201072012, 201072013,

201072014, 201072015, or 201072016, on any airplane unless the

requirements of this AD have been accomplished on that MLG.

Following its installation, the repetitive inspections required by

paragraph (b) of this AD shall be accomplished on that MLG.

(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, 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: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Standardization Branch, ANM-113.

(g) Special flight permits may be issued in accordance with FAR

21.197 and 21.199 to operate the airplane to a location where the

requirements of this AD can be accomplished.

Issued in Renton, Washington, on January 27, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-2335 Filed 2-1-94; 8:45 am]

BILLING CODE 4910-13-U